[Federal Register Volume 75, Number 1 (Monday, January 4, 2010)]
[Proposed Rules]
[Pages 186-218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-30884]
[[Page 185]]
-----------------------------------------------------------------------
Part II
Department of Energy
-----------------------------------------------------------------------
10 CFR Part 431
Energy Conservation Program: Test Procedures for Walk-In Coolers and
Walk-In Freezers; Proposed Rule
Federal Register / Vol. 75, No. 1 / Monday, January 4, 2010 /
Proposed Rules
[[Page 186]]
-----------------------------------------------------------------------
DEPARTMENT OF ENERGY
10 CFR Part 431
[Docket No. EERE-2008-BT-TP-0014]
RIN 1904-AB85
Energy Conservation Program: Test Procedures for Walk-In Coolers
and Walk-In Freezers
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.
ACTION: Notice of proposed rulemaking and public meeting.
-----------------------------------------------------------------------
SUMMARY: Pursuant to the Energy Policy and Conservation Act, as
amended, the U.S. Department of Energy (DOE) is proposing test
procedures for measuring the energy consumption of walk-in coolers and
walk-in freezers (collectively ``walk-in equipment'' or ``walk-
in(s)''), definitions to delineate the products covered by the test
procedures, and provisions (including a sampling plan) for
manufacturers to implement the test procedures. The notice also
addresses enforcement issues as they relate to walk-in equipment.
Concurrently, DOE is undertaking an energy conservation standards
rulemaking for this equipment. Any data gathered through the use of the
test procedure adopted by DOE will be used in evaluating any potential
standards for this equipment. Once these standards are promulgated, the
adopted test procedures will be used to determine equipment efficiency
and compliance with the standards.
DATES: DOE will hold a public meeting in Washington, DC on Thursday,
February 11, 2010, beginning at 9 a.m. DOE must receive requests to
speak at the meeting before 4 p.m., Thursday, January 28, 2010. DOE
must receive a signed original and an electronic copy of statements to
be given at the public meeting before 4 p.m., Thursday, January 28,
2010.
DOE will accept comments, data, and information regarding this
notice of proposed rulemaking (NOPR) before or after the public
meeting, but no later than March 22, 2010. See section V, ``Public
Participation,'' of this NOPR for details.
ADDRESSES: The public meeting will be held at the U.S. Department of
Energy, Forrestal Building, Room 8E-089, 1000 Independence Avenue, SW.,
Washington, DC 20585-0121. To attend the public meeting, please notify
Ms. Brenda Edwards at (202) 586-2945. Please note that foreign
nationals participating in the public meeting are subject to advance
security screening procedures, requiring a 30-day advance notice. If
you are a foreign national and wish to participate in the public
meeting, please inform DOE as soon as possible by contacting Ms. Brenda
Edwards at (202) 586-2945 so that the necessary procedures can be
completed.
Any comments submitted must identify the NOPR for Test Procedures
for Walk-in Coolers and Freezers, and provide docket number EERE-2008-
BT-TP-0014 and/or Regulation Identifier Number (RIN) 1904-AB85.
Comments may be submitted using any of the following methods:
1. Federal eRulemaking Portal: http://www.regulations.gov. Follow
the instructions for submitting comments.
2. E-mail: [email protected]. Include the docket number
EERE-2008-BT-TP-0014 and/or RIN 1904-AB85 in the subject line of the
message.
3. Postal Mail: Ms. Brenda Edwards, U.S. Department of Energy,
Building Technologies Program, Mailstop EE-2J, 1000 Independence
Avenue, SW., Washington, DC 20585-0121. Please submit one signed
original paper copy.
4. Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department of
Energy, Building Technologies Program, 950 L'Enfant Plaza, SW., 6th
Floor, Washington, DC 20024. Please submit one signed original paper
copy.
For detailed instructions on submitting comments and additional
information on the rulemaking process, see section V, ``Public
Participation,'' of this document.
Docket: For access to the docket to read background documents or
comments received, visit the U.S. Department of Energy, Resource Room
of the Building Technologies Program, 950 L'Enfant Plaza, SW., 6th
Floor, Washington, DC 20024, (202) 586-2945, between 9 a.m. and 4 p.m.
Monday through Friday, except Federal holidays. Please call Ms. Brenda
Edwards at the above telephone number for additional information
regarding visiting the Resource Room.
FOR FURTHER INFORMATION CONTACT: Mr. Charles Llenza, U.S. Department of
Energy, Building Technologies Program, EE-2J, 1000 Independence Avenue,
SW., Washington, DC 20585-0121, (202) 586-2192,
[email protected] or Mr. Michael Kido, Esq., U.S. Department of
Energy, Office of General Counsel, GC-72, 1000 Independence Avenue,
SW., Washington, DC 20585- 0121, (202) 586-8145,
[email protected].
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Authority and Background
II. Summary of the Proposal
III. Discussion
A. Overall Approach
1. Basic Model
2. Approach Option 1: Test the Unit as a Whole
3. Approach Option 2: Allow Manufacturers To Use Alternative
Energy Determination Methods (AEDMs)
4. Proposed Option and Recommendation: Separate Envelope and
Refrigeration Tests
B. Envelope
1. Overview of the Test Procedure
2. Test Methods
a. Insulation
b. Air Infiltration
c. Steady-State Infiltration Test
3. Calculations
a. Energy Efficiency Ratio
b. Heat Gain Through the Envelope Due to Conduction
c. Heat Gain Due to Infiltration
d. Envelope Component Electrical Loads
e. Normalization
f. Daily Energy Consumption Coefficients
C. Refrigeration System
1. Overview of the Test Procedure
2. Test Conditions
3. Test Methods
4. Measurements and Calculations
D. Compliance, Certification, and Enforcement
1. Provisions for Energy Conservation Standards Developed by the
Department of Energy
2. Provisions for Existing Design Standards Prescribed by
Congress
IV. Regulatory Review
A. Review Under Executive Order 12866
B. Review Under the National Environmental Policy Act
C. Review Under the Regulatory Flexibility Act
D. Review Under the Paperwork Reduction Act
E. Review Under the Unfunded Mandates Reform Act of 1995
F. Review Under the Treasury and General Government
Appropriations Act, 1999
G. Review Under Executive Order 13132
H. Review Under Executive Order 12988
I. Review Under the Treasury and General Government
Appropriations Act, 2001
J. Review Under Executive Order 13211
K. Review Under Executive Order 12630
L. Review Under Section 32 of the Federal Energy Administration
(FEA) Act of 1974
V. Public Participation
A. Attendance at Public Meeting
B. Procedure for Submitting Requests to Speak
C. Conduct of Public Meeting
D. Submission of Comments
E. Issues on Which DOE Seeks Comment
1. Test Procedure Improvements
2. Basic Model
3. Separate Envelope and Refrigeration Tests
4. Definition of Envelope
5. Effect of Impermeable Skins on Long-Term R Value
6. Measuring Long-Term R Value Using American Society for
Testing and Materials (ASTM) C1303-08
7. Infiltration
[[Page 187]]
8. Nominal Coefficient of Performance of Refrigeration
9. Measuring the U Value of glass
10. Floor R Value
11. Electrical Duty Cycle
12. Normalization Factor
13. Daily Energy Consumption Coefficients
14. Definition of Refrigeration System
15. Measurements and Calculations of Energy Use of Refrigeration
Systems
16. Impacts on Small Businesses
VI. Approval of the Office of the Secretary
I. Authority and Background
Title III of the Energy Policy and Conservation Act of 1975, as
amended (EPCA or the Act) sets forth a variety of provisions designed
to improve energy efficiency. Part B of Title III (42 U.S.C. 6291-6309)
provides for the Energy Conservation Program for Consumer Products
Other Than Automobiles. The National Energy Conservation Policy Act
(NECPA), Public Law 95-619, amended EPCA to add Part C of Title III,
which established an energy conservation program for certain industrial
equipment. (42 U.S.C. 6311-6317) (These parts were subsequently
redesignated as Parts A and A-1, respectively, for editorial reasons.)
Section 312 of the Energy Independence and Security Act of 2007 (EISA
2007) further amended EPCA by adding certain equipment to this energy
conservation program, including walk-in coolers and walk-in freezers
(collectively ``walk-in equipment'' or ``walk-ins''), the subject of
this rulemaking. (42 U.S.C. 6311(1), (2), 6313(f) and 6314(a)(9))
EPCA defines walk-in equipment as follows:
(A) In general.--
The terms ``walk-in cooler'' and ``walk-in freezer'' mean an
enclosed storage space refrigerated to temperatures, respectively,
above, and at or below 32 degrees Fahrenheit that can be walked into,
and has a total chilled storage area of less than 3,000 square feet.
(B) Exclusion.--
The terms ``walk-in cooler'' and ``walk-in freezer'' do not include
products designed and marketed exclusively for medical, scientific, or
research purposes. (42 U.S.C. 6311(20))
Walk-ins covered by this rulemaking may be located indoors or
outdoors. They may be used exclusively for storage, but they may also
have transparent doors or panels for the purpose of displaying stored
items. Examples of items that may be stored in walk-ins include, but
are not limited to, food, beverages, and flowers. DOE notes that any
equipment that meets the above definition is potentially subject to
regulation.
Under the Act, the overall program consists essentially of the
following parts: testing, labeling, and Federal energy conservation
standards. The testing requirements for covered equipment consist of
test procedures, prescribed under EPCA. These test procedures are used
in several different ways: (1) Any data from the use of these
procedures are used as a basis in developing standards for covered
products or equipment; (2) the test procedure is used when determining
equipment compliance with those standards; and (3) manufacturers of
covered equipment must use the procedure to establish that their
equipment complies with energy conservation standards promulgated
pursuant to EPCA and when making representations about equipment
efficiency.
Section 343 of EPCA (42 U.S.C. 6314) sets forth generally
applicable criteria and procedures for DOE's adoption and amendment of
such test procedures. That provision requires that the test procedures
promulgated by DOE be reasonably designed to produce test results which
reflect energy efficiency, energy use, and estimated operating costs of
the covered equipment during a representative average use cycle. It
also requires that the test procedure not be unduly burdensome to
conduct. See 42 U.S.C. 6314(a)(2). As part of the process for
promulgating a test procedure, DOE must publish the procedure that it
plans to propose and offer the public an opportunity to present oral
and written comments on them. Consistent with Executive Order 12889 and
EPCA (see 42 U.S.C. 6314(b)), DOE provides a minimum comment period of
75 days on a proposed test procedure. As to the test procedures for
walk-in equipment, EPCA prescribes the following requirements:
(A) In general.--
For the purpose of test procedures for walk-in coolers and walk-in
freezers:
(i) The R value shall be the 1/K factor multiplied by the thickness
of the panel.
(ii) The K factor shall be based on ASTM [American Society for
Testing and Materials] test procedure C518-2004.
(iii) For calculating the R value for freezers, the K factor of the
foam at 20 [deg]F (average foam temperature) shall be used.
(iv) For calculating the R value for coolers, the K factor of the
foam at 55 [deg]F (average foam temperature) shall be used.
(B) Test Procedure.--
(i) In general.--Not later than January 1, 2010, the Secretary
shall establish a test procedure to measure the energy-use of walk-in
coolers and walk-in freezers.
(ii) Computer modeling.--The test procedure may be based on
computer modeling, if the computer model or models have been verified
using the results of laboratory tests on a significant sample of walk-
in coolers and walk-in freezers. (42 U.S.C. 6314(a)(9))
On February 4, 2009, DOE held a public meeting on the framework
document it issued concerning the DOE rulemaking to evaluate walk-in
equipment for energy conservation standards. See 74 FR 411 (Jan. 6,
2009) and 74 FR 1992 (Jan. 14, 2009). Both the framework document and
meeting discussed the possible test procedures for this equipment that
DOE was considering at that time, and gave interested parties an
opportunity to submit comments. Today's notice addresses those comments
and proposes test procedures for walk-in equipment.
II. Summary of the Proposal
In today's notice, DOE proposes to adopt new test procedures for
determining the energy use of walk-in cooler and walk-in freezer
equipment to address the statutory requirement to establish a test
procedure by January 1, 2010. (42 U.S.C. 6314(a)(9)(B)) Concurrently,
DOE is undertaking an energy conservation standards rulemaking for
walk-in equipment to address the statutory requirement to establish
performance standards no later than January 1, 2012. (42 U.S.C.
6313(f)(4)(A)) DOE will use any data resulting from use of the test
procedure that DOE adopts to evaluate potential performance standards
for this equipment. Furthermore, once performance standards are issued,
manufacturers would be required to use the test procedures to determine
compliance with such standards and for any representations regarding
the energy use of walk-in equipment they produce. This test procedure,
once adopted, would serve as the means for ascertaining compliance with
the appropriate standards in an enforcement action.
For the reasons described below, DOE proposes to adopt a test
procedure that contains two separate test methods. This approach is
necessary because there are typically two manufacturers of walk-in
equipment: One who manufactures the envelope (i.e., the insulated box
in which the refrigerated or frozen items are stored) and one who
manufactures the refrigeration system (i.e., the mechanism that
provides the means by which to feed chilled air into the envelope). One
method determines the
[[Page 188]]
energy consumption of the refrigeration system of the walk-in cooler or
freezer. The other method determines the energy consumption of the
envelope, which is the sum of the energy use associated with heat
transmission through the envelope in the form of conduction through the
walls and air infiltration through openings, and the power consumed by
electrical components that are part of the envelope. Each of the two
components, the refrigeration system and the envelope, is considered
separately and the energy consumption of each component is calculated
using the applicable test procedure. DOE believes that the approach is
consistent with the requirements in EPCA because the results of the two
tests will represent, in the aggregate, the total energy consumption of
walk-in coolers and freezers.
Using this approach, DOE believes that the proposed test procedures
will adequately measure the energy consumption of walk-in equipment by
capturing the energy consumption of both components. However, DOE
requests comment from stakeholders on improvements or changes to the
proposed test procedures and will consider modifications that improve
the accuracy, appropriateness for the equipment being tested,
repeatability of test results for the same or similar units,
comparability of results for different types of units, burden on
manufacturers, precision of language, or other elements of the
procedures. In submitting comments, interested parties should state the
nature of the recommended modification and explain how it would improve
upon the test procedure proposed in this NOPR. Commenters should also
submit data, if any, to support their positions.
DOE's adoption of the proposed test procedures, which would be
applicable to all walk-in equipment, would not necessarily mean that
DOE would adopt a single energy conservation standard or set of
labeling requirements for all walk-in equipment. In the separate
rulemaking proceeding concerning energy conservation standards for
walk-in equipment, DOE may divide such equipment into classes and may
conclude that standards are not warranted for some classes of equipment
that are within the scope of today's test procedure. Furthermore, DOE
may create a separate standard for each class of equipment that
includes a utility- or performance-related feature that another
equipment class lacks, and that affects energy consumption.
DOE also notes that the National Technology Transfer and
Advancement Act of 1995 (Pub. L. 104-113) directs Federal agencies to
use voluntary consensus standards in lieu of Government standards
whenever possible. Consequently, as described in the following
paragraphs, DOE attempted to incorporate by reference in its test
procedures generally accepted rules or recognized industry standards
such as those issued by the Air-Conditioning, Heating and Refrigeration
Institute (AHRI), the American Society of Heating, Refrigerating, and
Air Conditioning Engineers (ASHRAE), the American National Standards
Institute (ANSI), and/or ASTM International (ASTM), that provide either
specific aspect(s) of the test procedure, or the complete test
procedure, for the specified equipment.
III. Discussion
In the following section, DOE describes the overall approach it
proposes to follow with respect to the adoption of a test procedure for
walk-ins. This approach results from the characteristics of walk-in
equipment and is based in part on the basic model definition that DOE
currently uses to help establish testing requirements for manufacturers
to follow. The following section also addresses issues raised by
commenters, which included: Manufacturers (Craig Industries (Craig),
Manitowoc, Nor-Lake); trade associations (AHRI); utility companies
(Southern California Edison (SCE), Sacramento Municipal Utility
District (SMUD), San Diego Gas and Electric (SDG&E)); and advocacy
groups (Appliance Standards Awareness Project (ASAP), American Council
for an Energy-Efficient Economy (ACEEE), Natural Resources Defense
Council (NRDC), Northwest Energy Efficiency Alliance (NEEA)).
A. Overall Approach
DOE developed today's proposed test procedure to set forth the
testing requirements for walk-in equipment. In the framework document,
DOE considered two overall approaches manufacturers could take to
determine the energy consumption of walk-in coolers and freezers.
First, DOE considered using a modified version of the Air-Conditioning
and Refrigeration Institute (ARI) Standard 1200-2006, ``Performance
Rating of Commercial Refrigerated Display Merchandisers and Storage
Cabinets'' (ARI 1200-2006), which uses the test method described in the
American National Standards Institute/American Society of Heating,
Refrigerating, and Air Conditioning Engineers (ANSI/ASHRAE) Standard
72-2005, ``Method of Testing Commercial Refrigerators and Freezers''
(ANSI/ASHRAE 72-2005). Second, DOE considered allowing manufacturers to
determine the efficiency of some of their products using alternative
efficiency determination methods (AEDMs). (An AEDM is a predictive
mathematical model, developed from engineering analyses of design data
and substantiated by actual test data, which represents the energy
consumption characteristics of one or more basic models.)
DOE received comments on these proposed approaches, many of which
were opposed to both approaches. The comments DOE received, and DOE's
responses, are discussed in more detail below. After considering these
comments and reviewing the matter further, DOE is proposing separate
test procedures for the envelope (insulated box) and the refrigeration
system. DOE discusses the details of its proposals and addresses
manufacturer comments in the following subsections.
1. Basic Model
Under EPCA, which prohibits the distribution in commerce of covered
equipment that do not comply with the applicable standard, each model
of covered equipment is potentially subject to energy efficiency
testing consistent with the relevant requirements for that equipment.
However, walk-in manufacturers typically make numerous envelope models
and, even within a single model, the units are often customized in
multiple ways. To reduce this potential burden, DOE proposes following
the approach it has used for other equipment by allowing manufacturers
to group equipment or models with essentially identical energy
consumption characteristics into a single family of models, called a
basic model. This concept has been established both for residential
appliances and commercial and industrial equipment covered under EPCA.
(See Title 10 of the Code of Federal Regulations (10 CFR) 430.2, which
covers 26 products, and 10 CFR 431.12, 431.62, 431.132, 431.172,
431.192, 431.202, 431.222, 431.262, and 431.292, which cover various
equipment.)
Walk-in refrigeration systems are often manufactured according to
the same basic blueprint design, and any particular model could
incorporate modifications that do not significantly affect the energy
efficiency of the system. For example, manufacturers often sell systems
that are designed to operate at different voltages. This allows them to
market to customers with different electrical capabilities. The
operating voltage affects the energy
[[Page 189]]
efficiency of the system, but very minimally. If manufacturers were
required to test the efficiency of each model with a different feature,
the testing burden would be significant, but yield effectively
redundant results. Therefore, DOE provides for testing of a basic model
of refrigeration systems that may not be identical, but would not have
any electrical, physical, or functional characteristics that
significantly affect energy consumption. Features that may affect the
energy consumption of walk-in cooler and freezer refrigeration systems
include compressor size, fan motor type, and heat exchanger coil
dimensions.
Walk-in envelopes are often manufactured according to the same
basic design, but the equipment is so highly customized that each walk-
in a manufacturer builds may be unique, and potentially subject to
testing as a separate basic model. For instance, changing the size of
the envelope would affect the energy consumption obtained by the test
procedure, even if the construction methods and materials were the
same. To address this possibility, DOE proposes (1) grouping walk-in
envelopes with essentially identical construction methods, materials,
and components into a single basic model, and (2) adopting a
calculation methodology for determining the energy consumption of units
within the basic model. This methodology would require a manufacturer
to test one unit of the basic model and then calculate daily energy
consumption coefficients (DECCs) for that basic model according to the
test procedure. The manufacturer could then apply those DECCs to other
units within a basic model even if those units were not identical, to
obtain the energy consumption of those units. Although units within a
basic model need not share identical dimensions, finishes, and non-
energy-related features (e.g., shelving or door kick plates), they must
have been manufactured using substantially the same construction
methods, materials, and components. A few examples of factors that
would necessitate a different basic model include changing the type of
insulating foam, the method of locking together the panels of the walk-
in envelope, or the electrical characteristics of the lighting.
Examples of factors that may not constitute a different basic model
include the type of exterior metal finish, the dimensions of the
envelope, and the number of doors of the same type. The exterior metal
finish would not have a substantial impact on the efficiency of the
envelope. Dimensions and number of doors, on the other hand, would be
accounted for in the energy consumption calculation using the DECCs
from the unit of the basic model that was tested. (See section
III.B.3.f for further discussion of DECCs.)
All of the equipment included in a basic model must be within the
same equipment class. Components of similar design may be substituted
in a basic model without requiring additional testing if the
represented energy consumption measurements continue to satisfy the
provisions for sampling and testing. Only representative samples within
each basic model would be tested.
For walk-ins, DOE is considering adopting the following definition
of ``basic model:'' ``Basic Model means all units of a given type of
walk-in equipment manufactured by a single manufacturer, and--(1) With
respect to envelopes, which do not have any differing construction
methods, materials, components, or other characteristics that
significantly affect the energy consumption characteristics. (2) With
respect to refrigeration systems, which have the same primary energy
source and which do not have any differing electrical, physical, or
functional characteristics that significantly affect energy
consumption.'' DOE requests comment on its proposed basic model
approach.
2. Approach Option 1: Test the Unit as a Whole
In the framework document, DOE considered developing a test
procedure for walk-ins by adapting an existing test procedure for
commercial refrigeration equipment, such as ARI 1200-2006. This
approach would require an entire walk-in cooler or freezer to be
physically tested within a controlled test chamber in order to evaluate
its energy consumption over a period of time. During the standards
framework public meeting, DOE requested comments on the feasibility of
this approach. Interested parties responded with significant
reservations about using a modified version of the ARI 1200-2006 test
procedure, citing crucial differences between walk-ins and commercial
refrigeration equipment.
In particular, interested parties noted that walk-ins are
physically different from commercial refrigerators in ways that make a
full-system test burdensome or impractical. Manitowoc stated that for
very large walk-ins, around the 3,000-square-foot limit in the EPCA
definition, manufacturers might not have a large enough test facility
to make the measurements necessary for the ARI 1200-2006 test procedure
in a controlled environment. (Manitowoc, Public Meeting Transcript, No.
15 at p. 59) (In this and subsequent citations, ``Public Meeting
Transcript'' refers to the transcript of the February 4, 2009, public
meeting on standards for walk-in coolers and freezers. ``No. 15''
refers to the document number of the transcript in the Docket for the
DOE rulemaking on standards for walk-in coolers and freezers, Docket
No. EERE-2008-BT-TP-0014; and the page references refer to the place in
the transcript where the statement preceding appears.) Kason Industries
also stated that it would be practically impossible to have a large
enough controlled climate enclosure to test medium to large walk-ins,
and added that if a walk-in were a free-standing structure, testing it
as a whole building would not be practical. (Kason, No. 16 at pp. 1, 4)
(In this and subsequent citations, the document number refers to the
number of the comment in the Docket for the DOE rulemaking on standards
for walk-in coolers and freezers, Docket No. EERE-2008-BT-TP-0014; and
the page references refer to the place in the document where the
statement preceding appears.) The Air-Conditioning, Heating, and
Refrigeration Institute (AHRI) stated that the proposed test procedures
were not practical because it would be costly to physically test walk-
ins. (AHRI, No. 33 at p. 2)
Commenters also noted that the market for walk-in coolers and
freezers is structured differently from the market for commercial
refrigeration equipment, making a direct comparison between these types
of equipment difficult. Manitowoc stated that the envelope of a
particular unit of walk-in equipment may be manufactured by one company
and the refrigeration system by another company. ARI 1200-2006 would
require the two systems to be integrated before running the test, which
would place the burden on the installer or someone beyond the
manufacturer of the subsystems. (Manitowoc, Public Meeting Transcript,
No. 15 at p. 59) AHRI agreed that the ARI 1200-2006 standard might not
be the right approach and that DOE would need to separate the
mechanical system from the envelope. (AHRI, Public Meeting Transcript,
No. 15 at p. 62)
In addition to these concerns, commenters identified a deficiency
in the ARI 1200-2006 test procedure. SCE stated that the majority of
potential energy savings can be achieved using floating head pressure
and variable-speed evaporator fans, both of which have varying effects
depending on the time of day and the regional climate
[[Page 190]]
because the savings associated with each feature can depend on the
ambient temperature and usage patterns of the walk-in over the course
of a day. Because ARI 1200-2006 is a steady-state test, it would not
capture the energy savings from either option. (SCE, Public Meeting
Transcript, No. 15 at p. 63) AHRI agreed that the test procedure should
capture savings from a control strategy or variable-speed components,
both of which could optimize the operation of the walk-in for a variety
of ambient conditions and usage patterns. An example of optimization
would be allowing elements of the refrigeration system to turn off or
reduce their operation at night when the walk-in is not being accessed.
(AHRI, No. 33 at p. 2)
After considering these comments, DOE believes that an adapted
version of ARI 1200-2006 would be inadequate to use as the test
procedure for walk-in equipment. ARI 1200-2006 contains too many
limitations and practical difficulties that would make it very
difficult to effectively implement as a workable test procedure for
walk-in. Therefore, DOE is no longer considering this approach.
3. Approach Option 2: Allow Manufacturers To Use Alternative Energy
Determination Methods (AEDMs)
DOE's framework document also presented an alternative that would
permit the use of an AEDM when determining walk-in energy consumption
to help relieve the testing burden on manufacturers. An AEDM is a
predictive mathematical model, developed from engineering analyses of
design data and substantiated by actual test data which represents the
energy consumption characteristics of one or more basic models. After
confirming the accuracy of an AEDM, the manufacturer would apply the
AEDM to basic models to determine their energy consumption without
conducting any physical testing.
Applying this approach, the manufacturer would confirm the accuracy
of the AEDM using the following method. First, the manufacturer would
determine through actual testing the energy consumption of a certain
number of its basic models that would be selected in accordance with
criteria specified in the procedure. Second, the manufacturer would
apply the AEDM to these same basic models. The AEDM would be considered
sufficiently accurate only if: (1) The predicted total energy
consumption of each of these basic models, calculated by applying the
AEDM, is within a certain percentage of the total energy consumption
determined from the testing of that basic model; and (2) the average of
the predicted total energy consumption for the tested basic models,
calculated by applying the AEDM, is within a certain percent of the
average of the total energy consumption determined from testing these
basic models. Under this approach, once the manufacturer verifies the
accuracy of the AEDM, the manufacturer can use the AEDM to determine
the energy consumption of other basic models without having to test
those models. DOE requested comments on this approach during the
framework public meeting, both in terms of how to implement the
approach and whether such an approach was valid for walk-ins at all.
DOE received several relevant comments, which are described and
addressed below.
Given the unprecedented nature of using an AEDM to rate this type
of equipment, DOE needed to determine both an appropriate sample size
for verifying an AEDM and an acceptable minimum accuracy percentage for
an AEDM. During the framework public meeting, DOE requested comments on
these two values. AHRI could not provide feedback on how accurate the
AEDM should be because DOE had not yet determined the test metric to
apply. (AHRI, Public Meeting Transcript, No. 15 at p. 69) Manitowoc
agreed that the test methodology needs to be established and
experiments conducted to collect data that would be used to validate
AEDMs. (Manitowoc, Public Meeting Transcript, No. 15 at p. 70) In a
written comment, Kason Industries stated that an AEDM with a minimum
accuracy of 66 percent would encompass a majority of the wide range of
walk-in cooler and freezer applications. (Kason, No. 16 at p. 2) No
commenter provided substantive data that DOE would use in its analysis
to help support a particular sample size. Accordingly, DOE did not
receive enough data from stakeholders that could help it determine an
appropriate sample size or accuracy range to substantiate an AEDM.
During the public meeting, DOE also requested comments on the
possibility of allowing manufacturers to take this approach to rate
their walk-ins. Kason stated that an AEDM procedure would be preferable
to using a physical test because the majority of walk-ins are custom-
made by size, ambient temperature, and refrigeration demands.
Therefore, it would be very difficult to create a test procedure that
encompasses the range of walk-in equipment. (Kason, No. 16 at p. 1)
Kason suggested that, as an alternative to testing the system as a
whole, an AEDM could be based on determining efficiencies and
performance characteristics for the principal components of a walk-in
considering three factors: insulation and air tightness of the external
envelope and door, efficiency of the refrigeration system for steady-
state storage load (similar to the efficiency rating system for HVAC),
and performance of the refrigeration system for removal of process heat
and equipment-generated heat. (Kason, No. 16 at p. 2)
Other interested parties commented that allowing manufacturers to
develop their own calculation methodology or software program as an
AEDM could be problematic. Owens Corning questioned whether there could
be a comparison among ratings published by manufacturers that developed
different AEDMs. (Owens Corning, Public Meeting Transcript, No. 15 at
p. 64) Craig stated that manufacturers who devise their own test
procedures could write them in a way that benefits their own company.
(Craig, Public Meeting Transcript, No. 15 at pp. 68-69) SCE stated that
allowing manufacturers to develop their own software as an AEDM could
be unfair to manufacturers with fewer resources, because the software
is expensive and time-consuming to develop. Instead, SCE suggested that
it would be better to have a transparent analysis method with the
algorithms available to all participants and the data in a standardized
format. (SCE, Public Meeting Transcript, No. 15 at p. 71) Craig replied
that many manufacturers have sizing programs, which may be proprietary,
to calculate the total load of the walk-in, accessories, and product
load, and to size the refrigeration system properly for the energy
requirements of the envelope. (Craig, Public Meeting Transcript, No. 15
at pp. 77-78 and No. 22 at p. 4) However, Craig stressed that requiring
manufacturers to follow the same model developed or approved by DOE,
would be fair to different manufacturers and provide consistent
information to end users. (Craig, Public Meeting Transcript, No. 15 at
p. 94 and No. 22 at p. 5)
ACEEE asserted that it would be difficult for DOE to work with many
proprietary models, some of which might be difficult to verify. (ACEEE,
Public Meeting Transcript, No. 15 at p. 94) NEEA also said that if an
AEDM were used, the software should be equally available to all
manufacturers and code officials for the purpose of determining
compliance. (NEEA, No. 18 at p. 3) Crown Tonka stated that a standard
configuration and standard test should be developed to create a
baseline
[[Page 191]]
for energy usage, with normalizing factors associated with
configuration changes. (Crown Tonka, No. 23 at p. 1) Owens Corning
reiterated that a single AEDM should be accepted to keep comparisons
consistent. (Owens Corning, No. 31 at p. 2)
DOE had previously understood that manufacturers would develop
their own AEDMs and would verify their accuracy by testing a small
number of walk-in models. However, as discussed above, most interested
parties indicated that allowing manufacturers to develop their own
rating calculations or software could be problematic, despite the fact
that the calculations and software would need to be verified.
Therefore, DOE does not propose to allow manufacturers to develop their
own AEDMs. Instead, DOE developed its own calculation methodology for
manufacturers to use in rating similar, but not identical, units of
walk-in equipment. For further discussion on this methodology, see
section III.B.3.f.
4. Proposed Option and Recommendation: Separate Envelope and
Refrigeration Tests
Both methods described above were predicated on the assumption that
an entire walk-in unit is manufactured by a single entity, which could
either test the walk-in as a whole according to ARI Standard 1200-2006,
or calculate the overall efficiency using an AEDM. In fact, as DOE
learned, most walk-ins have two main manufacturers: One who
manufactures the envelope and one who manufactures the refrigeration
system that cools the interior of the envelope. (Other manufacturers
may be involved in producing secondary components --such as fan
assemblies or lighting-- that are then purchased by the main
manufacturers and incorporated as part of the refrigeration system or
envelope.) These two parts are manufactured separately, and are often
assembled together in the field by a third-party contractor who may not
have been responsible for the manufacture of either part, and who may
not have testing or evaluation capabilities. Because of this situation,
DOE developed, and is proposing, a different approach for testing walk-
ins, as described below.
Specifically, DOE proposes separate test procedures for the
envelope and the refrigeration system. The envelope manufacturer would
be responsible for testing the envelope according to the envelope test
procedure, and the refrigeration system manufacturer would be
responsible for testing the refrigeration system according to the
refrigeration system test procedure. Such an approach would be more
likely to generate usable data in support of standards for both the
envelope and the refrigeration system during the development of any
energy conservation standards for walk-in coolers and freezers. The two
test procedures are described in sections III.B and III.C,
respectively.
There are several advantages to this approach. First, having
separate test procedures would allow individual component manufacturers
to test their components--the envelope and the refrigeration system.
These component manufacturers would be more likely to have access to
the resources, equipment, and personnel needed to conduct the tests. On
the other hand, the ``manufacturer'' of an entire walk-in system (i.e.,
envelope and refrigeration system combined), could be a third party: A
contractor who assembles the walk-in from the separate components and/
or installs it in the field. This third-party assembler may even be the
end-user or owner of the equipment. If a walk-in is assembled in the
field, testing of the entire assembled system may not be feasible due
to lack of expertise and the need for additional testing equipment.
Second, this approach would result in a significantly reduced
testing burden while ensuring compliance with any standard DOE may
develop. There are many more assemblers and installers of walk-ins than
there are component manufacturers. Because EPCA requires manufacturers
to demonstrate compliance with energy conservation standards,
interpreting the term ``manufacturer'' to include assemblers and
installers, who may be contractors or end-users, to demonstrate
compliance with a standard would impose the compliance burden on
entities who, more likely than not, may not have participated in the
design and manufacture (and therefore energy efficiency) of the
component parts. Furthermore, this approach would create substantial
difficulties for DOE to enforce any standards it promulgates for walk-
in equipment. While DOE considered the possibility that including
assemblers and installers as parties involved in the manufacture of
this equipment could encourage these parties to take steps to ensure
that compliant equipment is installed, at this time, DOE believes that
the testing burdens are best met by the envelope and refrigeration
system manufacturers for the reasons discussed above. Accordingly,
under today's proposal, only envelope and refrigeration system
manufacturers would need to demonstrate compliance with any proposed
standard through the use of the test procedure. (DOE notes that
possible remedial action for failing to satisfy these requirements
include civil penalties and injunctive relief to prevent the continued
sale and distribution of noncompliant equipment.) (42 U.S.C. 6303-6304)
DOE requests comment on this proposed approach and whether it is
appropriate for walk-ins.
B. Envelope
As described earlier, the envelope consists of the insulated box in
which the stored items reside. The following discussion describes in
greater detail the test procedure DOE is proposing for the walk-in
envelope. DOE also addresses issues raised by interested parties.
This procedure contains the proposed methodology for evaluating the
performance characteristics of the insulation as well as methods for
testing thermal energy gains related to air infiltration caused by use
(door openings) and imperfections in wall interfaces or door gasketing
material. Heat gain due to internal electrical components is an
additional consideration.
The proposed procedure utilizes the data obtained to calculate a
measure of energy use associated with the envelope. In other words, the
test procedure calculates the effect of the envelope's characteristics
and components on the energy consumption of the walk-in as a whole.
This includes the energy consumption of electrical components present
in the envelope (such as lights) and variation in the energy
consumption of the refrigeration system due to heat loads introduced as
a function of envelope performance, such as conduction of heat through
the walls of the envelope. The effect on the refrigeration system is
determined by calculating the energy consumption of a theoretical, or
nominal, refrigeration system, were it to be paired with the tested
envelope. Using the same nominal refrigeration system characteristics
allows for direct comparison of the performance of walk-in envelopes
across a range of sizes, product classes, and levels of feature
implementation.
The test procedure obtains a metric of energy use associated with
the envelope of a walk-in cooler or freezer, consistent with the
statutory requirement (42 U.S.C. 6314(a)(9)(B)(i)). For purposes of
this rulemaking, DOE interprets the term ``energy use'' to describe the
sum of (a) the electrical energy consumption of envelope components and
(b) the energy consumption of the walk-in refrigeration equipment that
is
[[Page 192]]
contributed by the performance of the envelope.
1. Overview of the Test Procedure
In accordance with EPCA, DOE is developing test procedures to
evaluate the energy use associated with the envelope of walk-in coolers
and freezers. The walk-in envelope includes, but may not be limited to,
walls, floor, ceiling, seals, windows, and/or doors comprised of single
or composite materials designed to isolate the interior, refrigerated
environment from the ambient, external environment. For the purposes of
developing this test procedure and evaluating potential performance
standards for walk-in equipment, DOE considers the envelope to also
include lighting and other energy-consuming components of the walk-in
that are not part of its refrigeration system (e.g., motors for
automatic doors, anti-sweat heaters, etc.). DOE is considering the
following definition for ``envelope,'' which would be inserted into 10
CFR part 431:
(1) The portion of a walk-in cooler or walk-in freezer that
isolates the interior, refrigerated environment from the ambient,
external environment; and
(2) All energy-consuming components of the walk-in cooler or walk-
in freezer that are not part of its refrigeration system.
DOE requests comments on this proposed definition.
DOE also evaluated several available industry test procedures to
measure the energy performance of various components of the walk-in
envelope, but was unable to find a test procedure that would evaluate
the entire envelope system. Consequently, DOE developed its own
methodology, including a prescriptive calculation procedure, which
incorporates specific component tests and allows for an overall energy
performance value of the envelope to be determined. The proposed test
measurements and accompanying calculation procedures to ascertain the
overall energy performance value are described in the following
sections.
2. Test Methods
As discussed above, DOE was unable to find a single, existing
comprehensive test procedure for evaluating walk-in cooler and freezer
envelopes. However, DOE identified and evaluated many recognized
industry standards that could be applied to the testing of certain
components and characteristics of walk-in envelopes. DOE incorporated
an insulation test and an air infiltration test, with some
modifications, into the proposed test procedure. The evaluation
process, the results of the evaluation, and details of the proposed
test methods are described in the following sections.
a. Insulation
Insulation comprises a significant component of walk-in units. EPCA
specifies that ASTM C518-04, ``Standard Test Method for Steady-State
Thermal Transmission Properties by Means of the Heat Flow Meter
Apparatus,'' must be used, along with specific foam temperatures for
freezer or cooler applications specified in EPCA, to determine the R
value of individual walk-in envelope insulation materials. (42 U.S.C.
6314(a)(9)(A)) Commenters identified two issues of significance for DOE
to consider when developing a test procedure for insulation: aging and
moisture absorption. DOE discusses these issues in the subsections that
follow.
i. Aging of Foam Insulation
EPCA requires that the test procedure for walk-ins use an R value
that shall be the 1/K factor multiplied by the thickness of the panel.
(42 U.S.C. 6314(a)(9)(A)) The Act does not specify when the R value
should be calculated, a key issue interested parties raised at the
framework public meeting. Specifying when the R-value should be
calculated is a critical consideration because several sources indicate
that the R-value of certain materials can change over time.
Craig stated that R values tend to deteriorate over time and that
different materials exhibit unique rates of deterioration. (Craig,
Public Meeting Transcript, No. 15 at p. 215 and No. 8 at p. 1) Craig
expressed concern that using an initial R value (R value as measured
within two weeks of manufacture) to determine compliance would ignore
deterioration that occurs in blown foams over time. Craig argued that
underestimating the energy use of walk-ins would be the likely outcome
of using initial R-value, that it would be misleading for end-users,
and that it would be inconsistent with the goals of the EISA 2007
legislation and the rulemaking process. (Craig, Public Meeting
Transcript, No.15 at p. 215) A comment submitted jointly by
representatives of ASAP, ACEEE, and NRDC (hereafter referred to as the
``Joint Comment'') stated that the test procedures used should account
for the potential degradation of panel insulation and door seals over
time. (Joint Comment, No. 21 at p. 2) Craig also recommended that DOE
develop an accelerated test procedure that represents lifetime energy
use and can be completed within 6 months. (Craig, No. 8 at p. 1)
In the context of foam insulation for walk-ins and the building
industry, long-term thermal resistance (LTTR), described in greater
detail below, refers to the impact of diffusion on the thermal
resistance of insulation materials. In other words, the concentration
of gaseous blowing agents contained in the foam, and which provide the
foam with much of its insulating value, is reduced by both the
diffusion of air into the foam and the secondary process of the blowing
agent diffusing out of the foam. Because air has a significantly lower
insulating value, the increased ratio of air to blowing agent reduces
the foam insulation performance (this process is also known as
``aging''). This diffusion process causes foam to lose insulating
value, which is represented by its R-value. As a concept, LTTR
represents the R-value of foam material over its lifetime by describing
insulating performance changes due to diffusion over time.
DOE investigated the issue of aging in foam insulation and found
that it is widely accepted that the material properties of foam
insulation made with gaseous blowing agents, other than air and
including HFC-134a, HFC-245fa, HFC-365mfc, cyclopentanes, change over
time. The amount of degradation can range from roughly 10-35 percent
within 2 years of manufacture. Because use of ASTM C518-04 reflects the
properties of a material at the time it is tested, using ASTM C518-04
to measure the insulating performance of a foam material at the time of
manufacture would yield a result that differs from that produced by the
same test conducted at some later point in time. Additionally, research
has found that the vast majority of diffusion into and out of foam
materials manufactured with blowing agents other than air occurs within
the first 5 years of manufacture. Because the rate of diffusion follows
an exponential curve, the majority occurs within the first year, after
which the diffusion curve changes very little as it asymptotically
approaches the equilibrium point.
DOE found that various methods of ``conditioning'' foam prior to
measuring its insulating ability with American Society for Testing and
Materials (ASTM) C518 have been developed in order to test aged
insulating value, or LTTR. These standards are contained in five foam
material specifications:
(1) ASTM C578-09, ``Standard Specification for Rigid, Cellular
Polystyrene Thermal Insulation;''
(2) ASTM C591-08a, ``Standard Specification for Unfaced Preformed
Rigid Cellular Polyisocyanurate Thermal Insulation;''
[[Page 193]]
(3) ASTM C1029-08, ``Standard Specification for Spray-Applied Rigid
Cellular Polyurethane Thermal Insulation;''
(4) ASTM C1126-04, ``Standard Specification for Faced or Unfaced
Rigid Cellular Phenolic Thermal Insulation;'' and
(5) ASTM C1289-08, ``Standard Specification for Faced Rigid
Cellular Polyisocyanurate Thermal Insulation Board.''
DOE found that since their development in the 1980s, the most
widely accepted conditioning methods are the 180-day conditioning at 73
[deg]F or a 90-day conditioning at 140 [deg]F. The goal of the 90-day
conditioning method was to achieve the same aging result as the 180-day
method in a shorter period of time. 180-day conditioning is used by
ASTM C591-08a and ASTM C578-09 and the 90-day condition is typically
used for ASTM C1089-08 and ASTM C1126-04. By accelerating the
conditioning, the 90-day test sought to reduce the time and cost
burdens for manufacturers. Although elevating the temperature of foams
did achieve a faster rate of aging, subsequent research found that the
results were not reliable indicators of actual aging because the
relationship between the diffusion coefficient (a proportionality
constant that describes the force or rate of diffusion for a given
substance) and temperature are different for each gas. (Therese
Stovall, ``Measuring the Impact of Experimental Parameters upon the
Estimated Thermal Conductivity of Closed-Cell Foam Insulation Subjected
to an Accelerated Aging Protocol: Two-Year Results,'' p. 1)
DOE found that efforts to develop an accelerated aging method that
did not use elevated temperatures resulted in the creation of ASTM
C1303, which in 1995 introduced the slicing and scaling method, also
known as the ``thin slicing'' method (a technique used to slice the
foam so that it ages more rapidly as a function of reduced thickness).
In contrast to ASTM C578-09, ASTM C591-08a, ASTM C1029-08, ASTM C1126-
04, and ASTM C1289-08, which specify the use of either the 180-day
conditioning method or 90-day accelerate conditioning method to age the
foam before measuring its thermal resistance. In contrast, the thin
slicing method used in ASTM C1303-08 (the most recent version of ASTM
C1303) was designed specifically to test the aging of foam insulation
in duration shorter than 180 days, and without the temperature
elevation methodology used in the 90-day test. (ASTM C1303-08, section
5.3, at p. 3) By reducing the length of the pathway for diffusion to
take place, the ``aging'' can be accelerated without the confounding
effects caused by unique gas properties of the material and blowing
agent. The results are used to determine the R-value of foam 5 years
after manufacture, a value that has been shown to correlate strongly
with the average R-value of foam 15 years after manufacture. (ASTM
C1303-08, section 5.4, at p. 3)
In early 2000, the National Research Council Canada and Institute
for Research in Construction (NRC-IRC) developed CAN/ULC-S770-00. CAN/
ULC-S770-00 incorporated elements of ASTM C1303-95 (the first version
of ASTM C1303) but altered that standard by clarifying the slicing
procedure used in ASTM C1303-95, as differing interpretations of the
previous procedure were thought to be causing variations in the test
results among third-party testing facilities. These changes sought to
eliminate inconsistency in the interpretation of the slicing procedure
and test setup to ensure uniformity across testing labs. In December
2000, CAN/ULC-S770-00 became the Canadian national mandatory test for
calculating the LTTR of all foam insulation products (this test has
since been updated; the most recent version is CAN/ULC-S770-03).
Members of the U.S.-based Polyisocyanurate Insulation Manufacturers
Association (PIMA) began to test their products using the same
procedure on January 1, 2003. The LTTR calculated from this test
procedure is used for all building insulation product labeling in
Canada and PIMA products in the United States. Also in 2000, ASTM
C1303-95 was updated as ASTM C1303-00.
In a 2005 rule by the U.S. Federal Trade Commission (FTC) in which
the FTC considered requiring ASTM C1303-00 (the most recent version at
that time) for product labeling on all foam insulation products, the
FTC's review process revealed several unresolved issues related to the
test procedure. (70 FR 31258 (May 31, 2005); 16 CFR Part 460, Labeling
and Advertising of Home Insulation: Trade Regulation Rule, Final Rule)
Subsequently, ASTM C1303-00 was updated to address these issues, which
included foam stack composition, minimum slice thickness and slice
source, the time between manufacture and test initiation, preparation
of foam-in-place samples, and other clarifications of the procedure.
This updated version was published as ASTM C1303-08 and is the most
recent version of the standard to date.
Some commenters noted during the framework meeting that the
application of an impermeable vapor barrier to the surface of the foam
could reduce the impact of aging. Depending on its end use, foam
insulation may have facers or skins applied to act as a vapor barrier
and/or to enhance the bond of construction glues. Kysor stated that
proper use of skins eliminates aging and the associated reduction of R-
value in polyurethane panels. (Kysor (attachment), No. 29 at p. 1)
DOE examined this issue and found that foams used in walk-in panels
are sometimes protected by impermeable barriers designed to prevent
vapor and/or air exchange into or out of the foam or the interior of
the walk-in. DOE found research conducted by the National Resource
Council Canada (NRCC) suggesting that impermeable facers do not
eliminate aging but may delay the rate of aging and/or the final
equilibrium of the aged state. (Mukhopadhyaya, P.; Bomberg, M.T.;
Kumaran, M.K.; Drouin, M.; Lackey, J.; van Reenen, D.; Normandin, N.,
``Long-Term Thermal Resistance of Polyisocyanurate Foam Insulation With
Impermeable Facers''; Mukhopadhyaya, P.; Bomberg, M.T.; Kumaran, M.K.;
Drouin, M.; Lackey, J.; van Reenen, D.; Normandin, N., ``Long-Term
Thermal Resistance of Polyisocyanurate Foam Insulation With Gas
Barrier''; Mukhopadhyaya, P.; Kumaran, M.K. ``Long-Term Thermal
Resistance Of Closed-Cell Foam Insulation: Research Update From
Canada.'') In one of the summary observations of ``Long-Term Thermal
Resistance of Polyisocyanurate Foam Insulation With Gas Barrier,'' the
NRCC noted, ``a considerable amount of aging occurred in thin slice
specimens despite having untouched impermeable facers, as well as a
glass plate at the bottom of the specimens and edges sealed completely
with epoxy coating.''
Additionally, the relationship between the skin and the rate of
aging in foam depends on preserving the integrity of both the skin
surface and the bonding between the skin and insulation. Punctures,
made to allow for the installation of light fixtures, doors, and
shelving, undermine the integrity of the skin. Walk-in insulation
panels and their skins also typically separate over time due to
shrinkage of foam materials after manufacture. While most foam
materials contract by less than 1 percent of their total volume,
shrinkage at this level is enough to create significant air gaps. DOE
found that current methods of conditioning foam materials do not
account for impermeable facers.
Finally, like the conditioning standards that are currently in use,
ASTM C1303-08 is not designed to test impermeably faced foams that may
be
[[Page 194]]
used with walk-ins. Significant research has been underway by the NRCC
but no known test procedure is currently available that accounts for
the effect of impermeable barriers. DOE requests feedback on this
issue, including the submission of test results on the impact of
impermeable skins on long-term R-value. DOE specifically requests that
interested parties submit or identify peer-reviewed, published data on
this issue.
DOE also requests feedback on the use of ASTM C1303-08 with
impermeably faced foams. DOE may recommend the use of a test procedure
specifically designed for impermeably faced foam if one is developed.
As a result of this evaluation, DOE proposes requiring
manufacturers to use ASTM C1303-08 to determine the LTTR of walk-in
foam insulation for the purposes of calculating the energy consumption
of walk-in equipment. DOE requests comments on this proposal.
DOE is also proposing and seeking comment on the following
exceptions to ASTM C1303-08:
(1) Section 6.6.2 of C1303-08 suggests that two standards for
measuring the thermal resistance may be used. DOE proposes to allow use
only of ASTM C518-04 (in EPCA, an incorrect form of the date suffix was
used, e.g., ASTM C518-[20]04), as specified in EPCA. (42 U.S.C.
6314(a)(9)(A)(ii))
(2) In section 6.6.2.1, in reference to ASTM C518-04, the mean test
temperature of the foam during R-value measurement would be -6.7 2 [deg]C (20 4 [deg]F) with a temperature
difference of 22 2 [deg]C (40 4 [deg]F) for
freezers and 12.8 2 [deg]C (55 4 [deg]F) with
a temperature difference of 22 2 [deg]C (40 4
[deg]F) for coolers. This change replaces the standard mean temperature
of 75 [deg]F for ASTM C518-04 with the EPCA specified values.
(3) For the purposes of preparing samples with foam-in-place
method, section A2 should be followed exactly except for the following
modifications to accommodate foam-in-place methods that may be used
during the manufacture of walk-in panels:
(3.1) Instead of following A2.3, which specifies that the
foam be sprayed onto a single sheet of wood, the sample shall be foamed
into a fully closed box of internal dimension 60 cm x 60 cm by desired
product thickness (2ft x 2ft x Desired thickness). The box shall be
made of \3/4\ inch plywood and internal surfaces wrapped in 4 to 6 mil
polyethylene film to prevent the foam from adhering to the box
material.
(3.2) Instead of following section A2.4, which specifies
the spraying of foam layers onto a open sheet of plywood, the cavity
shall be filled using the manufacturer's typical foam-in-place method
through a standard injection port or other process typically used to
foam the product being tested.
(3.3) In section A2.6, which defines the single surface in
contact with the board to be the ``surface,'' the definition of the
foam's ``surface'' shall be the two surface regions in contact with the
60 x 60 cm sections of the box.
(3.4) Section A2.8 shall not be followed because the
prepared sample will not have any ``free rise'' component.
DOE proposes that manufacturers select foam test thicknesses based
on design specifications and practice. If a foam's thickness as
manufactured varies from the tested product thickness, DOE proposes
that the R-value of that foam at its manufactured thickness may be
interpolated using the results of ASTM C1303-08, provided that the
manufactured thickness does not vary from the tested product thickness
by more than 0.5 inches. For example, if 4-inch and 6-inch
products were prepared, interpolation between 3.5 and 4.5 inches would
be allowed for the 4-inch foam and 5.5 and 6.5 inches for the 6-inch
foam. If the manufacturer determines that final foam thickness should
be outside of the tested range, then additional testing would be
necessary to fit the criterion for interpolation. Manufacturers should
make their sample selections accordingly to avoid the need for
additional testing. DOE requests feedback on the use of interpolation
within the specified 0.5 inch range.
DOE proposes that the results for each of the sample sets of three
stacks should be reported as specified by ASTM C1303-08. As defined by
ASTM C1303-08, after thin slices of foam are cut, the slices are
organized into ``stacks'' of slices to match the original overall
thickness of the sample. The procedure defines three stack types: (1)
Stacks comprised of only surface slices of foam, (2) stacks of only
core slices and (3) a mixture of core and surface slices. A ``surface''
slice and a ``core'' slice are defined in ASTM C1303 as ``a thin-slice
foam specimen that was originally adjacent to the surface of the full-
thickness product and that includes any facing that was adhered to the
surface of the original full-thickness product'' and ``a thin-slice
foam specimen that was taken at least 5 mm (0.2 in.) or 25% of the
product thickness, whichever is greater, away from the surface of the
full thickness product,'' respectively. The R-value of only the mixed
stack would be used to calculate the energy performance of walk-ins.
DOE requests feedback on this approach. ASTM is currently conducting a
5-year ``ruggedness'' test. Upon completion of the test, DOE may
consider a rulemaking to modify the required number of stacks and/or
which stack is best suited for labeling and calculating energy
performance. DOE requests feedback on the use of the mixed stack R-
value for the purpose of calculating walk-in energy use.
Additionally, DOE notes that ASTM C1303-08 is specifically intended
for measuring the LTTR of foam materials. In light of this situation,
the process contained in this standard would not apply to advanced
insulation technologies such as vacuum insulated panels (VIPs) or
aerogels. However, ASTM C518-04 can be used to measure the thermal
properties of these new technologies, which, as specified in EPCA, is
the required test for measuring insulating performance. (42 U.S.C.
6314(a)(9)(A)(ii)) DOE requests feedback on whether non-foam advanced
technologies, such as VIPs or aerogels, would be likely to be used for
walk-ins in the next 5 years. If DOE determines that these materials
may be used in walk-ins in the next 5 years, DOE may consider
alternative test procedures for capturing the long-term insulating
value of any non-foam materials.
ii. Water Absorption in Foam
At the framework public meeting, interested parties raised the
issue of R-value deterioration in foams due to moisture absorption.
Craig stated that moisture penetration causes a decline in the R-value
of foam insulation, at a rate that depends on the type of foam used.
(Craig, No. 22 at p. 3) As is the case with aging, insulating foams
exhibit different characteristics in the presence of moisture.
Polystyrene foam is highly resistant to water absorption, whereas
polyurethanes and polyisocyanurates are more easily damaged by exposure
to moisture. In general, the solution to moisture issues involves
creating an impermeable barrier between the insulation and the moisture
source. However, Owens Corning asserted that customers routinely
puncture metal skins to allow for the installation of lighting
fixtures, shelving, and doors, creating holes that allow moisture to
enter the insulation. (Owens Corning, Public Meeting Transcript, No. 15
at p. 61)
Although vapor permeance and water absorption tests exist, they are
designed for measuring specific material properties rather than
measuring system performance of composite structures like walk-ins. For
a variety of reasons,
[[Page 195]]
these tests would be complex, costly, and time consuming to use because
several sub-methods would need to be developed to quantify the impact
of water on walk-ins. For every unique construction method and/or
combination of materials (e.g., blowing agent, foam type, barriers,
gasketing materials, panel joint type, and method), the following
considerations exemplify the challenges inherent in accounting for and
quantifying insulating performance: (1) The rate at which the walk-in
envelope collects water over its life must be measured or predicted
using an accelerated test; (2) a saturation level or maximum
absorption, if any, must be determined; and (3) a correlation between
water absorption levels and insulation performance must be quantified.
At this time, test procedures for each of these considerations are not
yet recognized by a nationally recognized organization such as ASTM.
DOE reviewed several methods for testing vapor permeance and water
absorption in foam insulation materials including ASTM E96, ``Standard
Test Methods for Water Vapor Transmission of Materials,'' ASTM C209,
``Standard Test Methods for Cellulosic Fiber Insulation Board,'' ASTM
C272-01 (2007), ``Standard Test Method for Water Absorption of Core
Materials for Structural Sandwich Constructions,'' and ASTM D2842-06,
``Standard Test Method for Water Absorption of Rigid Cellular
Plastics.'' Each of these standards describes a method for submerging a
sample in water for a specified amount of time and then measuring the
amount of water absorbed on a volume or weight basis. However, each one
specifies significantly different immersion durations (ranging from 2
to 96 hours) and methods of weighing samples (blotting surfaces before
measurement or using a buoyancy measurement). DOE believes that using
the longest test period, 96 hours, would likely result in near worst
case or maximum water absorption, but it is unclear how this directly
translates to reduction in insulation performance for various
materials.
Additionally, ASTM E96-05 measures vapor permeance under low vapor
pressure gradient conditions. However, the temperature differentials in
which walk-ins operate cause a high vapor pressure gradient, which has
the effect of continuously driving moisture through the envelope.
Neither ASTM E96-05 nor any other known procedures currently provide a
methodology to accurately calculate the vapor permeance in walk-ins at
the pressure gradients typically experienced in the field.
Some research has been completed, including a major study by the
Cold Regions Research and Engineering Lab (CRREL). The CRREL study
developed and applied a method for creating a vapor pressure gradient
across various materials to quantify the rate at which these materials
absorb and retain water over time. The insulating performance of the
materials was also tested at various levels of moisture content to
develop equations for the purpose of calculating the insulating
properties at any moisture percentage relative to its dry weight. No
other testing body has applied CRREL's testing procedures to replicate
the results and most of CRREL's research was completed nearly 20 years
ago. One of DOE's national labs has also begun development of
procedures to evaluate the impact of moisture on insulation R-values,
but this activity remains incomplete.
Given the discussion above, DOE does not propose to include the
impact of water absorption on R-value in the test procedure because no
well-accepted method has been developed. However, DOE will evaluate
such a procedure if it is developed in the future.
b. Air Infiltration
Another major pathway for energy loss in walk-ins is air
infiltration, or air exchanged into and out of a walk-in while all
access points are closed or during door-opening cycles (i.e., the
openings of doors for the removal or stocking of product, or passage of
customers, personnel, and/or machinery, also referred to as ``door-
opening events''). Compared with other energy consumption factors such
as conduction losses through insulation, air infiltration may be the
largest contributing factor to envelope energy losses. Air infiltration
can occur through steady-state leakage or from door opening events. As
a result, designs and technologies that reduce infiltration during
steady-state operation and door-opening events should be considered to
reduce these losses.
EPCA includes prescriptive requirements for doors used on walk-ins,
recognizing that a major portion of energy is lost through door opening
cycles. All walk-in coolers or freezers ``manufactured on or after
January 1, 2009, shall (A) have automatic door closers that firmly
close all walk-in doors that have been closed to within 1 inch of full
closure, except * * * doors wider than 3 feet 9 inches or taller than 7
feet; [and] (B) have strip doors, spring hinged doors, or other method
of minimizing infiltration when doors are open * * *'' (42 U.S.C.
6313(f)(1)) During the framework public meeting, interested parties
suggested methods for calculating infiltration from door-opening events
within the test procedure.
These two infiltration pathways, steady-state leakage, and air
losses due to door-opening events, are mitigated using distinct
methods.
Steady-state infiltration (the air exchanged between the interior
and exterior of a walk-in while all doors are closed, also referred to
as ``leakage'') occurs because of the significant pressure gradient
caused by the large temperature difference between the refrigerated
space and the external environment. This pressure differential
continuously induces air movement from the outside to the inside of a
walk-in where leakage pathways exist. Leakage typically occurs through
door frames, door gaskets, wall panel-to-panel interfaces, and wall-to-
floor and wall-to-ceiling junctions. While considered minimal for small
walk-ins, leakage becomes more significant as the walk-in size
increases.
Air infiltration due to door openings is mostly a function of door
area, opening frequency, duration, and air density. The primary means
of reducing the amount of infiltration is by the use of active or
passive infiltration reduction devices and devices that help reduce the
time that doors are left accidentally ajar. Air curtains and strip
curtains are good examples of active versus passive devices. The
sections below describe the methods for testing the effectiveness of
such devices and procedure for calculating air infiltration's impact on
energy use in walk-ins.
Hired Hand recommended that the energy analysis for warehouse
coolers and freezers include the performance of the door, including the
number of door-opening cycles each day or week and factoring in
optional door configurations such as automatic doors with or without
strip curtains. (Hired Hand, No. 27 at p. 1) Eliason recommended that
DOE consider average door cycling and door-ajar conditions in its test
procedure. (Eliason, No. 19 at p. 1) Eliason noted that both of these
conditions are part of the company's internal life-cycling test and
represent real-world conditions. (Eliason, No. 19 at p. 1) Hired Hand
stated that a simple rating for door infiltration performance could be
based on door-opening cycles per week. (Hired Hand, No. 27 at p. 2)
Hired Hand also suggested that DOE require consumer labeling to
indicate the cost per minute of leaving the door open based on door
[[Page 196]]
size and application. (Hired Hand, No. 27 at p. 2)
Based on stakeholder comments and DOE review of the impact of air
infiltration on energy use, DOE identified two methods that could be
used to measure air infiltration in walk-ins: the blower door method
and the gas tracer method. These methods are described in the following
subsections.
i. Blower Door Method
DOE reviewed ASTM E1827-96 (2007), ``Standard Test Methods for
Determining Airtightness of Buildings Using an Orifice Blower Door,''
as a possible candidate test procedure for testing walk-ins. This
method pressurizes or depressurizes the internal space using a large
fan, typically placed in a doorway. The infiltration rate of the space
can be directly calculated by measuring the pressure difference between
the exterior and interior space and the air-flow rate through the fan.
After reviewing this test method, DOE identified reasons why the
test might not be suitable for walk-ins. The blower door method is
better suited for structures with relatively high rates of
infiltration, such as buildings and homes, rather than the relatively
low levels typically observed in walk-ins. In addition, known
calibration curves for the blower door method require small temperature
differentials (generally less than 10 [deg]F) between the inside and
outside of the envelope. However, walk-ins typically operate with a far
greater differential that is normally greater than 40 [deg]F. Another
drawback to using this method with walk-ins is that the test setup
procedure requires blocking a main entrance to the structure with the
blower door. Because infiltration around the main door is a key source
of infiltration in walk-ins and would not be measured as part of the
test, this approach would not adequately capture the majority of the
infiltration. For these reasons, DOE does not propose the use of the
blower door method for measuring the air infiltration of walk-ins.
ii. Gas Tracer Method
DOE also reviewed ASTM E741-06, ``Standard Test Method for
Determining Air Change in a Single Zone by Means of a Tracer Gas
Dilution.'' Although not as widely used as the blower door method, the
gas tracer method has been used for decades by the building industry.
The test is conducted by injecting a tracer gas, such as carbon dioxide
or perfluorocarbons, into the internal space and measuring its
concentration at recorded times. From these measurements, the average
air change rate can be determined. While manual tools, such as
syringes, or automated systems can be used to sample the air spaces,
the test procedure lends itself to automation both for calibration and
data collection. Depending on the gas and sampling method used, the gas
concentration can be measured immediately with portable equipment. This
method is also more accurate than the blower door method because it
allows for direct measurement of infiltration without modification of
the design conditions. (ASTM, ASTM E741-06 (2006), ``Determining Air
Change in a Single Zone by Means of a Tracer Gas Dilution,'' section
5.6, p. 3)
c. Steady-State Infiltration Test
For the reasons described above, DOE proposes using the gas tracer
method described in ASTM-E741-06 for measuring the steady-state air
infiltration of walk-ins, with the following six exceptions:
First, DOE proposes using the ``concentration decay method''
instead of other available options described in ASTM E741-06. DOE
considers this method to be the simplest, fastest, most cost efficient,
and most accurate.
Second, carbon dioxide (CO2) is the recommended gas
tracer for all testing because of the few human hazards related to its
use, and the availability and relative cost of sampling equipment.
Third, the test would use the ``average air change rate'' method,
in changes per hour (1/h), rather than the ``average air change flow''
method described in ASTM E741-06. The ``air change flow'' method allows
for the direct measure of the exchange of air in cubic feet per hour
and does not require measurement of the internal volume of the space
but requires a more complex test setup and sampling method. In
contrast, the ``air change rate'' method measures the rate of exchange
of air per unit of time can be completed using relatively simple
equipment. However, converting this value to a measurement of the flow,
e.g., volume of air exchanged per unit time, requires a precise
measurement of internal volume. Since the precise internal volume of a
given walk-in is readily available, DOE considers the ``air change
rate'' method preferable to the ``air change flow'' method because the
equipment is less expensive and the measurements are easier to obtain.
Fourth, ASTM E741-06 describes the importance of verifying proper
gas mixing but does not describe where or how many spatial locations
should be sampled. DOE proposes that spatial measurements shall be
taken in a minimum of six locations or one location per 20 square feet
(ft\2\) of floor area (whichever results in a greater number of
measurements), at a height of 3 ft 0.5 ft, or a minimum of
2 ft 0.5 ft from the inside wall of the walk-in envelope,
to verify that the air space is uniformly mixed.
Fifth, DOE proposes the test be completed close to operational
temperature to mimic the thermally induced pressure gradient seen in
walk-ins. The internal air temperature shall be -23.3 (-10 [deg]F)
2 [deg]C (4 [deg]F) for freezers and 1.7 (35 [deg]F)
2 [deg]C (4 [deg]F) for coolers. The external air
temperature should be 24 [deg]C (75 [deg]F) 2.5 [deg]C (5
[deg]F).
Sixth, the test should be completed with all doors closed. The
resulting measurement shall be in units of changes per hour.
DOE requests feedback on its proposal to use ASTM E741-06 as the
method for determining air infiltration and on the proposed exceptions
to the test procedure.
For the purposes of administering the test, DOE considered the
following options for the location of the test: (1) Require testing at
a third-party testing facility. DOE believes that requiring that
manufacturers to ship every walk-in manufactured, or a representative
model, to a third-party facility for testing, would place a substantial
burden on manufacturers; (2) require testing by a third party on site
at a walk-in manufacturing facility. Completing the infiltration test
at the manufacturing facility reduces logistical complexity and costs
associated with testing. Since the equipment used to complete
infiltration testing was originally designed for testing the
performance of buildings, the equipment and protocols are designed to
be mobile.
DOE believes that the most viable option is allowing testing to
occur at the manufacturing facility, if preferred by the manufacturer.
DOE requests feedback on the flexibility of location required for
completion of any infiltration test.
iii. Door Infiltration Reduction Device Test
DOE is considering incorporating a door-opening test to quantify
the impact of technologies such as strip curtains, air curtains, or
other infiltration reduction devices during door-opening events. Due to
the limited data available on these devices and the variety of
technologies, DOE believes a standardized test would provide a more
comprehensive and accurate picture regarding the effectiveness of these
devices when compared to simply using effectiveness assumptions.
[[Page 197]]
DOE proposes a two-part test to account for the effect of the door
infiltration reduction device. First, measurements should be taken once
the tracer gas has uniformly dispersed in the internal space using the
methodology described in ASTM E741-06. Within 3 minutes 30
seconds, with the infiltration reduction device in place, a door should
be opened at an angle of 90 degrees over a period no longer than 3
seconds, then held at 90 degrees in the open position for 5 minutes
5 seconds, then closed over a period no longer than 3
seconds. The gas concentration should be sampled again after the door
has been closed. Samples should continue being taken until the gas
concentration is once again uniformly mixed within the walk-in. Second,
the test should be repeated exactly as described above with the
infiltration reduction device removed or deactivated.
Using the measured infiltration with the device in place and
without the device in place, the infiltration reduction effectiveness
can be directly calculated:
[GRAPHIC] [TIFF OMITTED] TP04JA10.025
Where:
Vrate,with-device = air infiltration rate, with door open
and reduction device active, using 4.2, 1/h;
Vrate,without-device = air infiltration rate, with door
open and reduction device disabled or removed, using 4.2, 1/h.
This calculation will yield a value between 0 and 100 percent, with
100 percent meaning that the device prevents all air infiltration when
the door is open. DOE proposes using this calculated effectiveness for
every unique door-device combination that a manufacturer may offer. DOE
requests feedback on the proposed method for measuring the
effectiveness of an infiltration reduction device.
iv. Infiltration Due to Door Openings
DOE does not propose to require manufacturers to measure the
infiltration from all door-opening events. The complexity of testing,
the variation of walk-in design, and various end-use behavior factors
would make such a recommendation very difficult to execute. Instead,
DOE proposes using analytical methods based on equations published in
the ASHRAE Refrigeration Handbook in combination with assumed door-
opening frequency, and duration of door cycles, to calculate the air
infiltration associated with each door-opening event.
ASHRAE recommends using Gosney and Olama's (1975) air exchange
equations for fully established flow through door openings (Equation
2). Several key assumptions have the greatest impact on predicated air
exchange and are related to the calculation of the decimal portion or
time a doorway is open, Dt. (ASHRAE, Refrigeration Handbook,
2006, section 13.5)
[GRAPHIC] [TIFF OMITTED] TP04JA10.026
Where:
Dt = fractional door opening,
P = the number of doorway passages (or number of door-opening cycles
for a given door),
[thetas]p = the door open-close time,
[thetas]o = the time the door stands open, and
[thetas]d = daily time period.
Dt is important for properly calculating the energy
impact of air infiltration due to door-opening events. Therefore, the
assumed values of P, [thetas]p, and [thetas]o
will drive the result. The daily time period, [thetas]d, is
simply assumed to be 24 hours.
For display glass doors, a P of 72 per day, [thetas]p of
8 seconds per passage, [thetas]o of 0 minutes and
[thetas]d of 24 hours could be used. P of 72 per day is
based on comments by Hired Hand and research on cold store
infiltration. Hired Hand commented that the reach in frequency is
approximately 400-600 per week (or one passage every 20 minutes
assuming 18 hours per day per week). (Hired Hand, Public Meeting
Transcript, No. 15 at p. 154) However, DOE identified a study by A.R.
East, P.B. Jeffrey, and D.J. Cleland, ``Air Infiltration into Walk-in
Cold Rooms,'' which suggested that this number should be closer to one
passage every 10 minutes (assuming 18 hours per day per week). DOE
suggests that the average of the two values of one passage every 15
minutes or P of 72 per day could be used. DOE chose the value of 8
seconds per passage but seeks comment on whether another value may be
more appropriate.
For all other door or access types, a P of 60 per day,
[thetas]p of 12 seconds per passage, [thetas]o of
15 minutes, and [thetas]d of 24 hours could be used. The
number of passages reflects that other door types are typically
accessed less frequently than glass doors. The value of 12 seconds per
passage was selected based on the assumption that non-glass doors, such
as those through which forklifts are driven in order to load product,
will be open for longer periods of time than a typical display door.
DOE selected the [thetas]o of 15 minutes due to the
probability that a non-glass door will be propped open accidentally or
intentionally. If an automatic door opener/closer is used for doors
larger than 7 feet tall and 3 feet, 9 inches wide, then a
[thetas]p of 10 seconds should be used.
DOE recognizes that with the variety of walk-in types and end-
users, the frequency and duration of door-opening events is likely to
vary significantly. As a result, DOE requests comments on the DOE
assumed values for P, [thetas]p, and [thetas]o.
3. Calculations
In this section, DOE proposes a calculation methodology for using
the results obtained from the measurements in the aforementioned tests,
along with other known quantities, to calculate an energy use metric
associated with the envelope. The steps in the proposed methodology are
explained below.
a. Energy Efficiency Ratio
EPCA requires that the test procedure ``measure the energy use of
walk-in coolers and walk-in freezers.'' (42 U.S.C. 6314(a)(9)(B)(i))
However, EPCA does not specify the units of measurement or units for
reporting that are required. Based on a review of commonly used energy
consumption metrics, DOE recommends the use of kWh/day as this unit is
commonly recognized by end-users, manufacturers and other interested
parties. However, a majority of metrics used to describe heat transfer
losses are in units of British Thermal Units (BTU) per unit time.
Therefore, to convert the British Thermal Units per hour (BTU/h)
thermal energy transmission calculation into a measure of electrical
energy consumed by the refrigeration equipment to remove the heat, DOE
proposes using an energy efficiency ratio (EER) conversion based on a
nominal efficiency of an assumed refrigeration system.
Because an envelope manufacturer cannot control where the
refrigeration equipment is sited and the EER is intended to provide a
means of comparison and not directly reflect a real walk-in
installation, DOE proposes that the EER be 12.4 Btu per Watt hour (Btu/
W-h) for coolers and 6.3 Btu/W-h for freezers. The difference in EER
for coolers and freezers reflects the relative efficiency of the
refrigeration equipment for the associated application. As the
temperature of the air surrounding the evaporator coil drops (that is,
when considering a freezer relative to a cooler), thermodynamics
dictates that the system effectiveness at removing heat per unit of
electrical input energy decreases. DOE requests feedback on the
relative EERs of refrigeration equipment for a comparison basis.
[[Page 198]]
b. Heat Gain Through the Envelope Due to Conduction
The energy calculation for all components that comprise the
external surface area of the walk-in may be determined using the
measured surface area, the measured foam R-value for the walls and
ceiling, the R-value (or U-value) for glass doors, the design operation
temperature, and the average ambient air temperature. Then, the
associated heat transfer due to conduction can then be directly
calculated.
i. Conduction Through Glass Display Doors
The heat conduction through the glass is one of the largest single
contributors to energy consumption for walk-ins with a high ratio of
glass surface area to non-glass surface. The thermal conductivity, the
inverse of thermal resistivity or R-value, is commonly represented by
the U-value in units of Btu/ft2-[deg]F-h. The thermal
conductivity for most glass products, such as glass doors and windows
used in buildings, is certified by a third party organization such as
the National Fenestration Rating Council (NFRC). After certification,
the product is granted a NFRC label and thermal conductivity
performance rating. This rating represents an overall component
performance including but not limited to the glass and the glass frame.
However, in the case of glass products manufactured for the use in
walk-ins, such as display doors, inset window and glass walls, DOE
believes that glass component manufacturers currently do not
participate in any third party rating programs nor do they provide
products with performance labels. In addition, the performance data of
these products is not readily available able in product literature.
In order for the thermal conductivity performance of glass products
be incorporated into the walk-in test procedure, DOE proposes these two
options: (1) If manufacturers of glass doors used in walk-ins
participate in the same NFRC rating program, the performance of the
door shall be simply read from its label and used for calculations in
this test procedure. If glass door manufacturers do not participate in
the same NFRC rating program, then (2) DOE would require manufacturers
to use the free software package Window 5.2 (available here: http://windows.lbl.gov/software/window/window.html), that calculates the U-
value, or thermal conductivity, of a glass door given precise
specifications such as the size of the door, the number of panes of
glass, the gas fill between the panes, etc. This tool was developed by
Lawrence Berkeley National Lab (LBNL) and is known in the glass
component industry to accurately predict glass door thermal performance
from the given door characteristics. It has been used for many years
and has been heavily verified by empirical test data. In order to
ensure that inputs used to calculate overall door performance are not
being manipulated by manufacturers, DOE intends to require the walk-in
manufacturer to report the exact inputs and settings used in Window 5.2
to represent the door materials and glazing system. This will ensure
transparency and accuracy by enabling other manufacturers and DOE to
verify the integrity of the data and calculated performance.
DOE seeks comment on the availability of performance data on glass
products used in walk-in applications, glass component manufacturers'
participation in third party certification programs such as NFRC, and
the proposed method for predicting the thermal performance of glass
components using LBNL's Window 5.2 software package.
ii. Conduction Through Floors
In general, walk-in coolers are installed on top of concrete
surfaces regardless of the walk-in type. For a walk-in cooler that does
not have a floor supplied by the manufacturer, the average insulating
performance of concrete will be assumed for the floor surface of the
walk-in. Therefore, DOE proposes using an R-value of 0.6 ft\2\- F-h/Btu
for calculating the energy lost assuming the walk-in cooler are sited
on 6-inch concrete floors of 150 lb/ft\3\ density (ASHRAE Fundamentals
Handbook). DOE requests feedback on the use of this R-value for coolers
that are not shipped with an insulated floor.
Generally, walk-in manufacturers that sell large freezers do not
install freezer floors. This task is normally subcontracted by the end-
user before the walk-in is installed to ensure EPCA compliance.
Therefore, DOE proposes using the minimum R-value specified in EPCA for
walk-in freezer floors, R-28 ft\2\-F-h/Btu, for energy performance
calculations if the manufacture does not supply a floor to ensure EPCA
compliance. (42 U.S.C. 6313(f)(1)(D)) DOE requests comments on the use
of this proposed R-value for freezer floors.
c. Heat Gain Due to Infiltration
The amount of embodied energy in an air sample is primarily a
function of its temperature and density or what is typically referred
to as the enthalpy in a thermodynamic system such as a walk-in. The
required amount of energy needed to remove heat from the air is
calculated as the difference between the enthalpy of air entering the
refrigerated space and enthalpy of the air inside the refrigerated
space. This calculation is commonly used when designing walk-ins and
typically uses dry-bulb and wet-bulb temperatures. The difference, per
unit mass or volume of air, is calculated using the functional
relationship between temperature and enthalpy. Using the measured
infiltration rate from the required steady-state test described above
or calculated analytical value for air infiltration for door-opening
events and the calculated internal and external enthalpy, a rate of
energy lost per hour (Btu/h) due to air exchange can be calculated.
d. Envelope Component Electrical Loads
Because the energy use of the walk-in refrigeration equipment is
being analyzed separately from the envelope energy use, DOE is
considering calculating the electricity consumption of lights, sensors,
and other miscellaneous electrical devices using name-plate rating and
assumptions about their daily operation, all of which would be
incorporated into the evaluation of envelope energy use. In addition,
because the test procedure for the refrigeration system will not
include heating loads caused by lighting, heater wires, and other
miscellaneous components, the thermal load from these components will
be factored into the envelope calculations. DOE proposes as part of the
test procedure calculations that 100 percent of the electrical energy
consumed to operate the devices that are internal located in the walk-
in, will be converted to thermal energy. This assumption is accurate
since at steady-state, all the input electrical energy is converted
completely into heat adhering to the physical laws of conservation of
energy. While some electrical energy, which has been converted into
light, may escape the controlled space via translucent glass display
doors, this escaping energy is negligible. The associated thermal
energy will then be used to calculate an additional compressor load
that would be required to remove the additional heat generated by these
components.
DOE recommends using the following equation to calculate the power
usage for each electricity-consuming device type, Pcomp,
(kWh):
[[Page 199]]
[GRAPHIC] [TIFF OMITTED] TP04JA10.027
Where:
Prated,t = rated power of each component,
PTOt = percent time off, and
nt = the number of devices at the rated power.
DOE proposes that the rated power must be read from each
electricity-consuming device product data sheet or name plate, and the
nt is the number of identical devices for which the
Pcomp calculation is being made.
DOE further proposes the use of the following equation to calculate
additional compressor load due to heat generated by electrical
components, Cload, (kWh):
[GRAPHIC] [TIFF OMITTED] TP04JA10.028
Where:
EER = EER of walk-in (cooler = 12.4 or freezer = 6.3), Btu/W-h
Ptot,int = The total electrical load due to components
sited inside the walk-in envelope
The percent time off (PTO) value accounts for the reduction in
energy use in walk-ins with component control systems installed and to
specify the possible number of hours for various component types. While
this value may not reflect behaviorally related energy consumption,
such as how long an end-user typically leaves the lights on, it will
provide a means for comparison of walk-in performance. To address the
wide variety of devices that could be employed in a walk-in unit, DOE
proposes the following PTO values:
(1) For lights, DOE proposes a PTO value of 25 percent for systems
without timers or other auto shut-off systems and 50 percent for
systems with timers or other auto shut-off systems installed.
(2) For anti-sweat heaters, DOE proposes a PTO value of 0 percent
for all systems without direct or indirect relative humidity sensing
controls. DOE further proposes that a PTO value of 75 percent be used
for walk-in coolers, and 50 percent for walk-in freezers with these
controls. (Focus on Energy, BP-3429-0304, ``Anti-Sweat Heater
Controls,'' 2004, p. 1)
(3) For electrically powered devices (such as air curtains) that
mitigate air infiltration but are not actively controlled based on door
open or closed positions, DOE proposes a PTO value of 25 percent.
(4) For electrically powered devices that mitigate air infiltration
that are also actively controlled based on door open or closed position
for display doors, DOE proposes a PTO value of 99.33 percent.
(5) For electrically powered devices that mitigate air infiltration
that are also actively controlled based on door open or closed position
for all other doors, DOE proposes a PTO value of 99.17 percent.
(6) For all other devices, DOE proposes a PTO value of 0 percent,
unless the walk-in manufacturer can demonstrate that the device is
controllable by a preset control system. If this can be demonstrated,
then DOE proposes a value of 25 percent for the device in question.
DOE seeks comments on these assumptions.
e. Normalization
A single metric would make comparing the energy use of walk-ins
much more straightforward. DOE proposes using a calculation for energy
consumption per unit time and a normalization factor to account for
differences in glass and non-glass external surface area depending on
the product class. During the framework public meeting and in written
comments, some interested parties recommended that DOE use volume as
the normalization factor for performance standards. (Manitowoc, Public
Meeting Transcript, No. 15 at p. 56; EEI, Public Meeting Transcript,
No. 15 at p. 116; NEEA, No. 18 at p. 3) Crown Tonka, in a written
comment, recommended that the test metric be kWh per cubic foot (i.e.,
energy consumption normalized by volume). (Crown Tonka, No. 23 at p. 1)
The Joint Comment recommended that DOE use surface area as the
normalization factor. (Joint Comment, No. 21 at p. 2) A comment
submitted jointly by representatives of SCE, SMUD, and SDG&E (hereafter
referred to as the Utilities Joint Comment) also stated that DOE should
use surface area as a normalization factor. (Utilities Joint Comment,
No. 32 at p. 7)
Many established metrics use a per-day time scale normalized by
product volume. However, surface area is the key geometric
characteristic related to both conduction and infiltration because
volumetric normalization cannot directly account for the higher
conduction and infiltration losses associated with glass doors and
windows. Conduction and infiltration losses through glass become
particularly important considerations as the ratio of glass door area
to total wall area increases, as is the case in walk-ins designed for
customer access. Using surface area as the normalization factor would
account for these losses through any glass door or window used in a
walk-in. Therefore, DOE proposes the use of surface area as a
normalization factor for performance calculations of walk-ins. DOE
requests comments on this proposed normalization method.
f. Daily Energy Consumption Coefficients
As discussed in section III.A.1, DOE proposes allowing
manufacturers to group similar units together into a single ``basic
model.'' This approach would reduce the testing burden as only one unit
of each basic model would be subject to testing. However, in the case
of envelopes, the equipment is so highly customized that each unit a
manufacturer builds may be unique. For example, units may have
identical materials, components, or construction methods, but may be
built to varied dimensions, which could result in different energy
consumption values being obtained using the proposed test methods.
In order to compare units that are similar enough to be included in
the same basic model, but that are not identical, the test procedure
allows for calculating daily energy consumption coefficients (or
DECCs), using test results from a particular unit within a basic model,
and then applying these DECCs to other units within a basic model to
calculate the energy consumption of the other units. DECCs are
essentially scaling factors that allow a manufacturer to change certain
parameters of an envelope and calculate the corresponding change in
energy consumption. In the case of today's proposed procedure, these
parameters would be wall surface area, non-glass door surface area,
glass display door surface area, glass wall and inset window surface
area, infiltration due to opening of non-display type doors and
infiltration reduction due to reduction devices in place on non-display
doors, infiltration due to opening of display type doors and
infiltration reduction due to reduction devices in place on display
doors, and electrical energy consumption due to devices including, but
not limited to, lights, anti-sweat heaters, and motors to drive air
mixing fans. The expression for daily energy consumption is formulated
on the assumptions that: (1) Energy consumption due to conduction
losses
[[Page 200]]
scales linearly with surface area; (2) energy consumption due to
infiltration scales linearly with the number of doors of each type and
total wall surface area; (3) energy consumption of anti-sweat door
heaters scales linearly with total door surface area; and (4) energy
consumption of other electrical components including lighting and
stirring fans scales linearly with the interior volume of the envelope.
Once the DECCs are calculated from a tested walk-in envelope, they
are combined to provide a linear expression of the daily energy
consumption of any walk-in envelope of the same basic model as the
tested envelope (that is, having the same construction methods,
materials, components, and other energy consumption characteristics as
the tested envelope), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.029
Where:
DECCnon-glass = DECC for non-glass,
Anon-glass,tot = total non-glass surface area,
DECCglass,door = DECC for glass doors,
Aglass,glass, tot = total glass surface area, and
DECCglass,wall = DECC for glass walls and inset windows,
Aglass,wall, tot = total glass wall and inset window
surface area, and
DECCinfilt,disp--dr--opn = DECC for opening of display
type doors,
Adisp--doors = total area of display doors,
DECC disp--dr--device = DECC for infiltration reduction
device in place for display doors,
ndisp--doors = total number of display doors,
DECCinfilt,non-display--,dr--opn = DECC for non-display
type doors,
Anon-display--doors = total area of non-display type
doors,
DECCnon-display--dr--device = DECC for infiltration
reduction device in place for non-display doors,
nnon-display--doors = total number of non-display doors,
DECClight = DECC for lights,
Vref--space = total enclosed refrigerated volume(ft\3\),
DECCASH = DECC for anti-sweat heaters,
DECCstir--fan = DECC for motors used to drive air mixing
fans, and
DECCother = DECC for other electricity consuming devices.
Only applicable DECCs shall be used. For example, if a certain
basic model did not have glass display doors, DECCs and variables
pertaining to glass display doors would not be calculated, nor would
they be included in the equation of energy consumption.
DOE believes that this approach would reduce the testing burden on
manufacturers because it would not require manufacturers to test every
unit produced with slight variations due to customer specification.
However, by specifying a calculation methodology that manufacturers
must use, the approach reduces the potential for inconsistency among
manufacturers' rating methods, a concern that interested parties raised
about DOE's previous idea to allow each manufacturer to develop its own
AEDM for rating similar, but not identical, equipment. (See section
III.A.3 for discussion of comments about this issue.) DOE requests
comment on the proposed approach of specifying a formula based on
DECCs, and on the assumptions that DOE made in generating this formula.
DOE also asks if there are other parameters it should consider when
calculating DECCs.
C. Refrigeration System
As previously discussed, a differentiation was made for the
purposes of this test procedure between the envelope or structure of
the walk-in cooler or freezer and the mechanical refrigeration system
performing the physical work necessary to cool the interior space. The
refrigeration system in this context is further subdivided into three
categories, consisting of single-package systems containing both the
condensing and evaporator units, split systems with the condensing unit
and unit cooler physically separated and connected via refrigerant
piping, and rack systems utilizing unit coolers, which receive
refrigerant from a shared loop. The proposed test procedure contains
separate specific provisions for the standardized testing of each
refrigeration system type. Later sections provide a general overview of
the test procedure for refrigeration systems of walk-in coolers and
freezers and address some of the technical issues pertinent to the
proposed test procedure. The following section also addresses issues
raised by interested parties.
1. Overview of the Test Procedure
In accordance with EPCA, DOE proposes to adopt a test procedure for
measuring the energy consumption of the refrigeration system of walk-in
coolers and freezers. (42 U.S.C. 6314(a)(9)(B)(i)) DOE is considering
adding the following definition for ``refrigeration system'' to 10 CFR
part 431, subpart R: ``Refrigeration system means the mechanism used to
create the refrigerated environment in the interior of a walk-in cooler
or freezer, consisting of an integrated single-package refrigeration
unit, or a split system with separate unit cooler and condensing unit
sections, or a unit cooler that is connected to a central rack system;
and including all controls and other components integral to the
operation of this mechanism.'' DOE requests comments on this proposed
definition.
In the framework document, DOE examined in detail six test
procedures developed either by AHRI or ASHRAE that relate to the
measurement of energy consumption of refrigeration equipment to
determine whether they could apply to walk-in refrigeration systems.
Although the six procedures collectively covered all of the components
of the refrigeration systems of walk-in coolers and freezers (i.e., the
compressor, the condenser, the condensing unit or the unit cooler),
each of these existing procedures covered only one or some of the
components, and none applied to the testing of the complete
refrigeration system. The rating conditions specified in those
procedures also are generally not representative of typical conditions
found in walk-in equipment.
During the framework public meeting and in a written comment, AHRI
informed DOE that it has begun developing a standard for the
performance rating of walk-in cooler and freezer refrigeration systems.
(AHRI, Public Meeting Transcript, No. 15 at p. 50; AHRI, No. 33 at p.
3) This standard, AHRI Standard 1250P, ``2009 Standard for Performance
Rating of Walk in Coolers and Freezers,'' was published in September of
2009. DOE has reviewed the final, published version of AHRI Standard
1250P and proposes to
[[Page 201]]
incorporate it by reference into this test procedure.
The test procedure DOE proposes to adopt covers testing of
refrigeration systems for walk-in coolers and freezers, including unit
coolers and condensing units that are sold together as a matched system
(i.e., paired with each other in a way that optimizes the performance
of the system), as well as unit coolers and condensing units sold
separately, including unit coolers connected to compressor racks. The
procedure describes the method for measuring the refrigeration capacity
and the electrical energy consumption for the condensing unit and the
unit cooler, as well as the off-cycle fan energy and the defrost
subsystem under specified test conditions. The standard test conditions
specify the dry-bulb and wet-bulb temperatures, the relative humidity
for both the unit cooler and the condensing unit, and require that the
system must operate under steady-state conditions. The test procedure
groups walk-in cooler and freezer systems into four categories by
distinguishing between indoor and outdoor locations for the condensing
unit, and between coolers and freezers. The test procedure also
specifies calculations for the nominal box loads for each of the four
categories under typical low- and high-load conditions, expressed as a
function of the ambient air temperature. (The ``nominal box load''
refers to the refrigeration load imposed on the system by the walk-in
envelope. Similar to the way in which the envelope was assumed to be
paired with a refrigeration system of a given EER to provide a means of
comparison between different envelopes, DOE assumes that the
refrigeration system is paired with an envelope of given heat transfer
characteristics. This assumption is made for comparison purposes. See
section III.B.3.a for further discussion of this concept.) For systems
in which the condensing unit is located outdoors, the test procedure
uses bin temperature data and bin hour data to represent the impact of
the seasonal variation in outside ambient air temperature on energy
use. The test procedure computes an annual walk-in efficiency factor,
or AWEF, for the refrigeration system under a specified thermal load
profile over a 24-hour operation period.
2. Test Conditions
DOE received several comments on test conditions. The Utilities
Joint Comment stated that most of the potential energy savings can be
achieved using floating head pressure and variable-speed evaporator
fans, both of which are time-varying and weather dependent, and a
steady-state test may not capture these savings adequately. (Utilities
Joint Comment, No. 32 at p. 4) Manitowoc stated that energy usage can
depend on the heat load in the box consisting of defrost energy and fan
energy, both of which depend on the refrigeration system control
strategy. (Manitowoc, Public Meeting Transcript, No. 15 at p. 76) NEEA
stated that the test conditions should reflect variations in the
location of the condensing unit, thermal load conditions, and outdoor
air temperature. (NEEA, No. 18 at p. 3)
The test procedure DOE proposes specific conditions for both the
interior and exterior of the walk-in to determine the net refrigeration
capacity. The interior conditions of the unit cooler are specified as
nominal temperature and humidity conditions: 2 [deg]C dry-bulb and less
than 50 percent relative humidity (RH) for coolers, and -23 [deg]C dry-
bulb and less than 50 percent RH for freezers. The proposed test
procedure would measure both net refrigeration capacity and off-cycle
fan power at those conditions for the unit cooler. For the condenser,
the test procedure would specify three different ambient conditions for
dry-bulb and wet-bulb temperatures: Hot (35 [deg]C/24 [deg]C), moderate
(15 [deg]C/12 [deg]C) and cold (2 [deg]C/1 [deg]C). The purpose of
specifying three sets of ambient conditions is to capture the variation
in capacity under different ambient temperatures.
For two-capacity condensing units, the test procedure would measure
the net refrigeration capacity under the same set of ambient conditions
for the condenser at both the minimum and maximum capacity levels.
Variable-speed condensing units would also have their refrigeration
capacities measured at an additional intermediate capacity level.
Because the test procedure provides for measurement of the compressor
power and the fan power at two compressor capacity levels for two-speed
systems and at three capacity levels for variable-speed systems at
multiple outside ambient air temperature levels, DOE believes that the
proposed test conditions reasonably reflect the energy savings that may
be achieved through the control strategies referred to by interested
parties. Also, as mentioned above, the proposed procedure includes a
measurement of off-cycle fan power, which would account for energy
savings due to variable-speed evaporator fans.
The Joint Comment stated that test procedures should account for
partial-load conditions as well as maximum loading, and that test
methods limited to maximum load conditions at steady-state operation
are insufficient. (Joint Comment, No. 21 at p. 2) ACEEE also stated
that the efficiency metric of the refrigeration system should reflect
part-load conditions. (ACEEE, Public Meeting Transcript, No. 15 at p.
99) In the proposed test procedure, DOE has provided for testing of
two-capacity and variable-capacity condensing units at the minimum
capacity level, which would correspond to the appropriate low-load
level condition for an appropriately sized unit. However, for a single-
capacity unit, low-load conditions would lead to a higher frequency of
equipment cycling because the equipment would be sized for a much
larger load; that is, a load consistent with worst-case conditions. For
single-speed equipment, the proposed test procedures do not capture the
impact of this cyclic degradation. DOE believes that capturing the
cyclic degradation is not necessary because, averaged over
representative locations in the entire country, walk-in coolers may
operate for many hours at the full-load condition. For instance, the
daily pull-down-load in typical walk-in cooler and freezer
installations is met over a period of 5 to 8 hours of full-load
operation for a properly sized unit. Consequently, the impact of the
cyclic degradation is not very significant for the walk-in cooler or
freezer refrigeration system.
Craig noted that the refrigeration systems of walk-in equipment are
often oversized to account for the worst weather conditions and
additional pull-down load (Craig, Public Meeting Transcript, No. 15 at
p. 97). Nor-Lake stated that its methodology for determining the
refrigeration load for the walk-in takes into account the worst
conditions over the typical annual cycle, as well as product load,
pull-down load, the number of door openings, and duration (Nor-Lake,
No. 30 at p. 2). The proposed test procedure computes the energy use on
the basis of a nominal box load, which takes into account product load,
infiltration load due to door openings, and transmission load through
the box walls and roof. DOE believes that the values for the nominal
box loads adequately reflect typical oversizing values. The proposed
annual energy efficiency metric is based on weather conditions that are
considered representative of the population-weighted average weather
conditions of the country as a whole.
3. Test Methods
The net refrigeration capacity of the system is determined by one
of the following test methods: (1) DX Dual Instrumentation measures the
enthalpy change and the mass flow rate of the
[[Page 202]]
refrigerant across the unit cooler using two independent measuring
systems; or (2) DX Calibrated Box measures the enthalpy change and the
mass flow rate of the refrigerant across the unit cooler and the heat
input to the calibrated box. In the first method, the test unit cooler
and the matched condensing unit are kept inside separate environmental
chambers. In the second method, the condensing unit is placed inside
the environmental chamber, while the unit cooler is kept inside a
calibrated box, which is inside a temperature-controlled enclosure.
DOE believes the test methods are appropriate for walk-ins because
they were adapted from AHRI Standard 420-2008, ``Performance rating of
forced-circulation free-delivery unit coolers for refrigeration,'' and
ASHRAE Standard 23, ``Methods of Testing for Rating Positive
Displacement Refrigerant Compressors and Condensing Units,'' and have
been widely used in the refrigeration industry for many years.
Furthermore, these test methods were developed and approved by the
industry and published by the industry trade association as a
sufficiently adequate means of assessing the net refrigeration capacity
of equipment that share many functional similarities with walk-ins,
such as components, materials, and substances (e.g., the refrigerant)
that provide the mechanical means of refrigeration. The test methods
DOE is proposing today also account for ways in which walk-in
refrigeration systems differ from commercial refrigeration equipment;
as in their operating conditions, configurations, or patterns of use.
For example, condensing units of walk-in refrigeration systems may be
located outdoors and experience a wider range of operating temperatures
than commercial refrigeration, which is generally located indoors; the
walk-in refrigeration test procedure specifies three different ambient
temperatures at which to test, in order to approximate actual
conditions under which the system might operate. Furthermore, DOE's
proposed methods improve upon previously developed refrigeration test
methods by accounting for the energy-saving effects of advanced
technologies such as variable-speed fans and defrost control
strategies.
4. Measurements and Calculations
The test procedure DOE proposes to adopt, AHRI Standard 1250P-2009,
measures certain parameters, including the net refrigeration capacity
and the off-cycle fan power for both coolers and freezers. The defrost
power and thermal energy transferred to the defrost drain water are
measured for a defrost cycle for freezers only. Separate calculation
procedures for single-capacity, two-capacity, and variable-capacity
equipment are included in the test procedure. The test procedure
determines the annual walk-in energy factor, or AWEF, as the ratio of
the annual net heat removed from the box, which includes the internal
heat gains from non-refrigeration components but excludes the heat
gains from the refrigeration components in the box, to the annual
electrical energy consumption. The final metric determined by this
procedure is a measure of efficiency. However, DOE is required by EPCA
to establish ``a test procedure to measure * * * energy use.'' (42
U.S.C. 6314(a)(9)(B)(i)) In light of this requirement, DOE proposes
that manufacturers determine both the AWEF and the annual energy
consumption of their equipment using the test procedure, which will
enable the test procedure to be consistent with the requirements of
EPCA to develop test procedures that measure the energy consumption of
walk-in equipment.
In the AHRI Standard 1250P-2009 calculations, the annual net heat
removed from the nominal box is represented as a function of ambient
temperature surrounding the condenser and the measured net
refrigeration capacity at the highest test temperature. For
refrigeration systems consisting of a unit cooler and a dedicated
condensing unit, the annual net heat removed from the box can be
calculated from the system capacity and, for systems located outdoors,
the net heat removed from the nominal box at a given bin temperature
weighted by the number of hours corresponding to the bin temperature.
The temperature bin data listed in Table D1 of AHRI Standard 1250P-2009
has been constructed from the ambient temperatures over a typical
meteorological year for a specified location, corresponding closely to
the use cycle parameters prescribed in other DOE standards. For
refrigeration systems consisting of a unit cooler connected to a remote
rack, the net heat removed is a function of the unit cooler capacity at
the test points specified in AHRI Standard 1250P-2009.
DOE is considering deriving the expressions for the annual net heat
removed from the box, that is, the numerator of the equations for
energy consumption, by simplifying the equations in AHRI Standard
1250P-2009. As an example, the calculation methodology for indoor
coolers using AHRI Standard 1250P-2009 would be as follows:
The AWEF, for walk-in cooler systems with dedicated condensing
units located indoors, is determined by
[GRAPHIC] [TIFF OMITTED] TP04JA10.030
Where [Sigma][BL(tj)] is the annual net heat removed from
the box over the course of the year, and [Sigma][E(tj)]
is the annual energy consumption of the system. Thus,
[GRAPHIC] [TIFF OMITTED] TP04JA10.031
AWEF is calculated directly using the test procedure, while
BL(tj) is calculated by:
[GRAPHIC] [TIFF OMITTED] TP04JA10.032
[[Page 203]]
For indoor units, tj is assumed to be constant; thus,
nj = 8760, the total number of hours in a year. BLH and
BLL are given by, respectively,
[GRAPHIC] [TIFF OMITTED] TP04JA10.033
and
[GRAPHIC] [TIFF OMITTED] TP04JA10.034
Where qss(90 [deg]F) is the system steady state
refrigeration capacity at 90 [deg]F. When terms are combined and the
expression simplified, the equation for annual energy consumption
becomes
[GRAPHIC] [TIFF OMITTED] TP04JA10.035
DOE requests comment on using these equations to derive annual energy
consumption.
D. Compliance, Certification, and Enforcement
Finally, DOE addresses below compliance, certification, and
enforcement issues involving walk-ins. At this time, DOE is not
proposing any specific requirements for this equipment. As discussed
below, DOE will consider addressing these issues in a separate
rulemaking. Any data on which a manufacturer relies for the purposes of
certifying compliance with any applicable standards that DOE
promulgates for this equipment would be derived from the test procedure
that DOE adopts. The adopted procedure would also be used by DOE during
enforcement-related testing.
1. Provisions for Energy Conservation Standards Developed by the
Department of Energy
The purpose of establishing compliance, certification, and
enforcement regulations is to provide reasonable assurance that
manufacturers appropriately test and accurately represent the
performance characteristics of commercial equipment. DOE recently
incorporated the standards prescribed by EISA 2007, including those for
walk-ins, into 10 CFR parts 430 and 431. 74 FR 12074 (March 23, 2009).
However, DOE has not yet proposed or issued amended energy conservation
standards for walk-ins. DOE will consider issuing compliance,
certification, and enforcement provisions for walk-ins in a future
rulemaking. Therefore, today's notice proposes no certification,
compliance, or enforcement provisions for energy conservation standards
for walk-ins.
2. Provisions for Existing Design Standards Prescribed by Congress
DOE is responsible for enforcing Federal energy standards, whether
those standards were developed through a DOE rulemaking pursuant to
EPCA or prescribed by Congress. In EISA 2007, Congress prescribed
design standards specifically for walk-ins that took effect on January
1, 2009. Typically, DOE establishes specific enforcement regulations
for each product covered by existing standards, which may require
manufacturers to file documents such as a compliance statement and a
certification report. In a compliance statement, the manufacturer
certifies its products meet the requirements. In a certification
report, the manufacturer provides product-specific information that
would enable DOE to determine whether the product meets the standard.
DOE has already established compliance and certification requirements
for other products.
Until DOE finalizes regulations that require compliance statements
and certification reports for walk-ins, manufacturers will not be
required to report data to DOE, but they must still meet all prescribed
design standards that went into effect on January 1, 2009. If there is
a question on compliance with design standards, the manufacturer must
make a reasonable case that the equipment meets those standards.
To address concerns about the EISA 2007 design requirements for
walk-ins, DOE maintains a Frequently Asked Questions page on the DOE
Web site at http://www1.eere.energy.gov/buildings/appliance_standards/commercial/wicf_faqs.html.
IV. Regulatory Review
A. Review Under Executive Order 12866
The Office of Management and Budget has determined that test
procedure rulemakings do not constitute ``significant regulatory
actions'' under Executive Order 12866, ``Regulatory Planning and
Review,'' 58 FR 51735 (October 4, 1993). Accordingly, this action was
not subject to review under that Executive Order by the Office of
Information and Regulatory Affairs (OIRA) of the Office of Management
and Budget (OMB).
B. Review Under the National Environmental Policy Act
In this proposed rule, DOE proposes to adopt test procedures and
related provisions for walk-in equipment. The test procedures would be
used initially for the purpose of considering the adoption of energy
conservation standards for walk-ins, and DOE would require their use
only if standards were subsequently adopted. The proposed test
procedures will not affect the quality or distribution of energy and,
therefore, will not result in environmental impacts. Therefore, DOE
determined that this rule falls into a class of actions that are
categorically excluded from review under the National Environmental
Policy Act of 1969 (42 U.S.C. 4321 et seq.) and the Department's
implementing regulations at 10 CFR part 1021. More specifically,
today's proposed rule is covered by the Categorical Exclusion in
paragraph A6 to subpart D, 10 CFR part 1021. Accordingly, neither an
environmental assessment nor an environmental impact statement is
required.
C. Review Under the Regulatory Flexibility Act
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
preparation of an initial regulatory flexibility analysis (IRFA) for
any rule that by law must be proposed for public comment, unless the
agency certifies that the rule, if promulgated, will not have a
significant economic impact on a substantial number of small entities.
As required by Executive Order 13272, ``Proper Consideration of Small
Entities in Agency Rulemaking'' (67 FR 53461 (August 16, 2002)), DOE
published procedures and policies on February 19, 2003, to ensure that
the potential impacts of its rules on small entities are properly
considered during the rulemaking process. 68 FR 7990. DOE has made its
procedures and policies available on the Office of General Counsel's
Web site, http://www.gc.doe.gov.
DOE reviewed the test procedures considered in today's notice of
proposed rulemaking under the provisions of the Regulatory Flexibility
Act and the procedures and policies published on February 19, 2003. As
discussed in more detail below, DOE found that because the proposed
test procedures have not previously been required of
[[Page 204]]
manufacturers, all manufacturers, including small manufacturers, could
potentially experience a financial burden associated with new testing
requirements. While examining this issue, DOE determined that it could
not certify that the proposed rule, if promulgated, would not have a
significant effect on a substantial number of small entities.
Therefore, DOE has prepared an IRFA for this rulemaking. The IRFA
describes potential impacts on small businesses associated with walk-in
cooler and freezer testing requirements.
DOE has transmitted a copy of this IRFA to the Chief Counsel for
Advocacy of the Small Business Administration for review.
1. Reasons for the Proposed Rule
Title III of the EPCA sets forth a variety of provisions designed
to improve energy efficiency. Part B of Title III (42 U.S.C. 6291-6309)
provides for the Energy Conservation Program for Consumer Products
Other Than Automobiles. NECPA (Pub. L. 95-619) amended EPCA to add Part
C of title III, which established an energy conservation program for
certain industrial equipment. (42 U.S.C. 6311-6317) (These parts were
subsequently redesignated as Parts A and A-1, respectively, for
editorial reasons.) Section 312 of EISA 2007 further amended EPCA by
adding certain equipment to this energy conservation program, including
walk-in coolers and walk-in freezers (collectively ``walk-in
equipment'' or ``walk-ins''), the subject of this rulemaking. (42 U.S.C
6311(1), (2), 6313(f) and 6314(a)(9)) The proposed rule would establish
a test procedure for walk-in coolers and walk-in freezers.
2. Objectives of, and Legal Basis for, the Proposed Rule
Under EPCA, the overall energy conservation program consists
essentially of the following parts: Testing, labeling, and Federal
energy conservation standards. The testing requirements for covered
equipment consist of test procedures, prescribed under EPCA. The test
procedures, if adopted, would be used in one of three ways: (1) Any
data from the use of the test procedure, would be used by DOE as a
basis for developing standards for walk-in equipment; (2) the procedure
would be used by DOE when determining equipment compliance with those
standards; and (3) manufacturers of covered equipment would be required
to use the procedure as the basis for establishing that their equipment
complies with the relevant energy conservation standards promulgated
pursuant to EPCA and when making representations regarding equipment
efficiency.
Section 343 of EPCA (42 U.S.C. 6314) sets forth generally
applicable criteria and procedures for DOE's adoption and amendment of
test procedures for covered equipment. That provision requires that the
test procedures promulgated by DOE be reasonably designed to produce
test results which reflect energy efficiency, energy use, and estimated
operating costs of the covered equipment during a representative
average use cycle. It also requires that the test procedure not be
unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)) Further
information concerning the background of this rulemaking is provided in
Section I of this preamble.
3. Description and Estimated Number of Small Entities Regulated
Small businesses, as defined by the Small Business Administration
(SBA) for the walk-in cooler and freezer manufacturing industry, are
manufacturing enterprises with 750 employees or fewer. DOE used the
small business size standards published on January 31, 1996, as
amended, by the SBA to determine whether any small entities would be
required to comply with the rule. 61 FR 3286; see also 65 FR 30836,
30850 (May 15, 2000), as amended at 65 FR 53533, 53545 (September 5,
2000). The size standards are codified at 13 CFR Part 121. The
standards are listed by North American Industry Classification System
(NAICS) code and industry description and are available at http://www.sba.gov/idc/groups/public/documents/sba_homepage/serv_sstd_tablepdf.pdf. Walk-in cooler and freezer equipment manufacturing is
classified under NAICS 333415, Air-Conditioning and Warm Air Heating
Equipment and Commercial and Industrial Refrigeration Equipment
Manufacturing.
DOE reviewed AHRI's listing of commercial refrigeration equipment
manufacturer members and surveyed the industry to develop a list of
domestic manufacturers. DOE also asked stakeholders and AHRI
representatives within the industry if they were aware of any other
small business manufacturers. DOE then examined publicly available
data, including regulatory databases such as state databases and the
National Sanitation Foundation (NSF) Section 7 database. DOE identified
at least 37 small manufacturers of walk-in cooler and freezer
envelopes, and at least 5 small manufacturers of walk-in cooler and
freezer refrigeration systems. However, some manufacturers that DOE
interviewed indicated that there could be many more small business
manufacturers than were publicly listed. Such unlisted manufacturers
could be very small (< 50 employees) and serve only a local market.
They also may not submit any information to state or national
regulators such as NSF. Therefore, DOE believes there may be more
affected small entities than it estimated and seeks comment on the
number of small entities that may be impacted by the test procedure.
4. Description and Estimate of Compliance Requirements
Potential impacts of the proposed test procedures on manufacturers,
including small businesses, come from impacts associated with the cost
of testing. In this test procedure NOPR, DOE proposes measures to
reduce the financial burden of testing on all manufacturers, including
small business manufacturers. First, where the procedure gives
manufacturers options in terms of materials, equipment, or methodology
to be used in performing the test, DOE proposes to allow manufacturers
to use the lowest-cost option, where possible. For instance, ASTM E741-
06 allows manufacturers to use any of about 12 tracer gases. DOE
specifies a tracer gas to ensure that all manufacturers report at the
same accuracy, but specifies the use of carbon dioxide, which would be
the lowest cost option. Second, DOE proposes to reduce the total number
of tests manufacturers would have to perform by allowing them to group
similar equipment into a single family, or basic model, and only
requiring them to test one unit of each basic model. (See section
III.A.1 for a more detailed discussion of the basic model proposal.)
The proposed test procedure for envelopes would require
manufacturers to perform testing in accordance with two industry test
standards: ASTM C1303-08, ``Standard Test Method of Predicting Long-
Term Thermal Resistance of Closed-Cell Foam Insulation,'' and ASTM
E741-06, ``Standard Test Method for Determining Air Change in a Single
Zone by Means of a Tracer Gas Dilution.'' DOE spoke with industry
experts to determine the approximate cost of each test and determined
that a test using ASTM C1303-08 costs between approximately $5,000 and
$10,000, and a test using ASTM E741-06 costs between $1,000 and $5,000.
A typical manufacturer would have approximately 8 basic models, so the
total cost of compliance would be approximately $84,000.
[[Page 205]]
The proposed test procedure for refrigeration systems would require
manufacturers to perform testing in accordance with a single industry
test standard: AHRI Standard 1250P-2009, ``2009 Standard for
Performance Rating of Walk-In Coolers and Freezers.'' Because this test
was recently developed by the industry and has not yet been widely used
to test refrigeration systems, DOE could not determine how much the
test currently costs. However, DOE researched the cost of other,
similar standards and subsequently estimated that a test using AHRI
Standard 1250P-2009 would likely cost approximately $5,000. A typical
refrigeration manufacturer could have approximately 50 basic models,
making the total cost of compliance approximately $250,000.
Because the cost of running each test is the same for all
manufacturers, and because DOE has proposed measures to reduce burden
on all manufacturers, DOE believes that all manufacturers would incur
comparable costs as a result of the proposed test procedures. However,
DOE does not expect that small manufacturers would have fewer basic
models than large manufacturers, because the equipment is highly
customized throughout the industry. A small manufacturer could have the
same total cost of testing as a large manufacturer, but this cost would
be a higher percentage of a small manufacturer's annual revenues. Thus,
DOE cannot certify that the differential impact associated with walk-in
cooler and freezer test procedures on small businesses would not be
significant.
5. Duplication, Overlap, and Conflict With Other Rules and Regulations
DOE is not aware of any rules or regulations that duplicate,
overlap, or conflict with the rule being considered today.
6. Significant Alternatives to the Rule
DOE considered a number of alternatives to the proposed test
procedure, including test procedures that incorporate industry test
standards other than the three proposed standards, ASTM C1303-08, ASTM
E741-06, and AHRI Standard 1250P-2009, described above. Instead of
requiring ASTM C1303-08 for testing the long-term thermal properties of
insulation, DOE could require only ASTM C518-04, ``Standard Test Method
for Steady-State Thermal Transmission Properties by Means of the Heat
Flow Meter Apparatus,'' which tests the thermal properties of
insulation at a certain point in time (i.e., the point of manufacture).
(Because ASTM C1303-08 incorporates ASTM C518-04, requiring ASTM C1303-
08 is consistent with the statutory requirement for basing measurement
of the thermal conductivity of the insulation on ASTM C518-04.) (42
U.S.C. 6314(a)(9)(A)) A test of ASTM C518-04 alone costs approximately
$500-$1,000. However, DOE is considering ASTM C1303 for other reasons;
namely, the concern that ASTM C518-04 alone does not capture the
performance characteristics of a walk-in over the period of its use,
because it does not account for significant changes in the thermal
properties of insulation over time. For more discussion on this issue,
see Section III.B.2.a.
DOE also considered ASTM E1827-96(2007), ``Standard Test Methods
for Determining Airtightness of Buildings Using an Orifice Blower
Door,'' instead of ASTM E741-06, for testing infiltration. ASTM E1827-
96(2007) costs about $300-$500 for a single test. However, DOE believes
that ASTM E1827-96(2007) is not appropriate for walk-ins because it is
conducted by placing test equipment in the door, and thus does not
account for in infiltration through the door, which is a major
component of infiltration in walk-ins. In addition, it is not intended
for testing envelope systems, such as a walk-in, that have a large
temperature difference between the internal and external air.
Therefore, to complete a blower-door test, the walk-in would not be
able to be tested at or close to operational temperatures, resulting in
a test that does not accurately reflect its performance. For more
discussion on this issue, see Section III.B.2.b.
In the framework document, DOE considered adapting an existing test
procedure for commercial refrigeration equipment, such as ARI Standard
1200-2006, ``Performance Rating of Commercial Refrigerated Display
Merchandisers and Storage Cabinets,'' as an alternative to AHRI
Standard 1250P-2009. The two tests are based on a similar methodology
for rating refrigeration equipment in general, but ARI Standard 1200-
2006 requires testing at only one set of ambient conditions, whereas
AHRI Standard 1250P-2009 requires testing at 3 sets of ambient
conditions for refrigeration systems with the condensing units located
outdoors. The additional time required to test the system at 3 sets of
conditions would incur additional cost and could make AHRI Standard
1250P-2009 more burdensome than ARI Standard 1200-2006. However, DOE
believes that AHRI Standard 1250P-2009 is more appropriate for testing
walk-ins than ARI Standard 1200-2006. A test procedure based on ARI
Standard 1200-2006 would require the entire walk-in to be tested as a
whole, but manufacturers might not have a large enough test facility to
make the measurements necessary for the ARI 1200-2006 test procedure in
a controlled environment. Also, the refrigeration system is often
manufactured separately from the insulated envelope. In this case,
whoever assembled the two components would bear the burden of
conducting ARI 1200-2006; this party might not be the manufacturer of
the refrigeration system. In contrast, AHRI 1250P-2009 tests only the
refrigeration system. It does not require a larger test chamber than
other, similar tests, and can be conducted by the manufacturer of the
refrigeration system. Furthermore, because AHRI 1250P-2009 requires the
system to be tested at 3 ambient temperatures, it captures energy
savings from features (for example, floating head pressure) that allow
the system to use less energy at lower ambient temperatures. For more
discussion on this issue, see Section III.A.2.
DOE requests comment on the impacts to small business manufacturers
for these and any other possible alternatives to the proposed rule. DOE
will consider any comments received regarding impacts to small business
manufacturers for all the alternatives identified.
D. Review Under the Paperwork Reduction Act
Today's proposed rule contains no record-keeping requirements.
Therefore, today's notice of proposed rulemaking would not impose any
new reporting requirements requiring clearance by OMB under the
Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The Department
recognizes, however, that if it adopts standards for walk-in coolers
and walk-in freezers, once the standards become operative,
manufacturers may become subject to record-keeping requirements
associated with compliance with the standards. Therefore, the
Department will comply with the record-keeping requirements of the
Paperwork Reduction Act if and when energy conservation standards are
adopted.
E. Review Under the Unfunded Mandates Reform Act of 1995
Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) (UMRA) requires each Federal agency to assess the effects of Federal
regulatory actions on State, local, and tribal governments and the
private sector. With respect to a proposed regulatory
[[Page 206]]
action that may result in the expenditure by State, local and tribal
governments, in the aggregate, or by the private sector of $100 million
or more (adjusted annually for inflation), section 202 of UMRA requires
a Federal agency to publish estimates of the resulting costs, benefits,
and other effects on the national economy. (2 U.S.C. 1532(a), (b)) UMRA
also requires a Federal agency to develop an effective process to
permit timely input by elected officers of State, local, and tribal
governments on a proposed ``significant intergovernmental mandate,''
and requires an agency plan for giving notice and opportunity for
timely input to potentially affected small governments before
establishing any requirements that might significantly or uniquely
affect small governments. On March 18, 1997, DOE published a statement
of policy on its process for intergovernmental consultation under UMRA
(62 FR 12820) (also available at http://www.gc.doe.gov). The proposed
rule published today does not provide for any Federal mandate likely to
result in an aggregate expenditure of $100 million or more. Therefore,
the UMRA does not require a cost benefit analysis of today's proposal.
F. Review Under the Treasury and General Government Appropriations Act,
1999
Section 654 of the Treasury and General Government Appropriations
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family
Policymaking Assessment for any rule that may affect family well-being.
This proposed rule would not have any impact on the autonomy or
integrity of the family as an institution. Accordingly, DOE has
concluded that it is not necessary to prepare a Family Policymaking
Assessment.
G. Review Under Executive Order 13132
Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4, 1999)
imposes certain requirements on agencies formulating and implementing
policies or regulations that preempt State law or that have federalism
implications. The Executive Order requires agencies to examine the
constitutional and statutory authority supporting any action that would
limit the policymaking discretion of the States and carefully assess
the necessity for such actions. The Executive Order also requires
agencies to have an accountable process to ensure meaningful and timely
input by State and local officials in the development of regulatory
policies that have federalism implications. On March 14, 2000, DOE
published a statement of policy describing the intergovernmental
consultation process it will follow in the development of such
regulations (65 FR 13735). DOE has examined today's proposed rule and
has determined that it does not preempt State law and does not have a
substantial direct effect on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government. EPCA
governs and prescribes Federal preemption of State regulations as to
energy conservation for the products that are the subject of today's
proposed rule. States can petition DOE for exemption from such
preemption to the extent, and based on criteria, set forth in EPCA. (42
U.S.C. 6297) No further action is required by Executive Order 13132.
H. Review Under Executive Order 12988
With respect to the review of existing regulations and the
promulgation of new regulations, section 3(a) of Executive Order 12988,
``Civil Justice Reform'' (61 FR 4729, February 7, 1996), imposes on
Federal agencies the general duty to adhere to the following
requirements: (1) Eliminate drafting errors and ambiguity, (2) write
regulations to minimize litigation, and (3) provide a clear legal
standard for affected conduct rather than a general standard and
promote simplification and burden reduction. Section 3(b) of Executive
Order 12988 specifically requires that Executive agencies make every
reasonable effort to ensure that the regulation (1) Clearly specifies
the preemptive effect, if any; (2) clearly specifies any effect on
existing Federal law or regulation; (3) provides a clear legal standard
for affected conduct while promoting simplification and burden
reduction; (4) specifies the retroactive effect, if any; (5) adequately
defines key terms; and (6) addresses other important issues affecting
clarity and general draftsmanship under any guidelines issued by the
Attorney General. Section 3(c) of Executive Order 12988 requires
Executive agencies to review regulations in light of applicable
standards in section 3(a) and section 3(b) to determine whether they
are met or it is unreasonable to meet one or more of them. DOE has
completed the required review and determined that, to the extent
permitted by law, this proposed rule meets the relevant standards of
Executive Order 12988.
I. Review Under the Treasury and General Government Appropriations Act,
2001
The Treasury and General Government Appropriations Act, 2001 (44
U.S.C. 3516, note) provides for agencies to review most disseminations
of information to the public under guidelines established by each
agency pursuant to general guidelines issued by OMB. OMB's guidelines
were published at 67 FR 8452 (February 22, 2002), and DOE's guidelines
were published at 67 FR 62446 (October 7, 2002). DOE has reviewed
today's notice under the OMB and DOE guidelines and has concluded that
it is consistent with applicable policies in those guidelines.
J. Review Under Executive Order 13211
Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355
(May 22, 2001) requires Federal agencies to prepare and submit to the
Office of Information and Regulatory Affairs (OIRA), Office of
Management and Budget, a Statement of Energy Effects for any proposed
significant energy action. A ``significant energy action'' is defined
as any action by an agency that promulgated or is expected to lead to
promulgation of a final rule, and that (1) Is a significant regulatory
action under Executive Order 12866, or any successor order; and (2) is
likely to have a significant adverse effect on the supply,
distribution, or use of energy; or (3) is designated by the
Administrator of OIRA as a significant energy action. For any proposed
significant energy action, the agency must give a detailed statement of
any adverse effects on energy supply, distribution, or use should the
proposal be implemented, and of reasonable alternatives to the action
and their expected benefits on energy supply, distribution, and use.
Today's regulatory action is not a significant regulatory action under
Executive Order 12866. Moreover, it would not have a significant
adverse effect on the supply, distribution, or use of energy. The
Administrator of OIRA also did not designate today's action as a
significant energy action. Therefore, it is not a significant energy
action, and DOE has not prepared a Statement of Energy Effects.
K. Review Under Executive Order 12630
DOE has determined pursuant to Executive Order 12630,
``Governmental Actions and Interference with Constitutionally Protected
Property Rights,'' 53 FR 8859 (March 18, 1988) that this proposed rule
would not result in any takings which might require compensation under
the Fifth Amendment to the United States Constitution.
[[Page 207]]
L. Review Under Section 32 of the Federal Energy Administration (FEA)
Act of 1974
Under section 301 of the Department of Energy Organization Act
(Pub. L. 95-91), DOE must comply with section 32 of the Federal Energy
Administration Act of 1974, as amended by the Federal Energy
Administration Authorization Act of 1977. (15 U.S.C. 788) Section 32
provides in part that, where a proposed rule contains or involves use
of commercial standards, the rulemaking must inform the public of the
use and background of such standards. The rule proposed in this notice
incorporates testing methods contained in the following commercial
standards: ASTM C1303-08, ``Standard Test Method of Predicting Long-
Term Thermal Resistance of Closed-Cell Foam Insulation;'' ASTM E741-06,
``Standard Test Method for Determining Air Change in a Single Zone by
Means of a Tracer Gas Dilution;'' and AHRI Standard 1250P, ``2009
Standard for Performance Rating of Walk in Coolers and Freezers.'' The
Department has evaluated these standards and is unable to conclude
whether they fully comply with the requirements of section 32(b) of the
Federal Energy Administration Act, i.e., whether they were developed in
a manner that fully provides for public participation, comment, and
review. As required by section 32(c) of the Federal Energy
Administration Act, of 1974, as amended, DOE will consult with the
Attorney General and the Chairman of the Federal Trade Commission
before prescribing a final rule concerning the impact on competition of
requiring manufacturers to use the methods contained in these standards
to test walk-in equipment.
V. Public Participation
A. Attendance at Public Meeting
The time, date, and location of the public meeting are provided in
the DATES and ADDRESSES sections at the beginning of this document.
Anyone who wants to attend the public meeting must notify Ms. Brenda
Edwards at (202) 586-2945. As explained in the ADDRESSES section,
foreign nationals visiting DOE headquarters are subject to advance
security screening procedures.
B. Procedure for Submitting Requests To Speak
Any person who has an interest in the topics addressed in this
notice, or who is a representative of a group or class of persons that
has an interest in these issues, may request an opportunity to make an
oral presentation at the public meeting. Such persons may hand-deliver
requests to speak to the address shown in the ADDRESSES section at the
beginning of this notice between 9 a.m. and 4 p.m., Monday through
Friday, except Federal holidays. Requests may also be sent by mail or
email to: Ms. Brenda Edwards, U.S. Department of Energy, Building
Technologies Program, Mailstop EE-2J, 1000 Independence Avenue, SW.,
Washington, DC 20585-0121, or [email protected]. Persons who
wish to speak should include in their request a computer diskette or CD
in WordPerfect, Microsoft Word, PDF, or text (ASCII) file format that
briefly describes the nature of their interest in this rulemaking and
the topics they wish to discuss. Such persons should also provide a
daytime telephone number where they can be reached.
DOE requests that those persons who are scheduled to speak submit a
copy of their statements at least one week prior to the public meeting.
DOE may permit any person who cannot supply an advance copy of this
statement to participate, if that person has made alternative
arrangements with the Building Technologies Program in advance. When
necessary, the request to give an oral presentation should ask for such
alternative arrangements.
C. Conduct of Public Meeting
DOE will designate a DOE official to preside at the public meeting
and may also employ a professional facilitator to aid discussion. The
public meeting will be conducted in an informal, conference style. The
meeting will not be a judicial or evidentiary public hearing, but DOE
will conduct it in accordance with section 336 of EPCA (42 U.S.C.
6306). Discussion of proprietary information, costs or prices, market
share, or other commercial matters regulated by U.S. anti-trust laws is
not permitted.
DOE reserves the right to schedule the order of presentations and
to establish the procedures governing the conduct of the public
meeting. A court reporter will record the proceedings and prepare a
transcript.
At the public meeting, DOE will present summaries of comments
received before the public meeting, allow time for presentations by
participants, and encourage all interested parties to share their views
on issues affecting this rulemaking. Each participant may present a
prepared general statement (within time limits determined by DOE)
before the discussion of specific topics. Other participants may
comment briefly on any general statements. At the end of the prepared
statements on each specific topic, participants may clarify their
statements briefly and comment on statements made by others.
Participants should be prepared to answer questions from DOE and other
participants. DOE representatives may also ask questions about other
matters relevant to this rulemaking. The official conducting the public
meeting will accept additional comments or questions from those
attending, as time permits. The presiding official will announce any
further procedural rules or modification of procedures needed for the
proper conduct of the public meeting.
DOE will make the entire record of this proposed rulemaking,
including the transcript from the public meeting, available for
inspection at the U.S. Department of Energy, 6th Floor, 950 L'Enfant
Plaza, SW., Washington, DC 20024, (202) 586-2945, between 9 a.m. and 4
p.m., Monday through Friday, except Federal holidays. Anyone may
purchase a copy of the transcript from the transcribing reporter.
D. Submission of Comments
DOE will accept comments, data, and information regarding the
proposed rule no later than the date provided at the beginning of this
notice. Comments, data, and information submitted to DOE's e-mail
address for this rulemaking should be provided in WordPerfect,
Microsoft Word, PDF, or text (ASCII) file format. Interested parties
should avoid the use of special characters or any form of encryption,
and wherever possible, comments should include the electronic signature
of the author. Absent an electronic signature, comments submitted
electronically must be followed and authenticated by submitting a
signed original paper document to the address provided at the beginning
of this notice. Comments, data, and information submitted to DOE via
mail or hand delivery/courier should include one signed original paper
copy. No telefacsimiles (faxes) will be accepted.
According to 10 CFR 1004.11, any person submitting information that
he or she believes to be confidential and exempt by law from public
disclosure should submit two copies: One copy of the document including
all the information believed to be confidential, and one copy of the
document with the information believed to be confidential deleted. DOE
will make its own determination as to the confidential status of the
information and treat it according to its determination.
Factors of interest to DOE when evaluating requests to treat
submitted information as confidential include (1) A description of the
items, (2) whether and why such items are customarily
[[Page 208]]
treated as confidential within the industry, (3) whether the
information is generally known by or available from other sources, (4)
whether the information has previously been made available to others
without obligation concerning its confidentiality, (5) an explanation
of the competitive injury to the submitting person which would result
from public disclosure, (6) a date upon which such information might
lose its confidential nature due to the passage of time, and (7) why
disclosure of the information would be contrary to the public interest.
E. Issues on Which DOE Seeks Comment
DOE is particularly interested in receiving comments on the
following issues:
1. Test Procedure Improvements
DOE requests comments on improvements in the test procedures that
it should consider. In submitting comments, interested parties should
state the nature of the recommended modification and an explanation of
how it improves upon the test procedure proposed in this NOPR. See
section II for details.
2. Basic Model
Because walk-in equipment tends to be highly customized, DOE is
considering allowing manufacturers to group similar walk-in equipment
under a single ``basic model'' and only subjecting one unit of each
basic model to testing. DOE will use the term ``basic model'' to
represent a single family of walk-in equipment, consisting of walk-in
equipment or models of equipment that do not have any differentiating
electrical, physical, or functional features that significantly affect
energy consumption characteristics. DOE requests comments on the
proposed basic model approach. See section III.A.1 for details.
3. Separate Envelope and Refrigeration Tests
For any walk-in, two different manufacturers may make the two main
components: The envelope, or insulated box, and the refrigeration
system. In this notice, DOE proposes separate test procedures for the
envelope and the refrigeration system. The envelope manufacturer would
be responsible for testing the envelope according to the envelope test
procedure, and the refrigeration system manufacturer would be
responsible for testing the refrigeration system according to the
refrigeration system test procedure. The purpose of this provision is
to accurately reflect the structure of the walk-in market and assign
testing responsibilities to the equipment manufacturers. DOE requests
comments on the proposed approach to develop separate test procedures.
See section III.A.4 for details.
4. Definition of Envelope
DOE requests comments on the following definition of ``envelope:''
``(1) a piece of equipment that is the portion of a walk-in cooler or
walk-in freezer that isolates the interior, refrigerated environment
from the ambient, external environment; and (2) all energy-consuming
components of the walk-in cooler or walk-in freezer that are not part
of its refrigeration system.'' See section III.B.1 for details.
5. Effect of Impermeable Skins on Long-Term R-Value
DOE received many comments on the framework document regarding
long-term R-value. After researching the issue, DOE determined that the
R-value of insulating foams diminish after manufacture at rates that
vary by material type and environmental conditions. Diffusion of gases
and moisture infiltration are the key mechanisms of R-value decline.
Many manufacturers seek to prevent or delay diffusion and moisture
infiltration by sealing the foam in a ``skin,'' typically a metal
material. DOE received comments suggesting that these skins can be made
fully impermeable while other comments argued that full impermeability
cannot be achieved due to imperfect sealing at panel joints, imperfect
adherence of foam to metal during manufacture, deliberate punctures for
fixtures and shelving, and/or inadvertent punctures that typically
occur in the field. DOE requests feedback on this issue, including the
submission of test results on the impact of impermeable skins on long-
term R-value. Specifically, DOE requests that interested parties submit
or identify any peer-reviewed, published data pertaining to the
efficacy of skins in preventing or delaying R-value decline. See
section III.B.2.a for details.
6. Measuring Long-Term R-Value Using American Society for Testing and
Materials (ASTM) C1303-08
DOE proposes accounting for R-value decline due to diffusion of
gases by requiring manufacturers to condition their foam prior to
testing. DOE proposes requiring manufacturers to condition foam using
ASTM C1303-08, which conditions foam using an accelerated aging method
prior to testing its R-value. Because ASTM C1303-08 uses ASTM C518-
2004, using ASTM C1303-08 would be consistent with EPCA. (42 U.S.C.
6314(a)(9)(A)(ii)) DOE requests feedback on the proposal to require
conditioning and testing foam using ASTM C1303-08. DOE recognizes that
ASTM C1303-08 is designed for unfaced and permeably faced foams rather
than the impermeably faced foams typical of walk-ins. DOE requests
feedback on the use of ASTM C1303-08 for foams that will be impermeably
faced.
DOE is considering several exceptions and clarifications to ASTM
C1303-08 to satisfy requirements of EPCA and to make the test procedure
more applicable to walk-ins. DOE requests feedback on the number of
samples and sample thicknesses, the use of interpolation of results for
foam thicknesses within the specified 0.5 inch range, and
the use of the core stack R-value out of a sample size of three stacks
for the purpose of calculating walk-in energy use.
Lastly, ASTM C1303-08 cannot be used for non-foam materials, but
DOE is not aware of any non-foam materials currently being used as
insulation in walk-in coolers or freezers. DOE requests comment on
whether non-foam technologies, such as vacuum insulated panels or
aerogels, are likely to be commercially available for walk-ins within
the next 5 years. See section III.B.2.a for details.
7. Infiltration
Air infiltration causes a substantial amount of heat gain through
the envelope. After evaluating several methods of testing and measuring
the air infiltration, DOE proposes requiring ASTM E741-06, also
referred to as the gas tracer method, as the test procedure for
measuring steady-state infiltration and the effectiveness of
infiltration reduction devices (for air infiltration unrelated to door
opening events). Because door opening also contributes to infiltration,
DOE proposes accounting for this infiltration pathway. DOE does not,
however, propose to require manufacturers to individually measure the
infiltration from door opening events, due to the complexity of this
type of testing and the availability of accurate analytical models,
which would make a test procedure very difficult to implement. DOE
proposes using analytical methods based on ASHRAE fundamentals as well
as assumed door-opening frequency and duration and the measured
infiltration barrier effectiveness to calculate the air infiltration
associated with each door-opening event. DOE requests comments on the
proposed test method for steady-state infiltration. DOE requests input
[[Page 209]]
and feedback on the calculations and assumptions proposed for
determining infiltration from door-opening events. See section
III.B.2.b for details on the proposed analytical methods.
8. Nominal Coefficient of Performance of Refrigeration
In developing a test procedure for the envelope alone, without a
refrigeration system, DOE had to determine the energy consumption
associated with heat gain through the envelope due to conduction and
infiltration. DOE proposes to assume a nominal EER for the
refrigeration system to convert the heat gain through the box into a
measure of the energy consumption of a theoretical refrigeration system
that would be removing this heat from the box. For comparison purposes,
DOE recommends that the EER be 12.4 Btu per watt hour (Btu/Wh) for
coolers and 6.3 Btu/Wh for freezers because these are typical EER
values. DOE requests comments on this proposal and on the assumed value
for the EER. See section III.B.3.a for details.
9. Measuring the U-Value of Glass
Because conduction through glass components can be a significant
source of heat transfer through walk-in envelopes, DOE seeks to order
to account for improvements in glass performance in the test procedure.
DOE proposes two options for manufacturers: (1) If manufacturers of
glass doors used in walk-ins participate in the NFRC rating program,
the performance of the door shall be simply read from its label and
used for calculations in this test procedure. If glass door
manufacturers do not participate in the NFRC rating program, then (2)
DOE proposes to require manufacturers to use the LBNL's publicly
available Window 5.2 software package to calculate glass door
performance. DOE seeks comment on the availability of performance data
on glass products used in walk-in applications, glass component
manufacturers' participation in third party certification programs such
as NFRC, and the proposed method for predicting the thermal performance
of glass components using Window 5.2. See section III.B.3.b for more
information.
10. Floor R-Value
EPCA does not require walk-in cooler floors to meet a specific R-
value. In many instances, walk-in coolers are shipped without
additional insulating floors and are simply placed on top of an
existing surface, such as a concrete slab. Since concrete is the floor
surface most commonly used with floorless walk-in coolers DOE is
considering using the R-value of 6-inch concrete to calculate energy
lost through these floors. DOE proposes using an R-value of 0.6 ft\2\-
[deg] F-hr/Btu for 6-inch concrete. Since walk-in freezers are required
to have a floor insulation of R-28, DOE will assume this R-value for
purposes of calculating the energy loss through walk-in freezer floors
if the manufacturer does not provide any additional insulating surface.
DOE requests comments on these assumptions. See section III.B.3.b for
details.
11. Electrical Duty Cycle
As part of the envelope test procedure, DOE recommends calculating
the electricity consumption of lights, sensors, and other miscellaneous
electrical devices not considered part of the refrigeration equipment
using name-plate rating and an assumed daily operation. DOE
incorporates assumed duty cycles of lights, anti-sweat heaters, and
other devices based on whether they are controlled by a preset control
system. While these assumptions may not reflect the actual behaviorally
related energy consumption, they will provide a means for comparison.
DOE requests comments on whether the duty cycle assumptions are
appropriate. See section III.B.3.d for details.
12. Normalization Factor
For the envelope test procedure, DOE proposes to normalize the
energy consumption by a certain factor related to the size of the walk-
in so that manufacturers of larger walk-ins and walk-ins with glass
doors are not unfairly penalized. DOE believes that the surface area of
the envelope is an appropriate normalization factor, because surface
area is the key geometric characteristic related to both conduction and
infiltration and is particularly important as the ratio of glass door
area to wall area increases. DOE requests comments on the proposal to
normalize the energy consumption by the surface area of the walk-in.
See section III.B.3.e for details.
13. Daily Energy Consumption Coefficients
In order to compare envelopes that are similar enough to be
included in the same basic model but are not identical, the test
procedure allows for calculating Daily Energy Consumption Coefficients,
or DECCs, using test results from a particular envelope within a basic
model, and then applying these DECCs to other envelopes within a basic
model to calculate the energy consumption of the other units. DECCs are
essentially scaling factors that allow a manufacturer to change certain
parameters of an envelope and calculate the corresponding change in
energy consumption. DOE believes that this approach would reduce the
testing burden on manufacturers because it would not require
manufacturers to test every unit produced with slight variations due to
customer specification. DOE requests comment on this rating
methodology. For formulas and more information, see section III.B.3.f.
14. Definition of Refrigeration System
DOE requests comments on the following definition of
``refrigeration system:'' ``the mechanism used to create the
refrigerated environment in the interior of a walk-in cooler or
freezer, consisting of an integrated single-package refrigeration unit,
or a split system with separate unit cooler and condensing unit
sections, or a unit cooler that is connected to a central rack system;
and including all controls and other components integral to the
operation of this mechanism.'' See section III.C.1 for details.
15. Measurements and Calculations of Energy Use of Refrigeration
Systems
The test procedure DOE proposes to adopt, AHRI Standard 1250P-2009,
determines the annual walk-in energy factor, or AWEF, which is a
measure of the efficiency of a walk-in's refrigeration system. However,
DOE is required by EPCA to establish ``a test procedure to measure * *
* energy use.'' (42 U.S.C. 6314(a)(9)(B)(i)) In light of this
requirement, DOE proposes that manufacturers determine both the AWEF
and the annual energy consumption of their equipment using the test
procedure, which will enable the test procedure to be consistent with
the requirements of EPCA to develop test procedures that measure the
energy consumption of walk-in equipment. DOE is considering satisfying
the statutory requirement by deriving the energy consumption of the
walk-in refrigeration system from data obtained when the test procedure
is performed. DOE's derivation process, and further information, can be
found in section III.C.4.
16. Impacts on Small Businesses
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
preparation of an initial regulatory flexibility analysis (IRFA) for
any rule that by law must be proposed for public comment, unless the
agency certifies that the rule, if promulgated, will not have a
significant economic impact on a
[[Page 210]]
substantial number of small entities. Upon examination of this NOPR,
DOE could not certify that the rule, if promulgated, would not have a
significant economic impact on a substantial number of small entities;
therefore, DOE prepared an IRFA for this rule. DOE requests comment on
the number of small businesses affected by the proposed rule, and seeks
comment on impacts to small business manufacturers for any possible
alternatives to the proposed rule. More information, along with the
text of the IRFA, can be found in section IV.C.
VI. Approval of the Office of the Secretary
The Secretary of Energy has approved publication of this proposed
rule.
List of Subjects in 10 CFR Part 431
Administrative practice and procedure, Confidential business
information, Energy conservation, Reporting and recordkeeping
requirements.
Issued in Washington, DC, on December 14, 2009.
Cathy Zoi,
Assistant Secretary, Energy Efficiency and Renewable Energy.
For the reasons stated in the preamble, DOE proposes to amend part
431 of chapter II of title 10, of the Code of Federal Regulations, to
read as set forth below.
PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND
INDUSTRIAL EQUIPMENT
1. The authority citation for part 431 continues to read as
follows:
Authority: 42 U.S.C. 6291-6317.
2. Section 431.302 is amended by adding, in alphabetical order,
definitions for ``Basic model,'' ``Envelope,'' ``Refrigeration
system,'' and ``Walk-in equipment'' to read as follows:
Sec. 431.302 Definitions concerning walk-in coolers and walk-in
freezers.
Basic Model means all units of a given type of walk-in equipment
manufactured by a single manufacturer, and--
(1) With respect to envelopes, which do not have any differing
construction methods, materials, components, or other characteristics
that significantly affect the energy consumption characteristics.
(2) With respect to refrigeration systems, which have the same
primary energy source and which do not have any differing electrical,
physical, or functional characteristics that significantly affect
energy consumption.
Envelope means (1) the portion of a walk-in cooler or walk-in
freezer that isolates the interior, refrigerated environment from the
ambient, external environment; and (2) all energy-consuming components
of the walk-in cooler or walk-in freezer that are not part of its
refrigeration system.
Refrigeration system means the mechanism used to create the
refrigerated environment in the interior of a walk-in cooler or
freezer, consisting of an integrated single-package refrigeration unit,
or a split system with separate unit cooler and condensing unit
sections, or a unit cooler that is connected to a central rack system;
and including all controls and other components integral to the
operation of this mechanism.
* * * * *
Walk-in equipment means either the envelope or the refrigeration
system of a walk-in cooler or freezer.
3. Section 431.303 is amended by adding new paragraphs (b)(2),
(b)(3), and (c) to read as follows:
Sec. 431.303 Materials incorporated by reference.
* * * * *
(b) * * *
(2) ASTM C1303-08, Standard Test Method of Predicting Long Term
Thermal Resistance of Closed-Cell Foam Insulation, approved September
15, 2008, IBR approved for Sec. 431.304.
(3) ASTM E741-06, Standard Test Method for Determining Air Change
in a Single Zone by Means of a Tracer Gas Dilution, approved October 1,
2006, IBR approved for Sec. 431.304.
(c) AHRI. Air-Conditioning, Heating, and Refrigeration Institute,
2111 Wilson Boulevard, Suite 500, Arlington, VA 22201, (703) 600-0366,
or http://www.ahrinet.org.
(1) AHRI Standard 1250P-2009, 2009 Standard for Performance Rating
of Walk-In Coolers and Freezers, approved September 2009, IBR approved
for Sec. 431.304.
(2) Reserved.
4. Section 431.304 is revised to read as follows:
Sec. 431.304 Uniform test method for the measurement of energy
consumption of walk-in coolers and walk-in freezers.
(a) Scope. This section provides test procedures for measuring,
pursuant to EPCA, the energy consumption of walk-in coolers and walk-in
freezers.
(b) Testing and Calculations.
(1) Determine the energy consumption of walk-in cooler and walk-in
freezer envelopes by conducting the test procedure specified in
Appendix A to this subpart.
(2) Determine the U-value of glass components from the product
label in compliance with the National Fenestration Rating Council's
Product Certification Program, PCP-2007, or by using the Window 5.2
software to calculate the performance of the glass.
(3) Determine the Annual Walk-in Efficiency Factor of walk-in
cooler and walk-in freezer refrigeration systems by conducting the test
procedure set forth in AHRI Standard 1250P-2009 (incorporated by
reference, see Sec. 431.303).
(4) Determine the energy consumption of walk-in cooler and walk-in
freezer refrigeration systems by:
(i) For refrigeration systems with the condensing unit located
inside a conditioned space, performing the following calculations for
coolers and freezers, respectively:
[GRAPHIC] [TIFF OMITTED] TP04JA10.036
Where qss (90 [deg]F) is the steady state net refrigeration
capacity measured at an ambient condition of 90 [deg]F, and the Annual
Walk-In Efficiency Factor is calculated from the results of the test
procedures set forth in
[[Page 211]]
AHRI Standard 1250P-2009 (incorporated by reference, see Sec.
431.303).
(ii) For refrigeration systems with the condensing unit located
outdoors, performing the following calculations for coolers and
freezers, respectively:
[GRAPHIC] [TIFF OMITTED] TP04JA10.037
Where qss (95 [deg]F) is the steady state net refrigeration
capacity measured at an ambient condition of 95 [deg]F; tj
and nj represent the outdoor temperature at each bin j and
the number of hours in each bin j, respectively, for the temperature
bins listed in Table D1 of AHRI Standard 1250P-2009 (incorporated by
reference, see Sec. 431.303); and the Annual Walk-In Efficiency Factor
is calculated from the results of the test procedures set forth in AHRI
Standard 1250P-2009 (incorporated by reference, see Sec. 431.303).
(iii) For refrigeration systems consisting of a unit cooler
connected to a rack system, performing the following calculations for
coolers and freezers, respectively:
[GRAPHIC] [TIFF OMITTED] TP04JA10.038
Where qmix,evap is the net capacity of the evaporator coil,
determined by testing the unit cooler at the 25 [deg]F suction dewpoint
for a cooler and the -20 [deg]F suction dewpoint for a freezer, at the
maximum evaporator fan speed, according to AHRI standard 1250P-2009
(incorporated by reference, see Sec. 431.303); and the Annual Walk-in
Efficiency Factor is calculated from the results of the test procedures
set forth in AHRI Standard 1250P-2009 (incorporated by reference, see
Sec. 431.303).
5. Appendix A is added to subpart R of part 431 to read as follows:
Appendix A to Subpart R of Part 431--Uniform Test Method for the
Measurement of Energy Consumption of the Envelopes of Walk-In Coolers
and Walk-In Freezers
1.0 Scope
This appendix covers the test requirements used to measure the
energy consumption of the envelopes of walk-in coolers and walk-in
freezers.
2.0 Definitions
The definitions contained in Sec. 431.302 are applicable to
this appendix.
2.1 Additional Definitions
(a) Unless explicitly stated otherwise, the surface area for all
measurements is the area as measured on the external surface of the
walk-in.
(b) A device or control system that ``automatically'' opens and
closes doors without direct user contact (i.e., a motion sensor that
senses when a forklift is approaching the entrance to a door, opens,
and then closes after the forklift has passed).
(c) Unless explicitly stated otherwise, all calculations and
test procedure measurements shall use the temperature and relative
humidity data shown in Table A.1. For installations where two or
more walk-in envelopes share any surface(s), the ``external
conditions'' of the shared surface(s) should reflect the internal
conditions of the neighboring walk-in.
Table A.1--Temperature and Relative Humidity Conditions
------------------------------------------------------------------------
Value Units
------------------------------------------------------------------------
Internal Conditions (cooled space within envelope)
------------------------------------------------------------------------
Cooler:
Dry Bulb Temperature............................... 35 F
Relative Humidity.................................. 60 %
Freezer:
Dry Bulb Temperature............................... -10 F
Relative Humidity.................................. 60 %
------------------------------------------------------------------------
External Conditions (space external to the envelope)
------------------------------------------------------------------------
Freezer and Cooler:
Dry Bulb Temperature............................... 75 F
Relative Humidity.................................. 40 %
------------------------------------------------------------------------
3.0 Test Apparatus and General Instructions
3.1 Conduction Heat Gain
3.1.1 Glass Doors
(a) All dimensional measurements for glass doors include the
door frame and glass.
(b) Calculate the individual and total glass door surface area
(Aglass) as follows:
[[Page 212]]
[GRAPHIC] [TIFF OMITTED] TP04JA10.039
Where:
i = index for each type of unique glass door used in cooler or
freezer being tested,
ni = number of identical glass doors of type i,
Wglass,i = width of glass door (including door frame), and
Hglass,i = height of glass door (including door frame).
(c) Calculate the temperature differential(s)
[Delta]Ti for each unique glass door ([deg]F) as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.040
Where:
i = Index for each type of unique glass door used in cooler or
freezer being tested,
TDB,int,i = dry-bulb air temperature inside the cooler or freezer,
[deg]F
TDB,ext,i = dry-bulb air temperature external to cooler or freezer,
[deg]F
(d) Calculate the conduction load through the glass doors,
(Qcond-glass,door):
[GRAPHIC] [TIFF OMITTED] TP04JA10.041
Where:
ni = number of identical glass doors of type i;
Uglass,i = thermal transmittance, U-value of the door, of type i,
Btu/h-ft\2\-[deg]F;
Aglass,i = total surface area of all walk-in glass doors of type i,
ft\2\; and
[Delta]T1 = temperature differential between refrigerated and
adjacent zones, [deg]F.
3.1.2 Wall Glass and Doors With Inset Glass
(a) Calculate the individual and total glass surface area
(Aglass,wall), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.042
[GRAPHIC] [TIFF OMITTED] TP04JA10.043
Where:
i = index for each type of unique glass door used in cooler or
freezer being tested,
ni = number of identical glass walls or insets of type i,
Wglass,wall,,i = width of glass wall (including glass framing)
Hglass,wall,i = height of glass wall (including glass framing)
(b) Calculate the temperature differential(s)
[Delta]Tglass,wall,i for each unique glass wall ([deg]F),
as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.044
Where:
i = Index for each type of unique glass door used in cooler or
freezer
TDB,int,glass,wall,i = dry-bulb air temperature inside the cooler or
freezer, [deg]F
TDB,ext,glass,wall,i = dry-bulb air temperature external to cooler
or freezer, [deg]F
(c) Calculate the conduction load through the glass walls and
glass insets, (Qcond-glass,wall), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.045
Where:
ni = number of identical glass walls or insets of type i;
Uglass,wall,i = thermal transmittance, U-value of the glass wall, of
type i, Btu/h-ft\2\-[deg]F;
Aglass,wall,i = total surface area of all walk-in glass walls and
insets of type i, ft\2\; and
[Delta]Tglass,wall,i = temperature differential between refrigerated
and adjacent zones, [deg]F.
3.1.3 Non-Glass Envelope Components
(a) Calculate the total surface area of the walk-in non-glass
envelope (Anon-glass,tot), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.046
[[Page 213]]
Where:
i,j,k,l = number of identical surface area regions of walls, floors,
ceilings and non-glass doors, respectively, comprised of the same
thickness and underlying materials and temperature differential--for
example, if a walk-in has wall sections that are of two different
thickness or of two different foam insulation products, i=2;
Awalls,i = area of walls, of thickness and underlying materials of
type i;
Afloor,j = area of floor, of thickness and underlying materials of
type j;
Aceiling,k = area of ceiling, of thickness and underlying materials
of type k; and
Anon-glass door,l = area of doors, of thickness and underlying
materials of type l.
(b) Determine the R-value (Thermal resistance) of the walls,
ceiling, and floor foam per 4.1, as follows:
(c) Calculate the conduction or transmission load through all
non-glass components (Qcond-non-glass), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.047
Where:
Rnon-glass,wall, i = R-value of foam used in wall panels, of type i,
h-ft\2\-[deg]F/Btu;
Rnon-glass,floor, j = R-value of foam used in floor panels, of type
j, h-ft\2\-[deg]F/Btu;
Rnon-glass,ceil, k = R-value of foam used in ceiling panels, of type
k, h-ft\2\-[deg]F/Btu;
Rnon-glass,door, l = R-value of foam used in non-glass doors, of
type l, h-ft\2\-[deg]F/Btu;
Awalls,i = area of wall, of thickness and underlying materials of
type i;
Afloor,j = area of floor, of thickness and underlying materials of
type j;
Aceiling,k = area of ceiling, of thickness and underlying materials
of type k; and
Anon-glass door,l = area of doors, of thickness and underlying
materials of type l.
[Delta]Ti = dry bulb temperature differential between internal and
external air, of type i, [deg]F
[Delta]Tj = dry bulb temperature differential between internal and
external air, of type j, [deg]F
[Delta]Tk = dry bulb temperature differential between internal and
external air, of type k, [deg]F
[Delta]Tl = dry bulb temperature differential between internal and
external air, of type l, [deg]F
3.1.4 Total Conduction Load
(a) Calculate total conduction load, Qcond, (Btu/h),
as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.048
Where:
Qcond-non-glass = conduction load through non-glass components of
walk-in, Btu/h; and
Qcond-glass,wall = total conduction load through walk-in glass walls
and inset windows, Btu/h.
Qcond-glass,door = total conduction load through walk-in glass
doors, Btu/h.
3.2 Infiltration Heat Gain
3.2.1 Steady State Infiltration Calculations
(a) Convert dry-bulb internal and external air temperatures from
[deg]F to Rankine ([deg]R), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.049
Where:
TDB-int,R = the dry-bulb temperature of internal walk-in air,
[deg]R; and
TDB-ext,R = the average dry-bulb temperature of air surrounding the
walk-in, [deg]R.
(b) Calculate the water vapor saturation pressure for the
external air and the internal refrigerated air, as follows:
(1) If TDB,R < 491.67 [deg]R (32 [deg]F), using
following equation to calculate water vapor saturation pressure
(Pws in psia):
[GRAPHIC] [TIFF OMITTED] TP04JA10.050
Where:
TDB,R = dry-bulb temperature in Rankine (for the internal or
external air),
C1 = -1.0214165 E+04,
C2 = -4.8932428 E+00,
C3 = -5.3765794 E-03,
C4 = 1.9202377 E-07,
C5 = 3.5575832 E-10,
C6 = -9.0344688 E-14, and
C7 = 4.1635019 E+00.
(2) If TDB,R > 491.67 [deg]R (32 [deg]F), use the
following equation to calculate water vapor saturation pressure
(Pws in psia):
[GRAPHIC] [TIFF OMITTED] TP04JA10.051
Where:
TDB,R = dry-bulb temperature (for the internal and external air),
[deg]R;
C8 = -1.0440397 E+04;
C9 = -1.1294650 E+01;
C10 = -2.7022355 E-02;
C11 = 1.2890360 E-05;
C12 = 2.4780681 E-09; and
C13 = 6.5459673 E+00.
(c) Calculate the absolute humidity ratio, [omega], as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.052
Where:
RH = relative humidity in decimal format (e.g., 0.40 for 40 percent)
(for the internal or external air), and
Pws = water vapor saturation pressure.
(d) Calculate air specific volume, [nu], (ft\3\/lb), as follows:
[[Page 214]]
[GRAPHIC] [TIFF OMITTED] TP04JA10.053
Where:
TDB,R = dry-bulb temperature (for the internal or external air),
[deg]R, and
[omega] = absolute humidity ratio.
(e) Calculate air density, air density (lb/ft\3\), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.054
Where:
[nu] = specific volume of air, ft\3\/lb.
(f) Calculate the enthalpy for the internal and external air, h,
(Btu/lb), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.055
Where:
TDB,F = dry-bulb temperature (for the internal or external air),
[deg]F; and
[omega] = absolute humidity ratio.
(g) Measure the steady-state infiltration rate per 4.2.,
Vrate(1/h)
(h) Convert Vrate to V, (ft\3\/h), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.056
Where:
Vref-space = the total enclosed volume of the walk-in, ft\3\
Vrate = the infiltration rate per 4.2, 1/h
(i) Calculate the total infiltration load due to steady-state
infiltration, Qinfilt, (Btu/h), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.057
Where:
V = the infiltration rate measured from 4.2, ft\3\/h;
[rho]int = internal air density, lb/ft\3\;
[rho]ext = external air density, lb/ft\3\;
hint = internal air enthalpy, Btu/lb; and
hext = external air enthalpy, Btu/lb.
3.2.2 Door Opening Infiltration Calculations
(a) Calculate the portion of time each doorway is open,
Dt, as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.058
Where:
i = index for each unique door. A unique door must be of the same
geometry, underlying materials, function, and have the same
temperature difference across the door
P = number of doorway passages (i.e., number of doors opening
events);
[thgr]p = door open-close time, seconds per opening P;
[thgr]o = time door stands open, minutes; and
[thgr]d = daily time period, h.
(1) Number of doorway passages: For display glass doors, P = 72,
and all other doors, P= 60
(2) Door open-close time: For display glass doors,
[thgr]p = 8 seconds. For non-glass doors, if an automatic
door opener/closer is used, [thgr]p = 10 seconds and all
other doors, [thgr]p = 15 seconds.
(3) Time door stands open: Display glass doors,
[thgr]o = 0 minutes and all other doors,
[thgr]o = 15 minutes.
(4) Daily time period: All walk-ins, [thgr]d = 24
hours.
(b) Calculate the density factor, Fm, for each door,
as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.059
Where:
i = index for each unique door
[rho]int,i = internal air density, of door type i, lb/
ft\3\; and
[rho]ext,i = external air density, of door type i, lb/ft\3\.
(c) Calculate the infiltration load for fully established flow
through each door, qi (Btu/h), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.060
Where:
i = index for each unique door
Ai = doorway area, of door type i, ft\2\;
hint,i = internal air enthalpy, of door type i, Btu/lb;
hext,i = external air enthalpy, of door type i, Btu/lb;
[rho]int,i = internal air density, of door type i, lb/ft\3\;
[rho]ext,i = external air density, of door type i, lb/ft\3\;
Hi = doorway height, of door type i, ft;
Fm,i = density factor, of door type i, and
g = acceleration of gravity, 32.174 ft/s\2\.
(d) Calculate the doorway infiltration reduction device
effectiveness, E (%), at the same test conditions as described in
steady-state infiltration section, as follows:
(1) A sample set must be taken once the tracer gas has uniformly
dispersed in the internal space using the methodology described in
4.2.
(2) The test should be repeated exactly as described with the
infiltration reduction device removed or deactivated.
(3) Calculate the infiltration reduction effectiveness:
[GRAPHIC] [TIFF OMITTED] TP04JA10.061
Where:
Vrate,with-device = air infiltration rate, with door open and
reduction device active, using 4.2, 1/h;
Vrate,without-device = air infiltration rate, with door open and
reduction device disabled or removed, using 4.2, 1/h.
(e) Calculate the total door opening infiltration load for a single
door, Qopen, (Btu/h), as follows:
[[Page 215]]
[GRAPHIC] [TIFF OMITTED] TP04JA10.062
Where:
q = infiltration load for fully established flow, Btu/h;
Dt = doorway open-time factor;
Df = doorway flow factor, 0.8 for freezers and coolers (from ASHRAE
Fundamentals);
E = effectiveness of doorway protective device, as measured by gas
tracer test, %; and
ni = number of doors (of the type i being considered in
calculation).
(f) Calculate the total load due to door opening infiltration
for all doors, Qopen, (Btu/h), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.063
3.3 Energy Consumption Due To Total Heat Gain
(a) Calculate the total thermal load, Qtot, (Btu/h),
as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.064
Where:
Qinfilt = total load due to steady-state infiltration, Btu/h;
Qcond = total load due to conduction, Btu/h; and
Qopen= total load due to door opening infiltration, Btu/h.
(b) Select Energy Efficiency Ratio (EER), as follows:
(1) For coolers, use EER = 12.4 Btu/Wh
(2) For freezers, use EER = 6.3 Btu/Wh
(c) Calculate the total daily energy consumption due to thermal
load, Qtot,EER, (kWh/day), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.065
Where:
Qtot = total thermal load, Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/Wh.
3.4 Energy Consumption Related To Electrical Components.
Electrical components contained within a walk-in could include, but
are not limited to: heater wire (for anti-sweat or anti-freeze
application); lights (including display door lighting systems);
control system units; and sensors.
3.4.1 Direct Energy Consumption of Electrical Components
(a) Select the required value for percent time off for each type
of electricity consuming device, PTOt (%)
(1) For lights without timers, control system or other demand-
based control, PTO = 25 percent. For lighting with timers, control
system or other demand-based control, PTO = 50 percent.
(2) For anti-sweat heaters on coolers (if required): Without
timers, control system or other demand-based control, PTO = 0
percent. With timers, control system or other demand-based control,
PTO = 75 percent. For anti-sweat heaters on freezers (if required):
Without timers, control system or other auto-shut-off systems, PTO =
0 percent. With timers, control system or other demand-based
control, PTO = 50 percent
(3) For active infiltration reduction devices: Without control
by door open or closed position, PTO = 25 percent. With control by
door open or closed position for display doors, PTO = 99.33 percent.
With control by door open or closed position for other doors, PTO =
99.17 percent.
(4) For all other electricity consuming devices: Without timers,
control system, or other auto-shut-off systems, PTO = 0 percent. If
it can be demonstrated that the device is controlled by preinstalled
timers, control system or other auto-shut-off systems, PTO = 25
percent.
(b) Calculate the power usage for each type of electricity
consuming device, Pcomp,t, (kWh), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.066
Where:
t = index for each type of electricity consuming device with
identical rated power;
Prated,t = rated power of each component, of type t, kW;
PTOt = percent time off, for device of type t, %; and
nt = number of devices at the rated power of type t.
(c) Calculate the total electrical energy consumption, Ptot,
(kWh), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.067
[GRAPHIC] [TIFF OMITTED] TP04JA10.068
Where:
t = index for each type of electricity consuming device with
identical rated power;
Pcomp,int, t = the energy usage for an electricity consuming device
sited inside the walk-in envelope, of type t, kWh.
Pcomp,ext, t = the energy usage for an electricity consuming device
sited outside the walk-in envelope, of type t, kWh.
3.4.2 Total Indirect Electricity Consumption Due to Electrical Devices
(a) Calculate the additional compressor load due to thermal
output from electrical components contained within the envelope,
Cload, (kWh), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.069
Where:
EER = EER of walk-in (cooler=12.4 or freezer=6.3), Btu/Wh;
Ptot,int = The total electrical load due to components sited inside
the walk-in envelope.
3.5 Total Normalized Energy Consumption
3.5.1 Total Energy Load
(a) Calculate the total energy load of the walk-in envelope per
unit of surface area, Etot (kWh/ft\2\), as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.070
[[Page 216]]
[GRAPHIC] [TIFF OMITTED] TP04JA10.071
[GRAPHIC] [TIFF OMITTED] TP04JA10.072
Where:
Qtot,EER = the total thermal load, kWh;
Ptot = the total electrical load, kWh;
Anon-glass,tot = total surface area of the non-glass envelope,
ft\2\;
Aglass,tot = total surface area glass envelope, ft\2\.
Cload = additional compressor load due to thermal output from
electrical components contained within the envelope, kWh.
4.0 Test Methods and Measurements
4.1 R-Value Testing and Measurements
4.1.1 Measuring R-Value of Insulating Foam
(a) Follow the test procedure in ASTM C1303-08 exactly, except
for these exceptions, (incorporated by reference, see Sec.
431.303):
(1) Section 6.6.2, where several types of hot plate methods are
recommended, ASTM C518-04, (incorporated by reference, see Sec.
431.303), must be used for measuring the R-value
(2) Section 6.6.2.1, in reference to ASTM C518-04, the mean test
temperature of the foam during R-value measurement must be:
(i) For freezers: - 6.7 2 [deg]C (20 4
[deg]F) with a temperature difference of 22 2 [deg]C
(40 4 [deg]F)
(ii) For coolers: 12.8 2 [deg]C (55 4
[deg]F) with a temperature difference of 22 2 [deg]C
(40 4 [deg]F)
(b) At least one sample set must be prepared, comprised of three
stacks, while adhering to all preparation methods and uniformity
specifications described in ASTM C1303-08, (incorporated by
reference, see Sec. 431.303).
(c) The value resulting LTTR for the foam shall be reported as
Rfoam, but for the purposes of calculations in this test
procedure calculations, it will be converted to
Rnon-glass, as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.073
Where:
Rfoam = R-value of foam as measured by ASTM C1303-08, h-ft\2\-
[deg]F/Btu-in.
4.1.2 Determining R-Value of Concrete Floors
(a) For walk-ins in which the floor is concrete instead of
insulated panels and has not been supplied by the walk-in
manufacturer:
(1) Coolers: Use an R-value of 0.6 for floors of walk-in
coolers.
(2) Freezers: Use an R-value of 28 for floors of walk-in
freezers.
4.2 Steady State Infiltration Testing
(a) Follow the test procedure in ASTM E741-06 exactly, except
for these changes and exceptions to the procedure, (incorporated by
reference, see Sec. 431.303):
(1) Concentration decay method: The ``concentration decay
method'' must be used instead of other available options described
in ASTM E741-06.
(2) Gas Tracer: CO2 must be used as the gas tracer
for all testing.
(3) Air change rate: Measure the air change rate in ft\3\/h,
rather than the air change flow described in ASTM E741-06,
(incorporated by reference, see Sec. 431.303).
(4) Spatial measurements: Spatial measurements must be taken in
a minimum of six locations or one location/20 ft\2\ of floor area
(whichever results in a greater number of measurements) at a height
of 3 ft 0.5 ft, at a minimum distance of 2 ft 0.5 ft from the walk-in walls or doors.
(b) The internal air temperature for freezers and for coolers
shall be 2 [deg]C (4 [deg]F) of the values shown in
Table A.1.
(c) The external air temperature must be 24 [deg]C (75 [deg]F)
2.5 [deg]C (5 [deg]F) surrounding the walk-in.
(d) The test must be completed with all reach or walk-in doors
closed.
(e) For testing the effectiveness ASTM E741-06 will be used,
with the following changes or exceptions to the procedure:
(1) Within 3 minutes 30 seconds, with the
infiltration reduction device in place, a hinged door should be
opened at an angle greater than or equal to 90 degrees. The elapsed
time, from zero degrees position (closed) to greater than or equal
to 90 degrees (open) must be no longer than 5 seconds. The door must
then be held at an angle greater than or equal to 90 degrees for 5
min 5 seconds and then closed over a period no longer
than 5 seconds. For non-hinged doors, the door must reach its
maximum opened position, be held open, and reach a fully closed
position for the same elapsed time as described above for hinge-type
doors.
(2) The gas concentration must be sampled again after the door
has been closed. Samples should continue being taken until the gas
concentration is once again uniform within the walk-in.
5.0 Calculation of Daily Energy Consumption Coefficients (DECC)
The calculation procedures described in this section are based
on the test measurements and other performance parameters discussed
and described in the previous sections. The Daily Energy Consumption
Coefficients are each combined to provide a linear expression of the
daily energy consumption of any walk-in system with the construction
features or component design parameters of a tested walk-in design
with similar components and features. The DECC figures established
using measurements on the test unit may be used to derive the daily
electrical energy consumption of other walk-in systems in the same
class constructed with similar components of construction as
follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.074
Where:
DECCnon-glass = DECC for non-glass,
Anon-glass,tot = total non-glass surface area,
DECCglass,door = DECC for glass doors,
Aglass,glass, tot = total glass surface area, and
DECCglass,wall = DECC for glass walls and inset windows,
Aglass,wall, tot = total glass wall and inset window surface
area, and
DECCinfilt,disp_dr_opn = DECC for opening of display type doors,
Adisp_doors = total area of display doors,
DECCdisp_dr_device = DECC for infiltration reduction device in
place for display doors,
ndisp_doors = total number of display doors,
DECCinfilt,non-display_,dr_opn = DECC for non-display type
doors,
[[Page 217]]
Anon-display_doors = total area of non-display type doors,
DECCnon-display_dr_device = DECC for infiltration reduction
device in place for non-display doors,
nnon-display_doors = total number of non-display doors,
DECClight = DECC for lights,
Vref_space = total enclosed refrigerated volume (ft\3\),
DECCASH = DECC for anti-sweat heaters,
DECCstir_fan = DECC for motors used to drive air mixing fans,
and
DECCother = DECC for other electricity consuming devices.
(a) Calculate DECCnon-glass as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.075
[GRAPHIC] [TIFF OMITTED] TP04JA10.076
[GRAPHIC] [TIFF OMITTED] TP04JA10.077
Where:
Qcond,non-glass = conduction load due to non-glass surface area,
Qcond,glass,wall = conduction load due to glass wall and inset
window surface area,
Qcond,glass,door = conduction load due to glass door surface area,
Qinfilt = load due to steady-state infiltration,
Anon-glass,tot = total non-glass surface area,
Aglass,wall,tot = total glass wall and inset window surface area,
Aglass,door,tot = total glass door surface area,
EER = energy efficiency ratio for freezer or cooler, as described
3.3(b)
(b) Calculate DECCglass,door as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.078
[GRAPHIC] [TIFF OMITTED] TP04JA10.079
[GRAPHIC] [TIFF OMITTED] TP04JA10.080
Where:
Qcond,non-glass = conduction load due to non-glass surface area,
Qcond,glass,wall = conduction load due to glass wall and inset
window surface area,
Qcond,glass,door = conduction load due to glass door surface area,
Qinfilt = load due to steady-state infiltration,
Anon-glass,tot = total non-glass surface area,
Aglass,wall,tot = total glass wall and inset window surface area,
Aglass,door,tot = total glass door surface area,
EER = energy efficiency ratio for freezer or cooler, as described
3.3(b)
(c) Calculate DECCglass,wall as follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.081
[GRAPHIC] [TIFF OMITTED] TP04JA10.082
[GRAPHIC] [TIFF OMITTED] TP04JA10.083
Where:
Qcond,non-glass = conduction load due to non-glass surface area,
Qcond,glass,wall = conduction load due to glass wall and inset
window surface area,
Qcond,glass,door = conduction load due to glass door surface area,
Qinfilt = load due to steady-state infiltration,
Anon-glass,tot = total non-glass surface area,
Aglass,wall,tot = total glass wall and inset window surface area,
Aglass,door,tot = total glass door surface area,
EER = energy efficiency ratio for freezer or cooler, as described
3.3(b)
[[Page 218]]
(d) Compute DECCglass in an identical manner to DECCglass,door,
described above.
(e) Compute DECCinfilt,disp_dr_opn and DECCdisp_dr_device as
follows:
[GRAPHIC] [TIFF OMITTED] TP04JA10.084
[GRAPHIC] [TIFF OMITTED] TP04JA10.085
Where:
Qopen,disp_dr = total infiltration load calculated for display door-
opening events, and
EER = energy efficiency ratio for freezer or cooler
(f) Determine DECCdisp_dr_device as follows:
(1) For passive infiltration reduction devices (e.g., strip
curtains), the DECCdisp_dr_device is zero.
(2) For active infiltration reduction devices (e.g., air
curtains), DECCdisp_dr_device = Pcomp where Pcomp is determined as
in section 3.4.1 using the appropriate PTO (percent time off)
(g) Compute DECCinfilt, non-display_dr_opn and DECC non-display_
dr_device in the same manner as DECCinfilt, disp_dr_opn and
DECCdisp_dr_device above.
(h) Compute DECCASH in the following manner:
[GRAPHIC] [TIFF OMITTED] TP04JA10.086
Where:
Pcomp,ASH = total energy consumed by anti-sweat heaters (per section
3.4.1), and
Adisp-door = total surface area of display doors.
(i) Compute DECCstir_fan, for stirring (non-evaporator) fans in
the following manner:
[GRAPHIC] [TIFF OMITTED] TP04JA10.087
Where:
Vref_space = total volume of the refrigerated space (ft \3\), and
Pcomp,stirring_fan = total energy consumed by stir fan(s) (per
3.4.1).
(j) Compute DECCother for all other electricity consuming
devices: For all lights and other electrical loads, Pcomp,j is
determined per the provisions of the section 3.4.1 and the DECCother
is obtained by dividing the respective Pcomp,j by Vref_spac.
[FR Doc. E9-30884 Filed 12-31-09; 8:45 am]
BILLING CODE 6450-01-P