1 | Energy Efficiency and Renewable Energy 

Details of Executing the Test

Procedures for Refrigeration

Systems used in Walk‐in Coolers

and Freezers

October 22, 2014

Department of EnBuilding Technolo

EERE‐2011‐BT‐TP
2

Welcome• Introductions (around the room)

• Ground Rules

– Speak one at a time.

– Say your name for the record – there will be a complete tra

this meeting.

– Be concise – share the ‘air‐time’.

– Keep the focus here – cell phones on silent; limit sidebar

conversations.

– Webinar participants turn phone on mute; “raise your hand

recognized to speak.

• Opening Remarks
3

Listening Via the Webcast• The Department is broadcasting this meeting live ov

Internet.

• DOE is providing the webcast to accommodate stake

that are unable to attend the public meeting in perso

• The web broadcast allows stakeholders to listen in an

the slides.
4

Purpose of the Public Meeting• Describe the scope of coverage in relation to walk‐in 

and freezer (WICF) refrigeration systems.

• Discuss how the test procedure can be used to test W

refrigeration systems.

• Discuss the sampling and AEDM requirements for WI

refrigeration systems.
5

Public Meeting Slides Topics

1 Overview of the Test Procedure2 Scope of Test Procedure for Refrigeration3 How the Test Procedure is Applied4 Sampling and AEDM Requirements5 Other FAQs
6

Test Procedure Overview• The test procedure for WICFs is found at: 10 CFR 431

• Generally, there is a separate method of test for diffe

components of a WICF: (1) the panels; (2) the doors; the refrigeration system.

• Today, we are discussing various aspects of the WICF

refrigeration system test procedure.

• In addition to the test procedure for individual units 

WICF refrigeration system, DOE has applicable samp

regulations that govern how manufacturers develop 

for each basic model of WICF refrigeration system, awith regulations that allow the use of alternative mefor rating equipment instead of testing if certain crite

met. We will also discuss these regulations today.
7

Public Meeting Slides Topics

1 Overview of the Test Procedure2 Scope of Test Procedure for Refrigeration3 How the Test Procedure is Applied4 Sampling and AEDM Requirements5 Other FAQs
8

Scope of the Coverage for WICF Refrigeration SWhat refrigeration systems are covered?

Generally speaking, refrigeration systems covered by WICF standa

include:• A packaged dedicated system (i.e., a matched unit cooler and c

unit sold as one package);

• A split, matched dedicated system (i.e., a matched unit cooler a

condensing unit sold as two parts); and

• A split system that is not matched, including:

• A unit cooler that is sold separately for use in connection with 

multiplex condensing system;

• A unit cooler that is sold separately for use with one or more 

condensing units; and

• A dedicated condensing unit that is sold separately for use wit

WICF (the WICF may contain one or more unit coolers).
9

Scope of the Test Procedure for RefrigerationExamples of packaged refrigeration systems:

Condensing side

or “Hot” side

Warm

Air

Evaporating side

or “Cold” side

Cold

Air

Re

syste
10

Scope of the Test Procedure for RefrigerationExamples of split refrigeration systems and their comp

Unit cooler (also calle

evaporator)

Diagram of a “Split” or

“Remote” System

Ou

conden

Indoor

condensing unit

Condensing side or

“Hot” side

Evaporating

side or

“Cold” side

Cold Air

Compressor Warm Air

Condenser

Coil & Fan

Evaporator

Coil & Fan
11

WICF Refrigeration System ExceptionsAt this time, the current and the future WICF test proce

and standards do not apply to:

• Condensing units solely designed and marketed to se

multiple WICFs or other pieces of refrigeration equip

(These are called “multiplex” condensing units. This includes refrigeration compressor racks sometimes f

supermarkets.)

• Water‐cooled condensing units or systems

• Equipment intended solely for scientific, medical, or 

purposes
12

Public Meeting Slides Topics

1 Test Procedure Background2 Scope of Test Procedure for Refrigeration3 How the Test Procedure is Applied4 Sampling and AEDM Requirements5 Other FAQs
13

How the Test Procedure is AppliedYou may have questions about how to apply the test

procedure in certain situations...

What if I only

make

condensing

units?

What if I only

make

condensing

units?

What if I only

make unit

coolers?

What if I only

make unit

coolers?

What options do I

have if I want to rate

walk‐in refrigeration

systems I

manufacture?

What options do I

have if I want to rate

walk‐in refrigeration

systems I

manufacture?

What 

manu

refrigerat

but sell c

made b

manuf

What 

manu

refrigerat

but sell c

made b

manuf
14

How the Test Procedure is AppliedYou can find answers in the CFR.

Here are some important sections:• 10 CFR 429, Subpart B—Certification

• §429.11 General sampling requirements for selecting u

tested

• §429.53 Walk‐in coolers and walk‐in freezers

• §429.70 Alternative methods for determining energy e

and energy use

• 10 CFR 431, Subpart R—Walk‐in Coolers and Walk‐in

Freezers

• §431.302 Definitions

• §431.304 Test Procedures
15

How the Test Procedure is AppliedNext, we will walk through some examples of how to the test procedure in several scenarios.1. What are my options for deriving the ratings of my 

models if I manufacture condensing units, unit cool

complete systems?

2. How do I test a refrigeration system?

3. How do I test a unit cooler?

4. How do I test a condensing unit?

5. Can I sell refrigeration systems that I did not manufa

a package with other WICF components (e.g., pane
16

How the Test Procedure is AppliedExample 1: I make matched, split‐system walk‐in refrig

systems, individual unit coolers, and individual conden

units. What are my options for rating my basic models

In general, DOE’s regulations are based on refrigeration efficiency (i.e., AWEF).In this case, a manufacturer may develop a certified ratits refrigeration systems, which can consist of unit coole

condensing units tested separately or as matchedsystems...with some important caveats.

Let’s look at an example.
17

How the Test Procedure is AppliedExample 1 (continued): Let’s say I make 4 basic models of unit co

3 basic models of condensing units. I can combine these into 12 b

models of refrigeration systems. I sometimes sell unit coolers sep

they can be used in supermarkets.

Unit

Coolers
18

How the Test Procedure is AppliedExample 1 (continued): What are my options for rating my equip

One option is to rate all 12 possible refrigeration system basic mod

would be rated and certified as dedicated condensing systems.
19

How the Test Procedure is Applied

Example 1 (continued):

If you wish to represent the efficiency of the refrigeration system 

models consisting of unit coolers used with a multiplex condensin

these basic models must also be certified.

Multiplex Condenser
20

How the Test Procedure is AppliedExample 1 (continued):

That is 16 basic models that have to be individually certified!

But there is an easier way...

Multiplex Condenser
21

How the Test Procedure is AppliedExample 1 (continued):

The recent test procedure final rule implemented §429.53(a)(1)(iii), which 

if the represented value of a refrigeration system basic model was based 

unit cooler for multiplex applications, that represented value may be used 

refrigeration systems containing that unit cooler.

Multiplex Condenser
22

How the Test Procedure is AppliedExample 1 (continued):

In other words, you still have to certify all 16 of the basic models t

manufacture, but you can use the same represented value for mu

systems. But there is an even easier way...

Multiplex Condenser
23

How the Test Procedure is AppliedExample 1 (continued):

The recent test procedure final rule also allows you to certify basic model

refrigeration systems by rating dedicated condensing systems on their ow

nominal values for a “dummy” unit cooler. (The basic models have to com

the dedicated system standards.)

Multiplex Condenser
24

How the Test Procedure is AppliedExample 1 (continued):

Now there are only 7 basic models that have to be individually cer

Multiplex Condenser
25

How the Test Procedure is AppliedExample 1 (continued):

If you have already certified the refrigeration systems using the no

approach of certifying the unit cooler and condensing unit separat

do not also have to certify the basic model of the matched system

Multiplex Condenser
26

How the Test Procedure is AppliedExample 1 (continued):

If you have already certified the unit cooler and condensing unit b

models that make up a basic model of matched system, you do no

have to certify the basic model of the matched system...

Multiplex Condenser

...unless you wish to represent the rating of the basic model of the matched refrigeration system as being more efficient than the nominal

approach.In that case, the more efficient rating

must be based on matched testing.
27

How the Test Procedure is AppliedExample 1 (continued):Condensing units with two‐capacity, multi‐capacity, or v

capacity compressors cannot be rated using the nomina

They must be rated as part of a matched refrigeration s

Condensing unit with a two‐capa

capacity, or variable capacity co
28

How the Test Procedure is AppliedExample 1 (continued):Representations of the energy efficiency of a basic modbe based on a sample of units of that basic model.We will cover this topic in more detail later.
29

How the Test Procedure is AppliedExample 2: I am a walk‐in refrigeration system manufaHow do I test a walk‐in refrigeration system?

Look in 10 CFR 431.304 for instructions.

• 431.304(c)(10) says: Determine the Annual Walk‐in E

Factor of walk‐in cooler and walk‐in freezer refrigerasystems by conducting the test procedure set forth i

1250‐2009 (incorporated by reference; see §431.303

modifications (i)‐(xv)).

Remember, representations of the energy efficiency of 

model must be based on a sample of units of that basic 
30

How the Test Procedure is AppliedExample 3: I am a walk‐in refrigeration system manufacture

unit coolers separately, but I don’t know where a given uni

goes after it leaves my factory. How should I test a unit coo

10 CFR 431.304(c)(12) tells you how to test a walk‐in cooler 

freezer refrigeration system component distributed individu

• 10 CFR 431.304(c)(12)(i) says: Calculate the AWEF for a

refrigeration system containing a unit cooler that is distrib

individually using the method for testing a unit cooler con

to a multiplex condensing system.

• Use the DOE test procedure as noted in 10 CFR 431.304(c

• The applicable standards are the multiplex system standa

§431.306(e).

Remember, representations of the energy efficiency of a basic model 

based on a sample of units of that basic model.
31

How the Test Procedure is AppliedExample 4: I am a walk‐in refrigeration system manufacture

condensing units separately, but I don’t want to have to ce

condensing units with every possible unit cooler they migh

installed with. How should I test a condensing unit?

10 CFR 431.304(c)(12) tells you how to test a walk‐in cooler 

freezer refrigeration system component distributed individu

• 10 CFR 431.304(c)(12)(ii) says: Calculate the AWEF for a

refrigeration system containing a condensing unit that is

distributed individually using the following nominal value

• Use the nominal values when conducting the DOE test pr

as noted in 10 CFR 431.304(c)(10).

• The applicable standards are the dedicated system standa

§431.306(e).

Remember, representations of the energy efficiency of a basic model 

based on a sample of units of that basic model.
32

How the Test Procedure is AppliedExample 4, continued: What are these nominal values? How do I use them?

• The nominal values are used to calculate “dummy” unit c

characteristics such as fan and defrost wattage so you do

to test an actual unit cooler (or every possible unit cooler

your condensing unit.

• The nominal values are designed so that the unit cooler v

scale with the size of the system you are trying to test. Fo

example, the bigger the system, the more fan power is as

• The nominal values are designed not to penalize you for u

them! In other words, they assume the unit cooler has ce

design options that help the system meet the dedicated s

standards in DOE’s analysis.
33

How the Test Procedure is AppliedExample 4, continued: Can you give an example of how the nominal values to find the AWEF for a condensing 

Yes! Let’s consider a condensing unit

with the following characteristics:• Fixed capacity

• Designed for indoor use• Designed for a walk‐in freezer• Implements hot gas as a defrost

mechanism and does not have anyinstructions for defrost frequency

• Has two ECM condenser fans with

1/15 horsepower motors
34

How the Test Procedure is AppliedExample 4, continued:Follow 3 basic steps to determine the AWEF for this uni

1. Test the condensing unit under the rating condition

the DOE test procedure.

2. Calculate the nominal values for the “dummy” unit 

3. Use the test values and nominal values to calculate 

AWEF.
35

How the Test Procedure is AppliedExample 4, continued:Step 1: Test the Condensing Unit• From 431.304(c)(10): Determine the Annual Walk‐in Energy Fa

walk‐in cooler and walk‐in freezer refrigeration systems by con

the test procedure set forth in AHRI 1250‐2009 (incorporated b

reference; see §431.303)

• Find the rating conditions in AHRI 1250‐2009 that correspond t

of equipment being tested.
36

How the Test Procedure is AppliedExample 4, continued:Step 1: Test the Condensing Unit (continued)• Note that you only have to perform the suction A tes

Suction B test is if you are testing an actual unit coolcalculating a combined rating using the mix‐match mSection 7.8 of AHRI 1250‐2009, but DOE does not us

method.)
37

How the Test Procedure is AppliedExample 4, continued:Step 1: Test the Condensing Unit (continued)• Let’s say you perform the test. You get the following 

• Gross refrigeration capacity = 5,500 Btu/h

• Input power of condensing unit = 1,500 Watts
38

How the Test Procedure is Applied

Example 4, continued:Step 2: Calculate the nominal values for the unit cooler10 CFR 431.304(c)(12)(ii) describes how to calculate the nomin

based on the type of system.

• First determine the nominal values for the evaporator fans:

• On‐cycle evaporator fan power EFcomp,on = 0.016 × Gross capa

• Off‐cycle evaporator fan power EFcomp,off = 0.2 × on‐cycle evap

power = 18 W

• Next determine the nominal values for defrost:

• Hot gas defrost heat contribution per cycle = 0.18 × Gross cap

990 Btu/h

• Hot gas defrost energy use per cycle = 0.5 × hot gas defrost h

contribution / 3.412 = 145 W

• # of defrost cycles = 2.5 (because there are no manufacturer

instructions)
39

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEFUse the calculations in AHRI 1250‐2009, Section 7:There are some intermediate values you need to find...
40

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEF (continued)• Calculate the net capacity:

• Net capacity qss = Gross capacity – EFcomp,on × 3.412 = 5,2

• Calculate the total on‐cycle energy use:

• Energy use Ess = Measured condensing unit energy use + 

evaporator fan power = 1,588 W
41

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEF (continued)• Calculate average daily defrost energy and heat load

• Daily defrost energy use DF = Defrost energy use per cy

cycles = 363 W

• Daily defrost heat contribution QDF = Heat contribution 

# of cycles = 2,475 Btu/h

• Calculate defrost energy and heat contribution using 

equations in section C11.3 of AHRI 1250‐2009:

• Average defrost watts ࡲࡰ

ሶ

ൌ

஽ி

ଶସ

܅	૞૚ ൌ

• Average defrost heat contribution ࡽ

ሶ

ൌ ࡲࡰ

ொವಷ

ଶସ

۰	૜૙૚ ൌ
42

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEF (continued)• Calculate the Box Loads using the equations in sectio

AHRI 1250‐2009:

• BLH = 0.8 × qss = 4,160 Btu/h

• BLL = 0.4 × qss = 2,080 Btu/h

• Calculate the Load Factors using the equations in sec

AHRI 1250‐2009:

• ࡴࡲࡸ ൌ ஻௅ுାଷ.ସଵଶൈாி೎೚೘೛,೚೑೑ା	ொ

ሶ

ವಷ

௤ೞೞାଷ.ସଵଶൈாி೎೚೘೛,೚೑೑

ൌ ૙. ૡ૛

• ࡸࡲࡸ ൌ ஻௅௅ାଷ.ସଵଶൈாி೎೚೘೛,೚೑೑ା	ொ

ሶ

ವಷ

௤ೞೞାଷ.ସଵଶൈாி೎೚೘೛,೚೑೑

ൌ ૙. ૝૜
43

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEF (continued)• Recap values that were just calculated:

• qss = 5,200 Btu/h

• Ess = 1,588 W

• EFcomp,off = 18 W

• ܳ

ሶ

஽ி = 103 Btu/h

ܨܦ •

ሶ

= 15 W

• n = 8760 h (since it is an indoor unit)

• Plug these values into the equation to calculate the A
44

How the Test Procedure is AppliedExample 4, continued:Step 3: Calculate the AWEF (continued)• Calculate the total annual box load and energy use:

• ∑ ࡸ࡮ ൌ 0.33 ൈ ܪܮܤ ൅ 0.67 ൈ ܮܮܤ ൈ ݊ ൌ ૛. ૝ ൈ ૚૙

ൌ ࡱ ∑ •

0.33 ൈ ܧ௦௦ ൈ ܪܨܮ ൅ ܨܧ௣௠௢௖, ௙௙௢ൈ 1 െ ܪܨܮ

ܨܦ ൅ ܮܨܮ െ 1 ൈ௢௙௙ ,௖௢௠௣ܨܧ ൅ ܮܨܮ ൈ ௦௦ܧ ൈ 0.67൅

ሶ ൈ 

ൌ ૠ. ૞ ൈ ૚૙૟	ܐ܅

• Finally, the AWEF:

ܐ܅/ܝܜ۰	૛૛ .૜ ൌ ா ∑ ஻௅ ∑ ൌ ۳۴܅ۯ •
45

How the Test Procedure is AppliedExample 4, continued: I’ve tested my unit and found it

How can I compare it to the new energy conservationstandard for this type of product?

Determine what equipment class the equipment is in:

• It is a condensing unit so it is dedicated condensing = 

• It is for a freezer so it is low temperature = L

• It is designed for use inside so it is indoor = I• Its gross capacity is 5,500 Btu/h which is < 9,000

The class is

DC.L.I, <9,000
46

How the Test Procedure is AppliedExample 4, continued• This equipment class has an equation for minimum A

shown in 10 CFR 431.306(e):
47

How the Test Procedure is AppliedExample 4, continued• Plugging the gross capacity into the equation:

• AWEF = 5.93 × 10‐5 × Q* + 2.33 = 2.62*Q = the gross capacity

• Compare this to the tested AWEF of 3.22• Calculated AWEF 3.22 > Minimum AWEF 2.62• The test result from the unit is higher than the minim

standard!

• Don’t forget that you need to test a sample of units t

and demonstrate compliance!
48

How the Test Procedure is AppliedExample 5: I am a walk‐in panel manufacturer. I want 

refrigeration systems with my panels. How do I make am in compliance with the refrigeration standards?Be sure you are selling certified refrigeration systems, w

can consist of unit coolers and condensing units tested

separately or as matched systems.That’s it! You do not have to do any testing or certificatthe refrigeration systems you sell...unless you wish to re

the efficiency of the refrigeration system as being highethe certified rating(s), or if you modify the refrigeration 

such that it changes the efficiency.
49

Public Meeting Slides Topics

1 Test Procedure Background2 Scope of Test Procedure for Refrigeration3 How the Test Procedure is Applied4 Sampling and AEDM Requirements5 Other FAQs
50

Sampling and AEDM Requirements

I am a walk‐in refrigeration system manufacturer. I want representations of the certified ratings of my equipment

do I do?• For each basic model, you have to determine your repr

value based on a sample of units within a basic model.

• In §429.53, Walk‐in coolers and walk‐in freezers:

(a) Determination of represented value—(1) Refrigeration equip

Manufacturers must determine the represented value, which 

the certified rating, for each basic model of walk‐in cooler or 

refrigeration equipment, either by testing, in conjunction wit

applicable sampling provisions, or by applying an AEDM satis

criteria provided at §429.70(f)(1).

(i) Units to be tested. (A) If the represented value for a given basic 

determined through testing, the general requirements of §429.1
51

Sampling and AEDM RequirementsWhat are the requirements in §429.11?

• Here are the main points:

• You have to test at least two units of a basic model to d

its certified rating.

• The units on which the rating is based must be producti

(or units representative of production units) – in other w

they have to be units produced for sale, not demo units

• The tested units must be selected at random.

• Components of similar design may be substituted witho

additional testing if the substitution does not affect the 

rating.

• Any represented values of measures of energy efficienc

efficiency, energy consumption, or water consumption f

individual models represented by a given basic model m

the same.
52

Sampling and AEDM RequirementsHow do I derive a rating for my equipment from my teresults?§429.53(a)(1)(i)(B)(2) says that the represented value o

efficiency of a basic model shall be less than or equal to lower of:

(i) The mean of the test sample resultsOr(ii) The lower 95 percent confidence limit (LCL)* of th

mean divided by 0.95.

*The LCL can be found using the equation: ܮܥܮ ൌ ݔ̅െ ݐ଴.ଽହ ௦௡Where:x

̅is the sample mean;

s is the sample standard deviation;

n is the number of samples; and

t0.95 is the t statistic for a 95% one‐tailed confidence interval with n−1 degrees of freedom

(from Appendix A to subpart B).
53

Sampling and AEDM RequirementsI want to minimize my test burden. Is there another way I c

determine the efficiency of a basic model of WICF refrigera

equipment?Yes! See §429.53(a)(1)(ii): Alternative efficiency determinatio

methods. In lieu of testing, a represented value of efficiency 

consumption for a basic model of a walk‐in cooler or freezer

refrigeration system must be determined through the applic

an AEDM pursuant to the requirements of §429.70 and the p

of this section.An Alternative Efficiency Determination Method (AEDM) is jit sounds like – an alternative method for determining the

represented value of a basic model of your equipment, that 

use in lieu of testing.
54

Sampling and AEDM RequirementsThat sounds easy! ...What’s the catch?

You can’t use just any method. §429.70 contains certain

requirements for using an AEDM.For instance, you can only use an AEDM if:

• The AEDM estimates the model’s energy consumptio

thought it were being measured by the DOE test pro

• The AEDM is based on engineering or statistical anal

computer simulation or modeling, or other analyticaevaluation of performance data; and

• You have validated the AEDM with testing of produc

units.
55

Sampling and AEDM RequirementsHow do I validate my AEDM?

§429.70(c)(2) contains instructions for validating AEDM

In summary, you must validate an AEDM by both testin

modeling one unit from each of at least 2 basic models validation class and comparing the results.

For each basic model, the efficiency predicted by the A

must not be more than 5 percent greater than the effic

determined through testing, and the efficiency predicte

AEDM must meet or exceed the applicable federal ener

conservation standard.
56

Sampling and AEDM RequirementsWhat is a validation class?

A validation class is a category of equipment from whic

must select products to test, if you want to use an AEDM 

that class.

Validation classes for walk‐in coolers and freezers can b

in 10 CFR 429.70(f)(2)(iv).
57

Sampling and AEDM RequirementsCan I use test results from one validation class to validanother class?Generally, AEDMs validated for outdoor classes may be 

indoor classes (of the same temperature class and cond

type).The opposite is not true – AEDMs validated for indoor cmay not be used for outdoor classes!
58

Sampling and AEDM RequirementsWhat other validation requirements are there?

There are a few additional requirements for the models validate the AEDM:

• Test data must be from physical tests of current mod

• Test results must meet or exceed current Federal sta• Tests must be performed in accordance with the app

DOE test procedure.

• For rating a refrigeration system consisting of an indi

component (unit cooler or condensing unit), the AED

estimate the system rating using the nominal values DOE test procedure for the other component.
59

Sampling and AEDM RequirementsI’ve validated my AEDM! How can I apply it to unteste

models to generate my ratings and reduce my testing 

Once your AEDM has met the validation criteria, you mto generate ratings for all of your untested basic model

which the AEDM has been validated.

While DOE does not require periodic testing to check o

AEDM’s accuracy over time, manufacturers are encouraensure the results of their AEDM remain accurate and t

represented ratings are valid.
60

Sampling and AEDM RequirementsI’ve validated and can begin using my AEDM! What recI need to keep?You need to have available on request for inspection by • The AEDM itself (including the mathematical model,

engineering or statistical analysis, and/or computersimulation that is the basis of the AEDM)

• Equipment information, complete test data, AEDM

calculations, and statistical comparisons from the un

were tested to validate the AEDM

• Equipment information and AEDM calculations for e

model to which the AEDM has been applied
61

Public Meeting Slides Topics

1 Test Procedure Background2 Scope of Test Procedure for Refrigeration3 How the Test Procedure is Applied4 Sampling and AEDM Requirements5 Other FAQs
62

FAQ 1Q:There are refrigeration units currently in production for th

market that contain multiple condensing units for dedicated

refrigeration systems. These condensing units are independe

each other except that they have a common enclosure and scommon condenser fan and fan motor. Are these units cove

the regulation?

A: Based on the characteristics of the WICF refrigeration syst

described above, this assembly seems to be a multiplex cond

unit since it is designed to serve multiple WICFs. In particula

condensing units share a common condenser fan and fan mo

there is no method within the test procedure to separate ou

power for each independent condensing unit. Remember, it ultimately the manufacturer’s responsibility to compare its p

characteristics to DOE’s regulations to determine applicabilit

test procedures and standards.
63

FAQ 2Q: There are refrigeration units, specifically Condensing 

on the market today for the WICF market that operate f

+40°F to ‐30°F. These units can be categorized as "Coole"Freezers." Most of the time, the manufacturer does no

how the unit will be applied in the field. Under what ca

should these units be tested?A: Such “convertible” products would need to be tested 

medium temperature and low temperature systems an

need to meet the applicable standards.
64

FAQ 3Q: There are refrigeration units currently in production 

WICF market that are capable of being used with multiprefrigerants without any changes to the equipment. Theare often sold under a single model number and the en

customer applies any approved refrigerant. Can these u

listed with the minimum AWEF for all compatible refrig

are separate model numbers and AWEF values required compatible refrigerants?A: These units can be listed as a single basic model base

the results from testing with the refrigerant that results lowest efficiency (assuming the manufacturer does not 

claim the differences in efficiency resulting from using vrefrigerants).
65

FAQ 4Q: When calculating the AWEF of a medium temperatu

dedicated condensing unit with electric or hot gas defro

which are sold separately, what value shall be assigned 

defrost energy per cycle and heat contribution per cycle

A: The test procedure does not have a method for testi

electric or hot gas defrost on medium temperature syst

AHRI 1250‐2009 specifies that the defrost test method freezers only. The basic model must meet the standard 

tested without defrost.
66

FAQ 5Q: If a piece of equipment is not capable of operating aspecified test conditions, can that piece of equipment b

at test conditions that are as close to the specified cond

possible? For example, if a condensing unit has a minimcapable SST of +40°F and the test procedure requires ru

+25°F, can the test be run at +40°F (similar to CRE testprocedure)?A: The test procedure does not have rating conditions f

equipment. The manufacturer must apply for a test prowaiver.
67

FAQ 6Q: If a manufacturer identifies a low volume energy sav

feature that will require extensive testing, to lower the burden, can the unit be tested with the feature deactiv

rate the unit at the least efficient point?A: Yes! 10 CFR 429.11 allows for components of similar 

to be substituted without additional testing if the subst

does not affect the certified rating.
68

FAQ 7Q: When calculating the heat load from hot gas defrostvalue is a manufacturer required to use for QDF on a tw

capacity or variable‐capacity refrigeration system?

A: Manufacturers would conduct the hot gas defrost te

using the calculations in 10 CFR 431.304(c)(10)(xii). For gross capacity term, the capacity as measured at the hiambient condition and at high‐speed operation should 
69

FAQ 8Q: For hot gas unit coolers sold separately the manufac

does not know how the unit is going to be applied (with multiplex condenser or dedicated condenser). How sho

these be rated?

A: 10 CFR 431.304(c)(12)(i) states that manufacturers m

calculate the AWEF for a refrigeration system containin

cooler that is distributed individually using the method testing a unit cooler connected to a multiplex condensisystem.