Department of Energy

Washington, DC 20585

MAR 16 2004-

Mr. Karim Amrane

Air-Conditioning and Refrigeration Institute

4100 N. Fairfax Dr., Suite 200

Arlington, VA 22203

Dear Mr. Amrane:

I am writing in response to your November 4, 2003, letter which was in response to our

letter of July 25, 2003, and a follow up to the October 1, 2003, meeting regarding Single

Packaged Vertical Units (SPVUs).

In our July 25th letter, we stated our belief that Addendum d to the American Society of

Heating, Refrigerating and Air-Conditioning Engineers (ASHRA.E) Standard 90.1-2001

(Addendum d), as originally presented, was intended to establish single packaged vertical

air conditioners (SPVACs) and single packaged vertical heat pumps (SPVHPs) as new

categories of heating, ventilating and air-conditioning equipment and to establish test

procedures and standards for these products, but that it did not accomplish what was

intended. We also stated that the Department could not adopt Addendum d's standards

and test procedures as Federal requirements, for the following reasons. First, under its

literal terms, the Addendum appears to prescribe requirements for few if any products

covered by the Energy Policy and Conservation Act (EPCA). Second, to the extent

Addendum d prescribed standards and test procedures for SPVUs that are covered by

EPCA, it did so in a way that was unclear and not in accord with the statutory scheme

because it disregarded EPCA's definitions and classification-, for air-conditioning

products. And third, for some categories of products, the Addendum appears to contain

standards that are lower than the minimum efficiency levels currently required under

EPCA. Finally, we indicated that, if these defects in Addendum d were corrected, the

Department would evaluate the minimum efficiency levels set for SPVIJs to determine

whether to adopt these levels or pursue higher levels, and would also evaluate the test

procedure adopted by ASHRAE for SPVU products to determine if it met EPCA

requirements.

The Department may not adopt changes in an industry test procedure prescribed by

ASHRAE Standard 90.1-2001 (Standard 90.1) if the amended industry test procedure

would not meet certain test procedure requirements established under EPCA. The

Department is also prohibited from prescribing any amended standard that increases the

maximum allowable energy use, or decreases the minimum required energy efficiency, of

a covered product.

As to the first of the issues identified in our July 25th letter, EPCA mandates that DOE

evaluate amendments to Standard 90.1, for adoption as Federal standards and test

procedures for commercial products, only if such amendments are for EPCA covered

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products. In light of the exclusions set forth in Section 3 of ARI Standard 390 (ARI 390),

however, the amendments contained in Addendum d appeared not to apply to products

covered by EPCA. The draft revision to ARI 390 provided in your November 4 letter

eliminates the exclusions just referred to and instead contains a subsection on

"Applicability" which provides that other ARI rating standards for small and large

commercial equipment will not apply to SPVUs. These proposed changes to ARI 390

indicate that any standards and test procedures that ASHRAE prescribes for SPVU

products would apply to equipment covered by EPCA, and appears to resolve the first

issue raised in our letter of July 25.

As to the second issue, you have redefined SPVACs and SPVHPs as a type of air-cooled

small or large commercial package air conditioning and heating equipment, and have

created categories for these products that correspond to product categories in EPCA, with

standards for each category. Included in these revisions is the removal of certain

products from Addendum d and ARI 390, so as to eliminate some overlapping product

categories. As now written for SPVUs:

• SPVAC do not include reverse cycle refrigeration as a heating means;

• SPVHPs use reverse cycle refrigeration as its primary heat source;

• The cooling capacity ranges for SPVAC products includes: <65,000 Btu/h (65

kBtu/h) three-phase single package equipment, <65 kBtu/h single-phase single

package equipment, X65 kBtu/h to 135 kBtu/h single-phase or three-phase

single package equipment, and >_ 135 kBtu/h to 240 kBtu/h single-phase or

three-phase single package equipment;

• All covered SPVU products use air cooled condensers; and

• Single-phase SPVU product condensers are located with the evaporator.

Your deletion of the term "unencased" from the SP v'U definition clearly differentiates

the SPVU class from packaged terminal air conditioners and packaged terminal heat

pumps and removes overlap with the EPCA definitions for these products.

Revised Tables 1 and 2 of ARI 390 and Addendum d now clearly show that the amended

standards and test procedures apply only to air-cooled air-conditioners (ACs) and heat

pumps (HPs). Previously the range of products covered by Addendum d was unclear. As

a result of the suggested modifications, the proposed ASHRAE 90.1-2001 Table 6.2.1D

now differentiates subcategory or rating conditions consistent with the product categories

in EPCA.

If the proposed ASHRAE addendum is accepted as shown, the amended ASHRAE

Standard 90.1-2001 and ARI 390-2003 would have product subcategories for SPVUs that

are uniquely defined, consistent with preexisting EPCA provisions and clearly delineated

products to which Standard 90.1 amendments apply.

The third issue concerned EPCA requirements that new standard levels not be lower than

current efficiency requirements. In its review of Addendum d, the Department identified

several instances where it appeared there was a lowering of standards:

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• AC/HP 65-135 kBtu/h cooling where your proposed 8.6 energy efficiency ratio

(EER) was below the EPCA 8.9 EER;

• AC/HP 65-135 kBtu/h heating where your proposed 2.7 COP was below the

EPCA 3.0 COP;

• HP 135-240 kBtu/h heating where your proposed 2.7 COP was below the EPCA

2.9 COP;

• Packaged terminal air conditioners/packaged terminal heat pumps

(PTAC/PTHP) cooling where your proposed 8.6 EER for products below 7000

Btu/h was below the EPCA 8.88 EER; and

• PTHP heating where your 2.7 COP for products below 7000 Btu/h was below

the levels established by EPCA for that capacity range of PTHP.

The statute prescribes the minimum efficiency standards just referred to in 42 USC

6313(a).

Your efforts to resolve efficiency standard problems in the revised Standard 90.1

Addendum d include:

• For SPVUs between 65-13 5 kBtu/h - You proposed a minimum EER of 8.9 for

SPVACs and a minimum EER of 8.9 and COP at 47°F of 3.0 for SPVHPs.

These levels are equivalent to the existing federal minimums.

• For SPVUs between 135 - 240 kBtu/h - You proposed a minimum EER of 8.6

for SPVACs and a minimum EER of 8.6 and COP at 47°F of 2.9 for SPVHPs.

The proposed EER is greater than the existing federal minimum 8.5 EER and

the proposed COP equivalent to the existing federal minimum.

• By removing PTACs and PTHPs from Addendum d and ARI 390, you have

eliminated the problem identified by DOE. There is no reduction in efficiency

as they are not covered in the proposed amended standard.

As to SPVU equipment less than 65 kBtu/h, in addition to your letter with attached

revised ARI Standard 390, we have reviewed the three graphs (exhibits 2-4) showing the

relationship between seasonal energy efficiency rating (SEER) and EER for SPVACs and

SPVHPs and the relationship between heating seasonal performance factor (HSPF) and

coefficient of performance (COP) for SPVHPs. ARI has proposed to change the rating

metrics associated with these products from SEER to EER for cooling and from HSPF to

heating COP for heating, and has proposed a standard level of 8.9 SEER and 2.7 COP.

We agree that the change to using the EERJCOP energy descriptors is significant and

more properly reflects the intended use of SPVUs as commercial equipment. However,

EPCA precludes the Department from adopting the proposed EER and COP levels in

Addendum d unless they are at or above EPCA's current required efficiency (expressed

in terms of SEER and HSPF levels) for three-phase products below 65 kBtu/h cooling

capacity.

The SEER and HSPF metrics were developed to measure efficiency in residential

applications based on operation of equipment throughout the course of a year, whereas

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the EER and COP metrics rate a product's efficiency without regard to its application or

seasonal variations. Because they take into account the variation of performance with

ambient conditions and with cycling losses, the SEER and HSPF metrics consider more

factors and are more complicated rating procedures than the EER and COP metrics. As

with many rating metrics that are used for essentially the same purpose, there is not a

one-to-one correspondence between ratings produced under SEER and EER or HSPF and

COP. Differences in product design may result, for example, in a group of products that

are all at one rating level under the first metric but have a distribution over a range of

levels under the second metric. Thus, assuring that standards prescribed under a new

metric would provide energy efficiency levels equivalent to the levels under the previous

metric is complicated and not an exact science.

The differences between SEER and EER are less significant, and the two metrics are

more comparable, than is true for the HSPF and COP metrics. As indicated above, both

SEER and HSPF include consideration of cycling losses, which are not part of EER or

COP. As a general rule, however, the impact of such losses is less significant in

commercial than residential equipment. In addition, the presence of a default value for

the cycling loss degradation coefficient in the SEER metric, limits the amount the SEER

test procedure actually constrains these losses. As to the other factors considered in the

SEER metric but not in EER, the absence of any of these factors from the EER metric

would intrinsically allow a product rated by EER to be less efficient than if rated by

SEER.

Comparing SEER and EER ratings for current models of SPVAC equipment less than 65

kBtu/h, the data that you provided identified only one SPVAC product with a SEER of

9.7, the minimum cooling efficiency level currently prescribed for these products by

EPCA. (One other product identified in your data as having a SEER of 9.7 appears to

have bcer1 an SPFiP misclassiiicd as an SPVAl C). The EER for this SSPVAC.. was 8.5.

Your proposal of an EER of 8.9 is clearly above this level. However, there were 16 other

products with a SEER of 10 and with EERs ranging from 8.9 to 9.7, averaging 9.21. The

average difference between SEER and EER ratings is, therefore, approximately 0.8

points. If the same difference in rating was added to your proposed 8.9 EER, the

corresponding SEER would be 9.7. This suggests that products designed to the proposed

8.9 EER level would provide roughly the same level of efficiency as products designed to

the existing SEER 9.7 rating.

For current models of SPVHP equipment less than 65 kBtu/h, the data that you provided

identified only one SPVHP product with a SEER of 9.7, and it had an EER of 8.5 (see

previous paragraph). There were, however, 14 SPVHP products with a SEER of 10.0.

The average EER for these products was 9.13. The average difference between SEER

and EER ratings for these products, therefore, is approximately 0.87 points, suggesting

that an EER of 8.9, as ARI is proposing, corresponds roughly to a SEER rating of nearly

9.8 for these products. This exceeds the current SEER rating of 9.7. This again suggests

that the proposed 8.9 EER will maintain roughly the same level of cooling efficiency as

the current standard and may even be a slight increase.

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The foregoing information indicates that the EER level proposed in Addendum d for

three-phase SPVU equipment less than 65 kBtu/h is at or above the current EPCA

cooling efficiency level for these products.

With respect to the proposed minimum COP, we note initially the differences between

the current HSPF metric and the COP metric. The HSPF procedure requires

measurement of full load performance (COP) at two sets of outside air conditions, 47°F

and 17°F. In addition, it includes provisions for a cycling loss degradation factor

(discussed above), provides assumptions for the fractions of heating hours at different

conditions, and takes into account the backup electric resistance heat typically installed

with these products. By contrast, COP is a full load measurement of performance at one

specified set of conditions.

For current models of SPVHP equipment less than 65 kBtu/h, the data you provided

indicates that 26 models have an HSPF of 6.6, the minimum heating efficiency level

currently permitted under EPCA. The COPs for these models range from 2.7 to 3.0,

averaging 2.86. You have proposed to set a minimum COP at 2.7. This is the COP

rating for approximately 10 percent of the current SPVHP models less than 65 kBtu/h,

and is the lowest COP rating for any SPVHP currently on the market. Moreover, this

proposed heating efficiency level does not address energy that SPVHPs use, first, to

provide electric resistance backup heat needed to meet the heating load at low

temperatures, and, second, to defrost the outdoor coil. Because the existing HSPF metric

takes account of such energy - particularly for electric resistance heat - it appears that

your proposed standard would allow any SPVHP subject to the standard to have a lower

overall efficiency (net space heating output over electrical input) than is currently

required.

lNotwithstanding, that the proposed 2.7 COP level may represent a towel efiieleilcy than

the current 6.6 HSPF level, conceivably the combined effect of the proposed EER of 8.9

and COP of 2.7 would be such that the proposed standard would not represent a decrease

of the minimum efficiency currently required for SPVHPs , although the Department is

aware of no information that would establish such a conclusion. But even if this type of

information exists, it may not be possible to accept a standard for SPVHPs that fails to

address electric resistance heat, because such a standard might inherently allow products

to be less efficient than required by current standards.

In sum, we are still concerned about whether Addendum d's COP level for three-phase

SPVUs below 65,000 Btu/h cooling capacity is at or above the current EPCA level for

these products. We would strongly suggest that, if ARI still wishes to pursue a new

heating efficiency level for these products, you either provide us with information

demonstrating that the proposed COP level meets this requirement , or consider proposing

a new heating efficiency requirement.

Finally, we intend to proceed with a screening analysis on those SPVU products for

which ARI's proposed standard is at or above the EPCA level, to determine whether

DOE should explore the development of more stringent standards. In addition, we are

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reviewing whether the new test procedures in ARI 390 meet the statutory.requirements

that they be reasonably designed to assess the products and produce accurate results, and

not be unduly burdensome to conduct. We also need to determine whether the ARI 390

test procedure would produce any changes in measured efficiency levels and, if so, what

those changes would be and whether they would affect your proposed standards.

The above represents staff opinion and does not necessarily represent the views of the

Secretary or official Department of Energy policy.

We hope this additional feedback is helpful in moving this issue forward. If you

have any questions or wish to discuss any of the above points further, please contact

Ms. Maureen Murphy of my staff at 202-586-0598.

Mic ael J. NCabe

Program Manager

Building Technologies Program

Energy Efficiency and Renewable Energy

Cc:

Claire Ramspeck

Manager of Standards

American Society of Heating , Refrigerating and Air-Conditioning Engineers, Inc.

17 911L Tullie Circle

Atlanta, GA 30329-2305

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