APPENDIX 5-C. ENGINEERING QUESTIONNAIRES
 

TABLE OF CONTENTS 


5-C.1 RESIDENTIAL CLOTHES DRYER ENGINEERING QUESTIONNAIRE....... 5-C-1
 

5-C.2 ROOM AIR CONDITIONER ENGINEERING QUESTIONNAIRE................ 5-C-11
 

5-C-i 

EERE-2007-BT-STD-0010 COMMENT 20.3
APPENDIX 5-C. ENGINEERING QUESTIONNAIRES 

5-C.1 RESIDENTIAL CLOTHES DRYER ENGINEERING 

QUESTIONNAIRE 

The engineering questionnaire used as a guide for engineering discussions during 

manufacturer interviews is shown in this section. Some of the information provided in 

the questionnaire has been redacted to protect vendor information. 

5-C-1 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

 

 

 

DESIGN FOR ENERGY IMPROVEMENT INFORMATION REQUEST 

The United States Department of Energy (DOE) is currently reviewing energy 

conservation standards for residential clothes dryers. DOE would like to confirm 

information on the incremental costs of increasing product efficiency by understanding 

the design options involved in the efficiency improvement. 

1. Market Share of products you sell 

To help DOE discover manufacturer sub-groups and the relative importance of various 

product classes to specific manufacturers, please disaggregate your annual unit shipments 

for each product category as shown below. Please also indicate whether you purchase 

these products from other manufacturers (i.e. private label), and whether the factory that 

supplies the product is located in the United States. 

Product Class % Private 

Label % Made in US Yearly Unit Shipments 

Vented Electric Standard 

Vented Electric Compact, 120V 

Vented Electric Compact, 240V 

Vented Gas 

Vent-less Electric Compact, 240V 

Vent-less Electric Combination 

Washer/Dryer 

2. Product Design Features 

The following series of exhibits and questions address technical characteristics of key 

residential clothes dryer components for both baseline and improved-efficiency products. 

Baseline Clothes Dryers 

Which design features impacting energy use are generally incorporated into a 

“baseline” clothes dryer (i.e. one that just meets existing energy factor standards, 

if any) in the following product classes: 

o Vented Electric Standard? 

o Vented Electric Compact, 120V? 

o Vented Electric Compact, 240V? 

o Gas? 

o Vent-less Electric Compact, 240V? 

o Vent-less Electric Combination Washer/Dryer? 

5-C-2 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

 

 

 

 

 

Vented Clothes Dryers 

DOE has updated the efficiency levels for the vented clothes dryer analysis that were 

presented in the Framework Document, based upon the more recent November 2008 

California Energy Commission (CEC) directory and 2008 Natural Resources Canada 

(NRCAN) directory (for electric compact (240V) only). Values that are different than 

those in the Framework Document are highlighted in blue in the table below. 

Since insufficient product data was available for electric compact (120V) clothes dryers, 

the efficiency levels for this product class were generated by applying a scaling factor 

developed using the relationship between the current standards for the electric standard 

and electric compact (120V) product classes (equal to 3.13/3.01 = 1.04). 

Are the updated maximum available efficiency levels appropriate?
 

Do you agree with the methodology that was used to generate the electric 


compact (120 V) efficiency levels?
 

Do you believe that the gap-fill efficiency levels defined by DOE for vented 


electric standard, electric compact, and gas clothes dryers are representative? If
 

not, can you suggest appropriate gap-fill values?
 

Level Efficiency Level Source 

Efficiency Level (lb/kWh) 

Electric 

Standard 

Electric 

Compact 

(120V) 

Electric 

Compact 

(240V) 

Gas 

baseline DOE Standard 3.01 3.13 2.90 2.67 

1 Gap Fill 3.10 3.22* 2.98 2.75 

2 Gap Fill 3.16 3.29* 3.09 2.85 

3 Maximum Available 3.4 3.54* 3.2 3.44 

* Estimated by scaling from electric standard clothes dryer efficiency levels. 

What design changes are associated with converting a baseline unit to the updated 

efficiency levels for each vented clothes dryer product class (see Tables below)? 

What are the costs of the individual design options selected? When considering 

energy efficiency improvements, do different product classes take different 

pathways or are pathways similar? 

Are the aggregated industry costs submitted by AHAM (highlighted in red in the 

Tables below) for the efficiency levels presented in the framework document 

representative of your firm’s costs? Please edit these values as appropriate. 

Are there fundamental differences between required design changes that make the 

cost increment much higher for some product classes than others? 

Would you help DOE understand and estimate the conversion capital investments 

that would be necessary at each candidate standard level? What is the nature of 

the capital investments? 

5-C-3 


EERE-2007-BT-STD-0010 COMMENT 20.3
Product Class � Vented Electric Standard Vented Electric Co

Efficiency Level 1 2 3 1 2 Updated EF (lb/KWh) 3.10 3.16 3.4 3.22 3.29 Framework Document EF (lb/KWh) 3.10 3.16 3.39 - - Design Options 

Average Incremental Costs ($ Per Unit) 

Material 9 42 140 Labor 2 11 45 Overhead# 2 4 12 

Minimum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Maximum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Conversion Capital Expenditures ($, Millions) 

Building CAPX 0.25 9.02 50.18 Tooling/ Equipment CAPX 5.25 37.68 118.93 

One-Time Product Conversion Expenses ($, Millions) 

R&D 3.62 15.87 58.97 Marketing # Depreciation on the conversion capital expenditure should NOT be included in the incremental overhead. * Incremental costs per unit should be reported relative to the baseline unit’s cost. The baseline unit complies with the current federal standard for residential clothes dry

Cost should be reported as a shipment weighted average value. The Minimum and Maximum Incremental Costs presumably reflect the costs associated with changes to Red highlighted text indicates AHAM submitted data for the efficiency levels presented in the framework document. Other Information: 1. What depreciation method would your company use to depreciate the conversion capital expenditures? _______________________________________________. Direct material – Costs of raw materials including scrap that can be traced to final or end products. Direct material costs do not include indirect material costs which arbe used in the production process but are not assigned to final products (e.g., lubricating oil for production machinery).
 

Direct labor – The earnings of workers who assemble parts into a finished good for operate machines in the production process. Direct labor includes the fringe benefit

health care, as well as overtime pay. Direct labor does not include indirect labor which is defined as the earnings of employees who do not work directly in assembling a 

janitors, stockroom personnel, inspectors, and forklift operators.
 Overhead – Factory overhead excluding depreciation. Factory overhead includes indirect labor, downtime, set-up costs, indirect material, expendable tools, maintenanc

assets, and utility costs. Factory overhead does not include selling, general, and administrative costs (SG&A); research and development (R&D); interest; or profit (accoFull Production Cost = Direct Material + Direct Labor + Overhead (factory) + Depreciation
 Full Cost of Product = Full Production Cost + Non-production Costs (SG&A, R&D, interest, and profit)
 

5-C-4 


EERE-2007-BT-STD-0010 COMMENT 20.3
Product Class � Vented Electric Compact 240 V Vented G

Efficiency Level 1 2 3 1 2 Updated EF (lb/KWh) 2.98 3.09 3.2 2.75 2.85 Framework Document EF (lb/kWh) 2.98 3.07 3.23 2.75 2.77 Design Options 

Average Incremental Costs ($ Per Unit)* 

Material 20 60 Labor 2 6 Overhead# 2 4 

Minimum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Maximum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Conversion Capital Expenditures ($, Millions) 

Building CAPX 0.46 29.83 Tooling/ Equipment CAPX 2.62 37.24 

One-Time Product Conversion Expenses ($, Millions) 

R&D 2.99 15.46 Marketing # Depreciation on the conversion capital expenditure should NOT be included in the incremental overhead. * Incremental costs per unit should be reported relative to the baseline unit’s cost. The baseline unit complies with the current federal standard for residential clothes dryCost should be reported as a shipment weighted average value. The Minimum and Maximum Incremental Costs presumably reflect the costs associated with changes to Red highlighted text indicates AHAM submitted data for the efficiency levels presented in the framework document. Other Information: 1. What depreciation method would your company use to depreciate the conversion capital expenditures? _______________________________________________. Direct material – Costs of raw materials including scrap that can be traced to final or end products. Direct material costs do not include indirect material costs which arbe used in the production process but are not assigned to final products (e.g., lubricating oil for production machinery).
 

Direct labor – The earnings of workers who assemble parts into a finished good for operate machines in the production process. Direct labor includes the fringe benefit

health care, as well as overtime pay. Direct labor does not include indirect labor which is defined as the earnings of employees who do not work directly in assembling a 

janitors, stockroom personnel, inspectors, and forklift operators.
 Overhead – Factory overhead excluding depreciation. Factory overhead includes indirect labor, downtime, set-up costs, indirect material, expendable tools, maintenanc

assets, and utility costs. Factory overhead does not include selling, general, and administrative costs (SG&A); research and development (R&D); interest; or profit (accoFull Production Cost = Direct Material + Direct Labor + Overhead (factory) + Depreciation
 Full Cost of Product = Full Production Cost + Non-production Costs (SG&A, R&D, interest, and profit)
 

5-C-5 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

 

 

Vent-less Clothes Dryers 

DOE derived efficiency levels for the analysis of vent-less electric compact (240V) and 

vent-less combination (washer/dryer) product classes using existing test data and 

available data from the CEC 2008 directory. DOE believes that the data derived from 

each of these sources was obtained using the DOE test procedure with the requirement 

for the exhaust simulator eliminated. 

Are the baseline and maximum available levels for vent-less electric clothes 

dryers representative? Can you suggest baseline, gap-fill, and max-tech efficiency 

levels for vent-less electric clothes dryers? 

Level Efficiency Level Source 

Efficiency Level (lb/kWh) 

Vent-less 

Electric 

Compact (240V) 

Vent-less 

Combination 

(Washer/Dryer) 

baseline Baseline 2.37* 1.95* 

1 Gap Fill 2.39** 3.23†† 

2 Gap Fill 2.49 3.51 

3 Maximum Available 2.59† 3.79†† 

*Based on DOE test data. 


**Determined by scaling the existing standard for vented electric compact (240V) based 


on Miele’s voluntary plan to maintain its condenser clothes dryer EF within 82.5 percent 


of the existing non-condenser clothes dryer standard. 60 FR 9332.
 

† Based on NIST test data.1 

†† Based on CEC model data. 

What design changes are implemented to achieve higher efficiency levels for 

vent-less electric compact clothes dryers? Are these design changes comparable 

for vent-less electric combination washer/dryers? What are the costs of the 

individual design options selected? 

Are there fundamental differences between required design changes that make the 

cost increment much higher for some product classes than others? 

Would you help DOE understand and estimate the conversion capital investments 

that would be necessary at each candidate standard level? What is the nature of 

the capital investments? 

1 Kao, J. “Energy Test Results of a Conventional Clothes Dryer and a Condenser Clothes Dryer”, National 

Institute of Standards and Technology, Gaithersburg, MD, 1998. 

5-C-6 


EERE-2007-BT-STD-0010 COMMENT 20.3
Product Class � Vent-less Electric Compact (240V) Vent-less Combination (W

Efficiency Level 1 2 3 1 2 EF (lb/KWh) 2.39 2.49 2.59 3.23 3.51 Design Options 

Average Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Minimum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Maximum Incremental Costs ($ Per Unit)* 

Material Labor Overhead# 

Conversion Capital Expenditures ($, Millions) 

Building CAPX Tooling/ Equipment CAPX 

One-Time Product Conversion Expenses ($, Millions) 

R&D Marketing # Depreciation on the conversion capital expenditure should NOT be included in the incremental overhead. * Incremental costs per unit should be reported relative to the baseline unit’s cost. The baseline unit complies with the current federal standard for residential clothes dry

Cost should be reported as a shipment weighted average value. The Minimum and Maximum Incremental Costs presumably reflect the costs associated with changes to Other Information: 1. What depreciation method would your company use to depreciate the conversion capital expenditures? _______________________________________________. Direct material – Costs of raw materials including scrap that can be traced to final or end products. Direct material costs do not include indirect material costs which arbe used in the production process but are not assigned to final products (e.g., lubricating oil for production machinery). 

Direct labor – The earnings of workers who assemble parts into a finished good for operate machines in the production process. Direct labor includes the fringe benefit

health care, as well as overtime pay. Direct labor does not include indirect labor which is defined as the earnings of employees who do not work directly in assembling a janitors, stockroom personnel, inspectors, and forklift operators. Overhead – Factory overhead excluding depreciation. Factory overhead includes indirect labor, downtime, set-up costs, indirect material, expendable tools, maintenanc

assets, and utility costs. Factory overhead does not include selling, general, and administrative costs (SG&A); research and development (R&D); interest; or profit (accoFull Production Cost = Direct Material + Direct Labor + Overhead (factory) + Depreciation Full Cost of Product = Full Production Cost + Non-production Costs (SG&A, R&D, interest, and profit 

5-C-7 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

Fans and Motors 

Is there any room for further, significant energy efficiency improvement via fan blade/air 


flow design improvements? If so, how much improvement can be achieved?
 

What types of fan/drum motors do you currently employ in your clothes dryers?
 

Do any of your fan motors run at multiple speeds, for example to match the output of a
 

modulating burner or heater?
 

Have you considered improved fan/drum motor efficiency as a design option? If so, how 


much improvement can be achieved?
 

What are the manufacturing costs associated with improved fan/drum motor efficiency?
 

Automatic Termination Technologies 

What percentage of your clothes dryer shipments for each product class use automatic 

termination? What percentage of your shipments for each product class use moisture 

sensors? Temperature sensors? What drives your decision of what sensor technology to 

incorporate in a given platform? 

Are consumers aware of the specific sensor technology being used inside a clothes dryer? 

o If so, are consumers demanding specific sensor technologies? 

o If not, are they drawn principally to the presence of an automatic termination 

system and care less about how it is achieved? 

How are the sensor functions implemented by consumers on your clothes dryers? Are 

they enabled by default for some drying operations? 

For what percentage of dry cycles do consumers use automatic termination? How many 

of these cycles are actively selected as sensor drying? 

Do certain sensor technologies have better performance characteristics than others? If so, 

please elaborate on which sensor types? 

Have you performed or are you aware of any research/studies that show the effects on 

energy efficiency or annual energy consumption associated with the use of automatic 

termination sensors? In particular, is there any data indicating that one sensor technology 

performs better than another? 

What are the manufacturing costs associated with each of your automatic termination 

sensor technologies? 

What are the standby power requirements for the sensor that you use? Do the sensors 

that you use have a warm-up time, and if so, what is the warm-up time? Are you aware 

of any automatic termination sensors that do not consume standby power? If not, what 

would you consider to be the lowest achievable standby power level associated with these 

sensors? 

Are you aware of any other sensor or alternative technologies you would consider for 

automatically terminating the drying cycle? 

How wide of a supplier base can you choose from when sourcing sensors, or do you 

make your own? 

Are you aware of any intellectual property or patent infringement issues that might affect 

your choice of sensor technologies? 

5-C-8 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

 

 

 

 

 

 

 

Other Dryer Control or Drum Upgrades 

Have you considered increased insulation as a design option? If so, what thicknesses and 

insulation materials have you considered? How much efficiency improvement can be 

achieved? What would be the incremental manufacturing cost? 

Have you explored any ways of improving the air circulation in your dryers (i.e. directing 

and maintaining heat more efficiently)? If so, how much efficiency improvement can be 

achieved? What would be the incremental manufacturing cost? 

Do you have any data showing any efficiency improvements associated with reverse 

tumble (during the drying cycle, as opposed to after the cycle as wrinkle prevention)? 

What is the incremental manufacturing cost of this design option? 

DOE’s research showed that the efficiency of a clothes dryer can be improved slightly by 

the design of the drum (e.g., internal vane design or enhanced surface textures). Have 

you considered improvements to the drum design? If so how much efficiency 

improvement can be achieved? What would be the incremental manufacturing cost? 

Exhaust Heat Recovery and Infiltration Abatement (vented models) 

Do you manufacture vented clothes dryers with an outdoor air supply? If not, what are 

the reasons? If you do offer models with an outdoor air supply option, do they feature 

sealed combustion? 

Do you manufacture any dryers that recycle exhaust heat? If so, please elaborate on how 

this is done? For example, is some of the exhaust air recycled to the inlet during a certain 

portion of the drying cycle or is a heat exchanger used to recover exhaust heat energy and 

to preheat inlet air? How much efficiency improvement can be achieved? What is the 

incremental manufacturing cost? 

Modulating Heater Designs 

Do any of your gas dryer models use modulating gas burners? Have you considered this 

design option? 

Do you have any data showing the efficiency improvements associated with modulating 

gas burners? DOE’s research shows that a modulating gas dryer design can reduce 

energy consumption by up to 25% for small and medium sized loads, and 10% for larger 

loads. Would you consider this accurate? 

Do any of your clothes dryers use a multi-step or modulating electric heater? What is the 

associated efficiency improvement with using a modulating or stepped electric heater 

versus a standard on/off electric heater? 

Heat Pump Dryers 

Do you manufacture heat pump dryers? If not, have you considered this technology?
 

What type of refrigerant is used? What type of compressor? What types of heat
 

exchangers are used?
 

DOE’s research shows that this design option can achieve 50-68% efficiency
 

improvement compared to conventional electric dryers. Would you consider this 


accurate?
 

5-C-9 

EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

What are the manufacturing costs associated with this design option? 

Standby Power 

What are the consumer utilities associated with each type of display used in clothes 

dryers? (Example, cycle/temperature selection, delay start time, cycle time, etc.) 

What types of display technologies do you use in your clothes dryer product line? What 

are the standby power requirements for each display type assuming a comparable display 

(size and capability)? 

Are you aware of consumers demanding specific display types or is it other clothes dryer 

features that attract them? 

What are the manufacturing costs associated with various display technologies?
 

What drives the costs for each display technology?
 

What would be the manufacturing costs associated with adding a feature to dim or turn 


off the displays? How much could this potentially decrease power consumption?
 

What clothes dryer features other than displays contribute to standby power, and what is 


the standby power requirement associated with each of them?
 

3. Test Procedure Issues 

Have you observed significant test-to-test variation in EF measurements for a given 

clothes dryer unit? If so, how much is this variation? 

Do you have any data showing the effects of altering the ambient conditions on the 

measured EF for a give clothes dryer unit? The current DOE test procedure requires an 

ambient temperature of 75 ± 3°C and relative humidity of 50 ± 10%. 

Have you tested your clothes dryers with lower starting RMC of the test cloth load than is 

currently specified in the DOE test procedure (nominally 70%)? If so, how did EF vary 

with RMC? 

5-C-10 


EERE-2007-BT-STD-0010 COMMENT 20.3
5-C.2 ROOM AIR CONDITIONER ENGINEERING QUESTIONNAIRE 

The engineering questionnaire used as a guide for engineering discussions during 

manufacturer interviews is shown in this section. Some of the information provided in the 

questionnaire has been redacted to protect vendor information. 

5-C-11 


EERE-2007-BT-STD-0010 COMMENT 20.3
DESIGN FOR ENERGY IMPROVEMENT INFORMATION REQUEST 

ROOM AIR CONDITIONERS 

DOE would like to confirm information on the incremental costs of increasing product efficiency 

by understanding the design options involved in the efficiency improvement. 

1. Market Share of products you sell 

To help DOE discover manufacturer sub-groups and the relative importance of various product 

classes to specific manufacturers, please disaggregate your annual unit shipments for each 

product category as shown below. Please also indicate whether you purchase these products 

from other manufacturers (i.e. private label), and whether the factory that supplies the product 

is located in the USA. 

5-C-12 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

Product Class % Private 

Label? 

% Made in 

USA? 

Yearly Unit 

Shipments 

1. Without reverse cycle, with LS, and less 

than 6,000 Btu/h 

2. Without reverse cycle, with LS and 

6,000 to 7,999 Btu/h 

3. Without reverse cycle, with LS and 

8,000 to 13,999 Btu/h 

4. Without reverse cycle, with LS and 

14,000 to 19,999 Btu/h 

5. Without reverse cycle, with LS and 

20,000 Btu/h or more 

6. Without reverse cycle, without LS, and 

less than 6,000 Btu/h 

7. Without reverse cycle, without LS and 

6,000 to 7,999 Btu/h 

8. Without reverse cycle, without LS and 

8,000 to 13,999 Btu/h 

9. Without reverse cycle, without LS and 

14,000 to 19,999 Btu/h 

10. Without reverse cycle, without LS and 

20,000 Btu/h or more 

11. With reverse cycle, with LS, and less 

than 20,000 Btu/h 

12. With reverse cycle, without LS, and 

less than 14,000 Btu/h 

13. With reverse cycle, with LS, and 

20,000 Btu/h or more 

14. With reverse cycle, without LS, and 

14,000 Btu/h or more 

15. Casement-Only 

16. Casement-Slider 

5-C-13 


EERE-2007-BT-STD-0010 COMMENT 20.3
2. Product Technical Descriptions 

The following series of exhibits and questions address technical characteristics of key 

refrigerator and freezer components for both baseline and improved-efficiency products. 

Compressors 

Are the suggested compressor EERs representative for the Product Class and Efficiency? 

Product Class Typical Nominal 

Compressor EER for 

Minimum Efficiency 

Typical Nominal 

Compressor EER for 

EnergyStar 

1. Without reverse cycle, with 

LS, and less than 6,000 Btu/h 

10 to 11 11 

3. Without reverse cycle, with 

LS and 8,000 to 13,999 Btu/h 

10 to 11 11 

5. Without reverse cycle, with 

LS and 20,000 Btu/h or more 

10.5 11 

8. Without reverse cycle, 

without LS and 8,000 to 

13,999 Btu/h 

10 10.5 to 11 

Is the Illustrated Typical Cost vs. Capacity for HCFC-22 Baseline Product compressors (10 

EER) accurate (note that the plot is based on RAC capacity, not compressor rating point 

capacity)? 

Is 15% a good estimate of cost premium for 11 EER as compared with 10 EER compressors? 

5-C-14 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

Do any room air-conditioners use variable-speed compressors? Any other modulating or 

part-loading approaches? 

What are reasonable impacts for use of R-410 on compressor characteristics? 

Cost premium 10%? Expected trend in coming years? 

Rating point EER range 9.5 to 10.5 rather than 10 to 11? 

Different performance trends than HCFC-22 at varying condensing or evaporating 

temperatures? 

Maturity of product offerings? 

R-410a Conversion 

Expected change in EER of room air conditioners designed with refrigerant velocities 

appropriate for R-410A but with equivalent heat exchanger core sizes and air flow? 

Cost impacts of conversion (compressor, refrigerant, other?)? 

Evaporator and Condenser Heat Exchanger Characteristics 

Please comment on the typical key details of heat exchangers. 

Evaporators Condensers 

Tube Outer Diameter (inch) 0.28 0.25 

Tube Wall (inch) 0.015 0.020 

Tubes Always Rifled? Yes Yes 

Fin Type? Louvered or Lanced Louvered or Lanced 

Fins per inch? 18 18 

Standard-Efficiency Air 

flow (cfm/ton)? 

275 800 

Standard-Efficiency Air 

face velocity (fpm)? 

450 500 

Tubes always copper? Fins always aluminum?
 

Limitations of boosting fin density?
 

Trends in Air flow variation by capacity, efficiency level, product class differences: window 


vs. thru-wall vs. reversible-cycle vs. casement/slider?
 

Are you aware of any further significant system improvements that may be possible through 


heat exchanger changes?
 

Benefits of reduced tube diameters?
 

In spite of efforts to minimize room air conditioner size, typical coil depth is two rows: does 


the fan power increase with greater depth make additional rows counterproductive?
 

Benefits of microchannel heat exchangers?
 

Benefits of coil coatings to improve efficiency?
 

Coil fabrication usually outsourced or in-house?
 

Is air flow through the condenser always from inside out to assure cooling benefit of the 


condensate?
 

5-C-15 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

 

At rating conditions, is all of the condensate evaporated prior to air leaving the coil, with no 

spillage from the pan? 

Subcoolers using Condensate for Cooling 

Are these standard on Energy Star products?
 

Do their designs take full advantage of possible pan counterflow?
 

Evaporator Blowers and Condenser Fans 

Typical blower geometry: backward-inclined blades using plug fan arrangement, using
 

Styrofoam “scroll” to direct air from lower part of blower?
 

Typical blower efficiency? Typical fan efficiency?
 

Power requirement associated with water slinging function at design rating conditions? Are 


there more efficient ways to distribute the condensate?
 

Is there any room for significant energy efficiency improvement via blower or fan design
 

improvements?
 

Blower/Fan Motors 

Please comment on blower/fan motor characteristics. 

Generally use double-shafted PSC? Typical number of speeds? 

Shaft Power output 8W per 1000 Btu/hr capacity? 

Typical efficiency roughly 60% for standard-efficiency products? 

Motor cost $X for 75W shaft output? Variation vs. shaft output? 

Higher efficiency PSC levels up to 65% for Energy Star? What is the peak efficiency 

commonly available for RAC-sized PSC motors? What is the cost premium? 

Brushless DC motor efficiency for RAC size 80%? Does this technology provide a viable 

option for efficiency improvement? What is the efficiency improvement, cost impact, and 

size/weight impact? Typical motor vendor/model? 

Are there any other motor technologies which could contribute to efficiency improvement? 

Partition Insulation 

Usually 1⁄4 inch Styrofoam or 1/10 inch polystyrene? 

Air Leakage 

Is this a factor in rating point performance? 

Expansion Devices: 

Is there any performance improvement potential with expansion devices other than capillary
 

tube?
 

Do you use any expansion device besides capillary tubes? If so, what are the benefits and the 


cost impacts?
 

Energy Efficiency Conversion Costs 

5-C-16 


EERE-2007-BT-STD-0010 COMMENT 20.3
 

 

 

What design changes are typically associated with converting baseline products to Energy
 

Star?
 

When considering energy efficiency improvements to achieve or exceed Energy Star, do 


different product classes take different pathways or are pathways similar?
 

Are the cost increments higher for some classes than others for a given performance 


improvement over baseline?
 

5-C-17 


EERE-2007-BT-STD-0010 COMMENT 20.3