## 5 A

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# APPENDIX 5A. AHAM DATA SUBMITTAL

TABLE OF CO NTENTS

5A.1 INTRODUCTION

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- 1 5A.2 AHAM MICROWAVE OVEN DATA SUBMITTAL

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LIST OF FIGURE S
Figure 5A.2.1 AHAM Standby Power Test Data

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## 5A

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# APPENDIX 5A. AHAM DATA SUBMITTAL

5A.1 INTRODUCTION This appendix presents the shipments and incremental cost data submitted to the U.S. Department of En ergy (DOE) by the Association of Home Appliance Manufacturers (AHAM) in support of the engineering analysis for this rulemaking. See c hapter 5 of the technical support document (TSD) for details of the eng ineering analysis for which these data were used.

5A.2 AHAM MICROWAVE OVEN DATA SUBMITTAL

AHAM submitted the following microwave efficiency and standby tes t data and report to DOE on October 23, 2006.

October 23 , 2006

Mr. Michael Rivest Managing Director Navigant Consulting, Inc. 1801 K Street, NW , Suite 500 Washington, D.C. 20006

- 1301

Subject: AHAM Test Data on Microwave Ovens
Summary:
The Association of Home Appliance Manufacturers is the trade association representing the manufacturers of over 95% of the microwave ovens sold in the U.S. To assist the Department of Energy in its rulemaking for Microwave Ovens (MWOs), AHAM commissioned the independent testing at Inte r tek/ETL of 22 randomly selected MWOs (provided by 7 different manufacturers). The ovens represented a broad spectrum of un its presently in the market place, and varied by size, power rating, components, and features.

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# The tests were conducted using the DOE test procedures prescribed in 10 CFR Part 430 Appendix I, which references IEC Standard 705

- 1988 with Amendment 2

- 1993. The results of the tests are shown in the file embedded below. Each unit was tested 3 times. The average Energy Factor of the 3 runs for each unit is highlighted in yellow in the embedded file.
[File reproduced at the end of this letter]

The test resul ts show that there is a very narrow range in energy efficiency between the least and most efficient unit ( 54.8% minimum to 61.8% maximum

- less than a 13% spread)

. Using the annual useful cooking energy output of 79.8kWh/yr, as determined by DOE in its Se ptember 8, 1998 rulemaking, this range in efficiencies results in a difference of only about 16 kWh/yr (which is about $1.60/yr) between the least and most efficient unit

.
The September 8, 1998 Final Rule on cooking products states that, “DOE has determin ed that there would be no significant conservation of energy for ... microwave ovens, and standards would not be economically justified.” a 

# W e believe the test data and information provided herein confirms that an efficiency standard for MWOs is still not warranted.
DOE considered many design options for microwave ovens in its 1998 rule , and after extensive analysis, it was determined that no design options were technology feasibl e or economically justifiable. There have been no technologica l or economic breakthroughs since the previous determination which would change the previous conclusion.
Factors and Features Impacting Efficiency:
There are many factors tha t impact the efficiency of MWOs, and many different features that are d riven b y the demands of the marketplace. These features d etermine the need for components that consume electrical energy or absorb micr owave energy during operation. Common components that affect the energy efficiency are shown in the table below:

Turntable m otor Waveguide & cavity Magnetron tube Stirrer motor Glass turntable High Voltage Transformer Cavity lamp Turntable roller High Voltage Diode Fan motor Turntable hub High Voltage Capacitor Display, relays, & electronics Stirrer blade
Many of the components listed above may impact the energy consumption differently, depending upon the specific oven features and application. For example, an Over

- The

- Range (OTR) oven may require a larger cooling fan motor than a counter

- top oven. This is because the ambient air at the OTR air inlet is at an elevated temperature due to the range beneath being in operation.

W attage of the cavity lamp is another example. The consumer desires brightly illuminated oven cavities. Increasing the wattage of the lamp by on ly 10 watts c ould lower the efficiency of an oven by about 0. 5 %. Some manufacturers may choose higher wattage lamps for product differentiation.

a 

## 63 Fed. Reg. 48,038 (Tuesday, September 8, 1998).

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# Manufacturers do not optimize the efficiency of their designs around the DOE test procedure, which calls for a simplified method of heating one liter of water in the center of the oven. Rather, ovens are designed to heat various sizes, shapes, and types of food most efficiently and evenly. Again, consumer needs are the key drivers on MWO design.
For example, d esigners often use a stirrer to improve cooking performance as determined by Consumer Union testing in categories such as thermal uniformity and defrosting. The stirrer is a rotating device used to vary how the electromagnetic field is applied to the food in the oven cavity. As the stirrer sweeps through its rotation, the magnetron’s frequency and efficiency also change

. The net effect is to improve cooking performance for the consumer, in exchange for a small decrease in oven efficiency.
Design Options : In DOE’s March 15, 2006 Framework Document, several design options are listed for microwave ovens as possible considerations to improve energy efficiency. We offer the following comments on those design options:

**•** Add insulation

– This is not a practica l option, as it would not improve the Energy Factor. The DOE test is only about 45 seconds in duration and the temperature of the oven walls does not increase during use, thus no significant energy would be saved by adding insulation. It is likely that t he net result would not even be measurable.

**•** Reflective surfaces

– Manufacturers are already using surface finishes to optimize efficiency. If DOE is referring to the possibility of adding metallic plates inside the oven cavity to adjust cavity impedance to the highest oscillation impedance of the magnetron, this is best accomplished by better oven design without such metallic plates.

**•** More efficient fan

– A typical fan only draws about 30 watts, resulting in less than 2% of the total energy consumed durin g the DOE test. Therefore, improving the fan efficiency by going to more expensive motors would at best improve the energy factor by less than 0.5%. Thus more efficient fans motors are not economically justified.

**•** Improve efficiency of magnetron

– The ma gnetron tube is the heart of the MWO. As such, considerable engineering effort has already gone into optimizing their efficiency, and there is very little difference in available technologies. Virtually all magnetrons are the same. A review of magnetron manufacturers’ specifications shows that the typical efficiency is about 73%, with only a plus or minus 2% variance. Thus, there is no available technology for improvement.

**•** Improve efficiency of the power supply

– There are two types of high voltage pow er supplies that are used in MWOs. The predominant type is the inductive capacitance transformer, known as the LC power supply, which has an efficiency of about 82%. The other type is the inverter type, which is more expensive, and has an efficiency of a bout 84%. (General purpose transformers have higher efficiencies, but the need for stable output power in MWOs requires the use of special transformers which have inherently lower efficiencies.)
Three of the units tested utilized an inverter type power supply, whereas all others used the more typical LC transformer

. Even though inverter power supplies are slightly more efficient than LC types, t he Energy Factors of the 3 units with an inverter were right a round the median of all the units tested . They ranged around 56% to 59%, with the average of the 3 units being 58%

.

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# Therefore, the use of an inverter as a design option does not necessarily improve efficiency. We see no cost effective opportunity for improving the efficiency of the power supply.

**•** Eliminate or improve ceramic stirrer cover

– Virtually no residential solo

- function microwave ovens still use a ceramic stirrer. Almost all MWOs use a polypropylene or mica film, which are low energy loss materials resulting in less losses than the cerami c type. Thus this design option has already been optimized.

**•** Modify wave guide

– We are not aware of any improvement to the wave guide that would result in any significant increase in energy efficiency. Losses associated with the wave guide are typically less than 0.5% of the overall energy consumption.

**•** Dual magnetrons

– This would not be an effective way to improve energy efficiency since magnetrons require energy to heat the magnetron heater. This energy is not converted to microwave energy, and thus is wasted. Thus, the more magnetrons used, the more wasted energy is consumed, not to mention the additional cost of extra magnetrons.
Standby Power:
Standby power was measured on all the ovens tested, in accordance with IEC Standard 62301

- 2005, Househol d electrical appliances

– Measurement of standby power

. The measurements ranged between 1.5 and 5.8 watts, with an average of 2.9 watts. Each watt of standby power is approximately 8.7 kWh/yr, which amounts to about 85 cents/yr. Even if DOE limited the standby power of MWOs to 2 watts, it would only result in less than a dollar per year savings on average per unit.
There are three major types of displays used in microwave ovens today. They are LED (light emitting diodes), VFD (vacuum fluorescent display) and LCD (liquid crystal display). Typically, LCD without back

- lighting uses the least amount of energy while VFD uses the most. Energy consumed by LCD would depend on whether back

- lighting is present or not. And if present, the number of LEDs u sed for back

- lighting is a major factor in energy consumption.
For LEDs, the number of segments, color and operating temperature has an impact on its energy consumption. The size of the display (number of digits and icons) also affects the energy consume d by the display. For VFDs, the size of display is a major factor in its energy consumption.
The type of display used, its size, and type of back

- lighting, etc., all have a direct impact on the product’s appeal to the consumer. Thus, while an LCD with out back

- lighting may be most energy efficient, it may not have as much consumer appeal as a VFD, which is typically the best from a legibility perspective.
Manufacturers (driven by consumer/market desires) want the flexibility to produce microwave oven s using the various displays described above in order to provide products with market differentiation , in turn meeting the diverse needs of consumers . This is the reason for the variance in the test results for measured standby power. Therefore, AHAM reco mmends that standby power not be considered as a separate prescriptive requirement.

Conclusion:

All the ovens we tested were within a relatively narrow efficiency range without any current energy standards in effect. The tests indicated a range in eff iciencies that results in a difference of only about 16

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# kWh/yr (which is about $1.60/yr) between the least and most efficient unit . T his narrow range of efficiencies is a result of optimization of current cost effective design options and market competiti on to produce high quality microwave ovens at low prices for the consumer , while still being able to offer ample product features and differentiation.
Efficiency standards for microwave ovens are not justified, as very little energy savings would result. T he cost and risk of modifying today’s well

- performing products with questionable design options should not be underestimated. Microwave ovens are much more efficient than conventional cooking products, and their use should be encouraged, not discourage d by adding cost to the products for very little overall energy savings benefit.
Therefore, we recommend that a “No Standard, Standard” be re

- established for these products and that significant resources not be expended to conduct unnecessary analyses. S ufficient data and precedent exists to support and affirm DOE’s previous conclusion that standards for MWOs are not justifie d. DOE and industry resources w ould be better spent on expediting other rulemakings.
Thank you for the opportunity to provide this information. Please feel free to contact me with any questions that you might have.
Sincerely,

Lawrence R. Wethje, P.E. Vice President , Technical Services

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# Figure 5 A.2

. 1 AHAM Standby Power Test Data
Client: AHAM Project No.: 3100653 Microwave Oven Re-Testing: 09/20-22/06 Tested per IEC 705-1988 and Amendment 2-1993

Unit No. Rated Volume

(ft3) Humidity Sensor (Y/N) Rated Watts Mw , (g) Mc, (g) T0, (oC) T1, (oC) T2, (oC) t, (Sec.) Win Watts @ 20 Sec. P, (Watts) EF, (%) SP,** (Watts) 1000 515 20.8 10.0 19.5 52 18.9 1292 753.6 58.3 1000 515 19.6 10.4 19.7 52 18.8 1286 749.7 58.3 1000 515 19.9 10.0 19.1 52 18.8 1292 725.8 56.2 **57.6** 1005 515 19.5 10.4 19.9 35 18.4 1875 1147.3 61.2 1000 515 21.9 11.7 21.3 35 18.4 1876 1140.7 60.8 995 515 20.8 10.5 20.2 35 18.3 1872 1146.8 61.3 **61.1** 1000 515 18.9 9.8 20.0 42 20.0 1730 1028.7 59.5 1000 515 19.5 10.1 20.3 42 20.1 1735 1025.5 59.1 1000 515 19.9 10.4 20.3 42 19.7 1705 991.3 58.1 **58.9** 1000 515 19.5 10.1 19.9 42 19.6 1696 981.3 57.9 1000 515 20.7 10.5 20.2 42 19.7 1704 961.6 56.4 995 515 20.5 10.5 20.3 42 19.4 1678 969.9 57.8 **57.4** 1000 515 20.7 10.8 20.4 42 19.1 1604 953.8 59.5 1000 515 19.3 10.1 19.8 42 19.1 1602 972.4 60.7 1000 515 19.2 9.9 19.8 42 19.1 1607 993.4 61.8 **60.7** 1000 515 19.1 10.1 20.1 35 19.6 1946 1209.2 62.1 1005 515 19.2 10.1 20.1 35 19.6 1951 1213.9 62.2 1000 515 21.1 10.8 20.8 35 19.6 1950 1192.4 61.1 **61.8** 1000 515 19.2 9.8 18.8 32 17.6 1988 1171.9 59.0 995 515 20.4 10.2 19.4 32 17.6 1986 1183.6 59.6 1000 515 20.8 10.8 19.8 32 17.5 1984 1163.4 58.6 **59.1** 1000 515 21.3 11.0 20.4 34 18.7 2010 1145.6 57.0 1000 515 19.6 10.6 19.9 34 18.8 2010 1149.3 57.2 1000 515 20.0 10.7 19.9 34 18.8 2010 1131.6 56.3 **56.8** 1005 515 18.7 9.3 18.6 34 18.8 2008 1149.7 57.3 995 515 19.3 9.8 19.3 34 18.7 2006 1164.0 58.0 1000 515 19.2 9.7 19.3 34 19.1 2009 1183.5 58.9 **58.1** 2.2 Y **Average:** Y 1300 2.0 1.2 **Average:** Y 1200 3.7 1.6 **Average:**

1.6 N

9 8 **Average:** 1.5

3.0

3.9

4.2 **Average:**

**Average:**

**Average:**

**Average:**

1.2 N 1.8

1250 2.2

1250 2.9 **Average:** N 1200

1.6*

1000 1.6* 1.5

Y 1000 N 800

N 1000 0.8 1

3

4

5 2

6

7

## 5A

- 7 1000 515 19.6 10.0 19.8 60 20.2 1216 685.4 56.4 1000 515 21.8 11.8 21.3 60 20.3 1218 659.2 54.1 1000 515 21.7 11.8 21.4 60 20.0 1210 667.7 55.2 **55.2** 1000 515 19.7 10.1 20.3 60 20.0 1192 716.3 60.1 1000 515 21.6 11.4 21.4 60 19.6 1180 696.3 59.0 1000 515 21.7 11.1 21.0 60 19.6 1176 685.6 58.3 **59.1** 1000 515 21.8 11.3 21.0 42 19.8 1690 958.4 56.7 1000 515 19.2 10.1 19.9 42 20.1 1712 984.5 57.5 1000 515 19.6 10.0 19.6 42 19.6 1668 957.0 57.4 **57.2** 1000 515 18.5 9.1 19.2 38 20.9 1934 1121.2 58.0 1000 515 19.1 9.9 20.1 38 20.9 1959 1135.8 58.0 1000 515 19.1 9.9 19.8 38 20.6 1909 1099.2 57.6 **57.8** 1000 515 19.8 8.9 19.0 42 19.9 1670 998.2 59.8 1000 515 21.7 11.3 21.1 42 20.3 1686 970.5 57.6 1000 515 21.0 10.4 20.4 42 20.2 1683 990.4 58.8 **58.7** 1000 515 18.9 9.7 20.0 42 19.7 1672 1038.7 62.1 1000 515 19.1 10.1 20.3 42 19.7 1675 1029.8 61.5 1000 515 20.4 10.2 20.4 42 19.8 1676 1016.8 60.7 **61.4** 1000 515 19.5 10.0 20.0 52 21.0 1421 809.6 57.0 1000 515 21.7 11.2 21.1 52 20.6 1402 791.9 56.5 1000 515 21.6 11.0 20.8 52 20.6 1402 782.1 55.8 **56.4** 995 515 19.6 10.5 20.3 35 18.7 1878 1175.6 62.6 1000 515 21.1 11.1 20.7 35 18.6 1874 1143.3 61.0 1000 515 21.0 10.6 20.2 35 18.6 1875 1138.1 60.7 **61.4**

1000 515 21.3 10.6 20.7 42 20.8 1740 1000.4 57.5 1000 515 19.4 9.7 19.8 42 20.8 1745 1011.2 57.9 1005 515 20.0 10.5 20.3 42 20.8 1745 985.1 56.5 **57.3** 1000 515 19.4 9.2 18.8 42 19.9 1668 950.6 57.0 1000 515 20.7 10.3 19.7 42 19.8 1669 926.3 55.5 1000 515 21.3 11.6 20.8 42 19.8 1668 911.8 54.7 **55.7**

1000 515 20.0 10.7 20.2 38 21.1 1936 1049.1 54.2 1005 515 20.0 9.6 19.4 38 21.1 1941 1078.0 55.5 1000 515 20.1 10.0 19.6 38 20.8 1922 1051.8 54.7 **54.8** 1000 515 20.2 10.6 20.3 44 20.5 1630 924.1 56.7 995 515 21.1 11.1 20.6 44 20.5 1628 894.3 54.9 1000 515 19.9 10.4 19.9 44 20.2 1623 904.0 55.7 **55.8**

Legend: **P - is the microwave power output, in watts M w - is the mass of the water, in grams**  **M c - is the mass of the container, in grams T0 - is the ambient temperature, in degrees Celsius**  **T1 - is the initial temperature of the water, in degrees Celsius T2 - is the final temperature of the water, in degrees Celsius**  **t - is the heating time, in seconds, excluding the magnetron filament heating-up time Average:**  **Average:**

Y 1000 1000 N 1000

**Average: Average:** 

**Average:**

**Average:** N 0.7

Y 1100 1000 **Average:**

**Average:**

**Average:** N

DAMAGED UNIT!!!!!

5.8

22 1.4* N 950 2.6 1.5* Y 1100 **Average:**

**Average:** 21 4.4

20 1.0 N 1000 1.7 1.5 19 2.0

18 1.5 N

- 1.2 N 1200 **Average:**

**Average:** 17 1.8

16 0.8* Y 800 5.7 1.1 15 3.6

14 0.9* Not Listed 1000 2.0 2.0 13 700 2.0 0.7 2.1

1.9 700

1.6 N 12 10

11

## 5A

- 8 **Win - is the energy input, in watt-hours EF - is the Energy Factor, or efficiency, in percent**  **SP - is the standby power, in watts**

**All tests were performed at 120 Vac, 60 Hz** *** - Physical measurement performed by ETL**   - M easured with the microwave clock set to 12:00 and with door closed.**