WATER HEATER COMPANY

April 26, 2001

Assistant Secretary for Conservation and Renewable Energy

United States Department of Energy

1000 Independence Avenue, SW

Washington, DC 20585

To Whom It May Concern:

Subject: Application for Interim Waiver

American Water Heater Company seeks a waiver in the application of the "Uniform Test

Method for Measuring the Energy Consumption of Water Heaters" contained in 10 CFR

Part 430 Subpart B Appendix E as applied to electric water heater models that have

adaptive electronic controls. We are seeking this interim waiver to allow the initial

marketing of our new product to claim the benefits of the "Energy Saving Cycle" as

described in the petition for waiver.

We feel that the interim waiver should be granted because it is likely that the petition for

waiver will be granted. The new technology addressed by the petition for waiver yields a

legitimate energy savings and improvement in the energy efficiency level of this category

of appliance. This improvement serves the interest and goal of the Department of

Energy and thus should be supported. Allowing the waiver will encourage other

manufacturers to produce similar products creating a general improvement in energy

conservation. As new technology is developed, test procedures need to be modified to

accommodate the improvement and allow the benefits to be shown to the consumer.

These are all good arguments as to why the waiver should be granted and thus the

interim waiver be granted.

From an economic point of view, American Water Heater Company has invested

significantly in the development of this product and to not be able to present one of its

best features would cause loss of sales and discourage further development.

Respectfully submitted,

.. (I. '(\) I

Timothy

-60'~. J. S enbergerJ~~ Sr. Vice Presi ent - Product Engineering

TJS/meh

1100 E. Fairview Ave., P. O. Box 1378, Johnson City, TN 37605-1378, Tel: (423) 434-1500, Fax: (423) 434-1632

Case No. WH-010 COMMENT 01
I, the undersigned, on behalf of American Water Heater Company, hereby certify that a copy of the

foregoing Petition for Waiver and Petition for Interim Waiver, has been sent to each of the

following known manufacturers of domestically marketed units of the same product type (as listed

in Section 322(a) of the Act), as follows:

Rheem Water Heater Division

Rheem Manufacturing Company

2600 Gunter Park Drive East

Montgomery, AL 36109-1413

Attention: Scott D. Martin

A. O. Smith Water Products Company

Rochelle Park, Suite 200

600 E. John Carpenter Freeway

Irving, TX 75062-3990

Attention: Ronald Massa

Bradford White Corporation

200 Lafayette Street

Middleville, MI 49333-9492

Attention: Eric M. Lannes

State Industries

500 Lindahl Parkway

Ashland City, TN 37015-1234

Attention: John R. Lindahl, Jr.

Lochinvar Corporation

2005 Elm Hill Pike

Nashville, TN 37210-3807

Attention: Mr. William L. Vallett, Jr.

I further hereby certify that the Assistant Secretary for Conservation and Renewable Energy will

receive and consider timely written comments on the Application for Interim Waiver.

This the 26th day of April 2001.

Case No. WH-010 COMMENT 01
DOE Wavier Model Comparison

AWHC Wholesale AWHC Retail AWHC Wholesale AWHC Retail RHEEM A.a. SMITH BRADFORD STATE LOCHINAR

Models Electronic Models Electronic Models Standard Models Standard (RICHMOND, WHITE INDUSTRIES

RUDD, GE) (RELIANCE,

MAYTAG,

SEARS)

EE92-40H***D*** EE2H40HD****** E92-40H***D*** E2H40HD****** 81XH40D PEST-40 M-I-40T10DS PX-40-20RT STA040KK-3

MEH40-2 M-II-40T10DS 9-40-2KRT

82XR40-2 HE29-40T

EXR40-2 SSX-40-2LRT

32746

EE122-40H***D*** EE2J40HD****** E122-40H***D*** E2J40HD****** 81XH40D PEST-40 M-I-40T10DS PX-40-20RT STA040KK-3

MEH40-2 M-II-40T1 ODS 9-40-2KRT

82XR40-2 HE29-40T

EXR40-2 SSX-40-2LRT

32746

12-40-2ART

EE93-40H***D*** EE3H40HD****** E93-40H***D*** E3H40HD****** MR40245 PEHT-40 M-III-40T1 ODS 32049

MP40245 LT-40-2LRT

EE123-40H***D*** EE3J40HD****** E123-40H***D*** E3J40HD****** MR40245 PEHT-40 M-III-40T1 ODS 32049

MP40245 LT-40-2LRT

EE92-40R***D*** EE2H40RD****** E92-40R***D*** E2H40RD****** RMEMKR40-2 PES-40 M-II-40S10DS SSX-40-2LRS

PE40M9A 9-40-2KRS

EE122-40R***D*** EE2J40RD****** E122-40R***D*** E2J40RD****** RMEMKR40-2 PES-40 M-II-40S10DS SSX-40-2LRS

PE40M9A 9-40-2KRS

12-40-2ARS

EE93-40R***D*** EE3H40RD****** E93-40R***DH*** E3H40RD***H*** RMEMXR 40-2TI PEC-40 HE21240S LTSE40M12A 40-2LRS

EE123-40R***D*** EE3J40RD****** E123-40R***D*** E3J40RD****** RMEMXR 40-2TI PEC-40 HE21240S LTSE40M12A 40-2LRS

EE92-50H***D*** EE2H50HD****** E92-50H***D*** E2H50HD****** 81X52 D PEST-52 M-II-50T1 ODS PX-52-20RT STA052KK-3

ME52-2 9-52-2KRT

RMEKR 50-2 HE2950T

PE50T9A 32756

82XR52-2 SSX-52-2LRT

EXR52-2

EE122-50H***D*** EE2J50HD****** E122-50H***D*** E2J50HD****** RMEXR 50-2TI M-II-50T1 ODS 12-52-2ART

SE50T12A 32059

Page 1 of 2

Case No. WH-010 COMMENT 01
DOE Wavier Model Comparison

AWHC Wholesale AWHC Retail AWHC Wholesale AWHC Retail RHEEM A.O. SMITH BRADFORD STATE LOCHINAR

Models Electronic Models Electronic Models Standard Models Standard (RICHMOND, WHITE INDUSTRIES

RUDD, GE) (RELIANCE,

MAYTAG,

SEARS)

EE93-50H***D*** EE3H50HD****** E93-50H***DC*** E3H50HD***C*** MR50245 PEH-52 M-III-50T1 ODS HE21250T

MP50245 LT-52-2LRT

32151

EE123-50H***D*** EE3J50HD****** E123-50H***DC*** E3J50HD***C*** MR50245 PEH-52 M-III-50T10DS HE21250T

MP50245 LT-52-2LRT

32151

EE92-50R***D*** EE2H50RD****** E92-50R***D*** E2H50RD****** RMEMKR 50-2 PES-52 M-II-50S10DS PX-52-20RS

PE50M9A SSX-52-2LRS

82MXR52-2 9-52-2KRS

EMXR52-2 HE2950S ,

EE122-50R***D*** EE2J50RD****** E122-50R***D*** E2J50RD****** RMEMXR 50-2TI PEC-52 12-52-2ARS --" 1

!

SE50M12A HE21250S I

I

EE93-50R***D*** EE3H50RD****** E93-50R***DC*** E3H50RD***C*** LT-52-2LRS I

!

EE123-50R***D*** EE3J50RD****** E123-50R***DC*** E3J50RD***C*** --"I

I -~

EEZ3-50R***D*** EE3Z50RD****** EZ3-50R***DC*** E3Z50RD***C*** MSR50245 I

EE92-65H***D*** EE2H65HD****** E92-65H***D*** E2H65HD****** 81X66D PEC-66 M-II-65R10DS HE2966T STA066KK-3 ---i

ME66-2 32766 I

RMEKR65-2 SSX-66-2LRT !

I

82XR66-2

EXR66-2

PE65T9A

EE122-65H***D*** EE2J65HD****** E122-65H***D*** E2J65HD****** 12-66-2ART

EE93-65H***D*** EE3H65HD****** E93-65H***DC*** E3H65HD***C***

EE123-65H***D*** EE3J65HD****** E123-65H***DC*** E3J65HD***C*** RMEXR 65-2TI PEH-66 M-III-65R10DS 32069

EE92-80H***D*** EE2H80HD****** E92-80H***D*** E2H80HD****** RMEKR80-2 PES-80 32786 STA082KK-3

82XR80-2 SSX-82-2LRT

EXR80-2

EE122-80H***D*** EE2J80HD****** E122-80H***D*** E2J80HD****** PEC-80 12-82-2ART

EE93-80H***D*** EE3H80HD****** E93-80H***DC*** E3H80HD***C***

EE123-80H***D*** EE3J80HD****** E123-80H***DC*** E3J80HD***C*** RMEXR 80-2TI PEH-80 M-III-80R10DS HE21282T

SE80T12A 32089 LT

MR85245 82-2LRT

MP85245

Page 2 of 2

Case No. WH-010 COMMENT 01
WATER HEATER COMPANY

April 26, 2001

Assistant Secretary for Conservation and Renewable Energy

United States Department of Energy

1000 Independence Avenue, SW

Washington, DC 20585

To Whom It May Concern:

Subject: Petition for Waiver

Specific Requirements to be Waived:

American Water Heater Company seeks a waiver in the application of the "Uniform Test Method

for Measuring the Energy Consumption of Water Heaters" contained in 10 CFR Part 430 Subpart

B Appendix E as applied to electric water heater models that have adaptive electronic controls.

Utilizing a microprocessor-based control on an electric water heater allows a level of intelligence to

be added to the control logic that is not possible with the conventional electro-mechanical control

systems used today. One use of this intelligence is to have the control adjust the stored water

temperature based on the actual hot water usage pattern to determine the lowest possible

temperature to store water that will meet the needs of the consumer. The result of this new control

logic is a reduction in energy consumption. Such a control cycle will be identified as an "Energy

Saver Cycle".

American Water Heater plans to commercialize a microprocessor-based control system with an

Energy Saver Cycle. However, we are unable to characterize and market the true efficiency

benefit to the consumer through the "Uniform Test Method for Measuring the Energy Consumption

of Water Heaters" ratings process. The test procedure does not allow the efficiency benefit of an

Energy Saver Cycle to be demonstrated. These types of intelligent electronic controls are more

expensive and without the ability to demonstrate the benefits in terms of energy savings, it is

difficult to justify the additional cost to the consumer. We are specifically petitioning to allow the

use of an alternate test procedure described below to rate and label the efficiency of a water

heater when using the "Energy Saver Cycle".

Basic Models and all Manufacturers:

(See attached list)

Design Characteristics:

Background Information

The predominate energy loss of a tank type electric water heater is the standby loss associated

with storing the hot water. There are two methods of reducing these losses; one can increase the

effectiveness of the insulation system, or reduce the stored water temperature. The "Energy

Saver Cycle" saves energy by reducing the stored water temperature.

1100 E. Fairview Ave., P. O. Box 1378, Johnson City, TN 37605-1378, Tel: (423) 434-1500, Fax: (423) 434-1632

Case No. WH-010 COMMENT 01
Page 2

The study report "Baseline Results and Methodology of the Consumer Sub-group Analysis for

Residential Water Efficiency Standards", submitted to the Department of Energy October 1998,

shows that the average set point temperature of residential water heaters varies widely across the

United States. The northern states tend to be hotter with average set points as high as 142°F and

the south as low as 123°F. This corresponds inversely with the average inlet water temperature in

the same areas. At the time of use, the hot water is blended with cold water to produce the

desired use temperature. This process of blending causes the usage quantity of hot water to

change inversely with the stored water temperature. For example: A shower lasting 10 minutes

with a delivered water temperature of 105°F and a flow rate of 2.5 gallons/minute uses 25 gallons

of water. If 135°F hot water, supplied by a water heater, is blended with cold water at 58°F, the

shower will consume 9.74 gallons of cold water and 15.26 gallons of hot water. In contrast, if the

hot water supply temperature were reduced to 115°F the usage proportions would change to 4.39

gallons of cold water and 20.61 gallons of hot water. The energy consumed and the quantity of

water used in the shower is the same in both cases but the proportion of heated water goes up.

The important difference is that, in the time between showers, the energy consumed to maintain

the stored water temperature goes down by 29.85% when the water is stored at 115°F versus

135°F. The person taking the shower didn't know the difference except they had to use more hot

water to get the desired temperature. As the stored water temperature is further lowered,

eventually the water heater will not be able to supply the needed amount of blended hot water and

the water temperature will have to be increased.

The adaptive control logic continually adjusts stored water temperature within specified limits to

get to the temperature where the maximum demand event can be met by the quantity and

temperature of water stored in the heater. This "Energy Saver Cycle" will produce real energy

savings in a significant number of households and thus deserves to have a test procedure

designed to allow the efficiency benefits to be demonstrated. The current test procedure doesn't

allow this because the mean tank test temperature is fixed at 135°F.

Energy Saver Cycle Qualification test:

It is simple for a manufacturer to put an electronic control on a water heater and label a cycle as

an "Energy Saver Cycle" without having an adaptive control that will adjust stored water

temperature based on usage. Some examples of other controls that would not qualify for this

modified test procedure could be, a conventional control with a fixed but lower set point which is

identified as an "Energy Saver Cycle" or an off peak type control that simply adjusts the set point

based on the time of the day. This new test is required to prove that the control meets the "Energy

Saver Cycle" criteria as a qualifier to use the energy saver test modifications. The object of the

test is to confirm that the control does adapt the stored water temperature based on water usage.

The following simple test would be used to prove that the control adapts water temperature to

water usage.

1. The unit is set up per the "Uniform Test Method for Measuring the Energy Consumption of

Water Heaters", 10CFR430.23.

2. The unit is run on normal cycle and the thermostat is adjusted until the mean tank temperature

is 135°F. Then the control is switched to the "Energy Saver Cycle" and a series of small draws

are made. Each draw should be sufficient to cause the lower element to come on. The lower

element will reheat the water until it shuts off at which time another draw will start. This

sequence will continue until the mean tank temperature, at the element shutoff point, is 125°F

Case No. WH-010 COMMENT 01
Page 3

or less. The mean tank temperature after the first cycle should be 135°F and the last cycle will

be 125°F or less to show that the control will lower the set point in response to a low water

usage situation.

3. Then the draw size will be changed to be large enough that the control will adjust the

temperature up. After each reheat the draw will be repeated until the control has adjusted the

set point up enough to return the mean tank temperature back to the 135°F point. At this point,

the test would have proven that the control adjusts set point up and down based on actual

water usage. If the control can not demonstrate the adaptive ability to adjust stored water

temperature based on actual usage, it will not qualify to use the proposed modified procedure.

4. This test is somewhat cumbersome in that a large number of draw reheat cycles would be

required to complete the test. In our case, it would require approximately 100 cycles. The test

could be automated and allowed to run over night to speed up the qualification process. The

test should only have to be run once for a given manufacturer's control. Once the control has

been qualified, any units using that control would qualify for the Energy Saver Cycle test

sequence.

Test Procedure Changes:

Staying with the principal that the delivered hot water energy doesn't change as the stored water

temperature changes, the following changes are required to allow the energy savings of an

"Energy Saver Cycle" to be demonstrated and evaluated.

1. The size of the six water draws will be adjusted such that the BTUs of delivered hot water

(BTUs to heat the water from 58F to delivery temperature) is equal to BTUs for the six 10.7

gallon draws heated from 58F t0135F. This calculation = (Gallons X Lbs.lgal.X Specific Heat X

(delivered temp. -58F) =(6851 BTU for 10.7 gal. heated from 58F t0135F) Since the delivered

water temperature is not a constant during a draw, this calculation could be accomplished by

using "Simpson's Rule" method or another suitable numerical method to integrate the delivered

water temperature-volume function. The water draw is started and the total is calculated every

5 seconds until the 6851 BTU of delivered hot water energy is reached. The actual volume of

each draw will vary inversely as the delivered water temperature varies. The Energy Saver

Cycle typically draws about 90 t01 00 gallons versus the 64.2 gallons of the current test

procedure. The hot water energy delivered in both cases is the same.

One approach to running this modified test on a heater with an "Energy Saver Cycle" would be

to set up the heater as "normal" with the thermostat set to give a mean tank temperature of

135°F. Then run the test draw sequence repeatedly until the temperature adjustment logic of

the control lowers the temperature to the lowest stable temperature. At that point, a full 24

hour efficiency test would be conducted to determine the efficiency of the heater using Energy

Saver Cycle. This would require over 100 draw and reheat cycles using our control algorithm.

This approach is impractical. The practical approach is to run the control in normal mode and

adjust the water temperature to the lowest stable temperature that the "Energy Saver Cycle"

would reach if the above approach were used.

2. Definition of lowest stable temperature: This is the lowest water temperature set point such

that when the six draw sequence in step 1 is performed, the control will not adjust the set point

higher. In our control logic, the set point is increased if the cold water rises far enough in the

tank to cause the upper element to come on. Thus for our control logic, the lowest temperature

where the draw sequence in step 1 doesn't cause the upper element to come on is our "lowest

stable temperature". Other control logic could result in another "lowest stable temperature"

point. To determine this temperature, the tester would need to know the temperature

adjustment logic for the Energy Saver Cycle. He would set the test water temperature to the

lowest stable temperature based on that logic. He then would observe the draw quantities and

temperatures during the efficiency test to see that a temperature adjustment condition was not

Case No. WH-010 COMMENT 01
Page 4

present. If a temperature adjustment would have been made the test is invalid and the test

would need to be repeated at a higher temperature.

3. In the current procedure, the mean tank temperature is to be adjusted to 135F. There are three

places in the calculation of efficiency where the raw data is adjusted back to 135F to correct for

variation between actual and ideal test conditions. Since the Energy Saver Cycle test doesn't

run at 135F mean tank temperature, this correction needs to be changed to reflect the new test

conditions. This means that the hard coded 135 values in the calculations must be changed to

a variable so the actual value can reflect the current test conditions. The most appropriate

variable is "Tsu" which is the maximum mean tank temperature observed after the sixth draw.

In the current procedure, Tsu must be 135F ± 5F and is the logical equivalent of the 135F of

the current procedure. Thus the calculation of Qda is changed from

Qda =Qd - (( Tstby.2 - Ta.stby.2) - (135 - 67.5)) UA tstby.2 to

Qda =Qd - (( Tstby.2 - Ta.stby.2) - (Tsu - 67.5)) UA tstby.2 and

QHW.77 changed from

QHW.77 = :t Mi Cpi (135F - 58F) to QHW.77 = :t Mi Cpi (Tsu - 58F)

i=\ Nr i=\ Nr

Ef ' h d f Ef Mi Cpi (135F -58F) t Ef Mi Cpi (Tsu -58F) IS C ange rom =LJ 0 =LJ

i=\ Qdm i=l Qdm

Conclusion:

New technologies can foster changes that obsolete current practices. American Water Heater's

adaptive control has created an energy saving control method that was not anticipated or covered

by the current DOE test procedure. This waiver will allow the efficiency benefits of this improved

control method to be demonstrated while the test procedures are modified to keep up with

technology. This change in control method will reduce water heater energy consumption, and

thus its adoption by the industry should be encouraged. This can best be done by granting this

waiver and modifying the test procedure. Confidential test data, which demonstrates the energy

efficiency benefit, can be made available upon your request.

Respectfully submitted, ~------.",

/"

Ineering

Case No. WH-010 COMMENT 01