Field Test Results on the

Performance of A Refrigerator-Freezer

in A Single-Family Residence

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Building Equipment Division

Washington, DC 20234

January 1 983

muijpared f or; 100

. U56

y3-2653

1933

lited States Department of Energy

ashington, DC 205S5

1 1 1983

NBSIR 83-2653

FIELD TEST RESULTS ON THE

PERFORMANCE OF A REFRIGERATOR-FREEZER

IN A SINGLE-FAMILY RESIDENCE

Robert A. Wise

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Building Equipment Division

Washington, DC 20234

January 1 983

Prepared for: United States Department of Energy

Washington, DC 20585

U.S. DEPARTMENT OF COMMERCE, Malcolm Baidrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

t

ABSTRACT

The operation of a side-by-side 623 L (22 cubic foot)

refrigerator-freezer in use in a single family residence was

continuously monitored for over two years. During this time, the daily

cumulative number of freezer and fresh-food door openings, ice-maker

operations, defrost cycles, and compressor cycles were recorded. In

addition, the lengths of time the doors were open, the length of

defrost heater "on" time, and the watt-hours energy use were recorded.

On a weekly basis the amount of accumulated defrost water was measured.

All information was entered into a computer file and analyzed to

determine the magnitudes, variations, and trends of the data. The

effects of such variables as the season of the year, number of people

using the test unit, and a slow refrigerant leak were evaluated.

Graphic representations of many of the variables vs. time and

vs. each other are included in the report. The small effect that

ambient or variable use conditions had on long term cumulative energy

use and the great variation found in the use conditions on both a daily

and weekly basis are typical observations. Averaged over the entire

data collection period, the fresh food compartment door was opened 32.5

times per day for a total of 3.8 minutes per day. The freezer

compartment door was opened seven times per day for a total of 1 minute

per day, and the ice-maker operated 2.4 times per day producing 14 ice

cubes

.
iii

TABLE OF CONTENTS

Abstract 11

Preface Iv

List of Tables Iv

List of Figures Iv

1.0 Introduction 1 2.0 Test Procedure 1 3.0 Results 3

3.1

Door operations 3

3*2 Ice maker operations 5

3.3 Defrost water 6

3.4 Energy consumption 6

4.0 Conclusions 8

5.0 References 9

Figures Attached
iv

PREFACE

The data for this project were developed as an unfunded after-hours

personal activity to satisfy the author's curiosity. DoE funding was

provided to NBS for the analysis of the data and preparation of this

report.

LIST OP .TABLES

Table 1. Door Opening Data.... 5

LIST ££ ZIfillfiES.

Figure 1 1978-1980 Cumulative Weekly Average Values

Doors, Ice maker, and Energy

Figure 1A 1978-1979 Cumulative Weekly Average Values

Doors, Icemaker, and Energy

Figure IB 1979-1980 Cumulative Weekly Average Values

Doors, Ice maker, and Energy

Figure 2 1978-1980 Cumulative Weekly Average Values

Compressor, Defrost, and Energy

Figure 2A 1978-1979 Cumulative Weekly Average Values

Compressor, Defrost, and Energy

Figure 2B 1979-1980 Cumulative Weekly Average Values

Compressor, Defrost, and Energy

Figure 3 1978-1980 Weekly Average Values and Ratio

Fresh Food Compartment Door Operations

Figure 4 1978-1980 Weekly Average Values and Ratio

Defrost Water and Hours

Figure 5 1978-1980 Weekly Average of Per Day Values

Defrosts, Compressor, and Energy

1 . 0 INTRODUCTION

This field test was undertaken to develop in-home use data on variables other than room air temperature that could affect the energy

consumption of a side-by-side refrigerator-freezer. Door openings

combined with food loads and load removals, defrost operations and the

amount of frost removed, and ice-maker operations and ice cube usage

could effect energy use. The Department of Energy (DoE) test procedure

for refrigerators [1] measures energy consumption with the doors closed

but in an ambient temperature of 32.2 C (90 F). The elevated

temperature causes the unit under test to use more energy than in a more typical room ambient of 22.2 C (72 F). The increase is believed

to be equivalent to the energy used to cool the interior of the unit

after door openings and added food loads under average household use

conditions. The results and conclusions of the analysis of the home

test data can provide some of the information that would be needed for

consideration of possible changes in the test procedure simulation to

make it better correlate with national average "typical" home use conditions. All of the data values were recorded daily except for

defrost water. The defrost water was measured weekly. Data were taken

from July 1,1978, to November 2, 1980 in Gaithersburg, Maryland.

2.0 TEST PROCEDURE

The unit tested was a side-by-side, two-door 623 L (22 cubic foot)

refrigerator-freezer (hereafter called the "refrigerator") with an automatic icemaker. The refrigerator was purchased new in 1966 and

over the years was moved to homes in three different cities along with

other household goods. The refrigerator had been modified in a previous test at NBS by adding access valves to the suction and

discharge lines of the compressor, and the system had been recharged

several times. For this test, electrical connections were made to the

wiring underneath the food compartments across the compartment lights,

the icemaker water solenoid, and the compressor motor and the wires

were brought out to a terminal strip on the back of the refrigerator.

A hidden electrical wire was connected to the defrost heater and

brought out alongside the defrost drain tube to the terminal strip.

Electrical power from these connections was used to operate counters

and clock motors. The defrost water hose that ordinarily drained into

an evaporation pan in the condenser cooling hot air discharge passage

was rerouted to the back of the refrigerator. The water collection pan

was left in its customary position. The refrigerator was installed in

the authors home in the location provided for a refrigerator in the

kitchen of the detached single-floor, three-bedroom, full-basement home

near Gaithersburg, Maryland. The home heating system was a hot air oil

furnace with central air conditioning in the summer. There was a hot-air (cold in the summer) vent directly above the refrigerator but

there were no windows or return air vents nearby. The sink, range, and

dishwasher were about 1,4 meters (4.5 feet) away from the refrigerator.
In order not to affect the results of the* test, no instrumentation

was visible to the users. The wires to the instruments and the plastic

defrost water tube were passed through holes made in the floor behind

the refrigerator and down to a high shelf in a room in the basement

below. Energy consumption was measured with a small electronic

watt-hour integrator that utilized a mercury tube coulomb gage

calibrated in tens of kilowatt-hours on its scale. Since full scale

was 100 kilowatt-hours, the gage was reversed each time it neared its

limit. This instrument was about 50X75X 100 mm (2X3X4 inches)

in size and had a 900 mm (3 ft) power supply cord and a three-wire

outlet mounted on it. It was located behind the refrigerator and was

not readily visible to the users of the refrigerator but was accessible

for nightly readings. The defrost water was collected in a 1.8 liter

(61 oz.) loosely covered coffee carafe.

During most of the test period, there were three people in the

home, two adults and one young adult. For a five month and a two month

period, only the two adults were in residence.

Three times during the test period the refrigerator needed

servicing to add refrigerant and once to replace the condenser cooling

fan motor which was running slowly causing the motor thermal protector

to operate frequently.

All of the accumulated data were entered into a computer file and are available for further use if needed. During the test period of 857

days, 78 days of readings were missed. Of these, 56 were periods of one week or more and they occurred because of vacations. The remaining

22 missed readings were for three or fewer days at a time and were for

various reasons. They were scattered fairly uniformly throughout the

test period. Near the end of the test period, from September 15 to

November 2, 1980, data readings were taken weekly rather than daily.

Due to the failure of the watt-hour meter, no watt-hour readings were

taken during this period.

Prior to using the raw data in the computer file, the data were

manually reviewed to find any data points that were widely divergent

from the usual value for that particular recorded value. When such

points were obviously either misread or misrecorded they were replaced

with values Interpolated from the adjacent recorded cumulative data

values

.

-2-
3.0 RESULTS

A comprehensive diary of the user family's activities during the

test period was not kept, so only some notes on the data records are

available to correlate the variations in the recorded variables with

the activities and events that may have affected them. When

correlations with the notes are observed, they are mentioned in the

following discussion.

Figures 1 and 2 show the cumulative values of the variables over

the entire data collection period. Before plotting these curves, the

daily data were cumulated into 122 weekly values. The numbers at the

ends of the curves are the final cumulated values. The watt-hours

final value was at the end of week #144 since watt-hour readings were

discontinued that week. Week #0 was the first week in July 1978, week

#52 was July 1, 1979, etc. The position of the week numbers on the

time axis roughly correspond to the start of the seasons of the year. For instance, weeks #0, #52, and #104 represent the summers of 1978,

1979, and 1980. Figures 1A, IB, 2A, and 2B are plotted with the data

of the first two years of the test period. They are the same as Figures 1 and 2 but with a time scale of only one year.

3.1 Door operations

The straight dashed line manually drawn over the fresh food door

openings curve of Figure 1 shows an interesting trend in that the

plotted door openings curve seems to be slightly but constantly rising.

There is no logical explanation for this so one might conclude that, as the years go by, the use of the fresh food compartment is increasing.

This trend is better evaluated with the curves of Figures 1A and IB.

The fresh food door opening curve of Figure 1A is very nearly a straight line that results in a 31*3 openings-per-day rate. The effect

of a vacation during the last two weeks in August 1978, is just

noticeable on this curve. The fresh food door openings curve of Figure

IB deviates from a straight line from October 1, 1979, to January 1,

1980, but is nearly a straight line otherwise. The flat section of the

curve from late September to early October 1979, was a vacation period

when the refrigerator was turned off. There is no explanation of the

increase in door openings for the next three months. The overall door

opening rate for the second year, Figure IB, was 33.6 openings-per-day.

The difference between the first and second years fresh food door

opening rate is inexplicable. The average fresh food door opening rate

over the entire test period was 32.5 openings-per-day, obtained by

dividing the 27,782 openings by the total days of 854.

The curve of fresh food door open hours on Figure 1 and IB shows

abrupt rises at about weeks #58 and #84 (August 1979, and February

1980). The rise at week #84, late February 1980, was during the time

of repairs on the refrigerator. No notes recorded with the data

explain the other sharp rise, but it was probably caused by

accidentally leaving the door open for a long period of time. By

dividing the 54.52 total hours of fresh food door-open hours by 122

weeks and by 7 days per week, the door open time per day is calculated
as 3.8 minutes. This, when divided by the door openings per day,

results in an open time of 7.1 seconds per opening.

i Freezer door operation curves on Figures 1, 1A, and IB also show

the effects of vacations and repairs on the freezer door openings and

open time. The two discontinuities in the freezer door cumulative open

time were due to the freezer door having twice been left in a slightly

open position for several hours. Notes on the data records were made

when this was observed. On Figure 1, an extension of a straight line

has been drawn beyond the first portion of this curve. This dashed

line shows that the average door open time per week or month did not

change after the door was left open. The slopes of the curve sections

after the accidental open periods are the same as before these periods.

The accidents cannot be construed to be normal door open hours so the

freezer door open time can best be calculated using the slope of the

straight line drawn over the first part of the curve on Figure 1.

Using this method, the freezer door was found to be open 0.9 minutes

per day. It was opened nearly 7 times per day and open an average of

7.9 seconds each time.

Figure 3 was plotted to show the weekly values of door openings

and open time. These curves would 3how even greater variations when

plotted on a daily rather than a weekly average basis. One might

expect that, although the openings and length of time vary widely, the

length of open time per door opening would remain relatively constant.

As shown by the dotted line of Figure 3» this is not the case and all

three variables showed erratic and unpredictable variations. Rough

plots of door opening variables and ratios were made of the fresh food

compartment data and of the data using different time axis periods but

are not included with this report because insufficient additional

information was gained; the other curves were all similar to the curves

of Figure 3.

An observation from the analysis of the door operation data of

both compartments is that no correlation with either the season of the

year or the number of people in the household could be found.

The door operations information generated by this test can be

compared to two earlier publications containing similar information.

The first was a NBS report [2] on data taken on ten units in use in a town-house complex in Twin Rivers, N.J. The data were collected on one single-door refrigerator and nine automatic defrost

refrigerator-freezers. One of the latter was a side-by-side model.

The family sizes ranged from three to five, one to three children, and

the data collection period was for about six months in 1976. The

second source is contained in an Arthur D. Little report [3] that uses

usage values obtained from an NBS preliminary draft report [4] and an NBS interim memorandum [5]. The usage figures in this report were used

to analyze potential reductions in the energy consumption of household

appliances. The results of the report were used by the Department of

Energy to develop minimum energy consumption standards published in the

Federal Register [6] and later a revised proposal for no minimum

standards [7]. Table 1 lists the usage values from these references

and from this Home Use Test.

-4-
TABLE 1 - DOOR OPENING DATA

Door Opening Frequency and Time

Fresh-food Compartment Freezer Compartment

Source No./

Day

Sec./

Open

Min./

Day

No./

Day

Sec./

Open

Min./

Day

A. D. Little 50 12.5 10.4 25 12.5 5.2

Town-house 48 21.2 17.0 10 20.0 3.3

Home use 33 7.1 3.8 7 7.9 0.9

The table shows that the usage of the refrigerator in this test

was less than the usage reported in earlier publications. The door

opening values were much lower than those given in the Arthur D.

Little report but closer to the town-house data. The reverse is true

of the seconds-per-opening column. The factor that probably has most

effect on energy consumption is the length of time the doors are open

per day. The "Home Use" results were much lower than either of the

previously published values. It would be interesting to determine

whether the side-by-side door configuration permits faster access to

foods stored in the compartments, and perhaps to more orderly storage

that allows faster loading and retreival. Certainly the range of

values in the table indicates that test results of one family^ usage

is not sufficient to generalize conclusions for all users. It is

possible that the family usage and the results of this test are

atypical

.

3 .2 Ice maker operations

Icemaker operations, plotted on Figures 1, 1A, and IB, show the

frequency of operation of this device to be remarkably uniform. The

average overall frequency was 2.37 operations per day which equates to

14.2 ice cubes per day. The 14.2 cubes per day rate is surprising

since the high estimate of ice cube usage by the family is nine ice

cubes per day. Part of the high final value may be attributed to

occasional extra high usage periods. On each of the one year curves,

Figures 1A and IB, there are two noti cable increases. For instance in

early November 1980, on Figure IB. These rises represent extra

icemaker operations and, although not noted on the data sheets, the

rises are probably due to the emptying, clean-out, and remaking of a full container of ice cubes. A full container holds about 144 ice

cubes which requires 24 icemaker operations per refill. If it is

assumed that there were two clean outs per year, the ice cube usage

would become 13.4 ice cubes per day. If the extra usage is doubled to

account for a few parties and/or additional clean outs, the daily ice

cube usage would still be roughly three ice cubes per day higher than

the estimate of family usage. Thus, it appears that the sublimation of

ice cubes in this "Home Test" ice-maker refrigerator- freezer & about

three ice cubes per day. * coo Id be.

-5-
3.3 Defrost water

The curves of the cumulative amount of defrost water collected

weekly are on Figures 2, 2A, and 2B. These curves show that this

variable was not as constant as the variables already discussed. The

total amount of water collected during the 122 week test period was

130.2 liters (4404 fluid oz.). Thus, 1.07 liters of water per week

(36.1 oz.) or 152.5 ml per day (5.16 oz.) was collected. The total

volume of water can be divided by the total number of defrosts (2001)

to find the water collected per defrost was 65.1 cubic centimeters (2.2

oz.). From inspection of the Figure 2 curve , it appears that the

defrost water volume is cyclic. Figure 4 was plotted to evaluate this

possibility. The zero values at weeks #8 and #66 were vacation weeks

with the refrigerator turned off. Because defrost water was not

collected the same day each week and twice a week occasionally, the

origional data were modified for some weeks to correct for these data

collection variations. The "x" marks on the time axis indicate changed

values. Most of the changes were to eliminate zero water collection

points. In most cases, the change made was to duplicate the previous

weeks value. Although the water volume values are somewhat erratic, it

can be seen that the defrost water accumulation in the refrigerator was cyclic and at a maximum in July - August and minimum in January - February.

The defrost heater is turned off by a thermostat when the frost

has melted and the evaporator warmed up to the cut-off temperature

value of the thermostat. Thus, the length of time the heater is on should vary proportionally with the amount of frost melted (i.e.

defrost water collected); and the energy consumption of the defrost

feature should be dependent on the amount of frost to be removed. To

investigate this factor, two other curves are plotted on Figure 4. The

curve of defrost heater "on" hours per week (dotted line) seems to

follow the defrost water trend after week #66, but before that a reverse trend is noted. At weeks #15, #57, and #88 repairs were made

to the refrigerator. It is possible that, inadvertently, the defrost

control thermostat was not positioned firmly against the evaporator

structure. This would tend to increase the heater hours and make the

length of on time less dependent on the amount of frost accumulated.

The plot of ounces of water collected per hour of defrost heater

heating should be a constant value plus a variable proportional to the

amount of frost to be melted. This trend is shown on Figure 4 by the

points plotted as individual small circles. In the previous section it was noted that the sublimation of ice cubes might be as much as three

ice cubes per day. This sublimated water must deposit as frost onto

the evaporator. Since one ice cube weighs about 31 grams, three would

equal 93 grams (3.1 fluid ounces) of water. Thus, it is possible that,

of the 152.5 grams (5.16 oz.) of defrost water per day, 93 grams (3.1

oz.) could be from ice cubes and the remaining 59.5 grams (2.1 oz.)

from other sources.

3.4 Energy consumption

From the curves of Figures 1 and 2, the energy consumption

(kilowatt-hours) appears to show a slightly cyclic characteristic with

-6 -
the lower energy consumption periods about 52 weeks apart at weeks #26

and #78 which represent January 1, 1978 and 1979. To better show the

energy use data, Figure 5 was plotted. Kilowatt-hours per day,

defrosts per day and compressor cycles per day were plotted. Since the

defrost timer on the refrigerator requires eight hours of compressor

running time to initiate a defrost cycle, the number of defrost cycles

is a measure of the running time of the compressor. The compressor

cycles per day indicate the capacity of the cooling system, since the

greater the capacity in BTU's per hour of the system the less running

time it needs to provide the needed cooling. Assuming reasonably

constant loading conditions, the system should have shorter compressor

run times and cycle more frequently with a high capacity system.

Figure 5 shows that if there is a seasonal effect on energy

consumption it is small and masked by other factors. The compressor

cycles per day is an interesting curve because it shows the effect of

a slow refrigerant leak in the cooling system. The repairs noted in

the previous section occured in weeks #15, #57, and #88. The curve

shows that the system was losing capacity during the months prior to

the repairs since the number of compressor cycles was falling. The

repairs consisted of charging the system which caused the number of

cycles per day to rise to their normal level. Strangely enough, there

appears to be no clear correlation between the system capacity and the

kilowatt-hours energy consumption of the refrigerator. The average

energy consumption per day calculated by dividing the total cumulative

kilowatt-hours by 798 days (only 114 weeks of data were taken on this

variable) is 6.8 kilowatt-hours per day. No reliable energy

consumption value obtained by use of an elevated temperature - no door

opening test procedure could be obtained from the manufacturer for the

vintage 1966 unit used in these tests. However, an AHAM 1975 Directory

[8] lists the energy consumption of refrigerators in a table of costs

of energy vs. rated total volume. This table shows that the range of

daily energy use of refrigerator-freezers having volumes of from 21.5

to 22.5 cubic feet (609 to 637 L) was from 3.95 to 7.89 kWh per day in

1976. Considering the range of energy-use of typical units

manufactured nine years later, the results obtained from the data taken

for this test are on the high end of the range but reasonable.

A relatively high energy consumption is expected for the unit in

this test because the family prefers to keep the freezer compartment

very cold. The temperature in the freezer was usually at about -20.5

to -17.7 C (-5 to 0 F). The energy consumption determined by the DoE

test assumes a freezer temperature of -15 C (5 F). Other factors that

might contribute to a high energy consumption are normal manufacturing

tolerance, age, modification of the cooling system, etc. Plans are

underway to bring the refrigerator in to the NBS laboratory test

facility to perform the DoE standard test. The results will be

compared with actual use field data of this report.
f

4.0 CONCLUSIONS

The results of this study, relating to refrigerator-freezer

compartment door openings, show them to be quite variable on a day-to-day, week-to-week , or even a month-to-month basis but that

cumulative values are fairly linear on a yearly basis. Comparison with

previously published usage values shows that while the family usage

studied in this test may be representative of normal usage, it cannot

necessarily be considered typical or average. The large difference in

usage between published values and these test results shows that there

will be a broad range of usage among "typical" users. Thus, the use of

door openings as a test procedure method would have to be correlated

with an average value of number of openings, duration of the openings,

and ambient temperatures. Very extensive field tests extending over a number of years would be required to develop such averages for

correlative purposes. This test indicated that there may be

differences between types of refrigerators, ie. side-by-side vs. top-mount. The effects of other features such as ice makers, water

dispencers, etc. would also have to be evaluated.

The conclusions regarding door operations also apply to ice maker

operations and defrost water collection. The 14 ice cubes per day and

the 65 ml (2.2 ounce) of defrost water per defrost cycle may establish

the order of magnitude of the variables but cannot be considered as typical or average. The test results indicate that exposed ice cubes

may be a source of defrost water and thus a contrlbuter to defrost

energy consumption.

The energy consumption of the tested refrigerator under actual use conditions was on the high side of the range of energy use values of

similar units manufactured nine years later that were tested using a procedure quite like the present DoE test method. Considering the

fewer door openings and low door open time per opening of this home

test unit when compared to previously published values, the energy

consumption should be further investigated by testing it using the DoE

method to determine the correlation between the two energy use values.

-8-
5.-SL REFERENCES

1. Federal Register / Vol.47, No. 154 / Thursday, August 10,

1982, Rules and Regulations, pp 34517-34529.

2. Y-M. Chang and R. A. Grot, Field Performance of Residential

Refrigerators and Refrigerator-Freezers, National Bureau

of Standards, Washington D.C., 20234, NBSIR 79-1781.

3. Arthur D. Little, Inc., Study of Energy-Savings Options for

Refrigerators and Water Heaters, Vol.1: Refrigerators,

prepared for The Office of Transportation and

Appliance Programs, Federal Energy Administration,

May 1977, PP 15-18.

4. Mulroy,J. and J. Grimes, "Factors Affecting the In-Use

Energy Consumption of Household Refrigerators and

Freezers," National Bureau of Standards, Preliminary

draft report.

5. "Refrigeration Appliances" Field Tests, National Bureau of

Standards interim memorandum, provided by Bernard

McGuire, Appliance labelling Section.

6. Federal Register / Vol.45, No. 127 / Monday, June 30, 1980

Proposed Rules, pp 43976-44087.

7. Federal Register / Vol.47, No. 64 / Friday, April 2, 1982

Proposed Rules, pp 14424-14461.

8. Association of Home Appliance Manufacturers,

AHAM 1975 Directory of Certified Refrigerator/Freezers,

September 1975 - Second Special Edition.

HOME

USE

DATA,

1978-1980

REFR

I

GER

ATOR-FREEZER,

S

I

DE-BY-S

I

DE

Cumulative

Weekly

Average

Values

0'8 O'A OV OX O't OX OX 0‘T O'O samvA aannsvarAi

13.0

26.0

39.0

52.0

65.0

78.0

01.0

104,0

117.0

TIME,

Weeks

Figure
HOME

USE

DATA,

1978-1980

REFRIGERATOR-FREEZER,

SIDE-BY-SIDE

Cumulative

Weekly

Average

Values

samvA aamsv3H

JUL

AUG

SEP

OCT

NOV

DEC

JAN

FEB

MAR

APR

MAY

JUN

1978

1979

N.t.3,a

t~e 2

,RhM

Figure

1A

TIME,

Months
HOME

USE

DATA,

1978-1980

REFRIGERATOR-FREEZER,

SIDE-BY-SIDE

Cumulative

Weekly

Average

Values

TIME,

Months

HOME

USE

DATA,

1978-1980

REFR I

GER

ATOR-FREEZER, SI

DE-BY-S I

DE

Cumulative

Weekly

Average

Values

TIME,

Months
TIME,

Months
HOME

USE

DATA

-

1978,1980

Weekly

Avg.

of

Fresh-food

Door,

Daily

Openings,

Minutes

Open,

and

Ratio

co

samvA aannsvaw

13.0

26.0

39.0

52.0

65.0

78.0

91.0

104.0

117.0

TIME,

Weeks

Figure
HOME

USE

DATA,

1978-1980

Weekly

Averages

of

Defrost

Water,

Defrost

Hours,

and

Ratio

samvA aannsvaw
HOME

USE

DATA,

1978-1980

Weekly

Averages

of

Kilowatt-hours,

Compressor

Cycles,

and

Defrosts

samvA aannsvapt

130

28.0

39.0

52.0

05.0

78.0

91.0

104,0

117.0

TIME,

Weeks

Figure

Nm-IUA IRilTTWT

U.S. DEPT. OF COMM. 1. PUBLICATION OR 2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

REPORT NO.

SHEET (See instructions) NBSIR 83-2653 February 1983

4. TITLE AND SUBTITLE

Field Test Results on the Performance of a Refrigerator-Freezer in a SingleFamily Residence

5. AUTHOR(S)

Robert A. Wise

6. PERFORMING ORGANIZATION (If joint or other than N BS, see instructions) 7. Contract/Grant No. national bureau of standards

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

U.S. Department of Energy

1000 Independence Avenue, SW

Washington, DC 20585

10.

SUPPLEMENTARY NOTES

1 1 Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

The operation of a side-by-side 623 L (22 cubic foot) refrigerator-freezer in us,

in a single family residence was continuously monitored for over two years. During

this time, the daily cumulative number of freezer and fresh-food door openings, icemaker operations, defrost cycles, and compressor cycles were recorded. In addition,

the lengths of time the doors were open, the length of defrost heater ! 'on" time, and

the watt—hours energy use were recorded. On a weekly basis the amount of accumulated

defrost water was measured. All information was entered into a computer file and

analyzed to determine the magnitudes, variations, and trends of the data. The effects

of such variables as the season of the year, number of people using the test unit, and

a slow refrigerant leak were evaluated.

Graphic representations of many of the variables vs. time and vs. each other are

included in the report. The small effect that ambient or variable use conditions had

on long term cumulative energy use and the great variation found in the use conditions

on both a daily and weekly basis are typical observations. Averaged over the entire

data collection period, the fresh food compartment door was opened 32.5 times per day

for a total of 3.8 minutes per day. The freezer compartment door was opened seven

times per day for a total of 1 minute per day, and the ice-maker operated 2.4 times per

day producing 14 ice cubes.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) consumer; defrost; door-openings; energy use; field test; home; ice cubes; ice-maker;

refrigerator ; refrigerator-freezer

13.

AVAILABILITY

|Xij Uni imited

| | For Official Distribution. Do Not Release to NTIS

:

| Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

jXX Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

23

15. Price

$7.00

USCOMM-DC 6043-P80


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