EPA-600/2-91-060
October 1991
REVIEW OF ENERGY EFFICIENCY OF
REFRIGERATOR/FREEZER GASKETS
by
Majid Ghassemi
Howard Shapiro
Department of Mechanical Engineering
Engineering Research Institute
Iowa State University
Ames, Iowa 50011
EPA Contract No. 68-02-4286
Work Assignment 2/129
(Radian Corporation)
EPA Project Officer: Jane C. Bare
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
Prepared for:
U. S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology Iransfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
i i
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ABSTRACT
Home refrigerators are the largest consumers of electricity among household
appliances and are consuming an estimated 8% of the total electricity used in the
United States. Recent studies show that gasket area heat leakage may account for as
much as 21 % of the total thermal load.
The purpose of this study was to investigate the significance of heat leakage
through the gaskets in household refrigerator/freezers, explore different design
features, and suggest further study if necessary. This report presents the results of an
extensive literature review, interviews with refrigerator/freezer and gasket
manufacturers, and some engineering analysis.
The findings of this study included: 1) Manufacturers will likely incorporate
improved gasket technology in the 1993 models. 2) There is little certainty about the
magnitude of gasket heat leakage, although most believe it is significant. The
significance will increase with introduction of advanced types of insulation. 3) Double
door gaskets do not offer much potential due to several practical limitations and the
advancement in single gasket technology. 4) Gasket infiltration may cause a significant
portion of the load. 5) Safety requirements are critical for home refrigerator/freezers.
It is unlikely that a mechanical door latching device would meet these requirements,
even if it meets energy conservation goals.
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CONTENTS
Page
1.0 INTRODUCTION 1
2.0 REVIEW OF LITERATURE 3
3.0 FINDINGS AND DISCUSSION 7
3.1 Double Door Gaskets 8
3.2 Single Door Gaskets 8
3.2.1 Materials 9
3.2.2 Design Evolution 9
3.2.3 Other Possible Improvements 11
3.3 Gasket Infiltration 14
3.4 Gasket Heat Leakage 17
3.4.1 Analytical Estimates 17
3.4.2 Experimental Measurements 18
4.0 APPLICABLE LATCHING-DOOR SAFETY REGULATIONS 20
5.0 SUMMARY AND RECOMMENDATIONS 21
6.0 REFERENCES 22
FIGURES
Page
1 Typical door gasket configuration 2
2 ADL model of door closure area 5
3 Gasket evolution 10
4 Schematic of diverter 12
5 Load estimates due to infiltration 16
6 Examples of possible configuration 19
iv
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METRIC CONVERSION FACTORS
Readers more familiar with metric units may use the following factors to convert
the nonmetric units in this report.
Noiimetric
Times
Equals Met
Btu/hr
0.293
W
Btu/hr ft. °F
1.7306
W/mK
Btu/hr in. °F
20.7677
W/m K
Btu/lb
2.3244
kJ/kg
Btu/lb °F
4.1866
kJ/kg K
ft
0.3048
m
ft3
0.028317
m3
ft3/lb
62.43
cm3/g
ft3/min
4.719 x 10"4
m3/sec
in.
2.54
cm
in. H20
249.06
Pa
lb
0.4536
kg
°F
(°F - 32)/1.8
°C
v
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1.0 INTRODUCTION
Home refrigerators are the largest consumers of electricity among household
appliances and consuming an estimated 8% of the total electricity used in the United
States [1,2]*. The energy consumption for an average refrigerator sold in the United
States grew over 350 percent from post World War II until 1975 [3]. This was partly
due to larger and more feature-laden models of refrigerators. Since 1975, several
studies have been conducted to develop a high efficiency refrigerator-freezer. To
achieve this goal, various designs were developed and tested. Gasket improvements
appeared in most of the studies as ;m option.
The gaskets in a refrigerator/freezer act as seals to contain the cold air and to
thermally isolate the plastic liner from the outer steel structure (Fig. 1). Recent studies
show that gasket area heat leakage may account for as much as 21 % of the total thermal
load [4]. The heat leakage through the gasket itself and through the adjacent door and
cabinet surfaces is mostly through conduction. Some infiltration also occurs since the
door seal cannot be perfect. Another source of energy consumption is the anti-sweat
heaters placed near the gasket to eliminate condensation. Minimizing gasket heat
leakage in a refrigerator/freezer reduces the need for anti-sweat heaters and lowers
energy consumption.
Future generations of high efficiency refrigerator/freezers may well incorporate
advanced types of insulation and other features to reduce the heat leakage considerably
over present products. In this instance, the gasket heat leakage would become even
more significant as a percentage of energy consumption. In the near term, higher
energy efficiency standards are providing considerable impetus to reduce gasket heat
gain.
"Numbers in brackets denote references listed at the end of the report.
1
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Door
Fig, 1. Typical door gasket configuration.
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The purpose of this study was to investigate the significance of heat leakage
through the gaskets in household refrigerators/freezers, explore different design
features, and suggest further study if necessary.
This study consisted of three major activities, as follows:
An extensive literature review was conducted using the Iowa State University
Parks Library and inter-library loan.
Engineers were contacted at major appliance manufacturers and at gasket
suppliers to the refrigerator/freezer industry.
Analyses were conducted in-house.
2.0 REVIEW OF LITERATURE
A refrigerator/freezer cabinet consists of two or more compartments, with at least
one compartment designed for the refrigerated storage of fresh foods at temperatures
above 32 °F* and with at least one compartment designed for the storage of frozen
foods at 8°F or below. A significant portion of heat gain to a refrigerators/freezer
occurs around the edges of the doors, through nearby portions of the cabinet surface,
and through the door gaskets themselves. Gasket improvement was part of several
studies that have been conducted to reduce energy consumption of refrigerator/freezers.
Kammerer and Maxwell [5] explored means for reducing energy use in existing
refrigerator/freezer designs. They indicated that gasket heat gain might account for as
much as 19% of the total heat load. However, they didn't include gasket
improvements among their recommended design improvements.
Hoskins and Hirst [6] calculated the gasket loads for 12 and 16 cubic foot
refrigerator/freezers. Although they did not include gasket improvements in their list
of suggested design changes, their computer model simulated the open door condition
"Users more familiar with metric units may use the factors listed at the end of the front matter to convert to that system.
3
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and calculated the gasket load. The calculated heat loads for a 12 and a 16 cubic foot
refrigerator-freezer are 13.54 and 15.16 watts (13% and 12% of the total thermal
load), respectively.
Two major studies by Arthur D. Little Company (ADL) explored gasket
improvements as design options for higher efficiency refrigerator/freezers. In the first
ADL study [7], improvements were made to the door closure area to reduce infiltration
of room air into the refrigerator. The second study by ADL consisted of two phases.
Phase I, reported in reference [8], involved the design, construction, and laboratory
testing of a 16 cubic foot high efficiency refrigerator/freezer prototype. Phase II,
reported in reference [9], consisted of a field test that was carried out for an identical
setup with the exception of the size. An eighteen cubic foot refrigerator/freezer was
selected for the second phase. The use of a double door gasket was one of the seven
options that underwent comprehensive computer analysis and prototype testing in the
ADL Phase I study.
In phase I, a series of tests were conducted, and the energy saving potentials of
double-door gaskets were evaluated. ADL reported a 47% reduction in freezer heat
flow by incorporating a vinyl type secondary gasket into the freezer compartment of the
base line unit (Fig. 2). However, this reduced the overall energy consumption by only
3 %. The ADL study also showed that only the double door gasket in the freezer
effectively reduced the energy consumption. This was due to two factors: the higher
air flow in the freezer (air flow in the freezer is about six times that of the fresh food
compartment) and the greater temperature difference between the freezer compartment
and outside compared to the fresh food compartment and the outside. Infiltration of air
was considered insignificant according to the ADL study (about 5 Btu/hr). In the
Phase II study, double door gaskets on freezer doors were not considered due to the
limitation existing with double door gaskets associated with freezing of trapped
moisture which can jam the door shut.
4
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Kig. 2. ADL model of door closure urou.
5
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The results of the field tests as well as the data obtained from the Phase I study
were published in four different reports. References [10] and [11] identified the results
from Phase I, while references [12] and [13] highlighted the findings of the field test
(Phase II) study.
Sterling [14] calculated the hciat leakage through gaskets, using energy factor
concepts. He determined increase in energy usage as the volume ratio (freezer
volume/total volume) increases. According to Sterling, heat leakage through the gasket
of a 15.6 eft refrigerator/freezer was as follows:
Gasket Heat Leakage
Volume Ratio Freezer Fresh Food Total
freezer/total
Btu/hr
Watts
Btu/hr
Watts
Btu/hr
Watts
0.20 (20% freez
45.19
13.24
29.36
8.60
74.55
21.84
volume)
0.30
56.50
16.55
28.12
8.24
84.62
24.79
1.0
121.40
35.57
_
_
121.40
35.59
Sterling's work confirms that heat leakage through the fresh food gasket area is
significantly less than through the i'reezer gasket area.
Lawrence Berkeley Laboratory (LBL) also conducted research on home
appliances in order to update the selection of design options [15]. The LBL study
indicated that double door gaskets cause problems in the field due to freezing of
trapped moisture. An improved single door gasket, which provided some of the double
door gasket benefits without the indicated problems, was added to the list of new
design options for higher efficiency refrigerator/freezers. However, the LBL study did
not indicate any specific design improvements.
A study done by the Department of Energy (DOE) did not include the double door
gasket in the simulation analysis due to technical difficulties, but gasket improvement
6
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was among their design options [16]. These results were published in a paper by Turiel
and Heydari [17]. The most recent study by Abraham son, Turiel, and Heydari [4]
indicated that about; 21 % of thermal load is due to gasket loss. They predicted that 5.9%
of fresh food load and 16.5% of freezer load are due to gasket heat leakage.
In addition to the literature survey, the present study involved contacting major
refrigerator/freezer manufacturers and gasket suppliers. Interviews with engineers
indicated little agreement about the precise magnitude of gasket heat leakage. In
addition, the definitions of the particular area associated with "gasket" heat leakage
appeared to vary among manufacturers and among the other research studies discussed
above. This may account for the apparent variation of between 10% and 30% of the
energy consumption that different sources associate with gasket loads. Nevertheless,
all manufacturers agreed that improved gasket design to reduce heat leakage was a
priority for helping to meet new energy standards, and as such was receiving
considerable attention in their companies.
3.0 FINDINGS AND DISCUSSION
The present section of the report deals with the following topics, which represent
the major areas covered in the study:
Double Door Gaskets
Single Door Gaskets
- Materials
- Design Evolution
Possible Gasket Design Improvement
Gasket Infiltration
Gasket Heat Leakage Determination
- Analytical Estimates
- Experimental Measurements
Summary of Door Safety Regulations
7
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3.1 Double Door Gaskets
Gasket heat gain appears to account for at least 10% of the thermal load. One
concept for reducing the gasket loads is to insert an additional inner door gasket (Fig
2). This improves the insulating viilue of the gasket area and reduces energy
consumption. According to reference [8], incorporating a double door gasket in the
freezer compartment caused the following heat flow reduction:
Despite the possible energy benefits, double door gaskets haven't been used by
many manufacturers because of performance and cost. The limitations existing with
double-door gaskets include the following:
Ice has a tendency to form between the freezer compartment gaskets due to
trapped moisture. The ice greatly reduces the thermal effectiveness and can
freeze the door shut.
Inner seal problems exist due to requirements for special gasket materials. The
materials developed must be highly compliant and yet durable to serve as a
good inner seal held by the force of the magnetic outer gasket.
Double door gaskets tend to be visually unattractive.
Difficulties can exist with ease of door closing, which can detract from
consumer acceptance.
Double door gaskets can make it more difficult to meet the minimum door
opening force requirements of the Child Safety Act.
3.2 Single Door Gaskets
Due to double door gasket limitations, refrigerator/freezer manufacturers and their
gasket suppliers have focused their efforts on producing thermally improved single
gaskets with higher insulating values and better sealing characteristics. The
Gasket Heat Flow (Btu/hr)
Base Line Value Double Gasket
Evaporator fan on
Evaporator fan off
62.5
43.5
41.9
28.8
8
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improvements to single door gaskets make the double door gasket concept of energy
saving less important. According to [15], heat gain by the present improved single
gasket is only 10% less than the double gasket system proposed in 1980 in reference [8].
The following discussions detail some of the considerations which the present
investigation uncovered concerning materials, design evolution, and possible gasket
design improvements.
3.2.1 Materials. Door gaskets are usually made of flexible plastic. The most
common plastic materials used in gaskets are: thermoplastic elastometer (TPE) and
polyvinylchloride (PVC). These materials range from the very soft and delicate to
rigid and wear-resistant, and their suitability is mainly related to such considerations.
The primary thermal barrier in the gasket is trapped air "bubbles", which have low
thermal conductivity. The materials themselves do not contribute significantly to the
thermal resistance. The present study indicates that little improvement in thermal
performance is possible in the area of gasket materials.
3.2.2 Design Evolution. Early designs for extruded gaskets depended upon
mechanical compression provided by a latch mechanism to seal (Fig. 3a). While still
suited to some applications, the compression design was improved dramatically by a
development called "supported compression" (Fig. 3b). The next major design
improvement was done by inserting magnetized extrusions of ferrite compounds for
sealing (Fig. 3c). The magnets are used in place of latch and striker plate. This
improvement resulted in consumer satisfaction and improved safety.
Remaining improvements in gasket design involved improving the thermal
resistance. The next step was the "extended bubble magnetic" design (Fig. 3d). In
addition to compression and magnetic attraction, this design introduced the "wand"
which extended from the inner edge of the bubble. Currently the most efficient gasket
9
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(a)
(b)
Magnet
Air Bubble
(c)
Fig. 3. Gasket evolution.
10
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is the "multiple bubble magnetic" design (Fig. 3e), where the extra bubble acts as an
insulator, reducing heat leakage. Figure 3f shows the newest gasket design with
additional air pockets incorporated in the gasket and retainer area. These refinements
will assist in reducing the heat leakage, and therefore improve the energy efficiency by
an amount yet to be identified. Due to the expected enhanced performance, by 1993
the manufacturers of refrigerators/freezers will most likely standardize on this type of
improved gasket.
3.2.3 Other Possible Design Improvements. Other possible areas of design
improvement were identified in the course of the present study. These improvements
can be divided into two separate categories: (1) reduction of the gap between the gasket
and body, and (2) further increase in thermal resistance in the gasket area. It must be
noted that some of the following concepts are already being incorporated and/or
designed into existing products.
Possible areas of improvement include:
The use of a half-bellows design (Fig. 3d), which eliminates alignment
problems and turn over on the hinge side. In general, the bellows design
provides the ability to exp
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Flow Diverter
~V
/
/
r
^3
/
J3
t
i * \V
i
j~
; /¦
Fig. 4. Schematic of diverter.
12
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increase the thermal resistance of the gasket and thereby reduce heat gain.
However, the potential for this type of improvement is limited by the need for
flexibility. Gaskets must typically collapse or expand from about 0.65 inch to
about 1.0 inch.
Another suggested improvement is to fill some of the air pockets with
insulating materials such as fiberglass or foam. However, adding these
materials would reduce the flexibility of the gasket, and would therefore be
unacceptable. Further, a trapped bubble of stagnant air is one of the best
insulating mediums available, and it is doubtful that any improvement in
thermal performance would be realized by filling the pockets with solid
materials.
Mechanical door latching c
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3.3 Gasket Infiltration
Infiltration is the uncontrolled leakage of air into the refrigerator-freezer through
the door gasket. This is caused by a pressure difference across the boundary surface,
and it accounts for some of the thermal load. After several conversations with different
manufacturers and reviewing the literature, it is evident that there is no unanimity in
the importance of infiltration. In fact, some literature contradicted the views of experts
in the field. The literature showed that infiltration is about 5 Btu/hr, and some
manufacturers indicated as much as 100 Btu/hr.
Because of the apparent uncertainty about the importance of infiltration, a brief
engineering analysis was done as part of the present study. A summary of the analysis
follows.
The following design conditions are assumed for the purposes of this analysis:
Room temperature, T0 = 90°F
Room humidity, a>0 = 0.031 lb/lb (100% rel. humidity)
Specific heat of air, cp = 0.24 Btu/lb°F
Specific volume of room air, vQ = 13.986 ft3/lb
Freezer compartment temperature, Tin = 5°F
Inner humidity, coin = 0.0004 (10% rel humidity)
Enthalpy of vaporization, ifg = 1042.7 Btu/lb
The sensible heat load due to infiltration, can be expressed in terms of the leakage
flow rate, Q, as follows
Q °o (Tc - Tin)
^ (i)
vo
Further, the latent load, qlat, can be expressed as
Q ,
Qlat == v K - «in) !fg (2)
vo
Infiltration loads can be estimated using equations (1) and (2) for any given infiltration
rate.
14
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The infiltration rate is dependent upon the pressure differential that exists between
the inside and the outside of the refrigerator/freezer box. Because of frictional pressure
drop through the internal ducting, slight negative and positive gage pressures will exist
between the suction and the discharge sides of the fan, respectively. The infiltration
rate is also dependent upon the nature of the crack due to the gasket seal and any
penetrations of the liner or ductwork. An estimate of this relationship can be obtained
using Equation (7-10) of reference [18] and curve-fitting the relation for a tight-fitting
door from Figure 7-5 of reference [18] to obtain
Q/L = Ap°-<* (3)
where L is the effective crack length (one half the total gasket length for both doors) in
feet, Ap is the pressure differential in inches of water, and infiltration rate Q is in cubic
feet per minute.
Figure 5 shows the sensible, latent, and total loads as functions of pressure
difference, assuming a total gasket length of 19.48 feet as in reference [8]. The curves
show that the magnitude of the load due to infiltration may be substantial or may be
negligible compared to other loads, depending on the pressure difference.
One industry representative quoted a value of 0.01 inches of water as
characteristic of the magnitude of the pressure differential. With this value, the loads
as determined from Fig. 5 would be
Qsens = 44.76 Btu/hr
qIat = 70.47 Btu/hr
qtot = 115.23 Btu/hr
From the calculations presented here and from the literature cited, there exists
considerable uncertainty as to the magnitude of the infiltration effects. Although
companies most likely have proprietary information, little actual data is available in the
open literature.
15
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200 r
150
.c
"B
+-»
CQ
i
-a
fO
o
100
Total Load
0.001 0.005 0.01 0.015
Pressure Differential - inches of water
0.02
Fig. 5. Load estimates due to infiltration.
16
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3.4 Gasket Heat Leakage
Gasket heat leakage, not including infiltration, is estimated using both analytical
and experimental methods.
3.4.1 Analytical Estimates. Total gasket heat leakage is a combination of the
following components (refer to Fig. 2):
conduction along the flange
heat leakage through the small gap between the gasket and wedges
heat leakage through the gasket itself
heat leakage between the gasket and door
Total heat load due to the gasket is calculated in various ways by different
manufacturers. Two methods of determining this load are:
METHOD 1
gasket = Hg1At (4)
where
At = temperature differences between cabinet interior
1 = total gasket length
Hg = gasket heat leak coefficient
Gasket heat leak coefficients can be found in reference [16], and are as follows:
Value
Freezer-Fan on 0.0069 Btu/hr in °F
Freezer-Fan off 0.0041 "
Refrigerator 0.00141 "
METHOD 2
Qgasket = (Lr ATr + Lf . ATf)(« + £ f) (5)
Lr = length of fresh food gasket (door perimeter)
Lf = length of freezer gasket (door perimeter)
a = 0.05 Btu/hr Ft °F (static-fan off)
17
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/3 = 0.036 Btu/hr Ft °F (dynamic-fan on)
f = fan run time fraction
Using Equations (4) and (5) with the data from the infiltration calculation presented
earlier yields the following results:
METHOD 1: q = 60.12 Btu/hr (fan on)
METHOD 2: q = 82.84 Btu/hr (50% fan run time fraction)
In light of these results, and the other information presented above regarding the
importance of gasket heat leakage, it appears that there is considerable uncertainty
about the magnitude of this effect.
3.4.2 Experimental Measurements. Experimental measurement of heat leakage
through the gasket can be done in several ways. The following are two of the most
common methods used. Each is based on a reverse heat leakage test, in which a heat
source is placed inside the refrigerator/freezer, and the power input to the device is
measured along with the inside and! outside temperatures. Although the temperatures
are not the same as those obtained in actual operation, the thermal resistances
determined by such a test should be representative.
METHOD 1
Apply a constant heat source in the cabinet to measure the total heat loss of the
unit. Also connect the same cabinet with an identical cabinet excluding the doors (see
Fig. 6a) and measure the heat loss through the walls of the two cabinets. The
difference between the original test and one half the value measured in the second test
is the total door loss. The loss through the door itself could then be analytically
calculated. Finally, the gasket heat loss would be
Igasket Qtotal ~ (Qwalls Qdoor) (6)
This method leads to a plausible estimate of the heat gain through the gasket, but relies
on some speculation as to the door loss.
18
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V P gasket
3 door
y Cj walls x 2
/ !
CI wall
MS
(a)
Gasket Area
Heavily Insulated
(b)
Fig. 6. Examples of possible configuration.
19
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METHOD 2
A reverse heat leak test can also be applied to a cabinet that is insulated heavily
around the gasket
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These regulations govern any changes that would be made to the door closure which
are intended to improve energy conservation. It is unlikely that a mechanical door
latching device will return to the market place, despite energy considerations.
5.0 SUMMARY AND RECOMMENDATIONS
This report presents the results of an extensive literature review, interviews with
refrigerator/freezer and gasket manufacturers, and some in-house engineering analysis.
The purpose of this study was to investigate the significance of gasket heat leakage,
explore different design features, and to suggest further study if necessary.
The primary findings of this study were:
The gasket area, including the gasket itself and the adjacent areas of the door
and cabinet, has received considerable attention with respect to improvement of
energy efficiency. Manufacturers will likely incorporate improved gasket
technology in the 1993 models.
There is little certainty about the exact magnitude of gasket heat leakage,
although most believe it is significant. The significance will increase with
future introduction of advanced types of insulation.
Double door gaskets do not appear to offer much potential due to several
practical limitations and the advancement in single gasket technology.
Gasket infiltration may cause a significant portion of the load. There is little
agreement about the magnitude of infiltration. However, calculations done in the
present study suggest that infiltration may be an important cause of heat leakage.
Safety requirements are critical for home refrigerator/freezers. It is highly
unlikely that a mechanical door latching device could return to the market place
that would meet these requirements, even if it meets energy conservation goals
and can satisfy consumer interests.
Based upon the findings of this study, it appears that the uncertainty about the
magnitudes of the heat leakage and infiltration effects can only be resolved by further
21
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experimental work. Undoubtedly much proprietary work has been done, but little
information is available in the open literature. It is recommended that standard
methodology be developed for heat leakage testing, and that an extensive experimental
program be undertaken.
6.0 REFERENCES
1. Goldstein, D. B., "Refrigerator Reform: Guideline for Energy Glutton,"
Technology Review, 1983, pp. 36-44.
2. "Trends in the Energy Efficiency of Residential Electric Appliances," EPRI
EM-4539, Final Report, Palo Alto, CA, April 1986.
3. Harris, J., "What Works: Documenting Energy Conservation in Buildings,"
American Council for Energy Efficient Economy, 1984.
4. Abrahamson, D.S., Turiel, I., and Heydari, A., "Analysis of Refrigerator-Freezer
Design and Energy Efficiency by Computer Modeling: A DOE Perspective,"
ASHRAE Transactions, Vol. 96, Part 1, 1990.
5. Kammerer, J., and Maxwell, R., "Reduction of Energy on Combination
Refrigerator-Freezers Through Improved Design," Proceedings of ERDA
Conference on Technical Opportunities for Energy Conservation in Appliances,
May 1976, pp. 195-208.
6. Hoskings, R. A., and Hirst, E., "Energy and Cost Analysis of Residential
Refrigerators," Oak Ridge National Laboratory Report, ORNL/CON-6, 1977.
7. Little, Arthur D., Inc., "Study of Energy-Saving Options for Refrigerators and
Water Heaters, Volume 1 - Refrigerators," Cambridge, MA, 1977.
8. Lee, W. D., "Development of a High Efficiency, Automatic Defrosting
Refrigerator-Freezer, Phase I - Design and Development, Final Report, Volumes I
and II - R&D Task Reports," ORNL/Snb-7225/1, U. S. Department of Energy,
Washington, D.C., 1980.
22
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9. Lee, W. D., "Development of a High Efficiency Automatic Defrosting
Refrigerator/Freezer, Phase I - Design and Development, Final Report, Volume
III - R&D Task Reports," ORNL/Snb 7255/2, U. S. Department of Energy,
Washington, D.C., 1980.
10. Topping, R. F., and Lee, W. D., "Development of a High Efficiency, Automatic
Defrosting Refrigerator-Freezer," ASHRAE Transactions, Volume 87, Part 2,
pp. 859-867, 1981.
11. Bohman, R. H., and Harrison, F. L., "Engineering and Manufacture of a High
Efficiency, Automatic Defrosting Refrigerator-Freezer," ASHRAE Transactions,
Volume 88, Part 2, pp. 1053-1063.
12. Topping, R. F., and Vineyard, E. A., "Field Test of a High Efficiency, Automatic
Defrost Refrigerator-Freezer," ASHRAE Transactions, Volume 88, Part 2,
pp. 1064-1073, 1982.
13. Little, A. D., "Field Test of a High-Efficiency, Automatic Defrost Refrigerator-
Freezer," Oak Ridge National Laboratory Report, ORNL/77-7255/3, 1980.
14. Sterling, J., "Energy Factor-A Measure of the Efficiency of a Household
Refrigerator," ASHRAE Transactions, Volume 83 , Part 1, pp. 829-836, 1977.
15. Turiel, I., "Design Options for Energy Efficiency Improvement of Residential
Applications," Lawrence Berkeley Laboratory, LBL-22372, Berkeley, CA, 1986.
16. "Technical Support Document for the Analysis of Efficiency Standards for Small
Gas Furnaces, Television Sets, Refrigerators, and Refrigerator-Freezers,"
Department of Energy, Washington, D.C., 1988.
17. Turiel, I., and Heydari, A., "Analysis of Design Options to Improve the
Efficiency of Refrigerator-Freezers and Freezers," ASHRAE Transactions,
Vol. 94, Part 2, pp. 1988.
18. McQuiston, F. C., and Parker, J. D., "Heating, Ventilating, and Air Conditioning
Analysis and Design," Third Edition, John Wiley and Sons, Inc., New York,
1988, pp. 212-213.
19. Code of Federal Regulations, "Commercial Practices, Subchapter F - Refrigerator
Safety Act Regulations," 16CFR, Ch. 11, Sec. 1750.5, 1990, pp. 633-636.
20. Underwriters Laboratories, Inc., "Standard for Safety Household Refrigerators and
Freezers," American National. Standard, ANSI/UL 250, 1984.
23
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TECHNICAL REPORT DATA
(/'lease read Instructions on the reverse before completing}
1. REPORT NO.
EPA-600/2-91-060
4. TITLE AND SUBTITLE
Review of Energy Efficiency of Refrigerator/Freezer
Gaskets
October 1991
6. PERFORMING ORGANIZATION CODE
EPA/ORD
7. AUTHOR(S)
Majid Ghassemi and Howard Shapiro
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Iowa State University
Department of Mechanical Engineering
Engineering Research Institute
Ames, Iowa 50011
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-4286, Task 2/129
(Radian Corporation)
13. TYPE OF REPORT AND PERIOD COVERED
Task Final; 7-11/90
14. SPONSORING AGENCY CODE
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
15. supplementary NOTFSAEERL project officer is Jane C. Bare, Mail Drop 62B, 919/541"
1528.
EPA/600/13
16. ABSTRACT i
I The report gives results of an investigation of the significance of heat leak-
age through gaskets in household refrigerator/freezers, explores different design
features, and suggests further study if necessary. The report gives results of an
extensive literature review, interviews with refrigerator/freezer and gasket manu-
facturers, and some engineering analysis. (NOTE: Home refrigerators are the lar-
gest consumers of electricity among household appliances and are consuming an
estimated 8% of the total electricity used in the U. S. Recent studies show that gasket
area heat leakage may account for as much as 21% of the total thermal load.) The
study found that: (l) manufacturers will likely incorporate improved gasket technol-
ogy in 1993 models; (2) there is little certainty about the magnitude of gasket heat
leakage, although most believe it is significant (significance will increase with intro-
duction of advanced types of insulation); (3) double-door gaskets do not offer much
potential due to several practical limitations and the advancement in single-gasket
technology; (4) gasket infiltration may cause a significant portion of the load; and (5)
safety requirements are critical for home refrigerator/freezers (it is unlikely that
a mechanical door latching device would meet these requirements, even if it meets
energy conservation goals), g'
17.
KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. cos at I Field/Group
Pollution Heat Loss
Gaskets Safety
Refrigerators
Freezers
Energy Dissipation
Efficiency
Pollution Control
Stationary Sources
13B 20M
11A 13 L
13 A
20K
14 G
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report}
Unclassified
21. NO. OF PAGES
29
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
$17.00
EPA Form 2220-1 (9-73)
t
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