United States
Environmental Protection
Agency
Air and Radiation
6202J
EPA430-R-94-003
January 1994
v*EPA
Vacuum Panel and Thick Wall
Foam Insulation for Refrigerators:
Cost Estimates for Manufacturing
and Installation - Part II
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VACUUM PANEL AND THICK WALL FOAM
INSULATION FOR REFRIGERATORS:
Cost Estimates for Manufacturing and Installation - Part II
prepared for
US Environmental Protection Agency
Global Change Division
Office of Atmospheric Programs
Office of Air and Radiation
by
James M. Waldron
Stephen M. Poulter
Center for Robotics and Manufacturing Systems
University of Kentucky College of Engineering
Lexington, Kentucky 40506-0108
January 1994
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; ABSTRACT
i
''Vacuum Panel and Thick Wall Foam Insulation for Refrigerators: Cost
1
Estimates for Manufacturing and Installation," published in October 1992 [1],
established high volume manufacturing feasibility for Vacuum Insulation'Tanels
(VIPs) and estimated capital requirements for facilities and equipment. Product
costs for VIP manufacturing and installation into refrigerators were established
based upon a representative two-door cabinet and a generic manufacturing
facility at an annual output of 300,000 units. A short summary of the pertinent
conclusions of the 1992 study are detailed in Appendix A.
In the current analysis, an additional VIP is added to the back of the freezer and
the number of models using VIPs is increased. The annual refrigerator
production volume is also increased to simulate 100% usage in a plant producing
one million refrigerators per year in three different cabinet sizes. This study will
not cover installing the panels because the relative cost per line- for transportation
and installation will be the same as in the October '92 study.
[ I
The addition of a VIP to the freezer back yields a 1% energy savings. The addition
of two more models and a volume increase to one million refrigerators per year
results in a more efficient VIP plant and a slightly lower cost per board foot. This
decrease in cost results from the reduced amount of production time lost to VIP
size changeovers and from amortization of fixed cost over a much larger
production volume.
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TABUS OF CONTENTS
Abstract x
Table of Contents "
Figures • m
Tables iv
Introduction •*•
Findings 2
Freezer Back Redesign 3
Panels for 18ft3, 21ft3, & 24ft3 Refrigerators 5
Impact on VIP Plant 8
Panel Standardization • ^
Panel Standardization Summary 17
Product Cost 18
Energy Analysis 20
Summary 23
References 24
Appendix A 25
11
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FIGURES
i
Number
1. Current Freezer Back Design without VIP. .
2. Redesigned Freezer Back with VIP.
I •
3. VIP Placement in Refrigerator Cabinet
i
4. Energy Cost per Year
4
4
7
22
111
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TABLES
Number
1. VIP Sizes from "Vacuum Panel and Thick Wall Foam Insulation ^f
Refrigerators: Cost Estimates for Manufacturing and Installation" 5
2. Optimum Panel Sizes for 18ft8, 21ft8, & 24ft3 Refrigerators i . - 6
fi
3. Outer Case Sizes •
4. Panel Plant Equipment
5. Annual Operating Cost - Panel Plant 10
6. Panel Standardization - Base Case '. H
7. Weekly Operation Plan - Base Case 1:L
8. Panel Standardization - Scenario 1 ^
9. Weekly Operation Plan - Scenario 1 • ^
10. Panel Standardization - Scenario 2 • 14
10A. Frequency of Use and Annual Volume - Scenario 2 14
11. Weekly Operation Plan - Scenario 2 15
12. Panel Standardization - Scenario 3 ^
12A. Frequency of Use and Annual Volume - Scenario 3 16
13. Weekly Operation Plan - Scenario 3 16
14. Minimum Efficiency Requirement Comparison 17
15. Variable Manufacturing Cost for VIPs I8
16. Energy Consumption Comparison 2°
17. Energy Savings vs. VIP Cost for the 21 ft3 Refrigerator 23
IV
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INTRODUCTION
The impending phase-out of chloroflourocarbons (CFCs) used to expand foam
insulation combined with requirements for increased energy efficiency makes
the use of non-CFC-based high performance insulation technologies
increasingly attractive to refrigerator manufacturers. One such technology,
silica filled vacuum panels, has been the subject of research and development
for some time. The technical and economic feasibility of mass producing these
panels and installing them into refrigerators, however, continued to be a
question until the EPA publication, "Vacuum Panel and Thick Wall Insulation
for Refrigerators: Cost Estimates for Manufacturing and Installation," was
published in October 1992. [1]
i
This report, hereafter referred to as the October '92 study, develops a mass
production manufacturing process for vacuum insulation panels (VIPs) and
estimates capital cost for facilities and equipment and additional product cost
for adding ten VIPs to the refrigerator. The production costs and facilities
impact of an alternative energy-reduction design, thicker non-CFC-based foam
insulation, was also studied.
This study adds an eleventh panel to the refrigerator and looks at the impact
on VIP plant efficiency when panels are produced for three different size
refrigerators and at a volume over three times that assumed in the October '92
study. VIP sizes are optimized for each of the three cabinet sizes (instead of
using 18 ft3 panels in all sizes), and then a trade-off evaluation between VIP
plant efficiency and refrigerator energy reduction is made to arrive at an
optimum set of standard panel sizes.
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FINDINGS
• It is feasible to place a VIP in the freezer back section of the refrigerator.
The program cost to move the suction line exit point to make more space for the
panel is estimated at $275,000.
• The freezer back panel decreases energy consumption by only 1%
(approximately 7 kWh/year) compared to a refrigerator with 10 VIPs. This
small effect occurs because the freezer back already has 2.3 inches of foam
insulation.
• By standardizing VIP sizes for the three refrigerators studied, a significant
improvement in VIP plant productivity can be made with minimal sacrifice in
energy savings for the two larger models, (see Scenario 2)
• Of the three manufacturing scenarios evaluated in this study, both
Scenarios 1 and 2 (page 13 and 15) have good balance of required minimum
efficiency on the three manufacturing lines, with a maximum of 80.5%. This
is a productivity improvement over the October '92 line, which requires a
minimum efficiency of 83.3% to meet schedule.
• Scenario 2 also has the lowest product cost at $1.29 per board foot, which
equals the base case but with nine VIPs instead of fifteen. This was only $0.01
less than Scenario 1, but significant at $290,000 per year less cost for 29 million
board feet of VIPs.
• For the 18 ft3 refrigerator, Scenario 2 produces the largest energy savings
compared to a Base Model B refrigerator [2]. (see Table 16)
• Scenarios 1 and 2 are about equal in cost/kWh saved for the 21 ft3 model (see
summary table 17, page 22). Scenario 1, however, would probably compare
less favorably for the 18 ft3 and 24 ft3 models.
• The cost for panel plant equipment for three lines is estimated to be about $35
million, (see Table 4)
• The annual operating cost for the panel plant with three lines is about $3.6
million, (see Table 5)
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FREEZER BACK REDESIGN
In the October '92 study, ten VIPs were used in each refrigerator. A panel was
not planned in the freezer back because interference with the suction line and
ice maker fill tube (see Figure 1) necessitated a small panel which was deemed
ineffective.
In this analysis, it was determined that a one-half inch panel could be used
over the air duct if the suction line exit point could be moved to the side of the
freezer to eliminate interference with the foam block, (see Figure 2)
Relocation or redesign of the ice maker fill tube was deemed too expensive for
the limited increase in VIP size that would result. Recessing of the air duct
would allow application of a one inch VIP. This change was also deemed too
expensive and could have a negative impact on the freezer volume.
The program cost to move the suction line exit on three refrigerator sizes (18ft3,
21ft3, & 24ft3) was estimated to be about $275,000. This cost includes $200,000 for
tooling and fixture changes and test runs, and one man year of engineering
effort at $75,000. There would be no increase in product cost, since this change
involves only a relocation of components.
The energy improvement resulting from the addition of this freezer back VIP
was modeled using the EPA Refrigerator Analysis Program [2]. The results
are shown in Table 16.
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FIGURE 1
Current Freezer Back Design without VIP
(Front View)
-n
Ice Maker
Fill Tube
Block
FIGURE 2
Redesigned Freezer Back with VIP
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PANELS FOR 18ft3 21ft3!, & 24ft3 REFRIG1ERATORS
In the October '92 study, ten VIPs were planned for 21ft3 and 24ft3
refrigerators, (see Table 1) These Panels were sized to fit an 18ft3 refrigerator
for possible future application to that model. Also, the panels were
standardized to five sizes. A VIP was not planned for the freezer back which
would add one more panel size, making the total six.
i
TABLE 1
VIP Sizes From October'92 Study
Panel #
1&5
2&3
4&6
7
8, 9, & 10
Size (inches)
1x21x28
1x21x19
1x21x30
0.5x28x10
0.5x28x19
Location
Freezer Top & Fresh Food Back
Freezer Sides
I
Fresh Food Sides
Fresh Food Bottom
Doors
In this study, VIPs were re-sized for the 21ft3 and 24ft3 refrigerators to better
optimize panel fit and foam flow during fill, and a panel was added to the
freezer back, making a total of eleven VIPs per refrigerator. Also, VIP sizes
for the 18ft3 were reassessed, resulting in some size changes from the October
'92 study. New VIP sizes for all three cabinets are shown in Table 2. Letter
codes have been added to identify each panel size. Outer case dimensions are
shown in Table 3.
For the three cabinets, thirty three panels are required in sixteen different
sizes - seven one inch thick and nine one-half inch thick.
VIP placement in the refrigerator cabinet is shown in Figure 3.
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TABLE2
Optimum Panel Sizes-for 18ft8, 21ft«, & 24ft8 Refrigerators
(inches)
Panel #
1&5
2&3
4&6
7
8, 9, & 10
11
18ft3
1x21x26
1x21x17
1x21x30
0.5x26x10
0.5x26x19
0.5x14x20
code
a
d
f
h
k
n
21ft3
1x21x28
1x21x19
1x21x31
0.5x28x10
0.5x28x20
0.5x14x22
code
b
e
g
i
1
o
24ft3
1x21x31
1x21x19
1x21x31
0.5x31x10
0.5x31x20
0.5x14x25
c
e
g
j
m
P
inches
TABLES
Outer Case Sizes
60.80 29.38 28.80
62.94 31.25 28.80
63.35 34.25 28.80
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FIGURES
VIP Placement in Kefrigerator Cabinet
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IMPACT ON VIP PLANT
The impact of increasing panel production (from the level assumed in the
October '92 report) to support three refrigerator models is assessed in this
section. The assumptions for this analysis are:
1. Panels must be produced for three refrigerator sizes:
- 18ft3 @ 600,000 per year
- 21ft3 @ 250,000 per year
- 24ft3 @ 150,000 per year
2. Each refrigerator requires eleven VIPs (see Table 2).
With the increase in volume of refrigerators having VIPs from 300,000 per
year (October '92 study) to one million per year and the addition of a VIP to the
freezer back, eleven million panels must be produced each year. To
accomplish this, two more production lines would be added to the VIP plant,
making a total of three. The October '92 study took this into consideration and
the plant was sized for three VIP lines. That study also included panel plant
equipment cost and annual operating cost for one line. This information has
been updated to include the two additional production lines, and can be seen in
Tables 4 and 5. No adjustment from the October '92 study has been made for
inflation, since this small percentage is within the error level of the estimates.
Increasing VIP plant stock to sixteen panel sizes (see Table 6 - Base Case)
should not have a negative productivity impact on the VIP plant operation.
Since three productions lines will be available, the average number of panels
per line will be about the same as in the October '92 study.
In order to compare this "Base Case" with panel size standardization
alternatives, a base case weekly operating plan was developed, (see Table 7)
Two VIP lines will run five panels (lines 1 & 3) and the third line (line 2) will
run six. With a just-in-time plan to run each panel two times each week, line
2 will require 12 changeovers per week and 20 hours of set-up time.
Calculating weekly production hours required at 900 VIPs per hour per line
and adding that to needed changeover time yields a balance of time available
for maintenance and downtime. The ratio of production hours plus
changeover hours to the 120 hour work week schedule shows the minimum
efficiency which the line must operate to support the annual volume
requirements, (see Table 7)
8
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\
§
INSTALLATI
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1
TOTAL |
COST/UNIT |
VENDOR |
NUMBER |
EQUIPMENT 1
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rS o t^c^ininmoscD^cDCDcoooo in oo o c*» o o
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TABLE6
Panel Standardization - Base Case
Panel Sizes
(inches)
1 x 21 x 26
1 x 21 x 28
1 x 21 x 31
1 x 21 x 17
1 x 21 x 19
1 x 21 x 30
1 x 21 x 31
0.5 x 26 x 10
0.5 x 28 x 10
0.5 x 31 x 10
0.5 x 26 x 19
0.5 x 28 x 20
0.5 x 31 x 20
0.5 x 14 x 20
0.5 x 14 x 22
0.5 x 14 x 25
Panel
Code
a
b
c
d
e
f
g
h
i
j
k
1
m
n
o
P
Freqt
18ft3
2
2
2
1
3
1
lency C
21ft3
2
2
2
1
3
1
fUse
24ft3
2
2
2
1
3
1
Volume per
Year (000)
1200
500
300
1200
800
1200
800
600
250
150
1800
750
450
600
250
150
TABLET
Weekly Operation Plan - Base Case
(48 Weeks/Year, 120 Hours/Week, 900 VIPs/Hour per line)
Line
1
2
3
Panels
a, b, c,
d,e
f, g, h,
i, j, m
k, 1, n,
o, p
Annual
Volume
(000) .
4000
3450
3550
Change-
overs
per Week
10
12
10
# Hours
for Change-
overs
10
20
14
Production
Hours
92.6
79.9
82.2
Maintenance/
Downtime
Hours
! 17.4
1
| 20.1
23.8
Minimum
Efficiency
Required
85.5%
83.3%
80.2%
11
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PANEL STANDARDIZATION
There is an opportunity through further standardization of sizes to improve
VIP plant productivity. To examine the economic tradeoffs between panel
plant efficiency and refrigerator energy reduction, several different panel
standardization scenarios were studied. Three are discussed in this section:
Scenario 1 - use same size panels in all three cabinet sizes.
Scenario 2 - allow each panel to increase in size up to 1", and/or decrease
in size up to 2", keeping panel thickness constant.
Scenario 3 - allow each panel to increase in size up to 1" and/or decrease
in size up to 2", and make all panels 1/2" thick.
SCENAEIO 1
In this scenario panels sized for an 18ft3 cabinet would be used in all three
refrigerator sizes; the same as in the October '92 study except for modified
panel sizes and the addition of the freezer back VIP. This would require a total
of six panel sizes, (see Table 8)
TABLES
Panel Standardization - Scenario 1
Same size panels for all three cabinet sizes
Panel #
1&5
2&3
4&6
7
8, 9, & 10
11
Size (inches)
1x21x26
1x21x17
1 x 21 x 30
0.5x26x10
0.5x26x19
0.5x14x20
Location
Freezer Top & Fresh Food Back
Freezer Sides
Fresh Food Sides
Fresh Food Bottom
Doors
Freezer Back
The weekly operations plan for scenario 1 is shown in Table 9. Line 1 would
run panels 1, 5, 2, & 3 for an annual output of four million panels. Each panel
would be produced twice each week. Therefore; four line changeovers would
be made, requiring one hour per dimension change, for a total of four hours.
Ninety two and six tenths hours of production time would be required each
12
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week, leaving 23.4 hours for downtime and maintenance. This means a
minimum efficiency of 80.5% will be required on this line to meet schedule.
Minimum efficiency requirements for lines 2 and 3 are 67.8% and 80.5%
respectively. The one production line in the October '92 study was required to
be at least 83.3% efficient.
' i
It can be concluded that this plan would be more productive than the October
'92 plant and would also be more of a just-in-time operation, since each panel
is being produced twice per week instead of once per week.
TABLE9
Weekly Operation Plan - Scenario 1
(48 Weeks/Year, 120 HoursAVeek, 900 VIPs/Hour per line)
Line
1
2
3
Panels
1,5,
2,&3
4,6,
&11
7,8,
9,&10
Annual
Volume
(000)
4000
3000
4000
Change-
overs
per Week
4
4
4
# Hours
for Change-
overs
4
12
4
Production
Hours
92.6
69.4
92.6
Maintenance/
Downtime
Hours
23.4
38.6
23.4
Minimum
Efficiency
Required
80.5%
67.8%
80.5%
SCENARIO 2
i
Panels are standardized under this scenario to a rule wMch lets each panel
grow as much as one inch in height and/or width or shrink as much as two
inches while keeping the same thickness (see Table 10). The number of unique
panels would be reduced from sixteen to nine for the three different size
cabinets, (see Table 10A). Panel c is used ten times and a and e are used six
times each.
13
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TABLE 10
Panel Standardization - Scenario 2
Maximum Increase = 1"
Maximum Decrease = 2"
(inches)
Panel #
1&5
2&3
4&6
7
8, 9, & 10
11
18ft3
1x22x26
1x22x18
1x22x29
0.5x27x10
0.5x27x20
0.5x14x20
code
b
a
c
d
e
h
21ft3
1x22x29
1x22x18
1x22x29
0.5x27x10
0.5x27x20
0.5x14x23
code
c
a
c
d
e
i
24ft3
1x22x29
1 x 22 x 18
1x22x29
0.5 x 31 x 10
0.5 x 31 x 20
0.5x14x23
code
c
a
c
f
g
i
TABLE 10A
Frequency of Use and Annual Volume - Scenario 2
Panel Sizes
(inches)
1 x 22 x 18
1 x 22 x 26
1 x 22 x 29
0.5 x 27 x 10
0.5 x 27 x 20
0.5 x 31 x 10
0.5.x 31 x 20
0.5 x 14 x 20
0.5 x 14 x 23
Panel
Code
a
b
c
d
e
f
S
. h
i
Freqi
18ft3
2
2
2
1
3
1
lency C
21ft3
2
4
1
3
1
fUse
24ft3
2
4
1
3
1
Volume per
Year (000)
2000
1200
2800
850
2550
150
450
600
400
In the weekly operations plan for scenario 2, line 1 has the same operating
parameters as in scenario 1. The balance between lines 2 and 3 is improved
(see Table 11). All lines in this scenario are more productive than the one in
the October '92 study and have a lower minimum efficiency requirement.
14
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TABLE 11
Weekly Operation Plan - Scenario 2
(48 Weeks/Year, 120 Hours/Week, 900 VIPs/Hour per line)
Line
1
2
3
Panels
b, &c
d, e,
&f
a, g,
h, &i
Annual
Volume
(000)
4000
3550
3450
Change-
overs
per Week
4
6
8
# Hours
for Change-
overs
4
8
16
Production
Hours
92.6
82.2
79.9
Maintenance/
Downtime
Hours
23.4
29.8
24.1
.
Minimum
Efficiency
Required
80.5%
75.2%
79.9%
SCENAEIO 3
Panels are standardized under this scenario to a rule widen lets each panel
grow as much as one inch in height and/or width or shrink as much as two
inches and all panels are made 1/2" thick, (see Table 12) The number of
unique panels would be further reduced to only eight under this scheme, (see
Table 12A) Panel b could be eliminated, and replaced with panel e.
TABLE 12
Panel Standardization - Scenario 3
Maximum Increase = 1"
Maximum Decrease = 2"
All Panels 1/2" Thick
Panel #
1&5
2&3
4&6
7
8, 9, & 10
11
18ft3
0.5x27x20
0.5x22x18
0.5 x 22 x 29
0.5x27x10
0.5x27x20
0.5x14x20
code
e
a'
c1
d
e
h
21ft3
0.5x22x29
0.5x22x18
0.5x22x29
0.5x27x10
0.5x27x20
0.5x14x23
code
c1
a1
c1
d
e
i
24ft3
0.5x22x29
0.5x22x18
0.5 x 22 x 29
0.5 x 31 x 10
0.5x31x20
0.5x14x23
code
c1
a1
c'
f
g
i
15
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TABLE12A
Frequency of Use and Annual Volume - Scenario 3
Panel Sizes
(inches)
0.5 x 22 x 18
0.5 x 22 x 29
0.5 x 27 x 10
0.5 x 27 x 20
0.5 x 31 x 10
0.5 x 31 x 20
0.5 x 14 x 20
0.5 x 14 x 23
Panel
Code
a'
c1
d
e
f
g
h
i
Freqt
18ft3
2
2
1
5
I
tency C
21ft3
2
4
1
3
1
fUse
24ft3
2
4
1
3
1
Volume per
Year (000)
2000
2800
850
3750
150
450
600
400
This scenario offers very little advantage over scenario 2 and forces panels a
and c to one-half inch (a' & c') without gaining any further standardization.
The weekly operations plan for scenario 3 (see Table 13) does allow one line
(line 2) to be captive to one panel and run very efficiently. However, line 1 adds
one panel and the minimum efficiency required to meet schedule is raised
from 80.5% to 81.7%.
TABLE 13
Weekly Operation Plan - Scenario 3
(48 Weeks/Year, 120 Hours/Week, 900 VIPs/Hour per line)
Line
1
2
3
Panels
c1, d,
&f
e
a', g,
h, &i
Annual
Volume
(000)
3800
3750
3450
Change-
overs
per Week
6
0
8
# Hours
for Change-
overs
10
0
12
Production
Hours
88.0
86.8
79.9
Maintenance/
Downtime
Hours
22.0
33.2
28.1
Minimum
Efficiency
Required
81.7%
72.3%
76.6%
16
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PANEL STANDARDIZATION SUMMARY
A summary of the minimum efficiencies of each scenario can be seen in Table
14 along with that of the October '92 study. It can be seen that Scenario 2 has a
more even distribution of efficiency across all three lines, with the highest
minimum efficiency requirement being 80.5% for line 1.
TABLE 14
Minimum Efficiency Requirement Comparison
October '92 Study
Scenario 1
Scenario 2
Scenario 3
Line 1
83.3%
80.5%
80.5%
81.7%
Line 2
"g$y$3f"-£&®
' ,•. X4*™'»W.«»#».:.
80.5%
79.9%
76.6%
Average
83.3%
76.3%
78.5%
76.9%
17
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PRODUCTCOST
Product cost in the October '92 study included all direct material and labor
included in or added to the product and its packaging, shipping and
installation plus associated overhead cost. In this study, product cost for a
21ft3 refrigerator was recalculated, eliminating transportation and VIP
installation which includes adhesive and displaced foam. The recalculated
cost per board foot can be seen in Table 15, along with the product costs for the
part II base case and the three standardization scenarios considered in this
report.
TABLE 15
Variable Manufacturing Cost for VIPs
21 ft3 Refrigerator
1991 Dollars
October *92 Study - Recalculated (29 Board Feet of VIPs - 5 Panel Sizes)
ITEM
Silica (29 LBS)
Porous Bag (80 FT2)
Barrier (83 FT2)
Panel packaging
Panel manufacturing
Totals
DIRECT
MATERIAL
$21.75
$2.88
$9.21
$0.16
$34.00
DIRECT LABOR
& OVERHEAD
$4.49
$4.49
OTHER OPERATING
COST
$0.89
$0.89
TOTALS
$21.75
$2.88
$9.21
$0.16
$5.38
$39.38
$1.36 /board foot
Base Case (29.5 Board Feet of VIPs -16 Panel Sizes)
ITEM
Silica (29.5 LBS)
Porous Bag (84.37 FT2)
Barrier (88.19 FT2)
Panel packaging
Panel manufacturing
Totals
DIRECT
MATERIAL
$22.13
$3.04
$9.79
$0.16
$35.11
DIRECT LABOR
& OVERHEAD
$2.58
$2.58
OTHER OPERATING
COST
$0.45
$0.45
TOTALS
$22.13
$3.04
$9.79
$0.16
$3.03
$38.14
$1.29 /board foot
18
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Scenario 1 (28.3 Board Feet of VIPs - 6 Panel Sizes)
ITEM
Silica (28.31 LBS)
Porous Bag (80.95 FT2)
Barrier (84.53 FT2)
Panel packaging
Panel manufacturing
Totals
DIRECT
MATERIAL
$21.23
$2.91
$9.38
$0.16
$33.69
DIRECT LABOR
& OVERHEAD
$2.58
$2.58
OTHER OPERATING
COST
$0.45
$0.45
TOTALS
$21.23
$2.91
$9.38
$0.16
$3.03
$36.72
$1.30/board foot
Scenario 2 (30.4 Board Feet of VIPs - 9 Panel Sizes)
ITEM
Silica (30.41 LBS)
Porous Bag (86.98 FT2)
Barrier (90.69 FT2)
Panel packaging
Panel manufacturing
Totals
DIRECT
MATERIAL
$22.81
$3.13
$10.07
$0.16
$36.17
DIRECT LABOR
& OVERHEAD
$2.58
$2.58
OTHER OPERATING
COST
$0.45
$0.45
TOTALS
$22.81
$3.13
$10.07
$0.16
$3.03
$39.20
$1.29 /board foot
Scenario 3 (18.9 Board Feet of VIPs - 8 Panel Sizes)
ITEM
Silica (18.94 LBS)
Porous Bag (86.42 FT2)
Barrier (90.12 FT2)
Panel packaging
Panel manufacturing
Totals
DIRECT
MATERIAL
$14.21
$3.11
$10.00
$0.16
$27.48
DIRECT LABOR
& OVERHEAD
$2.58
$2.58
OTHER OPERATING
COST
$0.45
$0.45 i
TOTALS
$14.21
$3.11
$10.00
$0.16
$3.03
$30.51
$1.61/board foot
The base case and scenarios 1 and 2 all have lower product cost than the
October '92 study due to reduced line changeovers and better amortization of
panel manufacturing cost.
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ENERGY ANALYSIS
The EPA Refrigerator Analysis (ERA) program [2] was used to model energy
consumption for the base case panel sizes, with and without a freezer back
panel, and for each of the three scenarios described in the preceding section.
(see Table 16)
TABLE 16
Energy Consumption Comparison
ERA Model B Units -1991 Baseline
Model Description
ERA Base Model B
ERA Model B w/ 10 VIPs
ERA Model Bw/ 11 VIPs
Scenario 1
Scenario 2
Scenario 3
Energy Consumption / % Savings
(kWhr/day)
18ft3
2.29
1.92
1.90
1.90
1.88
1.99
% savings
16.4%
17.3%
17.3%
18.3%
13.2%
21ft3
2.40
1.98
1.96
2.00
1.98
2.08
% savings
17.3%
18.1%
16.6%
17.6%
13.3%
24ft3
2.52
2.08
2.05
2.13
2.08
2.18
% savings
17.4%
18.3%
15.3%
17.5% '
13.3%
ERA Model B, which is the 18ft3 model used to determine panel sizes, was the
base model in this energy analysis. The 21ft3 model was created by adding 2.54
cm (one inch) to the cabinet height and width, and 1.8 cm to the depth. The
distance to the top of the mullion from the top of the cabinet was also increased
by 1.27 cm. The 24ft3 model was created by adding 5.08 cm (two inches) to the
cabinet height and width, and 4.34 cm to the depth. The distance to the top of
the mullion from the top of the cabinet was increased by 2.54 cm.
This approach was used to facilitate the ERA modeling. The results should
not be significantly different from those which would be obtained using the
cabinet dimensions in Table 3.
Adding 10 VIPs to the base ERA Model B resulted in a 16.4% energy reduction
for the 18ft3 cabinet and slightly more for the 21ft3 and the 24ft3. However, the
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addition of a VIP to the freezer back did not significantly decrease energy
usage. 1 '
It can also be seen that Scenario 2 panel sizes resulted in .the largest energy
savings of the three panel standardization scenarios studied in this report,
having 1% greater savings over Scenario 1 and a 5% greater savings over
Scenario 3 for the 18 ft3. For the 21 ft3 and the 24 ft3, some loss in energy
savings is traded for higher VIP plant productivity. Energy cost per year was
calculated for all the scenarios in this report (see Figure 4). Scenario 2 has the
lowest cost/year with $54.75 for the 18 ft3 refrigerator. This is a savings of
$12.23 per year over the Base Model B refrigerator.
21
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oo
(N
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SUMMARY •
I
j
TAB1LE17
Energy Savings vs. VIP Cost for the 21 ft3 Refrigerator
ERA Model B
October '92 Study
(w/ VIP in freezer)
Scenario 1
Scenario 2
Scenario 3
kWh/day
2.40
1.96
2.00
1.98
2.08
kWh/day
saved
0.44
0.40
0.42
0.32
VIP cost/
refrigerator
$39.38
$36.72
$39.20
$30.51
Cost/kWh
saved *
$0.0129
$0.0132
$0.0135
$0.0137
Present value cost but assuming a refrigerator life of 19 years.
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1. Waldron, James M., "Vacuum Panel and Thick Wall Foam Insulation for
Refrigerators: Cost Estimates for Manufacturing and Installation," US EPA
Report # EPA/430/R-92/1101, U. S. Environmental Protection Agency,
Washington, D. C., October 1992.
2. Meniam, R. L., Varon, A., and Feng, H., "EPA Refrigerator Analysis
(ERA) Program: Version 1.0," US EPA Report # EPA/430/R-93/007, U. S.
Environmental Protection Agency, Washington, D. C., June 1993.
24
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APPENDIXA
Summary of "Vacuum Panel and Thick Wall Insulation for Refrigerators:
Cost Estimates for Manufacturing and Installation"
Purpose - establish cost and feasibility to manufacture and install Vacuum
Insulated Panels (VIPs) into a typical generic domestic refrigerator.
What is a VIP? - a product having a 67% lower thermal conductivity than CFC
blown foam, made by encapsulating micro grain silica within a plastic
laminate and evacuating and sealing the envelope.
Application - glued to the interior of the refrigerator liner or case (either
manually or automatically) and foamed in place.
Materials
- Porous Bag - TYVEK (Snow Filtration) - $0.036/ft2
- Barrier Bag - VECAT (FRES-CO System) - $0.111/ft2
- Silica - FK500LS (Degussa) - $0.75/lb
Product Cost - to manufacture, transport and install ten panels (5 different
sizes) per refrigerator:
- $1.39 per board foot (l"xl'xl')*
- 300,000 refrigerators per year (3,000,000 panels) |
- Assembly line rate - one unit per 20 seconds
- Panel plant output - one panel every 4 seconds
* A typical 21" ft3 refrigerator would use about 29 board feet of panels.
Program Cost
- Panel plant - $17 million*
- Refrigerator plant - $6.6 million*
* Investment, expense, manpower and start-up
Timetable - Approximately 2 1/2 years from "Go."
Results J
- Can be done!
- Increases thermal efficiency of a 21 ft3 refrigerator by about 14.5%.
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