These calculations are based on the following report:
A Study of the Energy Savings that can Occur when Using Insuladd Solar Reflective Paint on Irradiated Building Walls
As conducted by Dr. H. F. Poppendiek
GEOSCIENCE LTD
6260 Marindustry Drive
San Diego, California 92121
April 2003
The following calculation was carried out by engineers at M. J. Trading International, Inc., for Tech Traders, Inc. The purpose of this report is to calculate out how the equivalent “R-value,”as derived from the application of INSULADD added into ordinary paint. Geoscience calculated an equivalent “R”of “6” in the following report.
Our calculation is given below:
qcooling / A = (t - ti) / (Rr + Ri) …………………… (2)
* Heat flux without INSULADD application – from the report.
- Measured = 5.24
* Heat flux with INSULADD application – from the report.
- Measured = 3.57
- Calculated = 3.53 (using Equation (1) in the report)
- Very good agreement!
* The reasoning is that the reduction of heat flux from the application of INSULADD-added paint (from 5.24 down to 3.53), may be viewed as the result of a wall that has a higher value of thermal resistance than the R-value it has now. This additional thermal resistance may be calculated using Equation (2) above and the experimental data given in the report as shown below:
qcooling / A = (t - ti) / (Rr + Ri)
(t - ti) / (Rr + Ri + R) = 3.53
Where,
t = Irradiated wall temperature = 141.8oF
ti = Invariant interior air temperature of building = 75.8 oF
Rr = Thermal resistance of wall = 12 hr-ft2-oF/Btu
Ri = Interior air resistance = 1 hr-ft2-oF/Btu
R = The additional thermal resistance, or the equivalent “R”
Thus
(141.8 – 75.8) / (12 + 1 + R) = 3.53
(3.53) (R + 13) = 66
(R + 13) = 66 / 3.53 = 18.7
R = 5.7
Note that instead of using the calculated reduced heat flux of 3.53, we may use the measured value at 3.57. If so, then the equivalent “R” would be 5.5.
Thus, using this process as described in the report, yielded an “R = 5.5 to 5.7”.
IThis process of deriving an equivalent thermal resistance value is correct.
We are able to do the same on the tests Tech Traders did in late last March using an ESP board with a “R = 3 value shown below.
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Infrared Heat lamp tests of R-3 foam panels and Insuladd insulating paint additive mixed into latex primer.
3/19/07
A series of 6 tests were performed using a 450 watt heat lamp array positioned 18” from the exterior of 20” x 20” pieces of standard foam home insulation R-3 rated panels.
One panel was painted on one side with one coat of inexpensive latex primer to which Insuladd insulating additive for paint had been added. The coverage rate was based on 225 to 250 sq ft per gallon of primer.
The second panel was left uncoated.
During the tests each panel was covered on the side exposed to the heat lamp array with dark brown fabric to enhance heat gain and to negate the inherent reflective properties of the panels.
Each panel being tested had a heat flux transducer attached to the backside of the panel. Each panel was then attached with an airtight seal to a 16” x 16” x 13” insulated chamber and exposed to the infrared heat lamp array for 30 minutes by which time the heat flux had stabilized and no increases were occurring.
The exterior surface temperature of the dark brown fabric covered R-3 panel averaged 180 F throughout all of the tests. Ambient air temperature was 89 deg. F
The tests were run 6 times and the results of the tests were averaged to get the following results:
Uncoated R-3 panel: Heat Flux was measured at 25.8 BTU per hour per Ft (squared)
R-3 panel coated on exterior: (heat side) with Insuladd insulating additive for house paint: Heat Flux was measured at 17.2 BTU per Hour per Ft (squared)
Summary: The Insuladd/Primer coated panel consistently produced results showing a reduced heat flux through the R-3 panel of 33%.
Infrared Heat lamp tests of R-3 foam panels and Insuladd insulating paint additive mixed into latex primer.
3/19/07
A series of 6 tests were performed using a 450 watt heat lamp array positioned 18” from the exterior of 20” x 20” pieces of standard foam home insulation R-3 rated panels.
One panel was painted on one side with one coat of inexpensive latex primer to which Insuladd insulating additive for paint had been added. The coverage rate was based on 225 to 250 sq ft per gallon of primer.
The second panel was left uncoated.
During the tests each panel was covered on the side exposed to the heat lamp array with dark brown fabric to enhance heat gain and to negate the inherent reflective properties of the panels.
Each panel being tested had a heat flux transducer attached to the backside of the panel. Each panel was then attached with an airtight seal to a 16” x 16” x 13” insulated chamber and exposed to the infrared heat lamp array for 30 minutes by which time the heat flux had stabilized and no increases were occurring.
The exterior surface temperature of the dark brown fabric covered R-3 panel averaged 180 F throughout all of the tests. Ambient air temperature was 89 deg. F
The tests were run 6 times and the results of the tests were averaged to get the following results:
Uncoated R-3 panel: Heat Flux was measured at 25.8 BTU per hour per Ft (squared)
R-3 panel coated on exterior: (heat side) with Insuladd insulating additive for house paint: Heat Flux was measured at 17.2 BTU per Hour per Ft (squared)
Summary: The Insuladd/Primer coated panel consistently produced results showing a reduced heat flux through the R-3 panel of 33%.
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