ZEMCH 2019 International Conference Proceedings April.2020 | Page 306
U = 1/R = Q/ ((Th – Tc) * A) (1)
Where, U: Overall thermal transmittance (W/㎡ K)
R: Overall thermal resistance (㎡ K/W)
Q: Supplied heat (W)
Th: Temperature of hot region (℃)
Tc: Temperature of cold region (℃)
A: Area of specimen (m 2 )
Test results are contained in Table 2.
Table 2. Overall Thermal Transmittance and Thermal Resistance of Low‐E Insulation
Thickness
(mm) Overall Thermal
Transmittance
(W/m 2 K) (m 2 K/W) (ft 2 ℉hr/Btu)
10 1.12 0.89 5.10
20 0.55 1.82 10.3
30 0.45 2.22 12.6
40 0.32 3.13 17.8
50 0.27 3.70 21.0
60 0.22 4.55 25.8
80 0.19 5.26 29.9
100 0.14 7.14 40.5
Thermal Resistance
Table 2 shows that 100mm thick Low‐E Insulation can meet the overall thermal transmittance of
walls and roof of Passive Houses which is below 0.15W/m2K [3].
Figure 6 contains required thickness of various insulations to meet the overall thermal
transmittance of Passive Houses of 0.15W/m2K [5].
Figure 6. Required Thickness of various Insulations for Passive Houses
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ZEMCH 2019 International Conference l Seoul, Korea