4 Utilising Passive Design Strategies for Analysing Thermal …
51
Table 4.7 Window glazing properties
Parameters
Solar heat gain
coefficient
(SHGC)
U value (W/m 2
K)
Emissivity
Solar
transmittance
(T)
Internal External
Double pane
clear glass
0.76
2.9
0.84
0.84
0.70
Triple pane
clear glass
0.68
1.9
0.84
0.84
0.60
Tinted glass
0.60
5.7
0.5
0.1
0.47
Low-e glass
0.62
3.8
0.1
0.5
0.58
important parameter for analysing heat exchange through fenestrations. This study
has been done considering four different types of glazing systems—double pane clear
glass, triple pane clear glass, tinted glass and low-emissivity (low-e) glass, with their
properties mentioned in Table 4.7 (http://glassed.vitroglazings.com/topics/how-lowe-glass-works; EQUA 2013; https://www.commercialwindows.org/tints.php).
The input parameters for each of the three windows were modified according to
each of the case mentioned above and simulations were run for the cases to obtain the
thermal comfort indices for each of them throughout the simulation period. Figure 4.7
represents the PMV versus PPD curve for the case of double pane windows with clear
glass. The graph depicts that similar to the case of provision of wall insulation, the
PMV as well as PPD values have decreased in this case too. It can be observed that
the minimum PMV value has reduced from −1.22 to −0.61 and the maximum PMV
value has decreased from 1.11 to 0.85. The possible reason behind this could be that
its SHGC as well as transmittance value is comparatively high while its U value is
comparatively lower, hence admitting the solar heat to the inside while restricting
the heat from the inside to the outside. Correspondingly, the PPD value obtained in
this case has also reduced from 36.61 to 20.55%. It can be seen in this case as well
that the PMV as well as PPD ranges have been brought closer to the ideal ranges
Fig. 4.7 PMV versus PPD
curve for double pane clear
glass window
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
-1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4
PPD (%)
PMV
51
Table 4.7 Window glazing properties
Parameters
Solar heat gain
coefficient
(SHGC)
U value (W/m 2
K)
Emissivity
Solar
transmittance
(T)
Internal External
Double pane
clear glass
0.76
2.9
0.84
0.84
0.70
Triple pane
clear glass
0.68
1.9
0.84
0.84
0.60
Tinted glass
0.60
5.7
0.5
0.1
0.47
Low-e glass
0.62
3.8
0.1
0.5
0.58
important parameter for analysing heat exchange through fenestrations. This study
has been done considering four different types of glazing systems—double pane clear
glass, triple pane clear glass, tinted glass and low-emissivity (low-e) glass, with their
properties mentioned in Table 4.7 (http://glassed.vitroglazings.com/topics/how-lowe-glass-works; EQUA 2013; https://www.commercialwindows.org/tints.php).
The input parameters for each of the three windows were modified according to
each of the case mentioned above and simulations were run for the cases to obtain the
thermal comfort indices for each of them throughout the simulation period. Figure 4.7
represents the PMV versus PPD curve for the case of double pane windows with clear
glass. The graph depicts that similar to the case of provision of wall insulation, the
PMV as well as PPD values have decreased in this case too. It can be observed that
the minimum PMV value has reduced from −1.22 to −0.61 and the maximum PMV
value has decreased from 1.11 to 0.85. The possible reason behind this could be that
its SHGC as well as transmittance value is comparatively high while its U value is
comparatively lower, hence admitting the solar heat to the inside while restricting
the heat from the inside to the outside. Correspondingly, the PPD value obtained in
this case has also reduced from 36.61 to 20.55%. It can be seen in this case as well
that the PMV as well as PPD ranges have been brought closer to the ideal ranges
Fig. 4.7 PMV versus PPD
curve for double pane clear
glass window
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
-1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4
PPD (%)
PMV