4 Utilising Passive Design Strategies for Analysing Thermal …
49
Fig. 4.6 PMV versus PPD
curve for cellulose foam roof
insulation
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
Cellulose Foam
that though they are all following the same trend, still there are slight differences in
the magnitude of these materials, which might be possible because of the different
thermal properties they possess, as mentioned in Table 4.4. On assessing the results in
these cases against each other, it is observed that the fiber glass insulation for the same
thickness is performing better in improving the comfort conditions of the occupants
inside the office space, as compared to the base case, while the least enhancement
was seen in the case of polyurethane foam insulation.
Provision of Roof Insulation. The materials selected for studying the effect of provision of wall insulation have also been applied for analysing the effect of provision
of roof insulation on the comfort of the occupants. Similar to the previous case, each
of the insulation with a constant thickness of 0.04 m was applied to the existing roof
construction and the rest of the input parameters same as the base case, so that their
effects on the comfort levels can be analysed and compared with each other (Kapoor
et al. 2016).
The results of the case when cellulose foam has been applied as the roof insulation
can be seen in Fig. 4.6. The results clearly indicate an improvement in the comfort
levels as against the base case. In this case, the minimum PMV value has reduced
from −1.22 to −0.64, while there is only a slight reduction in the maximum PMV
value from 1.11 to 1.06, implying that there is a shift in the curve towards the warmer
side of the PMV scale, in comparison to the base case. This indicates that a 40 mm
thick cellulose foam roof insulation is acting as a barrier between the ambient and the
indoor conditions of the space, and hence, restricts the inside heat to cross and flow
towards the ambient, thus, leading to a zone of warmer environment. This warmer
zone, however, is still an improvement over the base case, as the maximum PMV
corresponding to this zone is still less than the maximum PMV value corresponding
to the warmer zone of the base case. This case also signifies that the PMV range has
come closer to the ideal range, in comparison to the base case, still it is far from the
ideal comfort range. In addition to this, it can be seen from Fig. 4.6 that the PPD
value too has decreased from 36.61 to 28.52%, suggesting that bringing the maximum
PMV value closer to ideal range has also led to a decrease in the percentage of people
49
Fig. 4.6 PMV versus PPD
curve for cellulose foam roof
insulation
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
Cellulose Foam
that though they are all following the same trend, still there are slight differences in
the magnitude of these materials, which might be possible because of the different
thermal properties they possess, as mentioned in Table 4.4. On assessing the results in
these cases against each other, it is observed that the fiber glass insulation for the same
thickness is performing better in improving the comfort conditions of the occupants
inside the office space, as compared to the base case, while the least enhancement
was seen in the case of polyurethane foam insulation.
Provision of Roof Insulation. The materials selected for studying the effect of provision of wall insulation have also been applied for analysing the effect of provision
of roof insulation on the comfort of the occupants. Similar to the previous case, each
of the insulation with a constant thickness of 0.04 m was applied to the existing roof
construction and the rest of the input parameters same as the base case, so that their
effects on the comfort levels can be analysed and compared with each other (Kapoor
et al. 2016).
The results of the case when cellulose foam has been applied as the roof insulation
can be seen in Fig. 4.6. The results clearly indicate an improvement in the comfort
levels as against the base case. In this case, the minimum PMV value has reduced
from −1.22 to −0.64, while there is only a slight reduction in the maximum PMV
value from 1.11 to 1.06, implying that there is a shift in the curve towards the warmer
side of the PMV scale, in comparison to the base case. This indicates that a 40 mm
thick cellulose foam roof insulation is acting as a barrier between the ambient and the
indoor conditions of the space, and hence, restricts the inside heat to cross and flow
towards the ambient, thus, leading to a zone of warmer environment. This warmer
zone, however, is still an improvement over the base case, as the maximum PMV
corresponding to this zone is still less than the maximum PMV value corresponding
to the warmer zone of the base case. This case also signifies that the PMV range has
come closer to the ideal range, in comparison to the base case, still it is far from the
ideal comfort range. In addition to this, it can be seen from Fig. 4.6 that the PPD
value too has decreased from 36.61 to 28.52%, suggesting that bringing the maximum
PMV value closer to ideal range has also led to a decrease in the percentage of people