ZEMCH 2019 International Conference Proceedings April.2020 | Page 253
11 NV B wall, 2 W & RV
12 NV HC wall, 2 W & RV
9.93%
15.80%
79
188
8
74
* B: Brick; HC: Hollow Concrete; W: Window; RV: Roof Vent
Category B: Natural ventilation in buildings with insulated iron sheet roof
Thermal comfort conditions significantly improved for insulated roof (Table 6 and 7). Indeed,
insulated roof alone has been much more effective than ventilation strategies. Unlike Category A, all
buildings with brick walls, regardless of ventilation strategy and geometry, passed thermal comfort
requirements (IDs 13, 15, 17, 19, 21 and 23 SV/NV). However, although significant, improvements have
not been enough for any of the buildings with hollow concrete walls to pass the requirements.
Table 6. Thermal comfort criteria for continuous daytime ventilation with insulated iron sheet roof
ID
Description *
13 SV
B wall, 1 W
14 SV
HC wall, 1 W
15 SV
B wall, 2 W
16 SV
HC wall, 2 W
17 SV B wall, 2 W & RV
18 SV HC wall, 2 W & RV
Criterion 1 (%)
0.86%
4.65%
1.13%
4.60%
1.08%
Criterion 2
Criterion 3
(Daily degree‐hours over 6) (ΔT over 4 K)
4
0
25
0
8
0
25
0
7
0
4.46%
25
1
* B: Brick; HC: Hollow Concrete; W: Window; RV: Roof Vent
Table 7. Thermal comfort criteria for continuous daytime and night ventilation with insulated iron
sheet roof
ID
Description *
19 NV
B wall, 1 W
20 NV
HC wall, 1 W
21 NV
B wall, 2 W
22 NV
HC wall, 2 W
23 NV B wall, 2 W & RV
24 NV HC wall, 2 W & RV
Criterion 1 (%)
0.68%
4.34%
0.86%
4.22%
0.95%
Criterion 2
Criterion 3
(Daily degree‐hours over 6) (ΔT over 4 K)
3
0
24
0
6
0
25
0
6
0
4.30%
25
0
* B: Brick; HC: Hollow Concrete; W: Window; RV: Roof Vent
Similar to Category A, night ventilation has overall improved the conditions. However, the results
indicate that unlike category A, where cross and roof ventilations have improved the conditions, the
situation for buildings with brick walls has slightly deteriorated for these scenarios compared to the
base case (i.e. ID 13 SV and 19 NV). Indeed, the best performances have been achieved for single sided
ventilation without a roof vent. A possible explanation for this is the increased level of solar heat gain
due to increased number of openings which has deteriorated comfort conditions. Further investigation
is required to study the effects of ventilation combined with shading strategies to assess whether
thermal comfort conditions improve.
The results also indicate that, similar to Category A, buildings with brick walls have performed
considerably better compared with hollow concrete walls. Overall, it could be argued that construction
methods and materials have been more effective than ventilation strategies in improving indoor
conditions. Therefore, improving construction methods/materials are arguably the first strategy that
should be considered to improve thermal comfort conditions in low‐income tropical housing.
Effects of Natural Ventilation on Thermal Comfort in Low-income Tropical Housing
242