formed on the various directions. The eight main directions( N, NW, W, SW, S, SE, E and NE) have been considered for the prototype school building, from 0 ° to 315 °. The building was rotated anti-clockwise for eight primary directions, starting with 0 ° in the North. Figure 4 shows the hourly variations in indoor air temperatures in classrooms S and N, based on the eight main geographic directions. It can be seen that the indoor air temperature was in the highest range when the south facade faced west and south-west respectively in Classroom S but when the facade faced north and north-east, the indoor air temperature dropped, compared to the other side. However, the indoor air temperature in Classroom N was increased in all directions. This is because the main facade of the classroom faced north in the base case and it received the minimum solar radiation, compared to the other directions.
Temperature ° C
26 25 24 23 22 21 20 19
S
02 / 02 / 11 12:02:13 AM 02 / 02 / 11 09:02:13 AM 02 / 02 / 11 06:02:13 PM 02 / 03 / 11 03:02:13 AM 02 / 03 / 11 12:02:13 PM 02 / 03 / 11 09:02:13 PM 02 / 04 / 11 06:02:13 AM 02 / 04 / 11 03:02:13 PM 02 / 05 / 11 12:02:13 AM 02 / 05 / 11 09:02:13 AM 02 / 05 / 11 06:02:13 PM 02 / 06 / 11 03:02:13 AM 02 / 06 / 11 12:02:13 PM 02 / 06 / 11 09:02:13 PM 02 / 07 / 11 06:02:13 AM 02 / 07 / 11 03:02:13 PM 02 / 08 / 11 12:02:13 AM 02 / 08 / 11 09:02:13 AM 02 / 08 / 11 06:02:13 PM 02 / 09 / 11 03:02:13 AM 02 / 09 / 11 12:02:13 PM 02 / 09 / 11 09:02:13 PM
Temperature ° C
27 26.5 26 25.5 25 24.5 24 23.5 23
N
02 / 02 / 11 12:02:13 AM 02 / 02 / 11 10:02:13 AM 02 / 02 / 11 08:02:13 PM 02 / 03 / 11 06:02:13 AM 02 / 03 / 11 04:02:13 PM 02 / 04 / 11 02:02:13 AM 02 / 04 / 11 12:02:13 PM 02 / 04 / 11 10:02:13 PM 02 / 05 / 11 08:02:13 AM 02 / 05 / 11 06:02:13 PM 02 / 06 / 11 04:02:13 AM 02 / 06 / 11 02:02:13 PM 02 / 07 / 11 12:02:13 AM 02 / 07 / 11 10:02:13 AM 02 / 07 / 11 08:02:13 PM 02 / 08 / 11 06:17:13 AM 02 / 08 / 11 04:02:13 PM 02 / 09 / 11 02:02:13 AM 02 / 09 / 11 12:02:13 PM 02 / 09 / 11 10:02:13 PM 02 / 10 / 11 08:02:13 AM
|
Time
S( base case) E N W
|
SE NE NW SW |
Time
N( base case) W S E
|
NW SW SE NE |
Figure 4: Indoor temperature profile for eight primary directions in classrooms S and N in February 2011
Based on Kasmai( 2008), the southern walls gain direct solar radiation for 10 hours a day in winter in the city of Tehran at 35 ° N latitude. However, the northern walls receive no solar radiation in the winter season. The east and west walls gain at least 4 hours a day of sunshine in the winter season. The comparison of indoor air temperature variations in all directions shows that the south and south west directions caused the maximum indoor air temperature in winter. However, when it faced north and north east, it had the minimum internal air temperature, compared to the other directions.
Glazing Improving the insulation of windows has a significant impact on heating in buildings. To reduce the heating demands of a building, it is suggested to decrease the U-value of the glazing area( Ford et al. 2007). The thermal characteristics of the glazing area are an important part of the window design, which has a considerable effect on thermal performance of indoor spaces. Thermal characteristics include U-values and insulation of the windows, the framing type and the overall area of the windows( Mikler et al. 2009). To improve the thermal insulation performance of the glazing area, it is suggested that the number of panes should be increased, up to triple glazing, which results in reducing the U-value of the windows( Ford et al. 2007). The effect of the windows on the indoor air temperature was investigated by applying various glazing types to the windows, such as double glazed and triple glazed windows. Figure 5 shows the impact of various glazing type on indoor air temperature. The actual glazing type for the given building was a 6 mm sin-
754 ZEMCH 2015 | International Conference | Bari- Lecce, Italy