Thermal Insulation in Roof The base case building had 5 cm of glass wool installed in the roof layer as a thermal insulation material. Three typical types of insulation materials were employed in the roof layer, in a similar way to the external wall experiment. The applied insulation materials included glass wool, XPS and EPS. They were applied to the outer and inner sides of roof separately, with 10 cm of thickness to investigate the effect of the positioning and thickness of the insulation materials on the indoor air temperature. Figure 7 presents the effects of various thermal insulation materials on outer side and inner side of the roof, on indoor air temperatures in the north-facing classroom only as the south-facing classrooms located on the first floor. It can be seen that the application of all types of thermal insulation with 10cm of thickness caused slightly higher indoor air temperatures in Feb 2010 on the top floor. The indoor air temperatures increased by around 0.3K only in this classroom which shows that 5 cm thickness of the thermal insulation is enough to keep the indoor air temperature in an acceptable range.
Temperature ° C
25 24.8 24.6 24.4 24.2
24 23.8 23.6 23.4 23.2
23
N
02 / 02 / 11 12:02:13 AM 02 / 02 / 11 07:02:13 AM 02 / 02 / 11 02:02:13 PM 02 / 02 / 11 09:02:13 PM 02 / 03 / 11 04:02:13 AM 02 / 03 / 11 11:02:13 AM 02 / 03 / 11 06:02:13 PM 02 / 04 / 11 01:02:13 AM 02 / 04 / 11 08:02:13 AM 02 / 04 / 11 03:02:13 PM 02 / 04 / 11 10:02:13 PM 02 / 05 / 11 05:02:13 AM 02 / 05 / 11 12:02:13 PM 02 / 05 / 11 07:02:13 PM 02 / 06 / 11 02:02:13 AM 02 / 06 / 11 09:02:13 AM 02 / 06 / 11 04:02:13 PM 02 / 06 / 11 11:02:13 PM 02 / 07 / 11 06:02:13 AM 02 / 07 / 11 01:02:13 PM 02 / 07 / 11 08:02:13 PM 02 / 08 / 11 03:02:13 AM 02 / 08 / 11 10:02:13 AM 02 / 08 / 11 05:02:13 PM 02 / 09 / 11 12:02:13 AM 02 / 09 / 11 07:02:13 AM 02 / 09 / 11 02:02:13 PM 02 / 09 / 11 09:02:13 PM
Time
Glass wool 5cm outside( base Case) Glass woll 10cm inside EPS 10cm inside XPS 10cm inside
Glass wool 10cm Outside EPS 10cm outside XPS 10cm outside
Figure 7: Indoor temperature profile with different roof insulation materials in classrooms N in May 2010
Table 3 presents the impact of various insulation types with various thicknesses on the U-value of the roof. The tested variations of thermal insulation materials including glass wool, XPS and EPS, reduced the U-value of the base case building from 0.53 W / K to 0.32, 0.28 and 0.32 W / K respectively. As can be seen, using 10 cm of XPS reduced the overall U-value of the roof more than the other types of thermal insulations, with similar thickness.
Table 3: Effect of thermal insulation materials and their thicknesses on U-value of the roof |
Insulation |
Thickness |
U-value |
( cm) |
( W / |
K) |
Base Case |
5 |
0.527 |
Glass Wool |
10 |
0.318 |
XPS |
10 |
0.279 |
EPS |
10 |
0.318 |
Passive design strategies on indoor comfort of school buildings in hot-dry climates 757