-
A brick wall (k = 0.9 W/mK) of thickness 0.18 m separates the warm air in a room from the cold ambient air. On a particular Winter day, the outside air temperature is - 5°C and the room needs to be maintained at 27°C. The heat transfer coefficient associated with outside air is 20 W/m2K. Neglecting the convective resistance of the air inside the room, the heat loss, in (W/m2), is
-
- 88
- 110
- 128
- 160
Correct Option: C
Total thermal resistance
= | ||||||
Rth | + | |||||
h | k |
= | = 4 w/m2K | |||||
Rth | + | |||||
20 | 0.9 |
Q = | [27 - (-5)] × 4 = 128 W/m2 | Rth |