A Trombe wall is a masonry wall often used in passive solar homes to store solar energy. Suppose such a wall, fabricated from 20 cm thick solid concrete blocks (k = 0.13 W/(mK), α = 0.05 \ 10^–5 m²/s is initially at 15°C in equilibrium with the room in which it is located. It is suddenly exposed to sunlight and absorbs 500 W/m² on the exposed face. The exposed face loses heat by radiation and convection to the outside ambient temperature of –15°C through a combined heat transfer coefficient of 10 W/(m² K). The other face of the wall is exposed to the room air through a heat transfer coefficient of 10 W/(m² K). Assuming that the room air temperature does not change, determine the maximum temperature in the wall after 4 hours of exposure and the net heat transferred to the room.

GIVEN

• Trombe wall suddenly exposed to sunlight