Question

SKMM 3433 A solid body which is initially at a uniform temperature Tİ is exposed to an ambient air at temperature Te. Explain how you would determine the maximum amount of heat that can be transferred to the body. What does this amount of heat represent? Q2. (a) (5 marks) A wall ofa room is made of lightweight concrete material (ρ= 1600 kg/m.に0.79 W/m K and cp 0.84 kJ/kg K) with a thickness of 150 mm. Initially the wall is at a uniform temperature of 25°C. The room is located in an environment where the air is at a temperature of 39°C, with a heat transfer coefficient of 35 W/m K. The temperature of the exterior surfaces of the wall then raises to 30°C. The thermal conductivity of the lightweight concrete can be assumed constant. For the wall surface area of I m, det İ) the time taken for the exterior surface temperature to reach 30°C, minutes. ii) the maximum amount of heat that can be transferred to the wall, kJ, and ii) the rate of heat transfer from the ambient air to the wall. ) (20 marks)

Answer 1

iven 123 W/ sa lunted heat cara utud method e Svc As - Cumfate ares 30 -3 9 2S -39 tota

ヲ4,ttae-Comx 1xo.ls x 6 gu Х1-3).(39-25) to 313 31s watt .