Question

Consider steady heat transfer through the wall of a room in winter. The convection heat transfer coefficient at the outer surface of the wall is three times that of the inner surface as a result of the winds. Hence, at the inner surface, the temperature will be closer to the surrounding air temperature. Explain.

Answer 1

The heat transfer which is in steady state, the heat transfer rate to the wall is equal to the wall.

Explanation:

• The convection transfer of heat to the wall is

         $Q=h A\left(T_{s}-T_{f}\right)$

• Here, $T_{S}$ is the temperature of solid surface, $T_{f}$ is the temperature of moving fluid stream which is adjacent of solid surface, h is the heat transfer coefficient.
• The coefficient of convection heat transfers outer surface contains 3 times to the inner surface which experience smaller drop of temperature for 3 times that compares to inner surface.
• Hence, the temperatures outer surface get close to the surroundings of air temperature.