The temperature controller for a clothes dryer consists of a bimetallic switch mounted on an electrical heater attached to a wall-mounted insulation pad.

The switch is set to open at 70°C, the maximum dryer air temperature. In order to operate the dryer at a lower air temperature, sufficient power is supplied to the heater such that the switch reaches 70°C (T _set) when the air temperature T is less than T set. If the convection heat transfer coefficient between the air and the exposed switch surface of 30 mm² is 25 W/m². K, how much heater power P_e is required when the desired dryer air temperature is T_x = 50°C?

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Dryer wall P.- Insulation pad | Electrical heater Bimetallic switch www -Tet = 70°C %3D Air set