The front window of a car is defogged by supplying warm air at 90°F to its inner surface. The glass has a thermal conductivity of k = 0.8 W 1m • °C with a thickness of approximately 114 in.
With the supply fan running at moderate speed, the heat transfer coefficient associated with the air is 50 W/m2. K. The outside air is at a temperature of 20°F with an associated
heat transfer coefficient of 110 W/m2. K. Determine
(a) the temperatures of the inner and outer surfaces of the glass and
(b) the heat loss through the glass if the area of the glass is
approximately 10 ft2.
