To defrost ice accumulated on the outer surface of an automobile windshield, warm air is blown over the inner surface of the windshield. Let’s consider the windshield of your car is 5-mm-thick glass. Your car is parked at outside in a cold winter day, and the outside air temperature is -10oC. Cold wind keeps blowing over the windshield surface, which results in the convection heat transfer coefficient on the outside windshield surface at 250 W/m2 -K. Now you are turning on your air conditioning and heater to blow warm air (25oC) to the inside of the windshield to remove the ice built on the windshield.
a) Draw a schematic.
b) Draw an equivalent thermal circuit for this problem.
c) Determine the heat transfer coefficient of warm air blowing to cause the accumulated ice to begin melting. Note that the temperature at which ice melts is 0oC.