Patent ID: 8136363

Claim:
A method of conditioning air in a vehicle load space, the method comprising the acts of: providing a refrigeration circuit including an evaporator and a throttle valve; directing refrigerant through the refrigeration circuit; directing load space air across the evaporator; sensing a first condition, the first condition being a function of one of a temperature and a pressure of the refrigerant in the refrigeration circuit away from the evaporator; measuring one of a temperature and a pressure of the refrigerant in the evaporator; using the one of the temperature and the pressure of the refrigerant in the evaporator to determine a second condition; determining a position of the throttle valve; determining a difference between the first condition and the second condition; initiating a defrost process of the evaporator in response to the throttle valve in a fully open position and the difference being greater than a threshold; and determining a saturation suction temperature; comparing the saturation suction temperature with an evaporator coil temperature; and initiating the defrost process in response to the saturation suction temperature being less than the evaporator coil temperature.