Patent ID: 6845627

Claim:
A method for regulating the air temperature in a food cart within an aircraft galley system, the galley system including a galley air cooling unit having the food cart and a galley plenum therein, the plenum including a heat exchanger, a fan which blows air across the heat exchanger, into the food cart via an air supply duct coupling the plenum to the food cart and back into the plenum via an air return duct coupling the food cart to the plenum, an air supply temperature sensor for measuring the temperature of the air entering the food cart from the plenum, and an air return temperature sensor for measuring the temperature of the air entering the plenum from the food cart, the method utilizing a control system for performing the steps including: regulating the return air temperature to a selected set point by controlling the amount of a liquid refrigerant flowing through the heat exchanger via a valve; regulating the supply air temperature if the return air temperature sensor fails, regulating the supply air temperature including, regulating the supply air temperature between a preset bottom threshold and a preset top threshold, closing the valve completely if the supply air temperature falls below the preset bottom threshold, opening the valve when the supply air temperature rises to the preset top threshold, and resuming regulation of the supply air temperature between the preset bottom threshold and the preset top threshold; and temporarily discontinuing regulation of the return air temperature if the supply air temperature drops below the preset bottom threshold, including, closing the valve completely until the supply air temperature increases to the preset top threshold, and resuming regulation of the return air temperature.