Liquid galley refrigeration system for aircraft

Abstract

The liquid galley refrigeration system for cooling food carts for aircraft employs an intermediate working fluid to transfer heat from one or more food carts to one or more remote chillers, allowing the carts and chillers to be advantageously distributed in the aircraft. While the chiller working fluid undergoes a phase change in order to transfer heat from the intermediate working fluid to the cooling air, the intermediate working fluid remains in its liquid phase throughout its circulation. A recirculation pump circulates the intermediate working fluid through a distribution system that may link a plurality of chillers to a plurality of food carts, and the temperature of the food carts is regulated by a combination of controls.

What is claimed is: 
     
         1 . A cooling system for use on aircraft, comprising:
 an onboard food cart;   a galley plenum configured to receive said onboard food cart, said galley plenum including a galley plenum heat exchanger for transferring heat from the galley plenum to a first working fluid, a proportional flow valve configured to control the flow of said first working fluid from said galley plenum heat exchanger within said galley plenum to an expelling heat exchanger, said first working fluid remaining in a liquid phase at all times, a first working fluid pump configured to pump said first working fluid to said galley plenum heat exchanger, said first working fluid pump being configured to pump said first working fluid through said expelling heat exchanger at a variable flow rate, and a blower for blowing supply air through said galley plenum heat exchanger and said galley plenum;   a chiller unit circulating a second working fluid through a condenser and through an evaporator associated with said expelling heat exchanger, said chiller unit including a second working fluid pump connected between said evaporator and said condenser, said second working fluid pump being configured to pump said second working fluid through said condenser to cool said second working fluid and through said evaporator to cool said first working fluid in said expelling heat exchanger; and   a monitoring and control system for monitoring temperature of said first working fluid and controlling said variable flow rate of said first working fluid pump responsive to the temperature of said first working fluid.   
     
     
         2 . The cooling system of  claim 1 , wherein said monitoring and control system is configured to monitor temperature of said supply air, and to control said variable flow rate of said first working fluid responsive to the temperature of said supply air. 
     
     
         3 . The cooling system of  claim 1 , further comprising an expansion tank connected in fluid communication with said first working fluid pump for accommodating any expansion or contraction of said first working fluid, wherein said monitoring and control system is configured to monitor a volume of said first working fluid within said expansion tank, and to control said variable flow rate of said first working fluid responsive to the volume of said first working fluid within said expansion tank.