High efficiency condenser

Abstract

A high efficiency condenser, in one embodiment, includes a phase change material in thermal contact with the condenser to assist in cooling the condenser during operation and particularly during pull-down operation to improve the cooling capacity of a compressor. In a preferred embodiment of such a system, a coaxial tube carrying the refrigerant through the condenser includes an inner conduit for the refrigerant and a coaxially arranged outer jacket with phase change material for extracting heat from the compressed refrigerant. In another embodiment, a secondary condenser is provided in a secondary coolant circuit and is in thermal contact with the primary condenser. Variable speed fans are associated with the condenser(s) and can be operated in the high speed (turbo) mode during pull-down of a refrigeration system for providing sufficient cooling capacity during a pull-down mode of operation.

1 . A continuous heat rejection condenser for a refrigeration system comprising:
 a compressor for a refrigerant;   a condenser coupled to an output of said compressor;   an evaporator coupled to said condenser; and   a heat exchanger in thermal communication with said condenser, wherein said heat exchanger includes a phase change material to absorb heat from said condenser.   
     
     
         2 . The system as defined in  claim 1  and further including a thermally controlled fan for circulating ambient air through said heat exchanger only when the heat exchanger temperature is above a threshold temperature above ambient temperature. 
     
     
         3 . The system as defined in  claim 1  wherein said heat exchanger includes a coaxial conduit with a center conduit for conveying a refrigerant and a surrounding conduit holding said phase change material. 
     
     
         4 . The system as defined in  claim 3  wherein said heat exchanger further includes cooling fins in thermal communication with said conduit. 
     
     
         5 . The system as defined in  claim 4  and further including a thermally controlled fan for circulating ambient air through said heat exchanger while the heat exchanger is above a threshold temperature above ambient temperature. 
     
     
         6 . The system as defined in  claim 5  wherein said system includes a secondary condenser coupled in series with said condenser and positioned in a spaced relationship to said condenser 
     
     
         7 . The system as defined in  claim 1  wherein said compressor is a linear compressor. 
     
     
         8 . The system as defined in  claim 1  wherein said phase change material includes one of a wax and Glauber's salt. 
     
     
         9 . A refrigerator having a linear compressor and an improved efficiency condenser comprising:
 a condenser coupled to a linear compressor in a refrigerant circuit; and   a heat exchanger in thermal communication with said condenser, wherein said heat exchanger includes a phase change material to absorb heat from said condenser.   
     
     
         10 . The refrigerator as defined in  claim 9  wherein said condenser includes a first section and a second section in spaced relationship to said first section and in a serial path with said refrigerant circuit. 
     
     
         11 . The refrigerator as defined in  claim 10  wherein at least one of said first and second sections includes a cooling fan associated therewith. 
     
     
         12 . The refrigerator as defined in  claim 11  wherein said heat exchanger including said phase change material is associated with said first section of said condenser. 
     
     
         13 . The refrigerator as defined in  claim 12  wherein said condenser includes a fan associated with at least one of said first and second sections. 
     
     
         14 . The refrigerator as defined in  claim 13  wherein said second section of said condenser has a larger surface area than said first section, and said fan associated with said second section of said condenser is a variable speed fan. 
     
     
         15 . The refrigerator as defined in  claim 14  wherein said phase change material includes one of a wax and Glauber's salt. 
     
     
         16 . A refrigerator having a linear compressor and an improved efficiency two section condenser comprising:
 a condenser including first and second sections in spaced relationship to one another and coupled to a linear compressor in a series refrigerant circuit;   a fan associated with at least said second section of said condenser; and   wherein said second section of said condenser has a larger surface area than said first section.   
     
     
         17 . The refrigerator as defined in  claim 16  wherein said fan associated with said second section of said condenser is a variable speed fan. 
     
     
         18 . The refrigerator as defined in  claim 17  and further including a heat exchanger in thermal communication with said first section of said condenser, said heat exchanger including a phase change material. 
     
     
         19 . The refrigerator as defined in  claim 18  wherein said heat exchanger includes a coaxial conduit with a center conduit for conducting a refrigerant and a surrounding conduit holding said phase change material. 
     
     
         20 . The refrigerator as defined in  claim 19  and further including a fan associated with said first section of said condenser. 
     
     
         21 . The refrigerator as defined in  claim 20  wherein said phase change material includes one of a wax and Glauber's salt. 
     
     
         22 . The refrigerator as defined in  claim 16  and further including hollow fins filled with the phase change material, said fins thermally coupling said first and second condenser sections.