Liquid-cooled heat exchanger in a vapor compression refrigeration system

Abstract

A refrigerant vapor compression system includes a compressor having a suction port and a discharge port, an air-cooled heat exchanger operatively coupled to the discharge port, a liquid-cooled heat exchanger operatively coupled to the air-cooled heat exchanger, a coolant pump operatively coupled to a liquid coolant inlet conduit of the liquid-cooled heat exchanger, an evaporator heat exchanger unit operatively coupled to the liquid-cooled heat exchanger and the suction port, a coolant pump operatively coupled to the liquid coolant inlet conduit for pumping a liquid coolant, and a controller operatively associated with the liquid coolant inlet conduit for controlling the flow of liquid coolant into the liquid-cooled heat exchanger. In one embodiment, the liquid-cooled heat exchanger comprises a low-profile enclosure defining an interior volume. The enclosure has a liquid coolant inlet port and a liquid coolant discharge port fluidly coupled to the interior volume, and a continuous refrigerant tube sealingly disposed within the enclosure. The refrigerant tube is fluidly isolated from and in heat exchange relationship with the interior volume in which the liquid coolant flows.

1 . A refrigerant vapor compression system comprising:
 a compressor for compressing a refrigerant, the compressor having a suction port and a discharge port;   an air-cooled heat exchanger operatively coupled to the discharge port;   a fan disposed proximate to the air-cooled condenser heat exchanger unit;   a liquid-cooled heat exchanger operatively coupled to the air-cooled heat exchanger, the liquid-cooled heat exchanger comprising an enclosure defining an interior volume, the enclosure having a liquid coolant inlet port and a liquid coolant discharge port fluidly coupled to the interior volume, and a continuous refrigerant tube sealingly disposed within the enclosure, the refrigerant tube fluidly isolated from and in heat exchange relationship with the interior volume;   a liquid coolant inlet conduit operatively coupled to the liquid coolant inlet port of the liquid-cooled heat exchanger;   a coolant pump operatively coupled to the liquid coolant inlet conduit for pumping a liquid coolant;   a liquid coolant discharge conduit operatively coupled to the liquid coolant discharge port of the liquid-cooled heat exchanger;   an evaporator heat exchanger unit operatively coupled to the liquid-cooled heat exchanger and the suction port;   an evaporator fan disposed proximate to the evaporator heat exchanger unit; and   a controller operatively associated with the coolant pump for controlling the flow of liquid coolant into the liquid-cooled heat exchanger.   
     
     
         2 . The refrigerant vapor compression system of  claim 1  wherein the refrigerant is carbon dioxide. 
     
     
         3 . The refrigerant vapor compression system of  claim 1  wherein the liquid coolant is water. 
     
     
         4 . The refrigerant vapor compression system of  claim 3  wherein the refrigerant vapor compression system is located on a cargo ship, and the liquid coolant is grey water. 
     
     
         5 . The refrigerant vapor compression system of  claim 4  wherein the controller is manual, and the flow of liquid coolant into the liquid-cooled heat exchanger is controlled by a hand-operated valve. 
     
     
         6 . The refrigerant vapor compression system of  claim 1  wherein the controller controls the coolant pump. 
     
     
         7 . The refrigerant vapor compression system of  claim 6  wherein the controller controls the coolant pump responsive to a parameter within the refrigerant vapor compression system. 
     
     
         8 . The refrigerant vapor compression system of  claim 7  wherein the parameter is ambient air temperature. 
     
     
         9 . A liquid-cooled heat exchanger for use in a refrigerant vapor compression system, the liquid-cooled heat exchanger comprising:
 an enclosure comprising a first interior surface defining a first interior volume, the enclosure further comprising a plurality of openings being fluidly coupled to the first interior volume, the plurality of openings comprising a first refrigerant tube opening, a second refrigerant tube opening, a first coolant port adapted to flow a liquid coolant into the enclosure, and a second coolant port adapted to flow the coolant out of the enclosure;   a first fitting sealingly engaged to the first coolant port, the fitting adapted to couple with a coolant inlet conduit;   a second fitting sealingly engaged to the second coolant port, the fitting adapted to couple with a coolant discharge conduit; and   a continuous refrigerant tube having a first end, a second end, and a first length disposed therebetween, the first end passing through and in sealing engagement with the first refrigerant tube opening, the second end passing through and in sealing engagement with the second refrigerant tube opening, the first length disposed in serpentine fashion within the first interior volume.   
     
     
         10 . The heat exchanger of  claim 9  wherein the enclosure is a low-profile enclosure. 
     
     
         11 . The heat exchanger of  claim 10  wherein the enclosure defines an aspect ratio, the aspect ratio being greater than 5:1. 
     
     
         12 . The heat exchanger of  claim 10  further comprising a rib coupled to an inner surface of the enclosure for securing the refrigerant tube and channeling a flow of coolant within the interior surface. 
     
     
         13 . The heat exchanger of  claim 9  wherein the enclosure is a coiled tube. 
     
     
         14 . The heat exchanger of  claim 13  further comprising a heat transfer element disposed within the coiled tube. 
     
     
         15 . The heat exchanger of  claim 13  further comprising a centering element disposed within the first interior volume. 
     
     
         16 . The heat exchanger of  claim 14  wherein the centering element is a crimp. 
     
     
         17 . The heat exchanger of  claim 9  further comprising a baffle disposed within the enclosure, the baffle defining a second interior volume within the first interior volume, the baffle having at least one aperture fluidly coupling the second interior volume to a remaining portion of the first interior volume. 
     
     
         18 . The heat exchanger of  claim 17  wherein the continuous refrigerant tube further comprises a second length disposed within the second interior volume. 
     
     
         19 . The heat exchanger of  claim 18  the first length and the second length are helical. 
     
     
         20 . The heat exchanger of  claim 19  wherein the first length of the refrigerant tube is spiraled helically in a direction opposite to the second length. 
     
     
         21 . The heat exchanger of  claim 9  wherein the enclosure is cylindrical. 
     
     
         22 . The heat exchanger of  claim 9  wherein the enclosure further comprises a removable cover, the refrigerant tube being removable from the enclosure when the cover is removed. 
     
     
         23 . The heat exchanger of  claim 9  further comprising a flow turbulator disposed within the first interior volume, the flow turbulator for creating turbulent flow to increase a heat transfer characteristic between the liquid coolant and the refrigerant tube. 
     
     
         24 . The heat exchanger of  claim 9  wherein the continuous refrigerant tube branches and converges. 
     
     
         25 . A method for liquid-cooling a vapor refrigerant in a refrigerant vapor compression system, the method comprising the steps of:
 providing an air-cooled heat exchanger;   providing a liquid-cooled heat exchanger coupled to the air-cooled heat exchanger, the liquid-cooled heat exchanger comprising an enclosure having a first interior volume;   providing in serpentine fashion a continuous refrigerant tube extending through the first volume of the liquid-cooled heat exchanger;   flowing a refrigerant through the air-cooled heat exchanger and, if the refrigerant is not sufficiently cooled,   simultaneously flowing the refrigerant through the continuous refrigerant tube in the liquid-cooled heat exchanger and flowing a liquid coolant through the first interior volume of the liquid-cooled heat exchanger.   
     
     
         26 . The method of  claim 25 , further comprising the step of providing a baffle within the first interior volume, the baffle defining a second interior volume within the first interior volume, the baffle comprising an aperture, the continuous refrigerant tube extending through the first volume of the liquid-cooled heat exchanger, through the aperture, and through the second interior volume of the liquid-cooled heat exchanger. 
     
     
         27 . The method of  claim 26  wherein the refrigerant is passed helically through the first interior volume and the second interior volume. 
     
     
         28 . The method of  claim 27  wherein a direction of the helical path through the first interior volume and the second interior volume is opposite to a direction of the liquid coolant flow. 
     
     
         29 . The method of  claim 25 , further comprising the step of providing a controller, the controller controlling the refrigerant flow through the liquid-cooled heat exchanger responsive to a parameter on the air-cooled heat exchanger. 
     
     
         30 . The method of  claim 29 , wherein the parameter is ambient air temperature. 
     
     
         31 . The method of  claim 29 , wherein the controller is manual. 
     
     
         32 . The method of  claim 25 , wherein the liquid-cooled heat exchanger is in serial relationship to the air-cooled heat exchanger.