Three-media evaporator for a cooling unit

Abstract

A three-media evaporator for a cooling unit utilizing the vapor compression refrigeration cycle. The apparatus includes a number of heat exchange tubes, each tube including an inner heat exchange tube adapted to carry a primary heat exchange medium and an outer heat exchange tube, adapted to carry an intermediate heat exchange medium. The intermediate heat exchange medium is in thermal communication with the primary heat exchange medium. A direct heat exchange mechanism, which in one aspect can be a set of fins, is in simultaneous thermal communication with the ambient medium and with the intermediate heat exchange medium. In each heat exchange tube the outer tube at least partially surround the inner tube, defining an annular space between the tubes. The intermediate medium is carried in the annular space.

1 . An evaporator in a unit for cooling an ambient medium, the evaporator comprising:
 an inner heat exchange tube adapted to carry a primary heat exchange medium;   an outer heat exchange tube, adapted to carry an intermediate heat exchange medium in thermal communication with the primary heat exchange medium; and   a direct heat exchange mechanism, in simultaneous thermal communication with the ambient medium and the intermediate heat exchange medium.   
     
     
         2 . The evaporator of  claim 1 , wherein the outer heat exchange tube surrounds at least a portion of the inner heat exchange tube to form a heat exchange tube. 
     
     
         3 . The evaporator of  claim 1 , wherein a heat exchange tube includes a primary heat exchange inlet, a primary heat exchange outlet, an intermediate heat exchange inlet, and an intermediate heat exchange outlet. 
     
     
         4 . The evaporator of  claim 1 , wherein the direct heat exchange mechanism includes a plurality of fins mounted on the outer heat exchange tube. 
     
     
         5 . The evaporator of  claim 2 , wherein a plurality of heat exchange tubes is arranged in a spaced array. 
     
     
         6 . The evaporator of  claim 2 , wherein adjacent heat exchange tubes are connected for continuous flow, with the primary heat exchange inlet of one connected heat exchange tube in fluid communication with the primary heat exchange outlet of the adjacent heat exchange tube and the intermediate heat exchange inlet of one connected heat exchange tube in fluid communication with the intermediate heat exchange outlet of the connected heat exchange tube, adapted to permit two continuous flows through the connected heat exchange tubes. 
     
     
         7 . The evaporator of  claim 2 , wherein adjacent heat exchange tubes are connected for continuous flow, and the outer heat exchange tubes of two adjacent heat exchange tubes fluidly communicate through a connecting pipe 
     
     
         8 . The evaporator of  claim 1 , further including a plurality of heat exchange tubes, and wherein all inner heat exchange tubes are interconnected to provide a single flow path for the primary heat exchange medium through the evaporator, and all outer heat exchange tubes are interconnected to provide a single flow path for the intermediate heat exchange medium through the evaporator. 
     
     
         9 . The evaporator of  claim 1 , wherein the primary heat exchange medium is a refrigerant. 
     
     
         10 . The evaporator of  claim 1 , wherein the intermediate heat exchange medium is chilled water. 
     
     
         11 . The evaporator of  claim 1 , wherein the intermediate heat exchange medium is chilled brine. 
     
     
         12 . The evaporator of  claim 1 , wherein the ambient medium is hot air. 
     
     
         13 . An evaporator in a unit for cooling an ambient medium, the evaporator comprising:
 a plurality of heat exchange tubes, each heat exchange tube including:
 an inner heat exchange tube adapted to carry a refrigerant, the inner heat exchange tube including a refrigerant inlet and a refrigerant outlet; 
 an outer heat exchange tube, adapted to carry an intermediate heat exchange medium in thermal communication with the primary heat exchange medium; and 
 a plurality of fins, mounted on the outer heat exchange tubes and in simultaneous thermal communication with the ambient medium and the intermediate heat exchange medium; 
   wherein the inner heat exchange tubes are carried at least partially coaxially within the outer heat exchange tubes.   
     
     
         14 . The evaporator of  claim 13 , wherein adjacent heat exchange tubes are arranged in a spaced array, connected for continuous flow, with the refrigerant inlet of one connected heat exchange tube in fluid communication with the refrigerant outlet of the adjacent heat exchange tube and the intermediate heat exchange inlet of one connected heat exchange tube in fluid communication with the intermediate heat exchange outlet of the connected heat exchange tube, adapted to permit two continuous flows through the connected heat exchange tubes. 
     
     
         15 . The evaporator of  claim 13 , wherein adjacent heat exchange tubes are arranged in a spaced array, and the outer heat exchange tubes of adjacent heat exchange tubes fluidly communicate through a connecting pipe. 
     
     
         16 . The evaporator of  claim 13 , wherein all inner heat exchange tubes are arranged in a spaced array, interconnected to provide a single flow path for the refrigerant through the evaporator, and all outer heat exchange tubes are interconnected to provide a single flow path for the intermediate heat exchange medium through the evaporator. 
     
     
         17 . The evaporator of  claim 13 , wherein all inner heat exchange tubes are arranged in a spaced array, interconnected to provide multiple flow paths for the refrigerant through the evaporator, and all outer heat exchange tubes are interconnected to provide multiple flow paths for the intermediate heat exchange medium through the evaporator. 
     
     
         18 . A heat exchange tube in an evaporator, comprising:
 an inner heat exchange tube adapted to carry a regrigerant;   an outer heat exchange tube, at least partially surrounding the inner heat exchange tube, the inner surface of the outer heat exchange tube defining an annular space between the outer heat exchange tube and the inner heat exchange tube, adapted to carry an intermediate heat exchange medium in thermal communication with the primary heat exchange mediumwithin the annular space; and   a plurality of fins, mounted on the outer heat exchange tube and in simultaneous thermal communication with an ambient medium and the intermediate heat exchange medium.   
     
     
         19 . The heat exchange tube of  claim 16 , wherein the outer heat exchange tube is sealingly attached to the inner heat exchange tube, with ends of the inner heat exchange tube protruding beyond the ends of the outer heat exchange tube. 
     
     
         20 . The heat exchange tube of  claim 16 , further including connection means for attaching the heat exchange tube to a second heat exchange tube.