Refrigeration system having an integrated bypass system

Abstract

A heat transfer system usable as an air conditioner, a heat pumpt or the like includes a compressor, a condenser, a main expansion device and an evaporator connected in a closed circuit through which a refrigerant is circulated, and a bypass device in which subcooling is performed rather than in the downstream portion of the condenser, as is conventional. The subcooling device is comprised of a unitary integrated structure having an inner tube connectable in a main refrigerant flow path at the outlet of a condenser, a concentric outer tube having end portions sealed to the outside of the inner tube thereby providing a chamber surrounding the inner tube, an inlet orifice connecting the inner tube to an upstream end of the outer tube that allows a portion of the refrigerant flowing in the inner tube to be diverted to the chamber, at a reduced temperature and pressure, an outlet orifice at the downstream end of the outer tube; and a return line in communication with the outlet orifice, and connectable to the main refrigerant path, whereby the diverted refrigerant can flow through the chamber, provide subcooling for refrigerant flowing in the inner tube, and then be returned to the main refrigerant flow path. The outlet orifice may also be sized to cause a pressure drop in the refrigerant as it exits the chamber, thereby accommodating a pressure differential between the refrigerant in the bypass device and the main refrigerant path at the point of reentry.

1 . A subcooling device for a heat transfer system, the subcooling device being in the form of a unitary integrated structure which includes: 
 a main refrigerant passage; a primary inlet by which the main refrigerant passage may be connected to an outlet of a condenser in a primary refrigeration path of a refrigeration system;    a primary outlet by which the main refrigerant passage may be connected to an inlet of an expansion device in the primary refrigeration path;    a bypass passage;    a secondary inlet operative to divert a portion of the refrigerant entering the subcooling device from the condenser to the bypass passage and to reduce the pressure and temperature of the diverted refrigerant; and    a secondary outlet by which the bypass passage may be connected to the primary refrigeration path downstream of the evaporator,    the bypass passage being thermally coupled to the main refrigerant passage to form a heat exchanger operable to transfer heat from refrigerant in the main refrigerant passage to refrigerant in the bypass passage.    
   
   
       2 . A subcooling device according to  claim 1 , wherein the secondary outlet further provides, as part of the integrated structure thereof, pressure differential accommodation for refrigerant in the bypass passage relative to refrigerant in the primary refrigeration path.  
   
   
       3 . A subcooling device according to  claim 1 , wherein: the main refrigerant passage is comprised of a first tube connectable between the outlet of the condenser and the inlet of the expansion device; 
 the bypass passage is comprised of a second tube which surrounds the first tube and has end portions sealed to the outside of the first tube thereby forming a chamber surrounding the first tube; and    the secondary inlet is comprised of an orifice connecting the first tube to an upstream end of the second tube,    whereby, when the refrigerant flows through the first and second tubes, heat is absorbed by the relatively cooler refrigerant in the second tube from the relatively warmer refrigerant in the first tube.    
   
   
       4 . A subcooling device as described in  claim 3 , wherein the secondary outlet is comprised of an orifice at the downstream end of the second tube connectable to the main refrigerant path.  
   
   
       5 . A subcooling device as described in  claim 4 , wherein the secondary outlet provides a pressure drop for the refrigerant flowing therethrough.  
   
   
       6 . A subcooling device as described in  claim 4 , wherein the secondary inlet is at an upstream end of the first tube, and the secondary outlet is at a downstream end of the first tube.  
   
   
       7 . A subcooling device as described in  claim 4 , wherein the secondary inlet is at a downstream end of the first tube, and the secondary outlet is at an upstream end of the first tube.  
   
   
       8 . A heat transfer system comprising: 
 a primary refrigeration path including a compressor, a condenser, an expansion device, and an evaporator, connected together to form a closed loop system with a refrigerant circulating therein; and    a subcooling device according to  claim 1 , wherein: 
 the primary inlet is connected to an outlet of the condenser;  
   the primary outlet is connected to the inlet of the primary expansion device; and    the secondary outlet is connected to return the diverted refrigerant to the primary refrigeration path downstream of the evaporator.    
   
   
       9 . A subcooling device for a heat transfer system comprising a unitary structure including: 
 inlet means for diverting a portion of a liquid refrigerant exiting a condenser means in a main refrigeration path of the refrigeration system;    expansion means for reducing the pressure and temperature of the diverted refrigerant,    heat exchange means thermally coupling the diverted refrigerant at the reduced pressure and temperature to a portion of the main refrigeration path downstream of the condenser to extract sufficient heat from the refrigerant therein sufficient to provide subcooling; and    outlet means connected to the heat exchange means for returning the diverted refrigerant to the main refrigeration path downstream of an evaporator means in the main refrigeration path.    
   
   
       10 . A device according to  claim 9 , wherein the outlet means is operative to reduce the pressure of the refrigerant as it passes therethrough.  
   
   
       11 . A heat transfer system comprising: 
 a primary refrigeration path including compressor means, condenser means, expansion means, and evaporator means, connected together to form a closed loop system with a refrigerant circulating therein; and    a subcooling device according to  claim 9  wherein: 
 the inlet means is connected to an outlet of the condenser means; and  
 the outlet means is connected to return the diverted refrigerant to the primary refrigeration path downstream of the evaporator means.