Refrigeration system with liquid refrigerant injection to the condenser

Abstract

A refrigeration system including a compressor, a condenser, an expansion device and an evaporator connected in a closed circuit through which a refrigerant is circulated. Liquid refrigerant is injected between an outlet of the compressor and an inlet of the condenser using a vacuum generator in which the vacuum is created by the geometry of the device and the dynamic properties of fluid flow therein, thereby allowing the refrigerant to be cooled at a temperature close to its saturation temperature when it enters the condenser without the need for a costly pump having moving parts. The vacuum may be produced by vortex flow of the superheated vapor output of the compressor, by flow of the superheated vapor through the throat of a venturi device, or in any other comparable manner. The refrigeration system may employ a single refrigerant or a mixture of refrigerants such as R-134a, R-32 and R-125.

We claim:  
     
         1 . A refrigeration system comprising: 
 a compressor, a condenser having an input and an output, an expansion device, and an evaporator, connected together to form a closed loop system with a refrigerant circulating therein; and    a vacuum generating device having no moving parts operative to inject a liquid portion of the refrigerant exiting the condenser into the closed loop between an outlet of the compressor and an inlet of the condenser.    
     
     
         2 . A refrigeration system according to  claim 1 , further including a valve that connects an inlet of the vacuum generating device to an outlet of the condenser.  
     
     
         3 . A refrigeration system according to  claim 1 , wherein the vacuum generating device without moving parts which generates a pressure differential as a result of fluid flow therethrough, and the geometry thereof.  
     
     
         4 . A refrigeration system according to  claim 3 , wherein the pressure differential is generated by vortex flow of a pressurized fluid.  
     
     
         5 . A refrigeration system according to  claim 3 , wherein the pressure differential is generated by flow of a pressurized fluid through a passage of gradually decreasing size.  
     
     
         6 . A refrigeration system according to  claim 3 , wherein the vacuum generator is comprised of: 
 a tubular body having an inlet end and an axially opposite outlet end;    a first inlet disposed axially at the inlet end of the tubular body; 
 a second inlet disposed tangentially at the inlet end of the body, the second inlet and the geometry of the inlet end of the body being operative to cause helical flow of fluid entering the second inlet toward the outlet end of the tubular body; and  
   an axially disposed outlet at the outlet end of the tubular body, 
 the helical flow path producing a lower pressure along the axis of the tubular member compared to that at the radially outer end thereof.  
   
     
     
         7 . A refrigeration system according to  claim 6 , wherein: 
 the first inlet of the vacuum generator is connected to an outlet of the condenser; 
 the second inlet of the vacuum generator is connected to the outlet of the compressor; and  
   the outlet of the vacuum generator is connected to the inlet of the condenser.    
     
     
         8 . A refrigeration system according to  claim 7 , wherein the first inlet of the vacuum generator is connected to the outlet of the condenser through a valve.  
     
     
         9 . A refrigeration system according to  claim 3 , wherein the vacuum generator is comprised of: 
 a tubular body having first and second opposite ends;    a first fluid inlet disposed axially at the first end of the tubular body;    a fluid outlet axially disposed outlet at the second end of the tubular body, 
 the passage between the first inlet and the outlet having a cross-sectional area which decreases to a throat of minimum cross-section; and  
   a second fluid inlet disposed radially at the throat inlet end of the body, 
 the flow of fluid from the first inlet through the throat being operative to produce a lower pressure at the throat and the second inlet compared to that at the first inlet.  
   
     
     
         10 . A refrigeration system according to  claim 9 , wherein: 
 the first inlet of the vacuum generator is connected to an outlet of the compressor;    the second inlet of the vacuum generator is connected to the outlet of the condenser; and    the outlet of the vacuum generator is connected to the inlet of the condenser.    
     
     
         11 . A refrigeration system according to  claim 10 , wherein the second inlet of the vacuum generator is connected to the outlet of the condenser through a valve.  
     
     
         12 . A refrigeration system comprising: 
 a compressor, a condenser having an input and an output, an expansion device, and an evaporator, connected together to form a closed loop system with a refrigerant circulating therein, the refrigerant including a plurality of components having differing thermal characteristics;    a liquid-vapor separator connected to an outlet of the condenser, and a operative to extract a liquid component from the refrigerant exiting from the condenser, to provide the liquid component at a first outlet thereof, and to provide the residual vapor component at a second outlet thereof; and    a vacuum generating device having no moving parts operative to inject the liquid component of the refrigerant extracted by the liquid-vapor separator into the closed loop between an outlet of the compressor and an inlet of the condenser.    
     
     
         13 . A refrigeration system according to  claim 12 , further including a valve that connects an inlet of the vacuum generating device to an outlet of the liquid-vapor separator.  
     
     
         14 . A refrigeration system according to  claim 12 , wherein the vacuum generator generates a pressure differential as a result of fluid flow therethrough, and the geometry thereof.  
     
     
         15 . A refrigeration system according to  claim 14 , wherein the pressure differential is generated by vortex flow of a pressurized fluid.  
     
     
         16 . A refrigeration system according to  claim 14 , wherein the pressure differential is generated by flow of a pressurized fluid through a passage of gradually decreasing size.  
     
     
         17 . A refrigeration system according to  claim 14 , wherein the vacuum generator is comprised of: 
 a tubular body having an inlet end and an axially opposite outlet end;    a first inlet disposed axially at the inlet end of the tubular body; 
 a second inlet disposed tangentially at the inlet end of the body, the second inlet and the inlet end of the body being operative to cause helical flow of fluid entering the second inlet toward the outlet end of the tubular body; and  
   an axially disposed outlet at the outlet end of the tubular body, 
 the helical flow path producing a lower pressure along the axis of the tubular member compared to that at the radially outer end thereof.  
   
     
     
         18 . A refrigeration system according to  claim 17 , wherein: 
 the first inlet of the vacuum generator is connected to an outlet of the condenser;    the second inlet of the vacuum generator is connected to the outlet of the compressor; and    the outlet of the vacuum generator is connected to the inlet of the condenser.    
     
     
         19 . A refrigeration system according to  claim 18 , wherein the first inlet of the vacuum generator is connected to the outlet of the condenser through a valve.  
     
     
         20 . A refrigeration system according to  claim 14 , wherein the vacuum generator is comprised of: 
 a tubular body having first and second opposite ends;    a first fluid inlet disposed axially at the first end of the tubular body;    a fluid outlet axially disposed outlet at the second end of the tubular body, 
 the passage between the first inlet and the outlet having a cross-sectional area which decreases to a throat of minimum cross-section; and  
   a second fluid inlet disposed radially at the throat inlet end of the body, 
 the flow of fluid from the first inlet through the throat being operative to produce a lower pressure at the throat and the second inlet compared to that at the first inlet.  
   
     
     
         21 . A refrigeration system according to  claim 20 , wherein: 
 the first inlet of the vacuum generator is connected to an outlet of the compressor;    the second inlet of the vacuum generator is connected to the outlet of the condenser; and    the outlet of the vacuum generator is connected to the inlet of the condenser.    
     
     
         22 . A refrigeration system according to  claim 21 , wherein the second inlet of the vacuum generator is connected to the outlet of the condenser through a valve.  
     
     
         23 . A refrigeration system according to  claim 12 , wherein: 
 the condenser is comprised of first and second condenser stages; 
 the inlet of the liquid-vapor separator is connected to an outlet of the first condenser stage;  
 the first outlet of the liquid-vapor separator is connected to an inlet of the vacuum generating device;  
 the second outlet of the liquid-vapor separator is connected to an inlet of the second condenser stage; and  
   an outlet of the second condenser stage is connected to an inlet of the expansion device.    
     
     
         24 . A refrigeration system according to  claim 12 , wherein the refrigerant is a mixture of R-32, R-125 and R-134a, and the liquid provided at the output of the LV separator is rich in R-134a.