Low compression ratio refrigeration system with low-pressure booster

Abstract

A refrigeration system, according to the present invention, has a standard refrigeration circuit, with a condenser connected to a low temperature evaporator and a medium temperature evaporator by a high-pressure liquid line, which are in turn connected to a compressor by a low-pressure vapour return line and a medium-pressure vapour return line, and the compressor is connected to the condenser by a high-pressure vapour line. A low-pressure booster is connected on the low-pressure vapour return line operating at a low compression ratio to boost the pressure of the low-pressure vapour return line to substantially the same pressure as the medium-pressure vapour return line.

What is claimed is: 
     
         1 . A refrigeration system, with a standard refrigeration circuit having a condenser connected to a low temperature evaporator and a medium temperature evaporator by a high-pressure liquid line, which are in turn connected to a compressor by a low-pressure vapour return line and a medium-pressure vapour return line, and the compressor is connected to the condenser by a high-pressure vapour line, comprising:
 a low-pressure booster on the low-pressure vapour return line operating at a low compression ratio of between 1.8:1 and 3:1 to boost the pressure of the low-pressure vapour return line to substantially the same pressure as the medium-pressure vapour return line;   a medium-pressure manifold connected to the low-pressure vapour return line, after the low-pressure booster, and the medium-pressure vapour return line to receive and combine refrigerant therefrom, and connected to the compressor to supply the combined refrigerant thereto; and   an accumulator connected between the medium-pressure manifold and the compressor and configured to pre-mix the refrigerant and reduce variations in refrigerant pressure being supplied to the compressor.   
     
     
         2 . The refrigeration system of  claim 1 , wherein the low compression ratio of the low-pressure booster is between 1.8:1 and 2.8:1. 
     
     
         3 . The refrigeration system of  claim 1 , wherein the low compression ratio of the low-pressure booster is about 2:1. 
     
     
         4 . The refrigeration system of  claim 1 , wherein the low-pressure booster is a scroll compressor. 
     
     
         5 . The refrigeration system of  claim 4 , wherein the scroll compressor is a double-sided scroll compressor having a first scroll and a second scroll. 
     
     
         6 . The refrigeration system of  claim 5 , wherein the first scroll is connected to the low-pressure vapour return line and the medium-pressure vapour return line to operate as the low-pressure booster, and wherein the second scroll is connected to the medium-pressure vapour return line and the high-pressure vapour line to operate as the compressor. 
     
     
         7 . The refrigeration system of  claim 5 , wherein the low-pressure vapour return line is split into two lines one of which is connected to the first scroll and the other of which is connected to the second scroll. 
     
     
         8 . The refrigeration system of  claim 4 , wherein the scroll compressor is a magnetic drive oil-less scroll compressor. 
     
     
         9 . The refrigeration system of  claim 1 , wherein the low-pressure booster is a turbine. 
     
     
         10 . The refrigeration system of  claim 1 , comprising one or more subcooling stages on the high-pressure liquid line. 
     
     
         11 . The refrigeration system of  claim 10 , wherein the one or more subcooling stages comprise a subcooling loop in the condenser. 
     
     
         12 . The refrigeration system of  claim 10 , wherein the one or more subcooling stages comprise a subcooling coil in the accumulator.