Two Stage Condensing and Metering Refrigeration System

Abstract

A refrigeration system, includes a main refrigeration system. The main refrigeration system includes a main refrigerant, a main compressor, a main condenser coil, a pre-metering device, a main metering device, a main evaporator, and a secondary refrigeration system. In flow sequence, the main refrigerant within the main refrigeration system is compressed by the main compressor, condensed by the main condenser coil, dropped in pressure by the pre-metering device, cooled by the secondary refrigeration system, dropped in pressure by the main metering device, vaporized by the main evaporator and returned to the main compressor. The secondary refrigeration system includes a secondary refrigerant, a secondary compressor, a secondary condenser coil, a secondary metering device, a secondary evaporator having a main refrigerant cooling path and a secondary refrigerant evaporator path in heat transfer communication. In flow sequence, the secondary refrigerant in the secondary refrigeration system is compressed by the secondary compressor, condensed by the secondary condenser coil, dropped in pressure by the secondary metering device, and vaporized by the evaporator path by heat transfer from the cooling path carrying the main refrigerant, and returned to the secondary compressor. The main condenser coil and the secondary condenser coil are located together in a housing to be cooled by the same flowing media. The secondary evaporator is a co-axial pipe heat exchanger.

The invention claimed is: 
     
         1 . A refrigeration system, comprising:
 a main refrigeration system including a main refrigerant, a main compressor, a main condenser coil, a pre-metering device, a main metering device, a main evaporator, and a secondary refrigeration system;   wherein an outlet of the main compressor is main-refrigerant-flow-connected to the main condenser coil, the main condenser coil is main-refrigerant-flow-connected to the pre-metering device, the pre-metering device is main-refrigerant-flow-connected to the secondary refrigeration system, the secondary refrigeration system is main-refrigerant-flow-connected to the main metering device, the main metering device is main-refrigerant-flow-connected to the main evaporator, and the main evaporator is main-refrigerant-flow-connected back to an inlet of the main compressor;   wherein, in flow sequence, the main refrigerant within the main refrigeration system is compressed by the main compressor, condensed by the main condenser coil, dropped in pressure by the pre-metering device, cooled by the secondary refrigeration system, dropped in pressure by the main metering device, vaporized by the main evaporator and returned to the main compressor;   wherein the secondary refrigeration system includes a secondary refrigerant, a secondary compressor, a secondary condenser coil, a secondary metering device, a secondary evaporator having a cooling path and evaporator path therein in heat transfer communication;   the secondary compressor is secondary-refrigerant-flow-connected to the secondary condenser coil, the secondary condenser coil is secondary-refrigerant-flow-connected to the secondary metering device, the secondary metering device is secondary-refrigerant-flow-connected to the evaporator path within the secondary evaporator, the evaporator path is secondary-refrigerant-flow-connected to the secondary compressor;   wherein the pre-metering device of the main refrigeration system is main-refrigerant-flow-connected to an inlet of the cooling path in the secondary evaporator of the secondary refrigeration system, wherein an outlet of the cooling path is main-refrigerant-flow-connected to the main metering device of the main refrigeration system;   wherein, in flow sequence, the secondary refrigerant in the secondary refrigeration system is compressed by the secondary compressor, condensed by the secondary condenser coil, dropped in pressure by the secondary metering device, and vaporized in the evaporator path by heat transfer from the cooling path carrying the main refrigerant, and returned to the secondary compressor;   wherein the main condenser coil and the secondary condenser coil are located together in a housing to be cooled by the same flowing media.   
     
     
         2 . The refrigeration system according to  claim 1 , wherein the secondary evaporator comprises a co-axial pipe heat exchanger. 
     
     
         3 . The refrigeration system according to  claim 2 , wherein an inside pipe of the co-axial pipe heat exchanger carries the secondary refrigerant, and an outside pipe of the co-axial pipe heat exchanger, surrounding the inside pipe, carries the main refrigerant. 
     
     
         4 . The refrigeration system according to  claim 1 , wherein the main evaporator comprises a co-axial pipe heat exchanger. 
     
     
         5 . A refrigeration system, comprising:
 a main refrigeration system including a main refrigerant, a main compressor, a main condenser coil, a pre-metering device, a main metering device, a main evaporator, and a secondary refrigeration system;   wherein an outlet of the main compressor is main-refrigerant-flow-connected to the main condenser coil, the main condenser coil is main-refrigerant-flow-connected to the pre-metering device, the pre-metering device is main-refrigerant-flow-connected to the secondary refrigeration system, the secondary refrigeration system is main-refrigerant-flow-connected to the main metering device, the main metering device is main-refrigerant-flow-connected to the main evaporator, and the main evaporator is main-refrigerant-flow-connected back to an inlet of the main compressor;   wherein, in flow sequence, the main refrigerant within the main refrigeration system is compressed by the main compressor, condensed by the main condenser coil, dropped in pressure by the pre-metering device, cooled by the secondary refrigeration system, dropped in pressure by the main metering device, vaporized by the main evaporator and returned to the main compressor;   wherein the secondary refrigeration system includes a secondary refrigerant, a secondary compressor, a secondary condenser coil, a secondary metering device, a secondary evaporator having a cooling path and evaporator path therein in heat transfer communication;   the secondary compressor is secondary-refrigerant-flow-connected to the secondary condenser coil, the secondary condenser coil is secondary-refrigerant-flow-connected to the secondary metering device, the secondary metering device is secondary-refrigerant-flow-connected to the evaporator path within the secondary evaporator, the evaporator path is secondary-refrigerant-flow-connected to the secondary compressor;   wherein the pre-metering device of the main refrigeration system is main-refrigerant-flow-connected to an inlet of the cooling path in the secondary evaporator of the secondary refrigeration system, wherein an outlet of the cooling path is main-refrigerant-flow-connected to the main metering device of the main refrigeration system;   wherein, in flow sequence, the secondary refrigerant in the secondary refrigeration system is compressed by the secondary compressor, condensed by the secondary condenser coil, dropped in pressure by the secondary metering device, and vaporized by the evaporator path by heat transfer from the cooling path carrying the main refrigerant, and returned to the secondary compressor;   wherein the secondary evaporator comprises a co-axial pipe heat exchanger.   
     
     
         6 . The refrigeration system according to  claim 6 , wherein an inside pipe of the co-axial pipe heat exchanger carries the secondary refrigerant, and an outside pipe of the co-axial pipe heat exchanger, surrounding the inside pipe, carries the main refrigerant.