Partitioned evaporator for a reversible heat pump system operating in the heating mode

Abstract

Disclosed are embodiments of a partitioned evaporator for a reversible heat pump system operating in the heating mode. Embodiments include a partitioned evaporator having a first part and a second part, the first part exchanging heat between a working fluid upstream from a reversible metering device, and the working fluid downstream from the reversible metering device. Heat energy from the upstream fluid is recovered and introduced into the first and second parts aiding in the evaporation of the working fluid rather than being rejected and unused.

What is claimed is: 
     
         1 . A reversible heat pump system having a partitioned evaporator evaporating a working fluid in a first part and a second part using heat energy recovered from the working fluid in the first part, comprising:
 a compressor coupled to a downstream condenser; and   a partitioned evaporator having a first part exchanging heat between a working fluid from the condenser at a first temperature and the working fluid from a metering device at a second temperature, the metering device receiving the working fluid at a third temperature from the first part, the first part exchanging heat so that a second delta between the second and third temperatures is less than about 6 times larger than a first delta between the first and third temperatures; and   a second part downstream from the first part and upstream from the compressor, the second part exchanging heat with an external medium;   wherein the compressor, the condenser, the first part, the metering device, and the second part are coupled together to form a reversible closed refrigeration circuit for circulating the working fluid, the reversible closed refrigeration circuit operating in a heating mode to heat an enclosed space.   
     
     
         2 . The heat pump system of  claim 1 , wherein the second delta is less than about 5 times larger than a first delta. 
     
     
         3 . The heat pump system of  claim 1 , wherein the second delta is less than about 3 times larger than a first delta. 
     
     
         4 . The heat pump system of  claim 1 , wherein the second delta is less than about 2 times larger than a first delta. 
     
     
         5 . The heat pump system of  claim 1 , wherein the second part is downstream from the metering device and receives working fluid directly from the metering device and from the first part. 
     
     
         6 . The heat pump system of  claim 1 , wherein the first part exchanges heat between the working fluid upstream and downstream of the metering device using any one of the following: a tube-in-tube heat exchanger, a coaxial coil heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger. 
     
     
         7 . The heat pump system of  claim 1 , wherein the external medium is any one of the following: ambient air, a liquid, or earth. 
     
     
         8 . A reversible heat pump system having a two-stage evaporator that transfers heat recovered from a working fluid in a first stage upstream from a metering device to the working fluid in a second stage downstream from the first stage, comprising:
 a condenser downstream from a compressor; and   a multi-stage evaporator downstream from the condenser and upstream from the compressor having;
 a first stage heat exchanger exchanging heat between a working fluid received from the condenser at an upstream temperature and the working fluid from a metering device, the metering device receiving the working fluid from the first stage at a downstream temperature, the first stage heat exchanger exchanging heat so that the downstream temperature of the working fluid is at least about 10 percent less than the upstream temperature during normal operations; and 
 a second stage heat exchanger upstream from the compressor and downstream from the first stage, the second stage heat exchanger exchanging heat between a working fluid and an external medium; 
   wherein the compressor, condenser, first heat exchanger, metering device, and second heat exchanger form a reversible closed refrigeration circuit for circulating the working fluid, the reversible closed refrigeration circuit operating in a heating mode to heat an enclosed space.   
     
     
         9 . The heat pump system of  claim 8 , wherein the downstream temperature of the working fluid is at least about 15 percent less than the upstream temperature during normal operations. 
     
     
         10 . The heat pump system of  claim 8 , wherein the downstream temperature of the working fluid is at least about 20 percent less than the upstream temperature during normal operations. 
     
     
         11 . The heat pump system of  claim 8 , wherein the first heat exchanger exchanges heat between the working fluid upstream and downstream of the metering device using any one of the following: a tube-in-tube heat exchanger, a coaxial coil heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger. 
     
     
         12 . The heat pump system of  claim 8 , wherein the external medium is any one of the following: ambient air, a liquid, or earth. 
     
     
         13 . The heat pump system of  claim 8 , wherein the second heat exchanger is downstream from the metering device and receives working fluid directly from the metering device and from the first heat exchanger. 
     
     
         14 . A reversible heat pump system having a two-stage evaporator that provides a metering device between a first stage for evaporating a working fluid by reclaiming waste heat energy from the working fluid, and a second stage for evaporating the remaining working fluid, comprising:
 a two-stage evaporator having a first stage upstream from a metering device and downstream from a condenser, and a second stage downstream from the first stage, the first stage exchanging heat between the working fluid upstream from the first stage having an upstream temperature and the working fluid upstream from the metering device having a downstream temperature, the first stage exchanging at least about 10 percent of heat exchanged by the second stage so that the downstream temperature is less than the upstream temperature, the second stage exchanging heat between the working fluid downstream from the first stage and an external medium; and   a compressor upstream from the condenser and downstream from the second stage of the two-stage evaporator, wherein the compressor, condenser, first stage, metering device, and second stage form a reversible closed refrigeration circuit for circulating the working fluid, the reversible closed refrigeration circuit operating in a heating mode to heat an enclosed space.   
     
     
         15 . The heat pump system of  claim 14 , wherein the first stage exchanges at least about 15 percent of heat exchanged by the second stage. 
     
     
         16 . The heat pump system of  claim 14 , wherein the first stage exchanges at least about 20 percent of heat exchanged by the second stage. 
     
     
         17 . The heat pump system of  claim 14 , wherein the downstream temperature of the working fluid is at least about 10 percent less than the upstream temperature during normal operations. 
     
     
         18 . The heat pump system of  claim 14 , wherein the downstream temperature of the working fluid is at least about 20 percent less than the upstream temperature during normal operations. 
     
     
         19 . The heat pump system of  claim 14 , wherein the first stage exchanges heat between the working fluid from the condenser and the working fluid downstream from the metering device using any one of the following: a tube-in-tube heat exchanger, a coaxial coil heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger. 
     
     
         20 . The heat pump system of  claim 14 , wherein the external medium is any one of the following: ambient air, a liquid, or earth.