Energy efficient heat pump with ejector system

Abstract

An energy efficient heat pump for a heating, ventilation, and air conditioning (HVAC) system includes a working fluid circuit configured to circulate a working fluid. The working fluid circuit includes a compressor, a first heat exchanger, a second heat exchanger, and a reversing valve configured to adjust a flow direction of the working fluid through the working fluid circuit. The energy efficient heat pump also includes an ejector system having an ejector configured to receive a first flow of the working fluid from the working fluid circuit as a suction fluid, receive a second flow of the working fluid from the working fluid circuit as a motive fluid, and direct a combined flow of the first flow of the working fluid and the second flow of the working fluid toward the compressor.

1 . An energy efficient heat pump for a heating, ventilation, and air conditioning (HVAC) system, comprising:
 a working fluid circuit configured to circulate a working fluid, wherein the working fluid circuit comprises a compressor, a first heat exchanger, a second heat exchanger, and a reversing valve, wherein the reversing valve is configured to adjust a flow direction of the working fluid through the working fluid circuit; and   an ejector system comprising an ejector configured to receive a first flow of the working fluid from the working fluid circuit as a suction fluid, receive a second flow of the working fluid from the working fluid circuit as a motive fluid, and direct a combined flow of the first flow of the working fluid and the second flow of the working fluid toward the compressor.   
     
     
         2 . The energy efficient heat pump of  claim 1 , wherein:
 the working fluid circuit comprises an expansion valve, a first circuit portion extending from the second heat exchanger to the expansion valve, and a second circuit portion extending from the expansion valve to the first heat exchanger; and   the ejector system comprises:
 a first conduit extending from the first circuit portion to the ejector and configured to direct the first flow of the working fluid from the first circuit portion to a chamber inlet of the ejector; and 
 a second conduit extending from the second circuit portion to the ejector and configured to direct the second flow of the working fluid from the second circuit portion to a nozzle inlet of the ejector. 
   
     
     
         3 . The energy efficient heat pump of  claim 2 , wherein:
 the working fluid circuit comprises a suction conduit extending from the reversing valve to a suction port of the compressor and a gas-liquid separator disposed along the suction conduit; and   the ejector system comprises an outlet conduit extending from a diffuser of the ejector to the gas-liquid separator, wherein the outlet conduit is configured to direct the combined flow of the first flow of the working fluid and the second flow of the working fluid from the ejector to the gas-liquid separator.   
     
     
         4 . The energy efficient heat pump of  claim 3 , wherein the gas-liquid separator is configured to separate the combined flow of the first flow of the working fluid and the second flow of the working fluid into vapor working fluid and liquid working fluid, and the working fluid circuit is configured to direct the vapor working fluid from the gas-liquid separator to the compressor and to direct the liquid working fluid from the gas-liquid separator to the reversing valve. 
     
     
         5 . The energy efficient heat pump of  claim 2 , wherein the ejector system comprises a first valve disposed along the first conduit and a second valve disposed along the second conduit. 
     
     
         6 . The energy efficient heat pump of  claim 5 , wherein the first heat exchanger is configured to place the working fluid in a first heat exchange relationship with a supply air flow directed across the first heat exchanger, and the second heat exchanger is configured to place the working fluid in a second heat exchange relationship with an ambient air flow directed across the second heat exchanger. 
     
     
         7 . The energy efficient heat pump of  claim 6 , comprising a controller communicatively coupled to the reversing valve, the expansion valve, the first valve, and the second valve, wherein the controller is configured to output one or more control signals to:
 adjust the reversing valve to a first configuration, open the expansion valve, and close the first valve and the second valve to operate the energy efficient heat pump in a cooling mode;   adjust the reversing valve to a second configuration, open the expansion valve, and close the first valve and the second valve to operate the energy efficient heat pump in a heating mode; and   adjust the reversing valve to the second configuration, close the expansion valve, and open the first valve and the second valve to operate to the energy efficient heat pump in an ejector heating mode of the energy efficient heat pump.   
     
     
         8 . The energy efficient heat pump of  claim 7 , wherein the controller is configured to operate the energy efficient heat pump in the ejector heating mode based on data received from one or more sensors of the energy efficient heat pump, wherein the data is indicative of one or more operating parameters of the energy efficient heat pump. 
     
     
         9 . The energy efficient heat pump of  claim 8 , wherein the one or more operating parameters comprises a first pressure of the working fluid within the working fluid circuit and a second pressure of the working fluid within the working fluid circuit, and the controller is configured to:
 determine a pressure differential of the working fluid based on the first pressure and the second pressure;   compare the pressure differential to a threshold pressure differential value; and   in response to a determination that the pressure differential is equal to or greater than the threshold pressure differential value, operate the energy efficient heat pump in the ejector heating mode.   
     
     
         10 . The energy efficient heat pump of  claim 8 , wherein the one or more operating parameters comprises a temperature of an ambient environment, and the controller is configured to:
 compare the temperature of the ambient environment to a threshold temperature value; and   in response to a determination that the temperature of the ambient environment is less than the threshold temperature value, operate the energy efficient heat pump in the ejector heating mode.   
     
     
         11 . The energy efficient heat pump of  claim 2 , wherein:
 the ejector system comprises an intermediate heat exchanger disposed along the second conduit upstream of the ejector, relative to a direction of the second flow of the working fluid from the second circuit portion to the nozzle inlet of the ejector; and   the working fluid circuit comprises a suction conduit extending from the reversing valve to a suction port of the compressor and a gas-liquid separator disposed along the suction conduit, wherein the gas-liquid separator is configured to receive the combined flow of the first flow of the working fluid and the second flow of the working fluid from the ejector, and the gas-liquid separator is configured to direct vapor working fluid toward the suction port of the compressor,   wherein the intermediate heat exchanger is disposed along the suction conduit between the gas-liquid separator and the suction port of the compressor, and the intermediate heat exchanger is configured to place the second flow of the working fluid in a heat exchange relationship with the vapor working fluid.   
     
     
         12 . An energy efficient heat pump, comprising:
 a working fluid circuit configured to circulate a working fluid therethrough, wherein the working fluid circuit comprises a first heat exchanger configured to exchange heat between the working fluid and a supply air flow, a second heat exchanger configured to exchange heat between the working fluid and an ambient air flow, and a reversing valve configured to adjust a flow direction of the working fluid along the working fluid circuit;   an ejector system comprising an ejector, a first conduit configured to direct the working fluid from the working fluid circuit to the ejector, a second conduit configured to direct the working fluid from the working fluid circuit to the ejector, and an outlet conduit configured to direct the working fluid from the ejector toward a compressor of the working fluid circuit;   a plurality of valves configured to control flow of the working fluid along the working fluid circuit and through the ejector system; and   a controller communicatively coupled to the plurality of valves and configured to adjust respective positions of the plurality of valves based on an operating mode of the energy efficient heat pump.   
     
     
         13 . The energy efficient heat pump of  claim 12 , wherein the controller is configured to adjust the respective positions of the plurality of valves to block flow of the working fluid through the ejector system in a cooling mode of the energy efficient heat pump, block flow of the working fluid through the ejector system in a heating mode of the energy efficient heat pump, and enable flow of the working fluid through the ejector system in an alternative heating mode of the energy efficient heat pump. 
     
     
         14 . The energy efficient heat pump of  claim 13 , wherein the plurality of valves comprises:
 a first valve disposed along the first conduit;   a second valve disposed along the second conduit; and   an expansion valve disposed along the working fluid circuit between the first heat exchanger and the second heat exchanger,   wherein the first conduit extends from the working fluid circuit between the second heat exchanger and the expansion valve, and the second conduit extends from the working fluid circuit between the first heat exchanger and the expansion valve.   
     
     
         15 . The energy efficient heat pump of  claim 14 , wherein the controller is configured to close the first valve and the second valve and to open the expansion valve in the cooling mode and in the heating mode, and the controller is configured to open the first valve and the second valve and to close the expansion valve in the alternative heating mode. 
     
     
         16 . The energy efficient heat pump of  claim 13 , wherein the working fluid circuit comprises a compressor and a gas-liquid separator, and, in the alternative heating mode, the gas-liquid separator is configured to receive the working fluid from the ejector via the outlet conduit and separate the working fluid into vapor working fluid and liquid working fluid, the working fluid circuit is configured to direct the vapor working fluid from the gas-liquid separator to the compressor, and the working fluid circuit is configured to direct the liquid working fluid from the gas-liquid separator to the reversing valve. 
     
     
         17 . The energy efficient heat pump of  claim 13 , wherein the controller is configured to operate the energy efficient heat pump in the alternative heating mode in response to a determination that a detected ambient temperature is less than a threshold temperature value. 
     
     
         18 . An energy efficient heat pump, comprising:
 a first heat exchanger disposed along a working fluid circuit and configured to transfer heat from a working fluid to a supply air flow in a heating mode of the energy efficient heat pump and in an alternative heating mode of the energy efficient heat pump;   a second heat exchanger disposed along the working fluid circuit and configured to transfer heat from an ambient air flow to the working fluid in the heating mode and in the alternative heating mode;   a gas-liquid separator disposed along the working fluid circuit;   an ejector system, comprising:
 an ejector comprising a nozzle inlet, a chamber inlet, and an outlet; 
 a first conduit comprising a first valve, wherein the first conduit is configured to direct a first flow of the working fluid from the working fluid circuit to the chamber inlet of the ejector; 
 a second conduit comprising a second valve, wherein the second conduit is configured to direct a second flow of the working fluid from the working fluid circuit to the nozzle inlet of the ejector; and 
 an outlet conduit configured to direct a combined flow of the first flow of the working fluid and the second flow of the working fluid from the outlet of the ejector to the gas-liquid separator; and 
   a controller configured to adjust the first valve and the second valve to respective closed positions in the heating mode of the energy efficient heat pump and to adjust the first valve and the second valve to respective open positions in the alternative heating mode of the energy efficient heat pump.   
     
     
         19 . The energy efficient heat pump of  claim 18 , wherein the first conduit is configured to direct the first flow of the working fluid from the second heat exchanger to the chamber inlet of the ejector in the alternative heating mode, and the second conduit is configured to direct the second flow of the working fluid from the first heat exchanger to the nozzle inlet of the ejector in the alternative heating mode. 
     
     
         20 . The energy efficient heat pump of  claim 18 , wherein the controller is configured to operate the energy efficient heat pump in the alternative heating mode instead of the heating mode in response to a determination that a detected ambient temperature is less than a threshold temperature value, in response to a determination that a pressure differential of the working fluid across the working fluid circuit is equal to or greater than a threshold pressure differential value, or both.