Heat pump with multi-pass refrigerant circuit

Abstract

The various embodiments described herein include methods, devices, and systems for cooling or heating an area (e.g., a vehicle, room, etc.). In one aspect, a refrigeration system includes a compressor, an external heat exchanger (HX), an internal HX, a multi-pass refrigerant circuit, one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external HX, (iii) the internal HX, (iv) the multi-pass refrigerant circuit, and (v) the first set one or more valve. The refrigeration system further includes a controller communicatively coupled to the one or more valves. The controller is configured to operate the refrigeration system in a plurality of modes including a cooling mode and a heating mode.

What is claimed is: 
     
         1 . A refrigeration system, comprising:
 a compressor;   an external heat exchanger;   an internal heat exchanger;   a multi-pass refrigerant circuit;   one or more valves;   a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, (iv) the multi-pass refrigerant circuit, and (v) the one or more valves, and   a controller communicatively coupled to the one or more valves and configured to operate the system in a plurality of modes, comprising:
 a cooling mode in which the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor, and 
 a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger. 
   
     
     
         2 . The refrigeration system of  claim 1 , further comprising:
 a metering device fluidically coupled between the external heat exchanger and the internal heat exchanger.   
     
     
         3 . The refrigeration system of  claim 1 , further comprising:
 a second valve fluidically coupled between the internal heat exchanger and/or the multi-pass refrigerant circuit.   
     
     
         4 . The refrigeration system of  claim 3 , further comprising:
 a third valve fluidically coupled between an inlet and an outlet of the second valve.   
     
     
         5 . The system of  claim 4 , wherein the third valve includes one or more check valves configured to inhibit reverse flow of the refrigerant. 
     
     
         6 . The refrigeration system of  claim 1 , further comprising:
 an accumulator fluidically coupled between the compressor and the multi-pass refrigerant circuit.   
     
     
         7 . The refrigeration system of  claim 1 , further comprising:
 a fan coupled with the external heat exchanger.   
     
     
         8 . The refrigeration system of  claim 1 , wherein the one or more valves is a four-way reversing valve configured to selectively change, via the controller, a direction of refrigerant flow in accordance with changing between heating and cooling modes. 
     
     
         9 . The refrigeration system of  claim 1 , wherein the plurality of refrigerant lines includes:
 a first refrigerant line fluidically coupling an output of the compressor to the one or more valves;   a second refrigerant line fluidically coupling the one or more valves to the external heat exchanger;   a third refrigerant line fluidically coupling the external heat exchanger to a first port of the multi-pass refrigerant circuit;   a fourth refrigerant line fluidically coupling a second port of the multi-pass refrigerant circuit to the internal heat exchanger;   a fifth refrigerant line fluidically coupling the internal heat exchanger to a third port of the multi-pass refrigerant circuit;   a sixth refrigerant line fluidically coupling a fourth port of the multi-pass refrigerant circuit to the one or more valves;   a seventh refrigerant line fluidically coupling the one or more valves to a fifth port of the multi-pass refrigerant circuit; and   an eighth refrigerant line fluidically coupling a sixth port of the multi-pass refrigerant circuit to an inlet of the compressor.   
     
     
         10 . The refrigeration system of  claim 9 , wherein operating in the cooling mode includes:
 causing a refrigerant to flow from the compressor to the external heat exchanger via the one or more valves, wherein the refrigerant is caused to flow from the compressor to the one or more valves and to the external heat exchanger;   causing the refrigerant to flow from the external heat exchanger to the internal heat exchanger via the multi-pass refrigerant circuit, wherein the refrigerant is caused to flow from external heat exchanger through the first and second ports of the multi-pass refrigerant circuit to the internal heat exchanger; and   causing the refrigerant to flow from the internal heat exchanger to the compressor via the multi-pass refrigerant circuit and the one or more valves, wherein the refrigerant is caused to flow from the internal heat exchanger to the third and fourth ports of the multi-pass refrigerant circuit to the one or more valves and from the one or more valves through the fifth and sixth ports of the multi-pass refrigerant circuit to the compressor.   
     
     
         11 . The refrigeration system of  claim 9 , wherein operating in the heating mode includes:
 causing the refrigerant to flow from the compressor to the internal heat exchanger via the one or more valves and the multi-pass refrigerant circuit, wherein the refrigerant is caused to flow from the compressor to the one or more valves through the fourth and third ports of the multi-pass refrigerant circuit and to the internal heat exchanger;   causing the refrigerant to flow from the internal heat exchanger to the external heat exchanger via the multi-pass refrigerant circuit, wherein the refrigerant is caused to flow from internal heat exchanger through the second and first ports of the multi-pass refrigerant circuit to the external heat exchanger; and   causing the refrigerant to flow from the external heat exchanger to the compressor via the one or more valves and the multi-pass refrigerant circuit, wherein the refrigerant is caused to flow from the external heat exchanger to the one or more valves through the fifth and sixth ports of the multi-pass refrigerant circuit and to the compressor.   
     
     
         12 . The refrigeration system of  claim 1 , wherein the plurality of refrigerant lines includes:
 a first refrigerant line fluidically coupling an outlet of the compressor to a first port of the multi-pass refrigerant circuit;   a second refrigerant line fluidically coupling a second port of the multi-pass refrigerant circuit to the one or more valves;   a third refrigerant line fluidically coupling the one or more valves to the external heat exchanger;   a fourth refrigerant line fluidically coupling the external heat exchanger to the internal heat exchanger;   a fifth refrigerant line fluidically coupling the internal heat exchanger to a third port of the multi-pass refrigerant circuit;   a sixth refrigerant line fluidically coupling a fourth port of the multi-pass refrigerant circuit to the one or more valves;   a seventh refrigerant line fluidically coupling the one or more valves to a fifth port of the multi-pass refrigerant circuit; and   an eighth refrigerant line fluidically coupling a sixth port of the multi-pass refrigerant circuit to an inlet of the compressor.   
     
     
         13 . The refrigeration system of  claim 12 , wherein operating in the cooling mode includes:
 causing a refrigerant to flow from the compressor to the external heat exchanger via the multi-pass refrigerant circuit and the one or more valves, wherein the refrigerant is caused to flow from the compressor through the first and second ports of the multi-pass refrigerant circuit to the one or more valves and from the one or more valves to the external heat exchanger;   causing the refrigerant to flow from the external heat exchanger to the internal heat exchanger; and   causing the refrigerant to flow from the internal heat exchanger to the compressor via the multi-pass refrigerant circuit and the of one or more valves, wherein the refrigerant is caused to flow from the internal heat exchanger through the third and fourth ports of the multi-pass refrigerant circuit to the of one or more valves and from the of one or more valves through the fifth and sixth ports of the multi-pass refrigerant circuit to the compressor.   
     
     
         14 . The refrigeration system of  claim 12 , wherein operating in the heating mode includes:
 causing the refrigerant to flow from the compressor to the internal heat exchanger via the multi-pass refrigerant circuit and the of one or more valves, wherein the refrigerant is caused to flow from the compressor through the first and second ports of the multi-pass refrigerant circuit to the of one or more valves and from the of one or more valves through the fourth and third ports of the multi-pass refrigerant circuit to the internal heat exchanger;   causing the refrigerant to flow from the internal heat exchanger to the external heat exchanger; and   causing the refrigerant to flow from the external heat exchanger to the compressor via the of one or more valves and the multi-pass refrigerant circuit, wherein the refrigerant is caused to flow from external heat exchanger to the of one or more valves and from the of one or more valves through the fifth and sixth ports of the multi-pass refrigerant circuit to the compressor.   
     
     
         15 . The refrigeration system of  claim 1 , wherein the refrigeration system is a heating, ventilation and air conditioning (HVAC) system. 
     
     
         16 . The refrigeration system of  claim 1 , wherein the compressor is an electrically-driven compressor. 
     
     
         17 . A method, comprising:
 at a refrigeration system including a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchange, (iii) the internal heat exchange, and (iv) the multi-pass refrigerant circuit via the one or more valves, and a controller communicatively coupled to the one or more valves:
 operating the refrigeration system in a cooling mode in which the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor, and 
 operating the refrigeration system in a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger. 
   
     
     
         18 . The method of  claim 17 , wherein the refrigeration system further comprises:
 a metering device fluidically coupled between the external heat exchanger and the internal heat exchanger.   
     
     
         19 . The method of  claim 17 , wherein the refrigeration system further comprises:
 a second valve fluidically coupled between the internal heat exchanger and/or the multi-pass refrigerant circuit.   
     
     
         20 . A non-transitory, computer-readable storage medium including instructions that, when executed by one or more processors of a refrigeration system including a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchange, (iii) the internal heat exchange, and (iv) the multi-pass refrigerant circuit via the one or more valves, cause the refrigeration system to:
 operate in a cooling mode in which a multi-pass refrigerant circuit uses a refrigerant flow from an internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from a compressor, and   operate in a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from a external heat exchanger.