Vehicle heat pump system and method utilizing intermediate gas recompression

• US 9,459,028 B2
• Filed: 01/25/2013
• Issued: 10/04/2016
• Est. Priority Date: 01/25/2013
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Styles, Bryan M., Nemesh, Mark D., Eustice, Harry E., Wankhede, Mukund S.
• Primary Examiner(s): Tran, Len
• Assistant Examiner(s): OSWALD, KIRSTIN U
• Application Number:
  US13/750,426
• Publication Number:
  US 20140208775A1
• Time in Patent Office: 1,348 Days
• Field of Search: 623/246, 622/386
• US Class Current: 1/1
• CPC Class Codes: B60H 1/00278 for the battery arrangement of batteries B60R16/04
• CPC Class Codes: B60H 1/00921 where the flow direction of the refrigerant does not change and there is an extra subcondenser, e.g. in an air duct
• CPC Class Codes: B60H 2001/00307 Component temperature regulation using a liquid flow
• CPC Class Codes: B60H 2001/00949 comprising additional heating/cooling sources, e.g. second evaporator
• CPC Class Codes: F25B 2400/0403 for the condenser
• CPC Class Codes: F25B 2400/13 Economisers
• CPC Class Codes: F25B 29/003 of the compression type system
• CPC Class Codes: F25B 30/02 of the compression type
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: F25B 6/02 arranged in parallel

Abstract

A vehicular heat pump system utilizing intermediate gas recompression is provided. The heat pump system is for use in a vehicle having a battery and a passenger compartment. The heat pump system may include a heating circuit and a cooling circuit each including a compressor having a first inlet and a second inlet and a vapor-liquid separator configured to separate intermediate pressure refrigerant supplied by a first expansion device into refrigerant in a gaseous state flowing therethrough and refrigerant in a liquid state flowing therethrough. The vapor-liquid separator may be configured to selectively inject refrigerant in a gaseous state into the compressor at the second inlet to increase the mass flow rate of the refrigerant. This allows the heat pump system to operate effectively in cold ambient temperatures. A method of operating a heat pump system utilizing intermediate gas recompression is also provided.

Claims

1. A heat pump system for use in a vehicle having a battery and a passenger compartment, the heat pump system comprising:

a heating circuit configured to circulate a refrigerant in a first operating mode, to heat the passenger compartment and cool the battery, wherein the heating circuit further includes a first condenser, such that the first condenser is a refrigerant-to-coolant condenser having a refrigerant cavity and a coolant cavity;

a cooling circuit configured to circulate the refrigerant in a second operating mode, to condition air received by the passenger compartment and cool the battery, wherein the cooling circuit further includes a second condenser;

a coolant loop configured to circulate a coolant therethrough, the coolant loop including the first condenser and a coolant heater core therealong;

a compressor having a first inlet and a second inlet, wherein the compressor is incorporated into each of the heating circuit and the cooling circuit and configured to receive the refrigerant at each of the first inlet and the second inlet and further configured to compress refrigerant;

a vapor-liquid separator incorporated in each of the cooling circuit and the heating circuit, wherein the vapor-liquid separator is configured to separate the refrigerant in a gaseous state from the refrigerant in a liquid state and further configured to transmit the refrigerant in the gaseous state to the compressor for injection at the second inlet;

a first expansion device incorporated in the heating circuit and disposed upstream of the vapor-liquid separator, wherein the first expansion device is configured to receive the refrigerant from the refrigerant cavity of the first condenser;

a first flow control valve incorporated in each of the heating circuit and the cooling circuit, wherein the first flow control valve is configured to receive the refrigerant from one of the first expansion device and the second condenser and further configured to transmit the refrigerant to the vapor-liquid separator;

a second flow control valve incorporated in each of the heating circuit and the cooling circuit, wherein the second flow control valve is configured to receive the refrigerant, in the gaseous state, from the vapor-liquid separator and transmit the refrigerant to the compressor at the second inlet, wherein the second flow control valve meters the flow of gaseous refrigerant between the vapor-liquid separator and the compressor;

a controller in communication with at least the compressor, the first flow control valve, and the second flow control valve, the controller having a processor and tangible, non-transitory memory on which is recorded instructions, wherein executing the recorded instructions causes the processor to;

evaluate an instantaneous pressure of the refrigerant flowing through the compressor;

compare the instantaneous pressure of the refrigerant to a minimum threshold pressure value written on the tangible, non-transitory memory of the controller; and

actuate the second flow control valve to an open position when the instantaneous pressure of the refrigerant is below the minimum threshold pressure value, such that the refrigerant from the vapor-liquid separator is injected into the compressor at the second inlet, wherein an injection of the refrigerant into the compressor at the second inlet increases the mass flow rate of the refrigerant entering the compressor.

2. The heat pump system of claim 1 wherein the first condenser is configured to receive the refrigerant from the compressor at the refrigerant cavity and further configured to receive the coolant from the coolant heater core at the coolant cavity, such that the refrigerant flowing through the refrigerant cavity is in heat exchange relation with the coolant flowing through the coolant cavity.

3. The heat pump system of claim 1 wherein the vapor-liquid separator is a combination receiver dryer and vapor-liquid separator.

4. The heat pump system of claim 3 wherein the heating circuit further comprises:

the first expansion device, which is configured to receive the refrigerant from the refrigerant cavity of the first condenser;

the first flow control valve, which is configured to receive the refrigerant from the refrigerant cavity of the first condenser via the first expansion device and transmit the refrigerant to the vapor-liquid separator;

the vapor-liquid separator, which is configured to receive the refrigerant from the first flow control valve and further configured to separate the refrigerant in the gaseous state from the refrigerant in the liquid state and to remove moisture from the refrigerant; and

wherein the vapor-liquid separator is configured to expel the refrigerant in the liquid state through the heating circuit and expel the refrigerant in the gaseous state to the compressor at the second inlet via the second flow control valve.

5. The heat pump system of claim 4 wherein the heating circuit further includes:

a second expansion device configured to receive the refrigerant from the vapor-liquid separator;

an RESS chiller configured to act as a heat pump evaporator in heat exchange relation with air surrounding the battery and the refrigerant flowing through the RESS chiller, the RESS chiller further configured to receive the refrigerant from the second expansion device and expel the refrigerant to the compressor at the first inlet;

a third expansion device configured to receive the refrigerant from the vapor-liquid separator; and

a cabin evaporator configured to receive the refrigerant from the third expansion device and expel the refrigerant to the compressor, wherein the cabin evaporator is in heat exchange relation with the refrigerant flowing through the cabin evaporator and air received by the passenger compartment.

6. The heat pump system of claim 3 wherein the cooling circuit further includes:

the compressor, which is configured to receive the refrigerant at the first inlet and the second inlet and further configured to compress the refrigerant;

the second condenser configured to receive the refrigerant from the compressor and further configured to condition air received by the passenger compartment;

the first flow control valve, which is configured to receive refrigerant from the second condenser and transmit refrigerant to the vapor-liquid separator; and

wherein the vapor-liquid separator is configured to expel liquid refrigerant through the cooling circuit and transmit gaseous refrigerant to the compressor via the second inlet.

7. The heat pump system of claim 6 wherein the cooling circuit further includes:

a second expansion device configured to receive refrigerant from the vapor-liquid separator;

an RESS chiller configured to act as a heat pump evaporator in heat exchange relation with the air surrounding the battery and refrigerant flowing through the RESS chiller, the RESS chiller further configured to receive the refrigerant from the second expansion device and expel the refrigerant to the compressor at the first inlet,

a third expansion device configured to receive the refrigerant from the vapor-liquid separator; and

a cabin evaporator, which is configured to receive the refrigerant from the third expansion device and expel the refrigerant to the compressor, wherein the cabin evaporator is in heat exchange relation with the refrigerant flowing through the cabin evaporator and air received by the passenger compartment.

8. The heat pump system of claim 1

wherein the coolant heater core is in heat exchange relation with the coolant flowing through the coolant heater core and air flowing across the coolant heater core and into the passenger compartment, the coolant heater core further configured to receive the coolant from the coolant cavity of the first condenser.

9. The heat pump system of claim 8 wherein the coolant circulating within the coolant loop is directed from the coolant cavity of the first condenser to the coolant heater core and back to the coolant cavity of the first condenser.

12. The heat pump system of claim 1 wherein the minimum threshold pressure value ranges from about 0 kPaG to about 150 kPaG.

10. A method of operating a heat pump system comprising the steps of:

providing a heat pump system including;

a heating circuit configured to circulate a refrigerant in a first operating mode, to heat the passenger compartment and cool a battery, wherein the heating circuit further includes a first condenser, such that the first condenser is a refrigerant-to-coolant condenser having a refrigerant cavity and a coolant cavity;

a cooling circuit configured to circulate the refrigerant in a second operating mode, to condition air received by the passenger compartment and cool the battery, wherein the cooling circuit further includes a second condenser;

a coolant loop configured to circulate a coolant therethrough, the coolant loop including the first condenser and a coolant heater core therealong;

a compressor having a first inlet and a second inlet, wherein the compressor is incorporated into each of the heating circuit and the cooling circuit and configured to receive the refrigerant at each of the first inlet and second inlet and further configured to compress refrigerant;

a vapor-liquid separator incorporated in each of the cooling circuit and the heating circuit, wherein the vapor-liquid separator is configured to separate the refrigerant in a gaseous state from the refrigerant in a liquid state and further configured to transmit the refrigerant in the gaseous state to the compressor for injection at the second inlet;

a first expansion device incorporated in the heating circuit and disposed upstream of the vapor-liquid separator, wherein the first expansion device is configured to receive the refrigerant from the refrigerant cavity of the first condenser;

a first flow control valve incorporated in each of the heating circuit and the cooling circuit, wherein the first flow control valve is configured to receive the refrigerant from one of the first expansion device and the second condenser and further configured to transmit the refrigerant to the vapor-liquid separator;

a second flow control valve incorporated in each of the heating circuit and the cooling circuit, wherein the second flow control valve is configured to receive the refrigerant, in the gaseous state, from the vapor-liquid separator and transmit the refrigerant to the compressor at the second inlet, wherein the second flow control valve meters the flow of the refrigerant between the vapor-liquid separator and the compressor; and

a controller in communication with at least the compressor, the first flow control valve, and the second flow control valve, the controller having a processor and tangible, non-transitory memory on which is recorded instructions;

supplying intermediate pressure refrigerant to the vapor-liquid separator with one of the first flow control valve and the first expansion device;

separating the intermediate pressure refrigerant into the refrigerant in the gaseous state and the refrigerant in the liquid state with the vapor-liquid separator;

evaluating an instantaneous pressure of the refrigerant entering the compressor with the controller;

comparing, with the controller, the instantaneous pressure of the refrigerant to a minimum threshold pressure value written on the tangible, non-transitory memory of the controller;

actuating the second flow control valve to an open position when the instantaneous pressure of the refrigerant is below the minimum threshold pressure value; and

injecting gaseous refrigerant from the vapor-liquid separator into the compressor at the second inlet, via the second flow control valve, to increase the mass flow rate of refrigerant entering the compressor when the refrigerant pressure entering the compressor reaches a minimum threshold value.

11. The method of claim 10 wherein the minimum threshold value ranges from about 0 kPaG to about 150 kPaG.