Vapor injection heat pump and control method

1. A vapor injection heat pump, comprising:

a compressor for compressing a refrigerant;

a first valve directing at least one of a first portion of the refrigerant output by said compressor to a first heat exchanger and a second portion of the refrigerant output by said compressor to a second air-to-refrigerant heat exchanger dependent upon a mode of operation;

a first expansion device receiving at least one of the first portion of the refrigerant directed through said first heat exchanger and the second portion of the refrigerant directed through said second air-to-refrigerant heat exchanger;

a vapor generator receiving a liquid and vapor refrigerant mix from said first expansion device and directing a vapor component of the liquid and vapor refrigerant mix to a first input port of said compressor and a liquid component of the liquid and vapor refrigerant mix to a second valve, said second valve directing the liquid component to said second air-to-refrigerant heat exchanger or a third air-to-refrigerant heat exchanger dependent upon the mode of operation, wherein a second input of said compressor receives an output refrigerant of the at least one of said second air-to-refrigerant heat exchanger and said third air-to-refrigerant heat exchanger dependent upon the mode of operation; and

a control module for controlling at least said first and second valves and said first expansion device dependent upon the mode of operation.

2. The vapor injection heat pump of claim 1 , further comprising an accumulator receiving the refrigerant output by said second air-to-refrigerant heat exchanger or said third air-to-refrigerant heat exchanger dependent upon the mode of operation and directing the vapor component of the refrigerant output by said second air-to-refrigerant heat exchanger or said third air-to-refrigerant heat exchanger to said second input port of said compressor.

3. The vapor injection heat pump of claim 1 , wherein said first heat exchanger is an air-to-refrigerant heat exchanger.

4. The vapor injection heat pump of claim 3 , wherein said first valve directs the refrigerant output by said compressor to said second air-to-refrigerant heat exchanger, and said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, in a cooling mode of operation.

5. The vapor injection heat pump of claim 3 , wherein said first valve directs the refrigerant output by said compressor to said first air-to-refrigerant heat exchanger, and said second valve directs the liquid component of the liquid and vapor refrigerant mix to said second air-to-refrigerant heat exchanger, in a heating mode of operation.

6. The vapor injection heat pump of claim 3 , wherein said first valve directs the refrigerant output by said compressor to said first air-to-refrigerant heat exchanger, and said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, in a reheating mode of operation.

7. The vapor injection heat pump of claim 3 , wherein said first valve directs the refrigerant output by said compressor to said first air-to-refrigerant heat exchanger and said second air-to-refrigerant heat exchanger, and said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, in a reheating mode of operation.

8. The vapor injection heat pump of claim 3 , wherein said first valve directs the refrigerant output by said compressor to said second air-to-refrigerant heat exchanger, said control module operates said first expansion device in an open mode providing minimal refrigerant flow restriction, and said compressor receives refrigerant vapor from said first input port via said vapor generator, in a deicing mode of operation.

9. The vapor injection heat pump of claim 3 , wherein said first valve and said second valve direct the refrigerant output by said compressor through said second air-to-refrigerant heat exchanger and a second expansion device, said second valve directs refrigerant output by said second expansion device through a fourth valve to said second input port of said compressor, and said control module further controls said second expansion device, in a deicing mode of operation.

10. The vapor injection heat pump of claim 1 , wherein said first heat exchanger is a refrigerant-to-coolant heat exchanger.

11. The vapor injection heat pump of claim 10 , further comprising a coolant loop including said refrigerant-to-coolant heat exchanger and a fourth air-to-coolant heat exchanger through which a coolant is pumped dependent upon the mode of operation.

12. The vapor injection heat pump of claim 11 , further comprising a refrigerant loop including said compressor, said first valve, said second air-to-refrigerant heat exchanger, said first expansion device, said vapor generator, said second valve, said third air-to-refrigerant heat exchanger.

13. The vapor injection heat pump of claim 12 , wherein said first valve directs the refrigerant output by said compressor to said second air-to-refrigerant heat exchanger and said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, in a cooling mode of operation.

14. The vapor injection heat pump of claim 12 , wherein said first valve directs the refrigerant output by said compressor to said refrigerant-to-coolant heat exchanger, said second valve directs the liquid component of the liquid and vapor refrigerant mix to said second air-to-refrigerant heat exchanger, and said pump pumps coolant through said refrigerant-to-coolant heat exchanger and said fourth air-to-coolant heat exchanger within said coolant loop, in a heating mode of operation.

15. The vapor injection heat pump of claim 12 , wherein said first valve directs the refrigerant output by said compressor to said first refrigerant-to-coolant heat exchanger, said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, and said pump pumps coolant through said first refrigerant-to-coolant heat exchanger and said fourth air-to-coolant heat exchanger within said coolant loop, in a reheating mode of operation.

16. The vapor injection heat pump of claim 12 , wherein said first valve directs the refrigerant output by said compressor to said first refrigerant-to-coolant heat exchanger and said second air-to-refrigerant heat exchanger, said second valve directs the liquid component of the liquid and vapor refrigerant mix to said third air-to-refrigerant heat exchanger, and said pump pumps coolant through said first refrigerant-to-coolant heat exchanger and said fourth air-to-coolant heat exchanger within said coolant loop, in a reheating mode of operation.

17. The vapor injection heat pump of claim 12 , wherein said first valve directs the refrigerant output by said compressor to said second air-to-refrigerant heat exchanger, said control module operates said first expansion device in an open mode providing minimal refrigerant flow restriction, and said compressor receives refrigerant vapor from said first input port via said vapor generator, in a deicing mode of operation.

18. The vapor injection heat pump of claim 12 , wherein said first valve and said second valve direct the refrigerant output by said compressor through said second air-to-refrigerant heat exchanger and a second expansion device, said second valve directs refrigerant output by said second expansion device through a fourth valve to said second input port of said compressor, and said control module further controls said second expansion device, in a deicing mode of operation.

19. The vapor injection heat pump of claim 1 , wherein said vapor generator is a separator.

20. The vapor injection heat pump of claim 1 , wherein said vapor generator is a refrigerant-to-refrigerant heat exchanger, said refrigerant-to-refrigerant heat exchanger receiving (1) a first portion of the refrigerant output by the at least one of said first heat exchanger and said second air-to-refrigerant heat exchanger and expanded within said first expansion device to the liquid and vapor refrigerant mix and directs the vapor component of the liquid and vapor refrigerant mix to said first input port of said compressor and (2) a second portion of the refrigerant output by the at least one of said first heat exchanger and said second air-to-refrigerant heat exchanger dependent upon the mode of operation.

21. A vapor injection heat pump, comprising:

a compressor for compressing a refrigerant;

a first valve directing the refrigerant output by said compressor, said first valve directing the refrigerant to a first heat exchanger in a heating mode of operation and to a second air-to-refrigerant heat exchanger in a cooling mode of operation;

a first expansion device receiving the refrigerant directed through said first heat exchanger in the heating mode of operation and the refrigerant directed through said second air-to-refrigerant heat exchanger in the cooling mode of operation;

a vapor generator receiving a liquid and vapor refrigerant mix from said first expansion device and directing a vapor component of the liquid and vapor refrigerant mix to a first input port of said compressor and a liquid component of the liquid and vapor refrigerant mix to a second valve, said second valve directing the liquid component to said second air-to-refrigerant heat exchanger in the heating mode of operation and to a third air-to-refrigerant heat exchanger in the cooling mode of operation, wherein a second input of said compressor receives an output refrigerant of the second air-to-refrigerant heat exchanger in the heating mode of operation and the third air-to-refrigerant heat exchanger in the cooling mode of operation; and

a control module for controlling at least said first and second valves and said first expansion device dependent upon the mode of operation.

22. A vapor injection heat pump, comprising:

a compressor for compressing a refrigerant;

a first valve directing the refrigerant output by said compressor to an air-to-refrigerant heat exchanger;

an expansion device receiving the refrigerant directed to said air-to-refrigerant heat exchanger;

a vapor generator receiving refrigerant from said first expansion device and directing a vapor component of the refrigerant to a first input port of said compressor in a deicing mode of operation; and

a control module for controlling said first valve and said expansion device.

23. The vapor injection heat pump of claim 22 , wherein said control module operates said first expansion device in an open mode providing minimal refrigerant flow restriction.

24. The vapor injection heat pump of claim 22 , further comprising second and fourth valves directing the refrigerant output by said compressor through said air-to-refrigerant heat exchanger and expansion device, said second valve directs refrigerant output by said expansion device through said fourth valve to said second input port of said compressor, in a deicing mode of operation.