Air conditioner

Patent metadata

Field	Value
Publication number	US-11047590-B2
Application number	US-201716338246-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Sep 30, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

An air conditioner, in which a liquid-pressure adjustment expansion valve that decompresses a refrigerant so that the refrigerant flowing through a liquid-refrigerant connection pipe is in a gas-liquid two-phase state is provided in an outdoor liquid-refrigerant pipe that connects a liquid-side end of an outdoor heat exchanger to the liquid-refrigerant connection pipe, properly transports the refrigerant in a two-phase state while suppressing an increase in a discharge temperature of a compressor. A liquid injection pipe that branches part of a refrigerant flowing through an outdoor liquid-refrigerant pipe and feeds the branched refrigerant to a compressor is connected to a portion of the outdoor liquid-refrigerant pipe on a side of an outdoor heat exchanger with respect to a liquid-pressure adjustment expansion valve.

First claim

The invention claimed is:

1. An air conditioner including an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a liquid-refrigerant connection pipe that connects the outdoor unit to the plurality of indoor units, the air conditioner being configured to perform an operation of sending a refrigerant, which has been discharged from the compressor, to the outdoor heat exchanger, the liquid-refrigerant connection pipe, and the indoor heat exchanger in that order, wherein
a liquid-pressure adjustment expansion valve that decompresses the refrigerant so that the refrigerant flowing through the liquid-refrigerant connection pipe is in a gas-liquid two-phase state is provided in an outdoor liquid-refrigerant pipe that connects a liquid-side end of the outdoor heat exchanger to the liquid-refrigerant connection pipe,
an outdoor expansion valve is provided in the outdoor liquid-refrigerant pipe between the liquid-pressure adjustment expansion valve and the outdoor heat exchanger, and
a liquid injection pipe is provided in the outdoor liquid-refrigerant pipe between the outdoor expansion valve and the liquid-pressure adjustment expansion valve, and is connected to a portion of the outdoor liquid-refrigerant pipe on a side of the outdoor heat exchanger with respect to the liquid-pressure adjustment expansion valve, wherein the liquid injection pipe branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe and feeds the branched refrigerant to the compressor.

2. The air conditioner according to claim 1 , wherein
the liquid injection pipe is connected to a suction refrigerant pipe through which the refrigerant to be sucked into the compressor flows.

3. The air conditioner according to claim 2 , wherein
an accumulator that temporarily stores the refrigerant is provided in the suction refrigerant pipe, and
the liquid injection pipe is connected to a portion of the suction refrigerant pipe on an outlet side of the accumulator.

4. The air conditioner according to claim 3 , wherein
a liquid-injection expansion valve that decompresses the refrigerant branched from the outdoor liquid-refrigerant pipe is provided in the liquid injection pipe, and
a controller that controls a component of the outdoor unit and the indoor units controls an opening degree of the liquid-injection expansion valve so that a temperature of the refrigerant discharged from the compressor does not exceed a predetermined discharge temperature threshold.

5. The air conditioner according to claim 2 , wherein
the liquid injection pipe is bifurcated, and
the liquid injection pipe is connected to both a portion of the suction refrigerant pipe on an inlet side of an accumulator and a portion of the suction refrigerant pipe on an outlet side of the accumulator.

6. The air conditioner according to claim 5 , wherein
a liquid relief valve that feeds the refrigerant branched from the outdoor liquid-refrigerant pipe to the accumulator is provided in a portion of the liquid injection pipe that is connected to the portion of the suction refrigerant pipe on the inlet side of the accumulator, and
the controller that controls a component of the outdoor unit and the indoor units controls the liquid relief valve so that a pressure of the refrigerant discharged from the compressor does not exceed a predetermined discharge pressure threshold.

7. The air conditioner according to claim 2 , wherein
a liquid-injection expansion valve that decompresses the refrigerant branched from the outdoor liquid-refrigerant pipe is provided in the liquid injection pipe, and
a controller that controls a component of the outdoor unit and the indoor units controls an opening degree of the liquid-injection expansion valve so that a temperature of the refrigerant discharged from the compressor does not exceed a predetermined discharge temperature threshold.

8. The air conditioner according to claim 1 , wherein
the liquid injection pipe is connected to an intermediate portion of a compression stroke of the compressor.

9. The air conditioner according to claim 8 , wherein
an accumulator that temporarily stores the refrigerant is provided in the suction refrigerant pipe through which the refrigerant to be sucked into the compressor flows,
the liquid injection pipe is bifurcated, and
the liquid injection pipe is connected to both a portion of the suction refrigerant pipe on an inlet side of the accumulator and the intermediate portion of the compression stroke of the compressor.

10. The air conditioner according to claim 1 , wherein
a refrigerant return pipe that branches part of the refrigerant flowing through the outdoor liquid-refrigerant pipe and feeds the branched refrigerant to the compressor is connected to the outdoor liquid-refrigerant pipe, and a refrigerant cooler that cools the refrigerant flowing through a portion of the outdoor liquid-refrigerant pipe on the side of the outdoor heat exchanger with respect to the liquid-pressure adjustment expansion valve using the refrigerant flowing through the refrigerant return pipe is provided in the outdoor liquid-refrigerant pipe.

11. The air conditioner according to claim 10 , wherein at least one of the liquid injection pipe and the refrigerant return pipe is connected to a suction refrigerant pipe through which the refrigerant to be sucked into the compressor flows.

12. The air conditioner according to claim 11 , wherein
an accumulator that temporarily stores the refrigerant is provided in the suction refrigerant pipe, and
at least one of the liquid injection pipe and the refrigerant return pipe is connected to a portion of the suction refrigerant pipe on an outlet side of the accumulator.

13. The air conditioner according to claim 11 , wherein
at least one of the liquid injection pipe and the refrigerant return pipe is connected to a portion of the suction refrigerant pipe on an inlet side of an accumulator.

14. The air conditioner according to claim 11 , wherein
the liquid injection pipe or the refrigerant return pipe is bifurcated, and
the liquid injection pipe or the refrigerant return pipe is connected to both a portion of the suction refrigerant pipe on an inlet side of an accumulator and a portion of the suction refrigerant pipe on an outlet side of the accumulator.

15. The air conditioner according to claim 14 , wherein
a liquid relief valve that feeds the refrigerant branched from the outdoor liquid-refrigerant pipe to the accumulator is provided in a portion of the liquid injection pipe or the refrigerant return pipe that is connected to the portion of the suction refrigerant pipe on the inlet side of the accumulator, and
the controller that controls a component of the outdoor unit and the indoor units controls the liquid relief valve so that a pressure of the refrigerant discharged from the compressor does not exceed a predetermined discharge pressure threshold.

16. The air conditioner according to claim 10 , wherein
at least one of the liquid injection pipe and the refrigerant return pipe is connected to an intermediate portion of a compression stroke of the compressor.

17. The air conditioner according to claim 16 , wherein
an accumulator that temporarily stores the refrigerant is provided in a suction refrigerant pipe through which the refrigerant to be sucked into the compressor flows,
the liquid injection pipe or the refrigerant return pipe is bifurcated, and
the liquid injection pipe or the refrigerant return pipe is connected to both a portion of the s

Assignees

• Daikin Ind Ltd

Inventors

• Yamada Takuro
• Nakagawa Yuusuke
• Honda Masahiro
• Oka Yuusuke

Classifications

• F25B31/008 Primary

  by injecting a liquid · CPC title

• F25B41/20

  Disposition of valves, e.g. of on-off valves or flow control valves (expansion valves F25B41/31) · CPC title

• F25B2313/0233

  in parallel arrangements · CPC title

• F25B2400/13

  Economisers · CPC title

• F25B1/10

  with multi-stage compression (with cascade operation F25B7/00) · CPC title