Air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-9638447-B2
Application number	US-201114119951-A
Country	US
Kind code	B2
Filing date	Jun 29, 2011
Priority date	Jun 29, 2011
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

In an air-conditioning apparatus, a controller controls an amount of refrigerant injection into a compressor by controlling an opening area of an expansion device such that the electric power consumption of the compressor becomes smaller, or such that a heating capacity or a cooling capacity of an intermediate heat exchanger becomes larger.

First claim

The invention claimed is:

1. An air-conditioning apparatus including a refrigerant circuit constituted by connecting, with a pipe, a compressor, a refrigerant flow switching device, a first heat exchanger, a first expansion device, and at least one second heat exchanger, the air-conditioning apparatus comprising:
an injection pipe configured to introduce a refrigerant from outside the compressor into a compression chamber through an opening port, the opening port being provided in a portion of the compression chamber of the compressor that is in midst of performing a compression process;
a second expansion device provided in the injection pipe; and
a controller configured to control an amount of refrigerant injection into the compressor by controlling an opening degree of the second expansion device such that
electric power consumption of the compressor reduces,
a heating capacity or a cooling capacity of a load-side heat exchanger that is either the first heat exchanger or the at least one second heat exchanger increases, or
COP obtained by dividing the heating capacity or the cooling capacity by the electric power consumption increases,

wherein the injection pipe connects the opening port to one of a branch pipe and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation,
the branch pipe is connected between a pipe connecting the first heat exchanger operating as a condenser in the cooling operation and the first expansion device, and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation, and
the controller has a function of controlling the amount of refrigerant injection on a basis of a state quantity of the refrigerant after the refrigerant inside the compression chamber and the refrigerant that has been introduced into the compression chamber have been merged and a state quantity of the refrigerant that has been discharged from the compressor.

2. An air-conditioning apparatus including a refrigerant circuit constituted by connecting, with a pipe, a compressor, a refrigerant flow switching device, a first heat exchanger, a first expansion device, and at least one second heat exchanger, the air-conditioning apparatus comprising:
an injection pipe configured to introduce a refrigerant from outside the compressor into a compression chamber through an opening port, the opening port being provided in a portion of the compression chamber of the compressor that is in midst of performing a compression process;
a second expansion device provided in the injection pipe; and
a controller configured to control an amount of refrigerant injection into the compressor by controlling an opening degree of the second expansion device such that
electric power consumption of the compressor reduces
a heating capacity or a cooling capacity of a load-side heat exchanger that is either the first heat exchanger or the at least one second heat exchanger increases, or
COP obtained by dividing the heating capacity or the cooling capacity by the electric power consumption increases,

wherein a suction pressure detection device is configured to detect a pressure of the refrigerant sucked into the compressor,
the injection pipe connects the opening port to one of a branch Pine and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation,
the branch pipe is connected between a pipe connecting the first heat exchanger operating as a condenser in the cooling operation and the first expansion device, and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation,
the controller has a function of measuring or estimating a state quantity of the refrigerant to be introduced into the compression chamber from the injection pipe, and a function of controlling the amount of refrigerant injection on a basis of the state quantity of the refrigerant that is to be injected by the refrigerant injection, and
the controller further has a function of estimating an intermediate pressure inside the compression chamber under a state in which the opening port of the compressor is opened to the injection pipe by using at least a detection pressure of the suction pressure detection device, and a function of computing, by using the intermediate pressure, a target value in control of a discharge temperature of the refrigerant discharged from the compressor, the target value being for controlling the amount of refrigerant injection.

3. The air-conditioning apparatus of claim 2 , wherein the state quantity of the refrigerant to be injected is any one of a degree of superheat of the refrigerant to be injected, a quality of the refrigerant to be injected, and an enthalpy of the refrigerant to be injected.

4. The air-conditioning apparatus of claim 1 , wherein
the state quantity of the refrigerant after the merge is any one of a quality of the refrigerant immediately after the merge, a degree of superheat of the refrigerant immediately after the merge, and an enthalpy of the refrigerant immediately after the merge, and
the state quantity of the discharge refrigerant is a temperature of the discharge refrigerant or an enthalpy of the discharge refrigerant.

5. The air-conditioning apparatus of claim 1 , wherein a state of the refrigerant after the merge is a two-phase state and the quality of the refrigerant after the merge is 0.9 or more and less than 0.99.

6. The air-conditioning apparatus of claim 2 , wherein the controller computes the intermediate pressure by using a prestored volume of the compression chamber in the state in which the opening port of the compression chamber is opened to the injection pipe or by using a prestored ratio of the volume of the compression chamber to a stroke volume of the compressor.

7. An air-conditioning apparatus including a refrigerant circuit constituted by connecting, with a pipe, a compressor, a refrigerant flow switching device, a first heat exchanger, a first expansion device, and at least one second heat exchanger, the air-conditioning apparatus comprising:
an injection pipe configured to introduce a refrigerant from outside the compressor into a compression chamber through an opening port, the opening port being provided in a portion of the compression chamber of the compressor that is in midst of performing a compression process;
a second expansion device provided in the injection pipe; and
a controller configured to control an amount of refrigerant injection into the compressor by controlling an opening degree of the second expansion device such that
electric power consumption of the compressor reduces
a heating capacity or a cooling capacity of a load-side heat exchanger that is either the first heat exchanger or the at least one second heat exchanger increases, or
COP obtained by dividing the heating capacity or the cooling capacity by the electric power consumption increases,

wherein the injection pipe connects the opening port to one of a branch pipe and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation,
the branch pipe is connected between a pipe connecting the first heat exchanger operating as a condenser in the cooling operation and the first expansion device, and a pipe connecting the first expansion device and the first heat exchanger operating as an evaporator in the heating operation,
at least a heating operation can be carried out in which a refrigerant of low pressure is made to flow into the first heat exchanger to operate the first heat exchanger as an evaporator and in which a refrigerant of high pre

Assignees

• Yamashita Koji
• Wakamoto Shinichi
• Takenaka Naofumi
• Tanaka Kosuke
• Mitsubishi Electric Corp

Inventors

• Yamashita Koji
• Wakamoto Shinichi
• Takenaka Naofumi
• Tanaka Kosuke

Classifications

• F25B2313/0231

  with simultaneous cooling and heating · CPC title

• F25B2313/0314

  Temperature sensors near the indoor heat exchanger · CPC title

• F25B49/02 Primary

  for compression type machines, plants or systems · CPC title

• F25B2313/0233

  in parallel arrangements · CPC title

• F25B2700/21174

  of the refrigerant at the inlet of the evaporator · CPC title