Patent ID: 9599378
Date: 2017-03-21
CPC Classifications: F25B

Claim:
1. An air-conditioning apparatus in which a refrigerant circuit is formed by connecting a compressor, a refrigerant flow switching device, a first heat exchanger, a first expansion device, and a second heat exchanger to one another by using a pipe, due to working of the refrigerant flow switching device, a cooling operation and a heating operation are switchable, wherein the cooling operation is an operation in which the first heat exchanger serves as a condenser due to a high-pressure refrigerant being flowed into the first heat exchanger and the second heat exchanger serves as an evaporator due to a low-pressure refrigerant being flowed into part of or whole of the second heat exchanger, and the heating operation is an operation in which the first heat exchanger serves as an evaporator due to a low-pressure refrigerant being flowed into the first heat exchanger and the second heat exchanger serves as a condenser due to a high-pressure refrigerant being flowed into part of or whole of the second heat exchanger, the air-conditioning apparatus comprising: an injection pipe that feeds the refrigerant into a compression chamber of the compressor, which is in a course of performing compression, from the outside of the compressor via an opening formed in part of the compression chamber; a second expansion device; a third expansion device; a controller that controls the second expansion device during the heating operation so as to adjust a flow rate of the refrigerant to flow through the injection pipe and that controls the third expansion device during the cooling operation so as to adjust a flow rate of the refrigerant to flow through the injection pipe; a first refrigerant branch portion that branches the refrigerant from a refrigerant flow channel through which the refrigerant flows from the first heat exchanger to the first expansion device; a second refrigerant branch portion that branches the refrigerant from a refrigerant flow channel through which the refrigerant flows from the first expansion device to the first heat exchanger; and a branch pipe that connects the first refrigerant branch portion and the second refrigerant branch portion and is connected to the injection pipe, wherein the injection pipe is a pipe which connects the branch pipe and the compression chamber of the compressor which is in a course of performing compression, the second expansion device is provided at a position where a pressure of the refrigerant flowing from the second heat exchanger to the first heat exchanger through the first expansion device is made to be a middle pressure lower than the high pressure and higher than the low pressure, the third expansion device is provided between the first refrigerant branch portion and the opening of the compressor, at least one of the second expansion device and the third expansion device is a device which is capable of sequentially changing an aperture area, and includes an agitator for agitating a two-phase refrigerant, the agitator being positioned in an inlet pipe for a refrigerant, and the at least one of the second expansion device and the third expansion device is configured such that the distance between the agitator and an expanding portion of the at least one of the second expansion device and the third expansion device is six times or less as large as the internal diameter of the inlet pipe.