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A heat pump hot-water supply apparatus controls a second expansion device during a heating operation so as to adjust the amount of refrigerant flowing through an injection pipe, and controls a third expansion device during a cooling operation so as to adjust the amount of refrigerant flowing through

A heat pump hot-water supply apparatus controls a second expansion device during a heating operation so as to adjust the amount of refrigerant flowing through an injection pipe, and controls a third expansion device during a cooling operation so as to adjust the amount of refrigerant flowing through the injection pipe.

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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 de

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; anda branch pipe that connects the first refrigerant branch portion and the second refrigerant branch portion and is connected to the injection pipe, whereinthe 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, andthe 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. 2. The air-conditioning apparatus of claim 1, further comprising: a backflow preventing device provided between the second refrigerant branch portion and a connecting portion between the branch pipe and the injection pipe. 3. 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 fourth 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; anda branch pipe that connects the first refrigerant branch portion and the second refrigerant branch portion and is connected to the injection pipe, whereinthe 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 between the second refrigerant branch portion and the opening of the compressor,the third expansion device is provided between the first refrigerant branch portion and the opening of the compressor,the fourth expansion device is provided at a position in a flow channel through which the refrigerant does not flow during the cooling operation and through which the refrigerant flows from the second refrigerant branch portion to the first heat exchanger during the heating operation,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, andthe 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. 4. The air-conditioning apparatus of claim 1, wherein, as the refrigerant circulating in the refrigerant circuit, R32, a mixed refrigerant of R32 and HFO1234yf, with a mass ratio of R32 being 62% or higher, or a mixed refrigerant of R32 and HFO1234ze, with a mass ratio of R32 being 43% or higher, is used. 5. The air-conditioning apparatus of claim 1, wherein the first refrigerant branch portion and the second refrigerant branch portion are configured such that a refrigerant flows from the bottom to the top side in the vertical direction. 6. The air-conditioning apparatus of claim 1, wherein the agitator is a porous metal having a porosity ratio (void ratio) of 80% or higher. 7. The air-conditioning apparatus of claim 1, wherein: the compressor, the refrigerant flow switching device, and the first heat exchanger are stored in an outdoor unit; the first expansion device and the second heat exchanger are stored in a heat medium relay unit;the outdoor unit and the heat medium relay unit are connected to each other with two refrigerant pipes; anda cooling only operation mode is provided in which a high-pressure liquid refrigerant flows through one of the two refrigerant pipes and a low-pressure gas refrigerant flows through the other one of the two refrigerant pipes, and the high-pressure liquid refrigerant is branched at the first refrigerant branch portion and is caused to flow through the injection pipe; anda heating only operation mode is provided in which a high-pressure gas refrigerant flows through one of the two refrigerant pipes and an intermediate-pressure two-phase refrigerant flows through the other one of the two refrigerant pipes, and the intermediate-pressure two-phase refrigerant is branched at the second refrigerant branch portion and is caused to flow through the injection pipe. 8. The air-conditioning apparatus of claim 3, wherein: the first expansion device and the second heat exchanger are stored in an indoor unit which is installed at a position at which the indoor unit is capable of air-conditioning an air-conditioning target space;the compressor, the refrigerant flow switching device, the first heat exchanger, the second expansion device, the third expansion device, and the backflow preventing device are stored in an outdoor unit which is installed outdoor or in a machine room;the outdoor unit and the indoor unit are separately formed, and a relaying unit which connects the outdoor unit and the indoor unit is provided;the outdoor unit and the relaying unit are connected to each other with a pair of two refrigerant pipes, and the indoor unit and the relaying unit are connected to each other with a pair of two refrigerant pipes;a cooling only operation mode is provided in which a high-pressure liquid refrigerant flows through one of the two refrigerant pipes and a low-pressure gas refrigerant flows through the other one of the two refrigerant pipes, and the high-pressure liquid refrigerant is branched at the first refrigerant branch portion and is caused to flow through the injection pipe; anda heating only operation mode is provided in which a high-pressure gas refrigerant flows through one of the two refrigerant pipes and an intermediate-pressure two-phase refrigerant flows through the other one of the two refrigerant pipes, and the intermediate-pressure two-phase refrigerant is branched at the second refrigerant branch portion and is caused to flow through the injection pipe. 9. The air-conditioning apparatus of claim 7, wherein: a cooling main operation mode is provided in which a high-pressure two-phase refrigerant flows through one of the two refrigerant pipes and a low-pressure gas refrigerant flows through the other one of the two refrigerant pipes, and the high-pressure two-phase refrigerant is branched at the first refrigerant branch portion and is caused to flow through the injection pipe; anda heating main operation mode is provided in which a high-pressure gas refrigerant flows through one of the two refrigerant pipes and an intermediate-pressure two-phase refrigerant flows through the other one of the two refrigerant pipes, and the intermediate-pressure two-phase refrigerant is branched at the second refrigerant branch portion and is caused to flow through the injection pipe. 10. The air-conditioning apparatus of claim 1, wherein, during the heating operation, the controller controls the second expansion device so that a state quantity corresponding to a refrigerant discharged from the compressor will approximate a target value, will not exceed the target value, or will be within a target range, and, during the cooling operation, the controller controls the third expansion device so that a state quantity corresponding to a refrigerant discharged from the compressor will approximate a target value, will not exceed the target value, or will be within a target range, thereby regulating a flow rate of the refrigerant to be injected to the compression chamber of the compressor. 11. The air-conditioning apparatus of claim 1, further comprising a discharge temperature detecting device that is capable of detecting a discharge temperature of the compressor, wherein, during the heating operation, the controller controls the second expansion device so that the discharge temperature will approximate a target value, will not exceed a target temperature, or will be within a target range, and, during the cooling operation, the controller controls the third expansion device so that the discharge temperature will approximate a target value, will not exceed a target temperature, or will be within a target range, thereby regulating a flow rate of the refrigerant to be injected to the compression chamber of the compressor. 12. The air-conditioning apparatus of claim 10, further comprising a discharge temperature detecting device that is capable of detecting a discharge temperature of the compressor, and a high-pressure detecting device that is capable of detecting a high pressure of the compressor, wherein, during the heating operation, the controller controls the second expansion device so that discharge superheat calculated from the discharge temperature and the high pressure will approximate a target value, will not exceed a target degree of superheat, or will be within a target range, and, during the cooling operation, the controller controls the third expansion device so that discharge superheat calculated from the discharge temperature and the high pressure will approximate a target value, will not exceed a target degree of superheat, or will be within a target range. 13. The air-conditioning apparatus of claim 7, further comprising an indoor unit which is installed at a position at which the indoor unit is capable of air-conditioning an air-conditioning target space and which stores therein a use side heat exchanger that exchanges heat with air in the air-conditioning target space, wherein: the indoor unit and the heat medium relay unit are connected to each other with a pair of two heat medium pipes through which a heat medium, which is different from a refrigerant, circulates; andheat exchange is performed between the refrigerant and the heat medium in the second heat exchanger. 14. The air-conditioning apparatus of claim 3, wherein, as the refrigerant circulating in the refrigerant circuit, R32, a mixed refrigerant of R32 and HFO1234yf, with a mass ratio of R32 being 62% or higher, or a mixed refrigerant of R32 and HFO1234ze, with a mass ratio of R32 being 43% or higher, is used. 15. The air-conditioning apparatus of claim 3, wherein the first refrigerant branch portion and the second refrigerant branch portion are configured such that a refrigerant flows from the bottom to the top side in the vertical direction. 16. The air-conditioning apparatus of claim 3, wherein: the compressor, the refrigerant flow switching device, and the first heat exchanger are stored in an outdoor unit;the first expansion device and the second heat exchanger are stored in a heat medium relay unit;the outdoor unit and the heat medium relay unit are connected to each other with two refrigerant pipes; anda cooling only operation mode is provided in which a high-pressure liquid refrigerant flows through one of the two refrigerant pipes and a low-pressure gas refrigerant flows through the other one of the two refrigerant pipes, and the high-pressure liquid refrigerant is branched at the first refrigerant branch portion and is caused to flow through the injection pipe; anda heating only operation mode is provided in which a high-pressure gas refrigerant flows through one of the two refrigerant pipes and an intermediate-pressure two-phase refrigerant flows through the other one of the two refrigerant pipes, and the intermediate-pressure two-phase refrigerant is branched at the second refrigerant branch portion and is caused to flow through the injection pipe. 17. The air-conditioning apparatus of claim 16, wherein: a cooling main operation mode is provided in which a high-pressure two-phase refrigerant flows through one of the two refrigerant pipes and a low-pressure gas refrigerant flows through the other one of the two refrigerant pipes, and the high-pressure two-phase refrigerant is branched at the first refrigerant branch portion and is caused to flow through the injection pipe; anda heating main operation mode is provided in which a high-pressure gas refrigerant flows through one of the two refrigerant pipes and an intermediate-pressure two-phase refrigerant flows through the other one of the two refrigerant pipes, and the intermediate-pressure two-phase refrigerant is branched at the second refrigerant branch portion and is caused to flow through the injection pipe. 18. The air-conditioning apparatus of claim 1, wherein the agitator and the expanding portion are both located within the at least one of the second expansion device and the third expansion device. 19. The air-conditioning apparatus of claim 3, wherein the agitator and the expanding portion are both located within the at least one of the second expansion device and the third expansion device.