Abstract: An air-conditioning apparatus is capable of completing heat medium freeze prevention control more quickly by performing heat medium temperature rise control for raising the temperature of a cooled heat medium and includes a controller that adjusts a current opening degree of a bypass device at a bypass pipe to an opening degree, and that makes an adjustment such that the flow passage resistance in the case of the opening degree becomes equal to the flow passage resistance in the case of an opening degree before an expansion device is adjusted to a minimum opening degree.

Abstract: A channel on an upstream side of a third expansion device and a channel on an upstream side of a second expansion device are connected during a heating operation, and medium pressure refrigerant generated by the third expansion device during the heating operation is introduced on a suction side of a compressor via the second expansion device and a suction injection pipe.

Abstract: An air-conditioning apparatus includes a refrigeration cycle circulating refrigerant and connecting a compressor, a heat-source-side heat exchanger, one or more of load-side expansion devices, and one or more of load-side heat exchangers by refrigerant pipes, a bypass having one end connected to a discharge side of the compressor of the refrigeration cycle and the other end connected to a suction side of the compressor of the refrigeration cycle to bypass a portion of the refrigerant discharged from the compressor, a first expansion device depressurizing the refrigerant flowing through the bypass, an auxiliary heat exchanger cooling the refrigerant depressurized at the first expansion device, a second expansion device controlling a flow rate of the refrigerant flowing from the auxiliary heat exchanger to the suction side of the compressor, and a controller controlling an opening degree of the second expansion device.

Abstract: An air-conditioning apparatus includes an outdoor-side flow rate control device (a fourth flow rate control device) that generates an intermediate pressure for injection into a compressor, and a bypass flow rate control device (a sixth flow rate control device) that is placed at a bypass pipe allowing bypassing of an outdoor heat exchanger in parallel to the outdoor-side flow rate control device and that controls the amount of heat exchange of the outdoor heat exchanger together with the outdoor-side flow rate control device.

Abstract: An air-conditioning apparatus includes a bypass pipe that has one end connected to the discharge side of a compressor and through which refrigerant exiting the compressor flows, an auxiliary heat exchanger that is connected to the other end of the bypass pipe and the suction part of the compressor, and cools refrigerant flowing through the bypass pipe and supplies the cooled refrigerant to the suction part of the compressor, and a flow regulating unit that is provided on the refrigerant outlet side of the auxiliary heat exchanger, and regulates the flow rate of refrigerant routed into the suction part of the compressor from the auxiliary heat exchanger.

Abstract: To obtain an air-conditioning apparatus that does not make a refrigerant circulate up to an indoor unit and further can achieve energy-saving. A refrigeration cycle is configured by connecting a compressor that pressurizes a refrigerant, a four-way valve that switches a circulation path of the refrigerant, a heat source side heat exchanger that performs heat exchange, expansion valves for pressure-adjusting the refrigerant, and a plurality of intermediate heat exchangers that performs heat exchange between the refrigerant and the heat medium to heat and cool the heat medium, with piping. A heat medium circuit is configured by connecting intermediate heat exchangers, pumps that pressurize the heat medium, and a plurality of use side heat exchangers that perform heat exchange between the heat medium and the air in the indoor space, with piping.

Abstract: A heat pump capable of operating in a high COP state even if influx temperature of a medium to be heated flowing into the radiators has increased. The heat pump includes a compressor, a first radiator, a second radiator, an expansion valve, and an evaporator sequentially connected by refrigerant piping to form a first refrigeration cycle, in which a first refrigerant circulates in the first refrigeration cycle, and in which the first radiator and the second radiator are serially connected. A first heat exchange unit that heats the first refrigerant is provided in a refrigerant piping at a refrigerant inlet side of the second radiator, and a second heat exchange unit that cools the first refrigerant is provided in a refrigerant piping at a refrigerant outlet side of the second radiator.

Abstract: A refrigeration cycle is configured by connecting a compressor, a four-way valve, a heat source side heat exchanger, expansion valves, and intermediate heat exchangers by piping. A heat medium circulation circuit is configured by connecting intermediate heat exchangers, pumps, and use side heat exchangers by piping. The outdoor unit accommodates the compressor, the four-way valve, and the heat source side heat exchanger, and the relay unit that is installed in a non-subject space which is different from an indoor space and is on an installation floor separated by two or more floors and accommodates the expansion valves, the pump, and intermediate heat exchangers are connected by two pipelines. The relay unit and an indoor unit that accommodates use side heat exchangers and is installed at a position where an indoor space can be air-conditioned are connected by two pipelines.

Abstract: An outdoor unit, connected with indoor units by pipes to constitute a refrigerant circuit, includes a compressor configured to compress and discharge refrigerant, a plurality of parallel heat exchangers configured to allow heat exchange between air and the refrigerant, a first defrosting pipe serving as a flow path for branching a part of the refrigerant discharged by the compressor and allowing the refrigerant to flow into the parallel heat exchanger to be defrosted for defrosting, a first expansion device configured to decompress the refrigerant passing through the first defrosting pipe, a second expansion device configured to adjust the pressure of the refrigerant that passed through the parallel heat exchanger to be defrosted, and a controller configured to control the second expansion device such that the pressure of the refrigerant that passed through the parallel heat exchanger to be defrosted falls within a predetermined range.

Abstract: An air-conditioning apparatus includes: an outdoor unit including a compressor, a first refrigerant flow path switching device, and a heat-source-side heat exchanger; a heat medium relay unit including an intermediate heat exchanger, an expansion device, a second refrigerant flow path switching device, and a pump; and at least one indoor unit including a use-side heat exchanger. A refrigerant pipe connects the compressor, the first refrigerant flow path switching device, the expansion device, the second refrigerant flow path switching device, and the intermediate heat exchanger, thereby making up a refrigeration cycle. A heat medium pipe connects the intermediate heat exchanger and the use-side heat exchanger, thereby making up a heat medium circulation circuit in which a heat medium different from the refrigerant circulates. The first refrigerant flow path switching device is switched to execute a defrost operation mode.

Abstract: An air-conditioning apparatus is capable of performing a heating-defrosting operation where a specific one of a plurality of parallel heat exchangers is a heat exchanger to be defrosted and serves as a condenser while at least one parallel heat exchanger other than the heat exchanger to be defrosted serves as an evaporator. The air-conditioning apparatus includes a liquid refrigerant transporting unit for transferring liquid refrigerant from an accumulator to the heat exchanger to be defrosted. To perform the heating-defrosting operation, the air-conditioning apparatus supplies, to the heat exchanger to be defrosted, the liquid refrigerant transferred by the liquid refrigerant transporting unit.

Abstract: In a refrigeration cycle device, a design volume ratio, obtained by dividing a stroke volume of a sub-compressor by a stroke volume of an expander, is set to be smaller than (DE/DC)×(hE?hF)/(hB?hA). With an operating efficiency being the maximum in an operating range allowed to be set of the refrigeration cycle device, DE is a density of a refrigerant, which has flowed out from a radiator, DC is a density of the refrigerant, which has flowed out from an evaporator, hE is a specific enthalpy of the refrigerant flowing into the expander, hF is a specific enthalpy of the refrigerant, which has flowed out from the expander, hA is a specific enthalpy of the refrigerant sucked by a main compressor, and hB is a specific enthalpy of the refrigerant at an intermediate position of a compression process of the main compressor.

Abstract: An air-conditioning apparatus in which entry of a refrigerant into a living space is suppressed and measures against refrigerant leakage are taken is provided.

Abstract: A refrigeration cycle apparatus includes a refrigeration cycle formed by a first compressor, a radiator, an expander that expands a refrigerant that has passed through the radiator, and an evaporator. A bypass piping has one end connected to a discharge piping of the expander and the other end connected to a suction piping of the first compressor. A pressure sensor and a temperature sensor detect the suction pressure and suction temperature of the expander as physical quantities of the refrigerant to be sucked into the expander. A bypass valve controls the flow rate of the refrigerant. A control device determines the appropriate discharge pressure of the expander on the basis of the suction pressure and suction temperature of the expander, and opens the bypass valve when the pressure at which the expander discharges the refrigerant is higher than the determined appropriate discharge pressure.

Abstract: A refrigeration cycle apparatus increases the cooling capacity even under overload conditions in a refrigeration cycle apparatus that uses a refrigerant which undergoes transition to a supercritical state and in which the high-pressure side enters a supercritical state. A refrigeration cycle apparatus adjusts a high-pressure-side pressure of a refrigerant flowing through a main refrigerant circuit by causing a controller to control an opening degree of a second expansion valve and a heat transfer area of a radiator.

Abstract: An air-conditioning apparatus includes: a compressor allowing refrigerant injection thereto and compress and discharge the refrigerant at a high temperature; an indoor heat exchanger exchanging heat between air and refrigerant; a first flow rate control device adjusting and controlling a flow rate of refrigerant; and a plurality of outdoor heat exchangers being in parallel to exchange heat between outside air and refrigerant, a first defrosting pipe allowing a branched part of the refrigerant discharged from the compressor to pass and flow into the outdoor heat exchanger to be defrosted; a reducing device adjusting a pressure of refrigerant passing through the first defrosting pipe to a medium pressure; a second defrosting pipe from which the refrigerant having passed through the outdoor heat exchanger to be defrosted is injected into the compressor; and a reducing device adjusting a pressure of refrigerant passing through the second defrosting pipe to an injection pressure.

Abstract: An air-conditioning apparatus including a refrigerant circuit having an excess refrigerant recovery pipe connected between an inlet of at least one of heat source side heat exchangers and a first refrigerant flow blocking device or between an outlet of the at least one of the heat source side heat exchangers and a second refrigerant flow blocking device, to a passage connected to a suction side of a compressor, and an excess refrigerant recovery device disposed in the excess refrigerant recovery pipe.

Abstract: An air-conditioning apparatus including a bypass pipe that branches off from a portion of a refrigerant pipe located at the refrigerant inlet side of a plurality of heat medium heat exchangers. The bypass pipe connects the refrigerant inlet side with a refrigerant outlet side of each of the plurality of heat medium heat exchangers in the cooling only operation mode. A flow switching device, disposed in the refrigerant pipe, on the outlet side of each of the plurality of heat medium heat exchangers and another flow switching device, disposed in the bypass pipe, on the refrigerant outlet side of each of the plurality of heat medium heat exchangers, cause refrigerant to flow in the bypass pipe in the cooling only operation mode.

Abstract: A refrigeration cycle apparatus includes a refrigerant circuit of a refrigeration cycle through which a refrigerant that transits in a supercritical state is allowed to flow, and a flow dividing device that divides the flow of a high-pressure liquid refrigerant in a subcritical state into two or more parts. The flow dividing device is configured such that the device is oriented substantially in the horizontal direction or upward in the vertical direction relative to the direction of flow of the refrigerant in a liquid state. With such a configuration, the flow of refrigerating machine oil is equally divided, thus offering high energy saving while keeping heat-medium conveyance power at a low level without reducing the heat exchanging performance.

Abstract: A refrigeration cycle is configured by connecting a compressor that compresses the refrigerant, a four-way valve that switches the circulation path of the refrigerant, a heat source side heat exchanger that exchanges heat, expansion valves that adjust the pressure of the refrigerant, and two or more intermediate heat exchangers that exchange heat between the refrigerant and the heat medium to heat and cool the heat medium, by piping. A heat medium circulation circuit is configured by connecting two or more intermediate heat exchangers, pumps that pressurize the heat medium, two or more use side heat exchangers that exchange heat between the heat medium and the air in the indoor space, and flow path switching valves that switch paths of the heated heat medium or the cooled heat medium to the use side heat exchangers, by piping.