Abstract: A multi-room air-conditioning apparatus includes an outdoor unit, a relay unit connected to an outdoor unit by first and second connection pipes, and a plurality of indoor units connected to the relay unit. The outdoor unit includes a second gas-liquid separating device provided on the suction side of the compressor. The suction side of the compressor and the second gas-liquid separating device are connected to each other by a gas-side outlet pipe and a liquid-side outlet pipe.

Abstract: An air-conditioning apparatus includes a refrigerant circuit including a low-pressure shell structure compressor into which a refrigerant flowing through an injection pipe flows, a first heat exchanger, a second heat exchanger, a first expansion device, a refrigerant flow switching device, and a second expansion device configured to allow the refrigerant which has passed through the first expansion device and flows from the second heat exchanger to the first heat exchanger to have an intermediate pressure, the compressor, the first heat exchanger, the second heat exchanger, the first expansion device, the refrigerant flow switching device, and the second expansion device being connected by pipes to constitute the refrigerant circuit, and further includes a controller that controls an amount of refrigerant flowing through the injection pipe into a compression chamber. A part of a high-pressure refrigerant flowing from the first heat exchanger to the second heat exchanger flows through the injection pipe.

Abstract: An air-conditioning apparatus includes a heat medium circuit with a heat medium flow reversing device that can switch the flow direction of a heat medium in the heat medium side passage of the heat exchanger related to heat medium.

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.

Abstract: An air-conditioning apparatus controls that a discharge temperature does not become too high with a refrigerant whose compressor discharge temperature readily rises, and thus suppress degradation of the refrigerant and a refrigerating machine oil. An injection pipe that injects a heat source side refrigerant into a compressor is installed, connected a pipe between a backflow prevention device and an opening and closing device installed on a branching pipe, and an aperture unit in the compressor.

Abstract: 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.

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: In an air-conditioning apparatus, an expansion device, a second refrigerant flow switching device, and heat exchangers related to heat medium, connected between the expansion device and the second refrigerant flow switching device such that a heat source side refrigerant flows in parallel, are connected in a part of refrigerant passages, and an expansion device, a second refrigerant flow switching device, and heat exchangers related to heat medium, connected between the expansion device and the second refrigerant flow switching device such that the heat source side refrigerant flows in series, are connected in the rest of the refrigerant passages.

Abstract: An air-conditioning apparatus has a controller that sets the target value of a difference between the temperatures of a secondary-side heat transfer medium at positions before and after a plurality of use side heat exchangers during a rated operation in a heating operation so as to have a larger magnitude than a target value of the difference between the temperatures of the secondary-side heat transfer medium at positions before and after the plurality of use side heat exchangers during a rated operation in the cooling operation.

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 uses R32, a refrigerant mixture containing R32 and HFO1234yf in which R32 has a mass percentage of 40% or higher, or a refrigerant mixture containing R32 and HFO1234ze in which R32 has a mass percentage of 15% or higher, as a heat-source refrigerant. The air-conditioning apparatus includes a low-pressure shell-structure compressor, a first flow switching valve, a heat-source-side heat exchanger, first flow control devices, and plural use-side heat exchangers connected by refrigerant pipes, forming a refrigeration cycle. The compressor includes a compression chamber within a sealed container including an opening extending between inside and outside of the sealed container. The air-conditioning apparatus can perform only a heating at the use-side heat exchangers, only a cooling at the use-side heat exchangers, and a mixed cooling and heating in a mixed fashion at the use-side heat exchangers.

Abstract: A first flow switching device causes part of a refrigerant discharged from an injection compressor to flow through a first bypass pipe and be supplied to an outdoor heat exchanger targeting for defrosting. A second flow switching device causes part of the refrigerant supplied to the outdoor heat exchanger targeting for defrosting to enter a second bypass pipe.

Abstract: An air-conditioning apparatus controls an opening degree of at least one of a second expansion device and a third expansion device to adjust the amount of refrigerant to flow through the injection pipe.

Abstract: An air-conditioning apparatus in which a heat source unit and a relay unit are connected by two pipings, and in which a hot water supply function can be readily added. The relay unit includes a connection circuit between a first branching unit and a second connecting piping that is capable of connecting a water heat exchanger that exchanges heat between a refrigerant and water.

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: When using at least one of heat exchangers related to heat medium that exchange heat between a heat source side refrigerant and a heat medium as an evaporator, in a case where an air-conditioning apparatus has detected, in the heat exchanger related to heat medium that functions as the evaporator, an evaporating temperature of the heat source side refrigerant which causes the temperature of the heat medium passing through this heat exchanger related to heat medium to become equal to or lower than a freezing temperature, the air-conditioning apparatus performs a heat medium anti-freezing operation by blocking entry of the heat source side refrigerant into the heat exchanger related to heat medium that functions as the evaporator, and causing the heat source side refrigerant to flow to a bypass pipe.

Abstract: An air-conditioning apparatus in which a primary-side refrigerant in a two-phase gas-liquid state that has flowed into each of intermediate heat exchangers absorbs heat from a secondary-side refrigerant flowing in counterflow to the primary-side refrigerant, and evaporates and turns into a low-temperature, low-pressure gas state. The air-conditioning apparatus ensures high heat exchange efficiency even when a direction of a heat source-side refrigerant (secondary-side refrigerant) flowing through an intermediate heat exchanger changes, and enables an appropriate operation in any operation mode.

Abstract: To provide an air-conditioning apparatus which achieves improvement of safety and further achieves saving of energy without circulating a refrigerant in or near an indoor unit. The air-conditioning apparatus includes one expansion device disposed on an outlet side of a heat exchanger related to the heat medium on the heating side. Another expansion device is disposed on an inlet side of a heat exchanger related to the heat medium on the cooling side such that the expansion devices are directly connected through a connecting pipe.

Abstract: An air-conditioning apparatus includes a refrigerant circuit formed by connecting, with pipes, a compressor, a first refrigerant flow switching device, a heat-source-side heat exchanger, an expansion device, and a plurality of intermediate heat exchangers. A heat medium circuit is formed by connecting, with pipes, a plurality of pumps configured to pressurize and circulate the heat medium subjected to heat exchange in the plurality of intermediate heat exchangers, a plurality of use-side heat exchangers each configured to exchange heat between the heat medium and air in an air-conditioned space, and a heat-medium flow switching/control device configured to switch which of the heat medium is to be allowed to flow into and out of each of the use-side heat exchangers; and a controller configured to perform processing for controlling the switching performed by the heat-medium flow switching/control device, in accordance with a capacity of each of the use-side heat exchangers.

Abstract: An air-conditioning apparatus has a controller that sets the target value of a difference between the temperatures of a secondary-side heat transfer medium at positions before and after a plurality of use side heat exchangers during a rated operation in a heating operation so as to have a larger magnitude than a target value of the difference between the temperatures of the secondary-side heat transfer medium at positions before and after the plurality of use side heat exchangers during a rated operation in the cooling operation.