There is disclosed a reversible heat pump system 100 and a method of operating a reversible heat pump system to control the temperature of a process fluid of a chiller system 500. In a cooling mode, a working fluid is circulated for co-current flow with a process fluid at a heat exchanger 104 functioning as an evaporator heat exchanger, whereas in a heating mode, the working fluid is circulated for counter-current flow with the process fluid at the same heat exchanger 104 functioning as a condenser heat exchanger.

The air-conditioning apparatus includes: a refrigerant cycle circuit through which a heat source side refrigerant circulates; a plurality of heat medium cycle circuits through which a heat medium circulates, the plurality of heat medium cycle circuits including a plurality of use-side heat exchangers, the heat medium exchanging heat with the heat source side refrigerant of the refrigerant cycle circuit in intermediate heat exchangers; and a heat medium distribution device provided in one of the plurality of heat medium cycle circuits to which a plurality of the use-side heat exchangers are connected, the heat medium distribution device controlling flow rates of the heat medium of the plurality of use-side heat exchangers connected to the heat medium cycle circuit.

Operation switching units, each changing directions of a refrigerant flowing through its associated indoor unit in response to a switch from a cooling operation to a heating operation, or vice versa, are each connected with the associated indoor unit through indoor communication pipes; a gas-liquid separation unit is connected with an outdoor unit through outdoor communication pipes; and the operation switching units are connected with the gas-liquid separation unit through two intermediate communication pipes preinstalled and one intermediate communication pipe newly installed. This provides a simple and cost-effective means for upgrading a preinstalled air conditioner making a switch from cooling to heating, and vice versa, into an air conditioner that can perform a cooling operation and a heating operation in parallel with each other.

Upon switching of an air-conditioning apparatus from an operation mode in which all of indoor units each including a use side heat exchanger are in non-operation to another operation mode in which at least one of the indoor units starts a cooling operation mode or a heating operation mode, a heat medium conveyed to the use side heat exchanger included in the indoor unit which has received a start instruction is cooled or heated to a predetermined temperature by a heat source side refrigerant, and after that, an air-sending device included in the indoor unit which starts the cooling operation mode or the heating operation mode is actuated.

A valve apparatus includes a valve main body, a shaft body, a first valve element, and a second valve element. The valve main body has a first depressed portion and a second depressed portion in a circular shape, and a first port, a second port, and a third port each communicating with the first depressed portion, and a fourth port and a fifth port each communicating with the second depressed portion. The first port is allowed to selectively communicate with one of the second port and the third port by closure of one of the second port and the third port by the first valve element rotating about an axial direction. A flow amount of a fluid flowing between the fourth port and the fifth port is allowed to be variable by closure of the fourth port by the second valve element rotating about the axial direction.

An air conditioning apparatus includes a refrigerant circuit in which a compressor for compressing heat source-side refrigerant, a first refrigerant channel switching device, a heat source side heat exchanger, an expansion device, and intermediate heat exchangers for performing heat exchange between the heat source-side refrigerant and a heat medium different from the heat source-side refrigerant are connected by pipes. Also, the air conditioning apparatus includes a heat medium circuit in which pumps for circulating the heat medium to be used for the heat exchange performed by the intermediate heat exchangers, a use-side heat exchanger, and channel switching devices for switching passages of the heat medium heated or cooled to the use-side heat exchanger are connected by pipes. The heat medium circuit includes a strainer configured to capture foreign matter contained in the heat medium; and a heat medium relay unit control device configured to perform an operation that causes the strainer to capture foreign matter contained in the heat medium circuit during construction of the heat medium circuit.

An air-conditioning apparatus includes an outdoor unit, indoor units, and a relay unit, and forms a refrigerant circuit. The air-conditioning apparatus further includes a fourth flow control device that regulates the flow rate of refrigerant flowing into the heat source unit-side heat exchanger, a switching valve that regulates the flow rate of the refrigerant passing through a bypass pipe, and a control unit that controls the first heat-source-unit flow control device and the switching valve based on a pressure on a refrigerant inlet side of the heat source unit-side heat exchanger, an inlet temperature and an outlet temperature of a medium passing through the heat source unit-side heat exchanger, and the ratio of a cooling operation capacity to a heating operation capacity of the use-side heat exchangers.

A controller, at least during the heating operation, controls the opening degree of a second expansion device and/or a third expansion device based on a discharge refrigerant temperature detected by a discharge refrigerant temperature detector, or a value computed using the discharge refrigerant temperature, and causes refrigerant having a quality equal to or greater than 0.9 and less than or equal to 0.99 to be suctioned into a compressor.

A heat source unit includes a first switching valve configured to switch between a first state where the first switching valve brings a high and low pressure gas connection pipe and a discharge side of a compressor into communication with each other and a second state where the first switching valve brings the high and low pressure gas connection pipe and a suction side of the compressor into communication with each other; and a second switching valve configured to switch between a third state where while the second switching valve brings the discharge side of the compressor and a gas end of a first heat exchange section into communication with each other, the second switching valve brings the suction side of the compressor and a gas end of the second heat exchange section into communication with each other and a fourth state where while the second switching valve brings the discharge side of the compressor and the gas end of the second heat exchange section into communication with each other, the second switching valve brings the suction side of the compressor and the gas end of the first heat exchange section into communication with each other.

An air-conditioning apparatus includes an outdoor unit including a compressor configured to compress refrigerant, a relay unit connected to the outdoor unit, and an indoor unit connected to the relay unit. The compressor is driven to circulate the refrigerant between the outdoor unit, the relay unit, and the indoor unit. The air-conditioning apparatus includes a supplementary heat source unit in parallel with the indoor unit and connected to the relay unit. The outdoor unit includes an outdoor heat exchanger configured to exchange heat between the refrigerant flowing through the outdoor heat exchanger and a fluid. The supplementary heat source unit includes a supplementary heat exchanger configured to exchange heat between the refrigerant flowing through the supplementary heat exchanger and hot water.