A heat pump system is provided. The heat pump system may include a compressor that compresses a refrigerant, a condenser that condenses the refrigerant, an expansion device that decompresses the refrigerant, and an evaporator that evaporates the refrigerant. The condenser may include a first heat exchanger of a first shell and tube heat exchanger and a second shell and tube heat exchanger. The evaporator may include a second heat exchanger of the first shell and tube heat exchanger and the second shell and tube heat exchanger. The first shell and tube heat exchanger or the second shell and tube heat exchanger may include a shell, in which the refrigerant may be introduced, a plurality of tubes disposed within the shell and into which a fluid heat-exchanged with the refrigerant may flow, two inlet/outlets disposed on a first side of the shell, and one inlet/outlet disposed on a second side of the shell.

An air conditioning system may include an outdoor unit including a compressor; at least one distributor connected to the outdoor unit and including a condenser and an evaporator that exchange heat between refrigerant and water; a plurality of heating pipes in communication with the condenser; a plurality of cooling pipes in communication with the evaporator; a plurality of fan coil units connected to the plurality of heating pipes or the plurality of cooling pipes; and a controller configured to perform a heating pipe search operation for matching a portion of the plurality of fan coil units with the plurality of heating pipes, and a cooling pipe search operation for matching another portion of the plurality of fan coil units with the plurality of cooling pipes, in parallel.

An air-conditioning apparatus includes a high-pressure side pressure detection device detecting high-pressure side pressure, a low-pressure side pressure detection device detecting low-pressure side pressure, a high-low pressure bypass pipe connecting a pipe on a discharge side of a compressor and a pipe on a suction side of the compressor, a bypass expansion device disposed in the high-low pressure bypass pipe, a high-pressure side temperature detection device detecting high-pressure side temperature, and a low-pressure side temperature detection device detecting low-pressure side temperature; an outdoor unit side controller that detects circulation composition of refrigerant on the basis of the high-pressure side pressure, the low-pressure side pressure, the high-pressure side temperature, and the low-pressure side temperature; and a relay unit side controller performing at least one of a calculation of evaporating temperature and degree of superheat, and a calculation of condensing temperature and degree of subcooling on the basis of the circulation composition.

An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, an expansion device, and a refrigerant flow path in at least one intermediate heat exchanger are connected by a refrigerant pipe, and a heat medium circuit in which a pump, a use-side heat exchanger, and a heat-medium flow path in the at least one intermediate heat exchanger are connected by a heat-medium conveying pipe, the heat medium circuit being configured to cause a heat medium to circulate therethrough. The at least one intermediate heat exchanger comprises a plurality of intermediate heat exchangers. The plurality of intermediate heat exchangers are operative in a heating only operation mode, a cooling only operation mode, and a cooling and heating mixed operation mode in which some of the intermediate heat exchangers serve as the condenser and others of the intermediate heat exchangers serve as the evaporator.

A refrigeration system includes a gas cooler or a condenser configured to reject first heat from a first fluid that is at a first pressure and that is in a supercritical state or subcritical state. The refrigeration system further includes an evaporator configured to absorb second heat into a second fluid that is at a second pressure that is lower than the first pressure and that is in a liquid state, a vapor state, or a two-phase mixture of liquid and vapor. The refrigeration system further includes a rotary pressure exchanger configured to receive the first fluid from the gas cooler or the condenser, to receive the second fluid from the evaporator, and to exchange pressure, via a rotor of the rotary pressure exchanger, between the first fluid and the second fluid.

An air-conditioning apparatus includes a controller which calculates a composition ratio of a refrigerant mixture using a high-pressure-side pressure of a refrigerant discharged from a compressor, a low-pressure-side pressure of a refrigerant to be sucked into the compressor, a high-pressure-side temperature of a refrigerant at an inlet side of a second expansion device in a high/low pressure bypass pipe, and a low-pressure-side temperature of a refrigerant at an outlet side of the second expansion device in the high/low pressure bypass pipe and which determines whether to open or close a bypass-channel opening/closing device.

An intermediate unit includes a liquid-side pipe, a first valve, and a refrigerant pressure sensor. The liquid-side pipe is connected to a liquid connection pipe connecting a heat source unit and a utilization unit together. A controller of the intermediate unit adjusts the opening degree of the first valve based on a value measured by the refrigerant pressure sensor. The pressure of a refrigerant to be sent through the liquid connection pipe from the intermediate unit to the utilization unit is adjusted by the first valve.

A CPU 110 compares the extracted outside air temperature with a first low pressure saturation temperature. When the outside air temperature is lower than the first low pressure saturation temperature, the CPU 110 switches a first three-way valve 22 and a second three-way valve 23 so that a second outdoor heat exchanger 25 is used as a condenser and that a first outdoor heat exchanger 24 is not used. When the outside air temperature is higher than a second low pressure saturation temperature which is the first low pressure saturation temperature to which a predetermined temperature is added, the CPU 110 switches the first three-way valve 22 and the second three-way valve 23 so that the first outdoor heat exchanger 24 is used as a condenser and that the second outdoor heat exchanger 25 is not used.

A valve body in each of heat medium flow switching devices has an open portion. When the length from a connection between a first passage pipe and a third passage pipe to a connection between a second passage pipe and the third passage pipe is defined as a casing passage width, a valve body passage width of the open portion in a direction substantially perpendicular to the axis of the valve body is smaller than the casing passage width.

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.