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 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.

An air-conditioning and hot water supplying composite system includes a heat source unit and a heat source-side heat exchanger, an indoor heat source unit, a hot water supply unit connected to the heat source unit and including a hot water supply-side heat exchanger and a hot water supply-side expansion device, and a controller that controls the heat source unit. The controller includes a mode switching unit that switches a control mode of the air-conditioning and hot water supplying composite system between a hot water supply control mode, a hot water supply preheating mode, and a condensing temperature control unit. The condensing temperature control unit determines the target condensing temperature according to a temperature of a heat medium subjected to heat exchange by the hot water supply unit, in the hot water supply control mode.

A heat exchange unit that performs at least one of a cooling and a heating of a liquid medium that is sent to a utilization side equipment includes: a heat exchanger that exchanges heat between a flammable refrigerant and the liquid medium; an electric component as an ignition source; a casing that accommodates the heat exchanger and the electric component; and a gas detection sensor with a detection element that is disposed below the electric component and that detects a gas from the flammable refrigerant.

A load unit includes a water circuit chamber configured to accommodate at least a part of a water circuit configured to allow water to flow therethrough, a fan, an air inlet formed at a height positioned different from that of the air inlet and configured to suck indoor air therethrough, an air outlet configured to blow indoors the air sucked through the air inlet, and an air passage formed between the air inlet and the air outlet so as to be isolated from the water circuit chamber. A load-side heat exchanger is provided in the air passage.

When indoor units are performing a cooling operation, an air-conditioning apparatus controls four flow passage switching valves, for example a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve, so that a number of intermediate heat exchangers operating as evaporators is greater than in a cooling main operation. During the cooling main operation, a target value for suction pressure or evaporating temperature at a compressor is set equal to or lower than that in a case in which the indoor units are performing the cooling operation, and a frequency of the compressor and a capacity of a heat-source-side heat exchanger are controlled.

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.

A heat pump device capable of efficiently and reliably preventing a liquid refrigerant from stagnating in a compressor an air conditioner, a heat pump water heater, a refrigerator, and a freezing machine including the heat pump device. The configuration is such that, when the compressor is under operation standby, a high-frequency voltage synchronizing with a carrier signal is supplied to the compressor motor to carry out the locked energization of the compressor motor. From respective inter-phase voltages, respective phase voltages, or respective phase currents of the compressor motor for a plurality of high-frequency energization cycles, the detection values for one high-frequency energization cycle are restored. A power value calculated using the restored detection values for one high-frequency energization cycle is controlled to coincide with a heating power command necessary for discharging the liquid refrigerant stagnated in the compressor to the outside of the compressor.

When a first temperature difference is the difference between an inlet temperature of a first refrigerant and an outlet temperature of the first refrigerant in the heat exchanger for heating, and a second temperature difference is the difference between an inlet temperature of a second refrigerant and an outlet temperature of the second refrigerant in the heat exchanger for heating, the difference between the first temperature difference and the second temperature difference is held in a predetermined value or less by controlling the opening degree of a second expansion device.

An apparatus using a heat pump includes a refrigerant circuit and a heat medium circuit. The refrigerant circuit is capable of performing a first operation, in which a load-side heat exchanger is used as a condenser, and a second operation, in which the load-side heat exchanger is used as an evaporator. A main circuit of the heat medium circuit has a branching part and a joining part. An overpressure protection device and a refrigerant leakage detecting device are connected to the main circuit. The overpressure protection device is connected to a connection part located between the load-side heat exchanger and one of the branching part and the joining part, or at the load-side heat exchanger. When leakage of refrigerant is detected, the state of a refrigerant flow switching device is set to a second state, an expansion device is set to a closed state, and a compressor is operated.