A first valve is connected between a compressor and a first heat exchanger. A second valve is connected between the first heat exchanger and a expansion valve. When a start condition of the heating operation is satisfied and when a specific condition is satisfied, a controller starts supplying refrigerant from the compressor to the first valve, and then, opens the first and second valves. The specific condition is a condition indicating that a first heat exchange capability of the first heat exchanger is higher than a second heat exchange capability of a second heat exchanger. When the start condition of the heating operation is satisfied and when the specific condition is not satisfied, the controller opens the first and second valves, and then starts supplying the refrigerant from the compressor to the first valve.

In an air-conditioning system, a gaseous refrigerant remaining in a reservoir can be discharged from the reservoir even when a cooling operation has started and the reservoir is being filled with a liquid refrigerant. Therefore, the reservoir can be filled with the liquid refrigerant at a faster speed.

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.

An intelligent heat pump system having a dual heat exchanger structure includes a heat source side heat exchange member, a heat pump, an external expansion valve, a refrigerant-water heat exchanger, a heat storage tank, and a target side end unit. A refrigerant flows through the heat pump, the refrigerant-water heat exchanger, and the target side end unit, and in a non-air-conditioning state for the target site, circulates between the heat pump and the refrigerant-water heat exchanger, so that cooled or heated water is stored in the heat storage tank. In an air-conditioning state for the target site, the heat pump and the heat storage tank supply cooling and heating to the target site, so that the power consumption for normal operation is reduced in order to improve the operation efficiency of the intelligent heat pump system.

An air-conditioning apparatus includes a refrigeration circuit, a first shut-off device provided at a pipe connecting a heat-source-side heat exchanger and an expansion device, a refrigerant leak detection device, and a controller. The controller controls a flow switching device to switch a connection state between a first connection state in which a discharge side of a compressor is connected to the heat-source-side heat exchanger, and a second connection state in which a suction side of the compressor is connected to the heat-source-side heat exchanger via an accumulator. When a refrigerant leak is detected, the controller performs a refrigerant retrieval operation and a refrigerant transfer operation.

An air-conditioning system that performs a refrigeration cycle in a refrigerant circuit, includes: an outdoor unit; a plurality of indoor units; and a connection pipe disposed between the outdoor unit and the indoor units and that forms at least a refrigerant passage through which refrigerant in a gas-liquid two-phase state flows. The connection pipe includes: a branch portion that includes an indoor-side pipe group including indoor-side pipes that each communicates with any one of the indoor units, and diverges refrigerant flowing from the outdoor unit side; and a trap portion disposed in at least any one of the indoor-side pipes and is filled with refrigerant in a gas state.

An air-conditioning apparatus includes a refrigeration circuit, a first shut-off device, a leakage detection device, and a controller configured to perform a refrigerant recovery operation in a case where refrigerant leakage is detected. At the time of the refrigerant recovery operation, the controller performs control to perform a first operation of recovering refrigerant from a load-side heat exchanger into an accumulator and a heat-source-side heat exchanger, and a second operation of moving refrigerant in the heat-source-side heat exchanger to the accumulator. In the first operation, the first shut-off device is closed, a flow passage switching device is brought into a first connection state, and a compressor is driven. The second operation is performed after the first operation, and in the second operation, the connection state of the flow passage switching device is switched to a second connection state in a state where the compressor is being operated.

An air conditioner including: an outdoor unit, an air conditioning indoor unit, a showcase indoor unit, and a combination unit, wherein the combination unit includes a first gas control unit which is connected to the air conditioning indoor unit gas pipe, a second gas control unit which is connected to the showcase indoor unit gas pipe, a first pipe which connects the outdoor unit liquid pipe and the indoor unit liquid pipe, and a second pipe which connects the first pipe and the second gas control unit, and the first gas control unit and the second gas control unit are converged to be connected to the outdoor unit gas pipe, so that the air conditioning indoor unit for cooling and heating operation and the showcase indoor unit for refrigeration operation can use a single outdoor unit, and the heat emitted from the air conditioning indoor unit to the room during the heating operation of the air conditioning indoor unit is used as the condensation heat of the showcase indoor unit so as to zero the energy use for heating.

An air conditioner including: a continuous refrigeration apparatus comprising a first gas control unit connected to a first indoor heat exchanger of the plurality of indoor heat exchangers, a second gas control unit connected to a second indoor heat exchanger of the plurality of indoor heat exchangers, a first pipe connecting a liquid pipe of the outdoor unit and a liquid of the indoor unit, and a second pipe which is branched from the first pipe and connected to the first gas control unit and the second gas control unit, wherein the first gas control unit comprises: a first-first flow path connecting the first gas control unit to the second pipe; a first-second flow path which is connected to the first-first flow path, and through which the refrigerant discharged from the first indoor heat exchanger flows during a refrigeration operation of the first indoor heat exchanger; and a first-third flow path which is connected in parallel with the first-second flow path, and guides the refrigerant discharged from the compressor to the first indoor heat exchanger during a defrosting operation of the first indoor heat exchanger, and connects a gas pipe of the outdoor unit and the first indoor heat exchanger.

A defrosting control method for a multi-split system is provided. A multi-split system comprises an outdoor unit and multiple indoor units. An expansion valve is provided on a connecting pipeline between each of the indoor units and the outdoor unit. When the expansion valve of each activated indoor unit is closed and the degree of opening of the expansion valve of each off-state indoor unit is less than or equal to a maximum set degree of opening, the system satisfies a defrosting requirement, and as a result the method controls the expansion valve of each activated indoor unit to remain closed, thereby resolving the issue of a dramatic temperature drop in a room having an activated indoor unit during defrosting and improving user satisfaction. The degree of opening of the expansion valve of a off-state indoor unit is Off_PLS, and is controlled such that Off_PLS=ALL_HP*Avg_PLS/Off_HP. The invention satisfies a defrosting requirement and reduces the degree of opening of the expansion valves as much as possible, thereby preventing damage to a compressor without affecting defrosting.