A thermal management system includes a refrigerant system, which includes a compressor, a flow control device, a valve member, a first heat exchanger, a second heat exchanger, and a third heat exchanger. The flow control device includes a first throttle unit, a second throttle unit, and a valve assembly; the flow control device includes a first port, a second port, and a third port; a first connection port of the first heat exchanger is in communication with the second port, and a first connection port of the second heat exchanger is in communication with the third port, while a first connection port of the third heat exchanger is in communication with the first port. The thermal management system includes a first operating state and a second operating state.

An air-conditioning apparatus according to the present disclosure includes a heat medium circulation circuit, a heat-source-side device, and a voltage drop device. In the heat medium circulation circuit, a pump, an indoor heat exchanger, and a flow control device are connected by pipes to circulate the heat medium. The pump sends a heat medium that contains water or brine and transfers heat. The indoor heat exchanger causes heat exchange to be performed between the heat medium and an indoor air in an air-conditioned space. The flow control device controls a flow rate of the heat medium in the indoor heat exchanger. The heat-source-side device heats or cools the heat medium before the heat medium is sent to the indoor heat exchanger.

The voltage drop device reduces a voltage that is applied to the pump based on a value of a current that is supplied to the pump, in association with a flow rate of the heat medium in the heat medium circulation circuit.

An air-conditioning apparatus includes an outdoor unit and a relay unit. The outdoor unit includes a compressor compressing and discharging refrigerant and a heat-source-side heat exchanger performing heat exchange between the refrigerant and outside air. The relay unit and the outdoor unit form a refrigerant circuit. The outdoor unit includes first and flow switching devices each switching an associated flow passage for the refrigerant between a plurality of flow passages, according to an operation mode. An outflow pipe and an inflow pipe through which refrigerant flows from the outdoor unit to the relay unit and from the relay unit into the outdoor unit, respectively, are between the outdoor unit and the relay unit. The first flow switching device is connected to the compressor, the second flow switching device, and the outflow pipe. The second flow switching device is connected to the first flow switching device and the inflow pipe.

An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a refrigerant flow switching device, a heat source side heat exchanger, an expansion device, a heat medium heat exchanger, and an accumulator are connected, a heat medium circuit in which a pump, the heat medium heat exchanger, a heat medium flow control device, and a load side heat exchanger are connected, at least one or more bypass pipes provided in the refrigerant circuit so that the refrigerant discharged from the compressor bypasses at least either one of the heat source side heat exchanger and the heat medium heat exchanger, a bypass opening and closing device provided at the bypass pipe, and a controller configured to control the bypass opening and closing device to carry out a start-up control function of causing low-pressure gas refrigerant with a high degree of superheat to flow into the accumulator.

According to one embodiment, an air conditioner carries out a heating operation, a cooling operation, a cooling/heating mixed operation in which a higher priority is given to cooling, and a cooling/heating mixed operation in which a higher priority is given to heating.

A defrosting control method of a multi-functional multi-split system with double four-way valves. The multi-functional multi-split system includes an outdoor unit, at least one set of hydraulic modules, and at least one set of indoor modules. When the multi-split system is switched from a normal operation mode to a defrosting mode, a first four-way valve and a second four-way valve are powered down, and operation modes of each set of indoor modules and each set of hydraulic modules, the on/off state of fans of an indoor heat exchanger and a hydraulic heat exchanger, opening degrees of a first electromagnetic valve of the indoor heat exchanger and a second electromagnetic valve of the hydraulic heat exchanger, and the on/off state of the first electromagnetic valve and the second electromagnetic valve are correspondingly adjusted based on the previous operation modes of each set of indoor modules and each set of hydraulic modules.

An oil return control method of a multi-functional multi-split system with double four-way valves. The multi-functional multi-split system includes an outdoor unit, at least one set of hydraulic modules and at least one set of indoor modules. When the multi-split system is switched from a normal operation mode to an oil return mode, a first four-way valve and a second four-way valve are powered down, and operation modes of each set of indoor modules and each set of hydraulic modules, the on/off state of fans of an indoor heat exchanger and a hydraulic heat exchanger, opening degrees of a first electronic expansion valve of the indoor heat exchanger and a first electronic expansion valve of the hydraulic heat exchanger, and the on/off state of a first electromagnetic valve and a second electromagnetic valve are correspondingly adjusted based on the previous operation modes.

The disclosure an air conditioning system and a method of controlling the same. During the heating operation of the A2W indoor unit, the A2A valve that connects the outdoor unit to the A2A indoor unit is closed to prevent the inflow of the refrigerant into the A2A indoor unit, so it is possible to prevent performance degradation by improving performance loss due to refrigerant bypass to a stationary A2A indoor unit. In addition, in order to improve the performance due to deterioration of heating performance, the system itself can cope with a control algorithm without any additional hardware configuration, thereby minimizing the installation cost.

A three-pipe, multi-split system and a control method thereof. The three-pipe multi-split system includes an outdoor unit, a multi-split indoor unit, and a hydraulic module. By optimizing a refrigerant system, the phenomenon that a refrigerant is throttled before flowing through a refrigerant heat dissipation module or supercooled when passing through a plate heat exchanger which causes a relatively low temperature of the refrigerant entering the refrigerant heat dissipation module and consequent condensation on the refrigerant heat dissipation module to produce condensate water and then causes a damage to a compressor frequency conversion module can be avoided. In addition, more refrigerant is caused to flow through the refrigerant heat dissipation module to reduce the temperature of the module.

A refrigeration cycle apparatus includes: an outdoor unit; a branch unit connected to the outdoor unit via a first pipe and a second pipe; a first indoor unit connected to the branch unit via a third pipe and a fourth pipe; and a second indoor unit connected to the branch unit via a fifth pipe and a sixth pipe. A refrigerant circuit includes a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, and a six-way valve. The six-way valve switches between a first state in which the first heat exchanger acts as a condenser and at least the second heat exchanger acts as an evaporator and a second state in which the first heat exchanger acts as an evaporator and at least the second heat exchanger acts as a condenser.