A heat pump system, a defrosting method for the heat pump system, and a controller. The heat pump system includes a heat exchanger assembly for exchanging heat with a fluid medium, the heat exchanger assembly comprised a first heat exchanger and a second heat exchanger arranged in parallel, the second heat exchanger being arranged upstream of the first heat exchanger in the flow direction of the fluid medium, and when the heat pump system is operating in a heating mode and the temperature and/or ambient humidity to which the heat exchanger assembly is currently exposed reach a pre-set value, the second heat exchanger and the first heat exchanger function as a condenser and an evaporator, respectively.

A multi-connected heat recovery air conditioning system and a control method thereof. The multi-connected heat recovery air conditioning system includes an indoor unit, an outdoor unit and a hydraulic module, wherein the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve. The multi-connected heat recovery air conditioning system further comprises an indoor unit temperature unit, a water temperature unit, a high-pressure sensor and a low-pressure sensor. The indoor unit temperature unit is arranged in the indoor unit for detecting and obtaining the outlet temperature value of the indoor unit, the water temperature unit is arranged at a heat exchange water tank for detecting and obtaining water temperature, and the high-pressure sensor and the low-pressure sensor are arranged at the output end and the air return end of the compressor respectively.

A heat pump system and a control method therefor. The heat pump system includes a compressor; an indoor heal exchanger; an outdoor heat exchanger, including a first heat exchange portion and a second heat exchange portion, wherein a flow path switching device is provided between the first heat exchange portion and the second heat exchange portion to disconnect or communicate the first heat exchange portion and the second heat exchange portion; a first four-way valve; and a second four-way valve, configured to enable a high-temperature refrigerant to be input into the first heat exchange portion in a heating mode, so as to enable the heat pump system to operate in a heating and deicing mode.

A refrigeration cycle apparatus includes a heat exchanger, and a flow switching circuit configured to switch the heat exchanger to act as any one of an evaporator and a condenser, the flow switching circuit is configured to allow refrigerant to flow into the heat exchanger in the same direction both in a case where the heat exchanger acts as an evaporator and in a case where the heat exchanger acts as a condenser, the heat exchanger includes a path switching circuit including a plurality of paths, and the path switching circuit is configured to switch an order of the plurality of paths through which refrigerant flows between an order of the plurality of paths in the case where the heat exchanger acts as an evaporator and another order of the plurality of paths in the case where the heat exchanger acts as a condenser.

An air-conditioning apparatus reduces occurrence of refrigerant accumulation on a downstream side of an evaporator to favorably circulate refrigerant. The air-conditioning apparatus includes: a main circuit in which a compressor, a refrigerant-flow switching device, a load-side heat exchanger, a load-side expansion device and three heat-source-side heat exchangers are connected by pipes to circulate refrigerant; and a heat-exchanger flow-passage switching device which performs switching to apply a first series refrigerant passage in the case where the three heat-source-side heat exchangers are used as condensers, and switching to apply a parallel refrigerant passage in the case where the three heat-source-side heat exchangers are used as evaporators. In the first series refrigerant passage, on an upstream side, the first and second heat-source-side heat exchangers are connected parallel to each other, and on a downstream side, the third heat-source-side heat exchanger is located. In the parallel refrigerant passage, first to third heat-source-side heat exchanger are connected parallel to each other.

A refrigeration cycle device includes a compressor, an air-refrigerant heat exchanger that exchanges heat between air and refrigerant, an expansion valve decompressing the refrigerant, a heat medium-refrigerant heat exchanger that exchanges heat between a heat medium and the refrigerant, a cold-heat utilization device that utilizes cold heat of the heat medium, and a hot-heat utilization device that utilizes hot heat of the heat medium. A refrigerant flow switching valve is provided to switch between a heat-medium cooling mode of cooling the heat medium in the heat medium-refrigerant heat exchanger, and a heat-medium heating mode of heating the heat medium in the heat medium-refrigerant heat exchanger. In addition, a heat medium flow switching device is provided such that, in the heat-medium cooling mode, the heat medium circulates between the heat medium-refrigerant heat exchanger and the cold-heat utilization device, and that in the heat-medium heating mode, the heat medium circulates between the heat medium-refrigerant heat exchanger and the hot-heat utilization device.

Provided is a refrigeration cycle apparatus configured to perform a heating operation and a simultaneous heating and hot-water supply operation. The refrigeration cycle apparatus is configured to execute an operation mode circulating refrigerant through, in order, a discharge outlet of a compressor, a first heat exchanger, an expansion device, a second heat exchanger provided to a water tank, and a suction inlet of the compressor, and causing the refrigerant flowing through the second heat exchanger to evaporate by heat generated by a heat source provided to the water tank.

An air-conditioning device including multiple outdoor units and an indoor unit through a pipe includes a control section that obtains a degree of supercooling at an outlet of a supercooling circuit of each outdoor unit based on a temperature detected by a temperature sensor that detects the temperature of refrigerant having passed through the supercooling circuit of each outdoor unit, obtain a target value of the degree of supercooling based on the obtained multiple degrees of supercooling, and perform the control of increasing the rotation speed of a compressor of an outdoor unit having a higher degree of supercooling than the target value and decreasing the rotation speed of a compressor of an outdoor unit having a lower degree of supercooling than the target value such that a difference in the degree of supercooling at the outlet of the supercooling circuit of each outdoor unit is decreased.

The present invention provides a heat pump system which comprises a compressor (110), a mode switch valve assembly (120), a mode switch flow path, and a first heat exchanger, a second heat exchanger and a heat recovery heat exchanger respectively connected between the mode switch valve assembly and the mode switch flow path, wherein the mode switch flow path is provided with a first flow path (160), a second flow path (170) and a third flow path (180) which converge at an intersection point, and at least the first flow path and the second flow path are respectively provided with a throttling section (161,171), and the first flow path, the second flow path and the third flow path are controllably switched on/off to realize different function modes. Therefore, a heat pump unit having a heat recovery function is provided, which has advantages of simple structure and high operational reliability, etc.

In a refrigeration cycle apparatus, at start-up of heating, a controller sets a first four-way valve to an ON state and sets a second four-way valve to an OFF state so as to form a flow path in which refrigerant flows through a compressor, a load-side heat exchanger, a first expansion valve, a heat-source-side heat exchanger, and an accumulator and returns to the compressor, and during a heating operation, the controller sets the first four-way valve to the ON state and sets the second four-way valve to the ON state so as to form a flow path in which the refrigerant flows through the compressor, the load-side heat exchanger, the first expansion valve, the receiver, and the heat-source-side heat exchanger and returns to the compressor.