An HVAC system includes an evaporator, a condenser, a compressor. A first refrigerant path flows through a first expansion valve, first evaporator inlet, within the evaporator, and out of the evaporator through a first evaporator outlet. A second refrigerant path flows through a second expansion valve, a second evaporator inlet, within the evaporator, and out of the evaporator through a second evaporator outlet. Refrigerant flows from the condenser to the first refrigerant path and the second refrigerant path, and from the first refrigerant path and the second refrigerant path to the compressor.

An HVAC system includes an evaporator, a condenser, a compressor. A first refrigerant path flows through a first expansion valve, first evaporator inlet, within the evaporator, and out of the evaporator through a first evaporator outlet. A second refrigerant path flows through a second expansion valve, a second evaporator inlet, within the evaporator, and out of the evaporator through a second evaporator outlet. Refrigerant flows from the condenser to the first refrigerant path and the second refrigerant path, and from the first refrigerant path and the second refrigerant path to the compressor.

An air conditioner may include: an outdoor unit including a compressor and an outdoor heat exchanger; a first indoor unit including a first indoor heat exchanger; and a second indoor unit including a second indoor heat exchanger and an indoor expansion valve, wherein the outdoor unit includes: a first outdoor pipe, an outdoor expansion valve provided in the first outdoor pipe, the first outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to pass through the outdoor expansion valve and flow to the first indoor unit; and a second outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to bypass the outdoor expansion valve and flow to the second indoor unit.

An air conditioner may include: an outdoor unit including a compressor and an outdoor heat exchanger; a first indoor unit including a first indoor heat exchanger; and a second indoor unit including a second indoor heat exchanger and an indoor expansion valve, wherein the outdoor unit includes: a first outdoor pipe, an outdoor expansion valve provided in the first outdoor pipe, the first outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to pass through the outdoor expansion valve and flow to the first indoor unit; and a second outdoor pipe allowing a refrigerant discharged from the outdoor heat exchanger to bypass the outdoor expansion valve and flow to the second indoor unit.

A vapor-compression system includes a centrifugal compressor configured to increase a pressure of a refrigerant based on at least one of an activation of a device or the device being equal to or above a first threshold temperature. A fluid communication system is configured to provide, to the device, a portion of the refrigerant in a liquid state. The portion of the liquid refrigerant in a liquid state is configured to have a saturation temperature equal to or below the first temperature threshold.

A vapor-compression system includes a centrifugal compressor configured to increase a pressure of a refrigerant based on at least one of an activation of a device or the device being equal to or above a first threshold temperature. A fluid communication system is configured to provide, to the device, a portion of the refrigerant in a liquid state. The portion of the liquid refrigerant in a liquid state is configured to have a saturation temperature equal to or below the first temperature threshold.

A microchannel heat exchanger is configured for use as an evaporator in a fluid cooling system and includes an inlet header, an outlet header, and a plurality of microchannel tubes extending between and in fluid communication with the inlet header and the outlet header. A microvalve actuated hybrid spool valve is attached to and in fluid communication with the inlet header.

A refrigerant/heat medium heat exchanger that heats a heat medium which circulates in a heater core of an HVAC unit is provided in a discharge pipe of a cooling refrigerant circuit, a heating bypass circuit that extends to a receiver is connected to a downstream side of the refrigerant/heat medium heat exchanger through a switching means, a second circuit having a second decompression means is provided between an outlet of the receiver and a first end of a vehicle exterior heat exchanger, and a third circuit having a solenoid valve is provided between a second end of the vehicle exterior heat exchanger and an intake circuit. In a vehicle air-conditioning system, a heating refrigerant circuit is configured by an electric compressor, a refrigerant/heat medium heat exchanger, a switching means, a heating bypass circuit, a receiver, a second circuit, a vehicle exterior heat exchanger, and a third circuit. Consequently, while simplification of a configuration and the like are attained by diverting cooling refrigerant circuit and an HVAC of a current system, cooling/heating capacity can be ensured by diversifying heating heat sources, and operation in a frost formation delay mode or the like is possible during heating.

An electronic expansion valve is provided, wherein a piston component and a valve needle component are located at the same side of a valve core seat. When refrigerant flows forwards, the piston component closes the bypass through hole, the refrigerant flows to a side of the vertical connecting pipe via the valve core valve port, and the valve needle component moves in the axial direction to regulate an opening of the valve core valve port. When the refrigerant flows reversely, the piston component moves upwards in the axial direction to open the bypass through hole, and the refrigerant flows to a side of the transverse connecting pipe via the bypass through hole. The electronic expansion valve ensures that the valve needle component seals the valve core valve port easily in a high pressure state when the refrigerant flows forwards, and reduces axial and radial dimensions of the valve seat.

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.