A system comprising a compressor coupled to a first coil through a first valve and a second coil through a second valve, wherein the first coil and the second coil are coupled to a third coil. The system further comprises a fan operable to blow ambient air across the first coil, a first expansion valve coupled to and positioned between the first coil and the third coil and a second expansion valve coupled to and positioned between the second coil and the third coil. The system comprises a controller operable to monitor a pressure of the refrigerant, operate the first expansion valve to reduce refrigerant flow into the first, and operate the second expansion valve to reduce refrigerant flow through the second coil.

A packaged terminal air conditioner unit includes a main expansion device connected to an interior coil such that the main expansion device is operable to throttle a flow of refrigerant to both a first coil section and a second coil section of the interior coil. A secondary expansion device is connected in series between the main expansion device and the second coil section of the interior coil such that the secondary expansion device is operable to throttle a flow of refrigerant to the second coil section of the interior coil. A controller is in operative communication with the secondary expansion device such that the controller adjusts the secondary expansion device to a configuration between a fully open configuration and a fully closed configuration during operation of the compressor.

A target condensing temperature and a target evaporating temperature are changed in accordance with a load of each load side unit obtained by using load detection means, and an operating frequency of a compressor and a rotation speed of a fan are controlled such that a condensing temperature obtained by using temperature detection means coincides with the target condensing temperature and an evaporating temperature obtained by using the temperature detection means coincides with the target evaporating temperature.

An air conditioning system according to the present invention changes a target supply temperature based on a magnitude relationship between an operating frequency of a first compressor and a first frequency at which an operating efficiency of the first compressor reaches a maximum, and a magnitude relationship between an operating frequency of a second compressor and a second frequency at which an operating efficiency of the second compressor reaches a maximum.

An air conditioner is provided that may include at least one compressor that compresses a refrigerant to a high pressure; a plurality of heat exchanger that condenses the refrigerant compressed in the at least one compressor; a plurality of outdoor valves, respectively, provided at an outlet side pipe of the plurality of heat exchangers; a gas liquid separator that separates the refrigerant into gas and liquid refrigerants and supplies the gas refrigerant to the at least one compressor; and one or more bypass devices connected to the outlet side pipe of one or more of the plurality of heat exchangers and an inlet side pipe of the gas liquid separator, the one or more bypass devices controlling a flow of the liquid refrigerant. During a cooling low load operation in which a portion of the plurality of heat exchangers is operating, a liquid refrigerant loaded into a heat exchanger of the plurality of heat exchangers, which is not operated, may flow through the one or more bypass device.

A heat pump system includes a refrigerant circuit comprising a compressor, a reversing valve, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, and a three-way valve. The reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant toward the three-way valve and a second configuration to direct the refrigerant toward the first heat exchanger. The three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the second heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.

A controller switches between and performs a first simultaneous heating and defrosting operation of supplying part of refrigerant discharged from a compressor is supplied to one or some parallel heat exchangers among a plurality of parallel heat exchangers through a defrosting circuit and allowing the other one or more parallel heat exchangers to operate as evaporators, and a second simultaneous heating and defrosting operation of, in one or some heat source units among a plurality of heat source units, supplying the refrigerant discharged from the compressor is supplied to all the plurality of parallel heat exchangers through the defrosting circuit, and in the other one or more heat source units, continuing heating by allowing all the plurality of parallel heat exchangers to operate as evaporators.

A refrigeration cycle apparatus includes a refrigerant circuit in which a compressor, a first heat exchanger, an expansion mechanism, and a second heat exchanger are connected by pipes. The first heat exchanger includes a first refrigerant passage and a second refrigerant passage that share a plurality of fins with each other and provided in parallel in the refrigerant circuit. The apparatus further includes a high-and-low-pressure switching mechanism which is located on an inlet side of the second refrigerant passage of the first heat exchanger in flowing of refrigerant in an operation in which the first heat exchanger functions as a condenser, and which performs switching between flow directions of the refrigerant. The apparatus further includes a refrigerant blocking mechanism located on an outlet side of the second refrigerant passage of the first heat exchanger in the flowing of the refrigerant in the operation, and which blocks the flowing of the refrigerant.

A heat source unit includes a compressor, first and second heat exchangers connected in parallel, first and second motor-operated valves regulating amounts of refrigerant that flow to the first and second heat exchangers, first and second temperature sensors measuring temperatures of refrigerant flowing from the first and second motor-operated valve to the first and second heat exchangers, a discharge temperature sensor measuring temperature of refrigerant discharged from the compressor, and a valve opening controller. The controller regulates valve openings of the first and second motor-operated valves based on the discharge temperature, refrigerant temperature detected by the first temperature sensor and refrigerant temperature detected by the second temperature sensor.

A refrigeration cycle apparatus is provided with a branch distribution portion configured to divide refrigerant in a two-phase state of liquid refrigerant and gas refrigerant into refrigerants having different liquid ratios. The branch distribution portion includes a pipe including a bent pipe, a branch pipe, a pipe, and a pipe. The refrigerant flowing through the pipe flows through the bent pipe and the branch pipe, thereby being divided into refrigerant having a high liquid ratio and refrigerant having a low liquid ratio. The refrigerant having a high liquid ratio is fed through a pipe to a heat exchanger having a large volume of air. The refrigerant having a low liquid ratio is fed through a pipe to a heat exchanger having a small volume of air.