A refrigeration cycle apparatus includes a primary-side refrigerant circuit in which a first refrigerant circulates and a secondary-side refrigerant circuit in which a second refrigerant circulates. The primary-side refrigerant circuit includes a primary-side compressor, a primary-side flow path of a cascade heat exchanger, a primary-side heat exchanger, and a primary-side switching mechanism. The secondary-side refrigerant circuit includes a secondary-side compressor, a secondary-side flow path of the cascade heat exchanger, a secondary-side switching mechanism, a suction flow path, a plurality of utilization-side heat exchangers, a first connection flow path, connecting the plurality of utilization-side heat exchangers and the secondary-side switching mechanism, including a secondary-side first connection pipe, a first heat source pipe, first branch pipes, junction pipes, first connection pipes, and first utilization pipes, a second connection flow path, connecting the plurality of utilization-side heat exchangers and the suction flow path, including a secondary side second connection pipe, a second heat source pipe, second branch pipes, the junction pipes, the first connection pipes, and the first utilization pipes, a third connection flow path, connecting the plurality of utilization-side heat exchangers and the secondary-side flow path of the cascade heat exchanger, including a secondary-side third connection pipe, a fourth heat source pipe, a fifth heat source pipe, third branch pipes, second connection pipes, and second utilization pipes.

An air-conditioning apparatus includes a four-way valve, a first three-way valve and a second three-way valve each having a closed port, a compressor, an indoor heat exchanger, an expansion valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a bypass expansion valve, a check valve, a discharge temperature sensor, an indoor pipe temperature sensor, an indoor temperature sensor, a current sensor, and a controller configured to detect switching failure at the four-way valve, the first three-way valve, and the second three-way valve. The controller is configured to detect switching failure at the four-way valve, the first three-way valve, or the second three-way valve by using the temperatures measured by the discharge temperature sensor, the indoor pipe temperature sensor, and the indoor temperature sensor and the current in consideration of an operation status.

A chiller includes an evaporator, a compressor including a prime mover, a first pressure sensor that detects a first pressure in the evaporator, a second pressure sensor that detects a second pressure in a condenser, and a controller. The controller determines a predicted energy level of the compressor based on the first pressure and the second pressure, the predicted energy level associated with liquid droplet flow into the compressor, compares the predicted energy level to an operating energy level, and modifies the at least one of the input power and the input current to the prime mover based on the comparison satisfying a modification condition.

An electronic expansion valve, a heat exchange system, and a control for controlling an electronic expansion valve. The electronic expansion valve includes: a valve body; a first temperature sensor configured to detect an evaporator temperature T.sub.eva; a second temperature sensor configured to detect a compressor inlet temperature T.sub.suc; a third temperature sensor configured to detect a compressor outlet temperature T.sub.dis; a fourth temperature sensor configured to detect a condenser temperature T.sub.con; and a controller, which is associated with the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor, and which adjusts an opening degree of the valve body based on temperature signals from the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor.

A showcase includes a refrigerant circuit and a refrigerant enclosed in the refrigerant circuit. The refrigerant circuit includes a compressor (121), a radiator (122), an expansion valve (123), and an evaporator (124). The refrigerant is a low-GWP refrigerant.

A refrigeration cycle device includes: a compressor having a compression mechanism forming a compression chamber for compressing refrigerant, and a cooled portion cooled by the refrigerant before being compressed by the compression mechanism; a radiator that radiates the refrigerant compressed by the compressor; a decompressor that decompresses the refrigerant radiated by the radiator; an evaporator that evaporates the refrigerant decompressed by the decompressor; an acquisition unit that acquires the state of the refrigerant after cooling the cooled portion and before flowing into the compression chamber; and a control unit that controls the superheat degree of the refrigerant flowing into the compression chamber based on the state of the refrigerant acquired by the acquisition unit.

A dual reclaim coil with a smart control application is provided that allows the refrigerant inlet to the HVAC unit switch between the two sides of the condenser is aimed to use the high temperature and pressure of the condenser/gas cooler outlet while a CO.sub.2 refrigerant system is operating above critical point. This occurs in hot ambient conditions, when the need for heating in the space is not as great as in the wintertime and the available heat at the condenser/gas cooler's outlet is sufficient to satisfy the heating load. This also mitigates space overcooling, while increasing the CO.sub.2 transcritical system's efficiency by subcooling the refrigerant for applications involving dehumidification HVAC systems which often results in a phenomenon called “overcooling” during the dehumidification season.

A refrigerant charging device and a refrigerant charging system include a refrigerant charging flour path having a refrigerant charging port connected to a refrigerant flow path of an air conditioner, a valve provided at the refrigerant charging flow path, and a control device configured to control the valve. The control device includes a discharging superheat calculator configured to calculate the discharging superheat degree from a refrigerant temperature and a refrigerant pressure at a discharge side of a compressor, and a valve controller configured to control the opening and closing state of the valve based on the calculated discharging superheat degree calculated by the discharge super-heat calculator.

A climate-control system may include a compressor, a condenser, an evaporator, a first sensor, a second sensor, a third sensor, and a control module. The compressor may include a motor and a compression mechanism. The condenser receives compressed working fluid from the compressor. The evaporator is in fluid communication with the compressor and disposed downstream of the condenser and upstream of the compressor. The first sensor may detect an electrical operating parameter of the motor. The second sensor may detect a discharge temperature of working fluid discharged by the compression mechanism. The third sensor may detect a suction temperature of working fluid between the evaporator and the compression mechanism. The control module is in communication with the first, second and third sensors and may determine whether a refrigerant floodback condition is occurring in the compressor based on data received from the first, second and third sensors.

A heat source controller performs a first operation when a compression element is in a stopped state and a pressure in a receiver exceeds a predetermined first pressure. The heat source controller allows an inlet of the compression element to communicate with the receiver, and drives the compression element in the first operation.