A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains is a small-GWP refrigerant.

Provided is an air conditioning apparatus. The air conditioning apparatus includes an outdoor unit through which a refrigerant is circulated, an indoor unit through which water is circulated, and a heat exchange device including a heat exchanger in which the refrigerant and the water are heat-exchanged with each other. The heat exchanger includes a high-pressure guide tube, a low-pressure guide tube, a liquid guide tube, a bypass tube configured to connect a bypass branch point of the high-pressure gas tube of the outdoor unit to a bypass combination point of the liquid guide tube to bypass a high-pressure refrigerant existing in the high-pressure tube to the liquid guide tube, and a bypass valve installed in the bypass tube. The outdoor unit includes a first valve device configured to guide a refrigerant compressed in the compressor to the outdoor heat exchanger and a second valve device configured to guide the refrigerant compressed in the compressor to the high-pressure guide tube of the heat exchange device.

A refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.

An air conditioning unit capable of performing a refrigeration cycle using a small-GWP refrigerant is provided. A refrigeration cycle apparatus (1, 1a to 1m) includes a refrigerant circuit (10) including a compressor (21), a condenser (23, 31, 36), a decompressing section (24, 44, 45, 33, 38), and an evaporator (31, 36, 23), and a refrigerant containing at least 1,2-difluoroethylene enclosed in the refrigerant circuit (10).

Provided is an air conditioning apparatus. The air conditioning apparatus includes an outdoor unit which includes a compressor and an outdoor heat exchanger and through which a refrigerant is circulated, an indoor unit through which water is circulated, a heat exchanger in which the refrigerant and the water are heat-exchanged with each other, a water tube configured to guide the water circulated through the indoor unit and the heat exchanger, a pump installed in the water tube, and a controller configured to analyze an output signal of the pump so as to calculate a ration of an air layer in the water tube, the controller being configured to control a target supercooling degree or target superheating degree of the heat exchanger according to the calculated ratio of the air layer.

A refrigeration cycle system includes a first cycle and a second cycle. The first cycle is connected with a first compressor, a cascade heat exchanger, a first expansion unit, and a first heat exchanger, and includes a first flow path that connects the first compressor to the cascade heat exchanger, a second flow path that connects the cascade heat exchanger to the first expansion unit, a third flow path that connects the first heat exchanger to the first compressor, and a bypass flow path that connects at least one of the first flow path and the second flow path to the third flow path. The second cycle includes the cascade heat exchanger. In a case of using the cascade heat exchanger as a radiator of the first cycle and a heat sink of the second cycle, the first compressor of the first cycle is started after a flow of a heat medium generates in the cascade heat exchanger in the second cycle.

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.

Provided is an air conditioning apparatus that sufficiently raises the temperature of hot air to be blown out when receiving a request for high-temperature air temporarily raising the temperature of the hot air. A first use side unit includes a first use side heat exchanger and a first use side fan. A second use side unit includes a second use side heat exchanger and a second use side fan. When the first use side unit receives a request for the high-temperature air and the second use side unit receives no request for the high-temperature air, the air conditioning apparatus shifts to a mode that performs control to reduce the airflow volume of the second use side fan or make the airflow volume of the second use side fan zero such as reducing the number of revolutions of the second use side fan in another room by 40 rpm.

A heating control device includes an estimating unit to estimate a latent heat load of air present in a ventilation target space as a ventilation target and a heating control unit to control, in accordance with the latent heat load estimated by the estimating unit, a temperature of heating outside air by a heat exchanger to heat outside air supplied to the ventilation target space, via control of a condensation temperature of a refrigerant in the heat exchanger. The estimating unit estimates the latent heat load from ΔX, which is a value obtained by subtracting, from a target absolute humidity (X0) set by a temperature/humidity setting device to set a target humidity of an interior as the ventilation target space, an absolute humidity (Xi) of the interior detected by an indoor humidity sensor.