An ejector draws a refrigerant on a downstream side of an exterior heat exchanger serving as an evaporator, from a refrigerant suction port by a suction effect of an injection refrigerant injected from a nozzle portion for decompressing a part of the refrigerant discharged from a compressor, and mixes the injection refrigerant with the suction refrigerant to pressurize the mixed refrigerant at a diffuser. The refrigerant flowing out of the diffuser is drawn into the compressor. In this way, the density of the refrigerant drawn into the compressor can be increased, thereby suppressing reduction in flow amount of the refrigerant flowing into an interior condenser serving as a radiator. Thus, even if the temperature of the outside air (heat-absorption target fluid) is decreased, the interior condenser is prevented from degrading its heating capacity for the ventilation air (heating target fluid).

A method of determining charge loss of a refrigeration system includes the steps of inputting an ambient temperature, a box temperature, and a compressor speed into an electronic controller of the refrigeration system, and calculating a first air side temperature difference across an evaporator by applying an algorithm having a first T-Map representative of normal operating conditions. The controller may then confirm a detection prerequisite is satisfied. Upon confirmation, the controller calculates a second air side temperature difference across the evaporator by applying the algorithm having a second T-Map representative of a loss of refrigerant charge. An action may then be taken from the controller if the first air side temperature difference is less than the second air side temperature difference.

The oil level in a compressor is lowered upon activation of the compressor. A heat pump-type heating device of the present invention includes: a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a motor-operated valve, and a target-side heat exchanger are provided; and an outdoor fan which is provided for the heat-source-side heat exchanger. The target-side heat exchanger is capable of heating, by a refrigerant, fluid supplied from outside. The rotation number of the outdoor fan upon activation of the compressor when a difference between a temperature of the fluid supplied to the target-side heat exchanger and an outside temperature is equal to or larger than a predetermined temperature difference is smaller than the rotation number when the difference is smaller than the predetermined temperature difference.

An air conditioner that is a refrigeration apparatus has, in a refrigerant circuit, a compressor, an outdoor heat exchanger that functions as an evaporator in a heating operation, an indoor heat exchanger that functions as a condenser in the heating operation, and a four way valve. The refrigerant circuit is configured in such a way that a high-pressure value of the refrigerant circuit in a defrost operation is lower than a high-pressure value of the refrigerant circuit in the heating operation. An end-of-defrost frequency decrease rate, which is a rate of decrease in the operating frequency of the compressor in the defrost operation, is set faster than a normal frequency decrease rate, which is a rate of decrease in the operating frequency of the compressor in the heating operation.

The air conditioner 1 includes an outdoor unit 10 and an indoor unit 30. The outdoor unit 10 includes an outdoor heat exchanger 16, a compressor 12, an outdoor fan 15, a temperature detector 23 for detecting a temperature of the outdoor heat exchanger 16, and a temperature detector 27 for detecting an outdoor temperature. The indoor unit 30 includes an indoor heat exchanger 33 and an indoor fan 32. The air conditioner 1 has a heating operation mode: that is, when the outdoor temperature reaches a predetermined first specified temperature or lower during a heating operation, the air conditioner 1 stops the heating operation and goes to standby, and thereafter, when the outdoor temperature reaches a temperature equal to or higher than a predetermined second specified temperature higher than the first specified temperature, the air conditioner 1 executes a defrosting operation and subsequently resumes the heating operation.

A refrigeration cycle apparatus avoids refrigerant conditions causing a disproportionation reaction and exhibit high performance with safety even when a refrigerant causing the disproportionation reaction is used in a zeotropic refrigerant mixture. The refrigeration cycle apparatus uses, as a working refrigerant, the zeotropic refrigerant mixture of a first refrigerant and a second refrigerant having a higher boiling point than that of the first refrigerant under the same pressure, and includes at least a main passage sequentially connecting a compressor, a first heat exchanger, an expansion valve, a gas-liquid separator, and a second heat exchanger. The first refrigerant causes the disproportionation reaction. In an initial state after startup of the compressor, the refrigeration cycle apparatus performs an initial operation decreasing a temperature or a pressure of refrigerant discharged from the compressor to be lower than that in a normal operation based on an amount of liquid refrigerant in the gas-liquid separator.

A multi-air conditioner for heating and cooling may include at least one indoor unit for both cooling and heating including an indoor heat exchanger, an outdoor unit, and a distributor disposed between the outdoor unit and the at least one indoor unit. The outdoor unit may include a compressor, a plurality of outdoor heat exchangers, and a switching unit disposed on a discharge side of the compressor to switch a flow of refrigerant. The plurality of outdoor heat exchangers may include a first heat exchanger, a second heat exchanger disposed under the first heat exchanger, and a third heat exchanger disposed under the second heat exchanger. A first end of the third heat exchanger may be connected to the discharge side of the compressor, and a second end of the third heat exchanger may be connected to the indoor unit.

A heat exchanger includes a first-row heat exchange module through which a refrigerant is introduced from the outside, a second-row heat exchange module through which the refrigerant is discharged to the outside, a third-row heat exchange module through which the refrigerant is discharged to the outside, and a flow-splitting module that splits the refrigerant from the first-row heat exchange module into the second-row heat exchange module and the third-row heat exchange module, wherein the refrigerant reciprocates one time in a flow path, the first-row heat exchange module constitutes a forward path of the flow path, and both the second-row heat exchange module and the third-row heat exchange module constitute backward paths of the flow path.

Disclosed herein is a method for failure prediction in an Air Cycle Machine (ACM). The method includes calculating a change in energy of an ACM airflow passing from an inlet of the ACM compressor to an outlet of the ACM compressor. The method may also include calculating a kinetic energy of the ACM compressor based on calculating the work of the ACM compressor on the ACM airflow as the ACM airflow passes through the ACM compressor, calculating the work of the ACM compressor based on the inlet temperature of the ACM airflow at the inlet of the ACM compressor, compressor pressure ratio of the ACM compressor, and a fluid property of the ACM airflow at the inlet of the ACM compressor. Additionally, the method can include calculating an ACM compressor efficiency as a ratio of the change in energy of the ACM airflow across the ACM compressor to the kinetic energy of the compressor. The method may further include predicting a failure state of the ACM compressor.

An air conditioning system including one or more supercooling heat exchangers, a supercooling expansion device, a temperature sensor, and a pressure sensor so as to accurately measure and control a current supercooling degree value of a fluid coolant flowing between a fluid pipe and a plurality of indoor devices.