There is described an air conditioning system with a refrigerant circuit, wherein the air conditioning system includes a leakage detection system. The leakage detection system comprises a room temperature sensor, an inlet temperature sensor for detection of a refrigerant temperature at a refrigerant inlet of a refrigerant evaporator, and an outlet temperature sensor for detection of a refrigerant temperature at a refrigerant outlet of the refrigerant evaporator. The sensors (34, 36, 40) are coupled with a calculating unit. In addition, there is described a method for leakage detection, in which a room temperature of the room to be air-conditioned is detected before the refrigerant evaporator on an air inlet side, a refrigerant inlet temperature is detected at the refrigerant inlet of a refrigerant evaporator, and a refrigerant outlet temperature is detected at a refrigerant outlet of the refrigerant evaporator.

A heat pump includes a refrigerant loop. The refrigerant loop includes a compressor, a first vapor generator, a second vapor generator, and a third vapor generator. The compressor includes a low-pressure inlet, a mid-pressure inlet, and an outlet. The first vapor generator, the second vapor generator, and the third vapor generator are each positioned downstream of the outlet of the compressor. The first vapor generator, the second vapor generator, and the third vapor generator are each positioned upstream of the mid-pressure inlet of the compressor.

An air conditioning system includes a first compressor and a second compressor arranged in parallel with the first compressor. The first compressor is a first type of compressor and the second compressor is a second type of compressor different from the first type of compressor. A valve is arranged upstream from both the first compressor and the second compressor relative to a flow of a fluid. The valve is operable to selectively supply the fluid to the first compressor, the second compressor, or both the first compressor and the second compressor.

Provided is a gas-liquid separator, including a connection pipe connected to a refrigerant pipe in the evaporator, the refrigerant pipe in which a two-phase refrigerant flows, a header connected to the connection pipe, wherein a gas refrigerant separated from the two-phase refrigerant flows inside the header, a bypass pipe connected to the header to guide a flow of the gas refrigerant to a compressor, a flow rate control valve installed at the bypass pipe, and a controller configured to control opening and closing of the flow rate control valve based on whether a preset condition is satisfied.

Provided is a gas-liquid separator, including a connection pipe connected to a refrigerant pipe in the evaporator, the refrigerant pipe in which a two-phase refrigerant flows, a header connected to the connection pipe, wherein a gas refrigerant separated from the two-phase refrigerant flows inside the header, a bypass pipe connected to the header to guide a flow of the gas refrigerant to a compressor, a flow rate control valve installed at the bypass pipe, and a controller configured to control opening and closing of the flow rate control valve based on whether a preset condition is satisfied.

A refrigeration cycle device is configured to be selectively switchable between an air-cooling first refrigerant circuit that causes refrigerant to flow out of a liquid-phase refrigerant outlet of a gas-liquid separator, and an air-heating second refrigerant circuit that causes the refrigerant to flow out of a gas-phase refrigerant outlet of the gas-liquid separator. In the refrigeration cycle device, an oil separator is disposed in a refrigerant passage that leads from a heat dissipation device to a first expansion valve. Thus, when the first refrigerant circuit is configured in the refrigeration cycle device, the refrigerant passing through the oil separator is in a single gas phase or in an almost gas phase, so that oil can be easily separated from the refrigerant. Furthermore, when the refrigerant circulates through the first refrigerant circuit, oil can be retained at a position other than the gas-liquid separator.

A device for heating by absorbing latent heat of solidification of water, including a compressor (1), a condenser (2) and multiple evaporators (E1, E2) connected in parallel, each evaporator (E1, E2) has an electronic expansion valve (D1, D2) at its inlet, a solenoid valve (V1, V2) at its outlet; after the evaporators (E1, E2) are connected in parallel, outlets of the evaporators (E1, E2) are connected to an inlet of the compressor (1) and inlets of the evaporators (E1, E2) are connected to an outlet of the condenser (2); an outlet of the compressor (1) is connected to an inlet of the condenser (2); the compressor (1), the condenser (2) and the multiple parallel evaporators (E1, E2) form a closed loop system through pipelines; there are circulating refrigerants in the closed loop system, and heating and deicing processes are realized through a circulation of refrigerants; the solenoid valves (V1, V2) at the outlets of the evaporators (E1, E2) are switched between opening or closing to realize switching between evaporating and deicing functions of the evaporators (E1, E2).

A device for heating by absorbing latent heat of solidification of water, including a compressor (1), a condenser (2) and multiple evaporators (E1, E2) connected in parallel, each evaporator (E1, E2) has an electronic expansion valve (D1, D2) at its inlet, a solenoid valve (V1, V2) at its outlet; after the evaporators (E1, E2) are connected in parallel, outlets of the evaporators (E1, E2) are connected to an inlet of the compressor (1) and inlets of the evaporators (E1, E2) are connected to an outlet of the condenser (2); an outlet of the compressor (1) is connected to an inlet of the condenser (2); the compressor (1), the condenser (2) and the multiple parallel evaporators (E1, E2) form a closed loop system through pipelines; there are circulating refrigerants in the closed loop system, and heating and deicing processes are realized through a circulation of refrigerants; the solenoid valves (V1, V2) at the outlets of the evaporators (E1, E2) are switched between opening or closing to realize switching between evaporating and deicing functions of the evaporators (E1, E2).

A transportation refrigeration unit (TRU) system is provided and includes a damper assembly configured to direct air flows through first or second pathways and an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element. With the PCM pre-cooled, the damper and routing assemblies are controllable to respectively direct the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met and to respectively direct the air flows through the second pathway when second conditions are met.

A transportation refrigeration unit (TRU) system is provided and includes a damper assembly configured to direct air flows through first or second pathways and an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element. With the PCM pre-cooled, the damper and routing assemblies are controllable to respectively direct the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met and to respectively direct the air flows through the second pathway when second conditions are met.