Provided is a heat pump system having a liquid-side on-off valve, a gas-side on-off valve, an ambient temperature detector configured to detect temperature of fluid which passes through a heatsource-side heat exchanger, and a controller. The controller is configured to perform a refrigerant recovery operation for recovering refrigerant from a utilization-side piping section to a heatsource-side piping section by operating a compressor while the liquid-side on-off valve is closed and the gas-side on-off valve is open, and control the compressor such that, when the ambient temperature is higher than or equal to a predetermined value, increase rate of compressor rotation speed is low compared with that of when the ambient temperature is lower than the predetermined value.

A refrigeration cycle device includes: a refrigerant circuit which circulates a mixed refrigerant containing at least CF3I and HFO1123, the RC including a compressor, an expansion valve, an indoor heat exchanger, an outdoor heat exchanger and a refrigerant reservoir; an injection pipe having a first end at a first height within the refrigerant reservoir and a second end connected to the compressor; and an injection valve included in the injection pipe. The CF3I has the greatest fluid density among refrigerants contained in the mixed refrigerant. The first height is higher than a height at which an end of a refrigerant pipe, other than the injection pipe, is located within the refrigerant reservoir.

An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

In a refrigeration cycle apparatus, a refrigerant pipe is connected to a compressor, a first heat exchanger, an expansion valve, a second heat exchanger, a heat absorber, and the compressor sequentially in this order. R290 is used as refrigerant flowing through the refrigerant pipe. The heat absorber is provided in a portion of the refrigerant pipe between the compressor and the first heat exchanger or the second heat exchanger serving as an evaporator. The heat absorber is disposed in contact with an electric component. A branch pipe is connected in parallel with the portion provided with the heat absorber in the refrigerant pipe. The branch pipe is provided with a flow rate regulating valve.

Thermal management systems are described. These systems include a refrigerant receiver configured to store a refrigerant fluid, an evaporator, a closed-circuit refrigeration system having a closed fluid circuit path, with the refrigerant receiver and evaporator disposed in the closed fluid circuit path, and the closed fluid circuit path including a condenser and compressor. These systems also include a modulation capacity control circuit configured to selectively divert refrigerant vapor flow to the condenser from the compressor by diverting a portion of refrigerant vapor flow (diverted flow) from the compressor to the refrigerant receiver in accordance with cooling capacity demand. These systems also include an open-circuit refrigeration system having an open fluid circuit path with the refrigerant receiver and the evaporator, and an exhaust line that discharges the refrigerant fluid from the exhaust line so that the discharged refrigerant fluid is not returned to the open-circuit and the closed-circuit refrigerant fluid flow paths.

A heat exchanger includes heat exchange fins, refrigerant pipes are arranged across the heat exchange fins, and connecting pipes connected to the refrigerant pipes to thereby define refrigerant passages. The connecting pipes include a first pipe portion having a first end connected to one of the refrigerant pipes, a branch pipe portion that is branched from the first pipe portion, that extends parallel to the first pipe portion, and that is connected to another of the refrigerant passages, and a second pipe that is connected to the first pipe portion and that is configured to guide gas-phase refrigerant separated from the refrigerant in the first pipe portion. The second pipe includes an inner insert portion inserted into a second end of the first pipe portion and an outlet portion that extends from the inner insert portion in direction opposite to the second end of the first pipe portion.

A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.

A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.

Aspects of the present disclosure include a system for turbo-compression cooling. The system may be aboard a marine vessel. The system includes a power cycle and a cooling cycle. The power cycle includes a first working fluid, a waste heat boiler configured to evaporate the working fluid, a turbine, and a condenser. The condenser condenses the working fluid to a saturated or subcooled liquid. The cooling cycle includes a second working fluid, a first compressor configured to increase the pressure of the second working fluid, a condenser configured to condense the second working fluid to a saturated or subcooled liquid after exiting the first compressor, an expansion valve, and an evaporator. The turbine and first compressor are coupled one to the other. The waste heat boiler receives waste heat from engine jacket water and lubricating oil from a ship service generator. The evaporator cools water in a shipboard cooling loop.

A packaged, pumped liquid, evaporative-condensing recirculating ammonia refrigeration system with charges of 10 lbs or less of refrigerant per ton of refrigeration capacity. The compressor and related components are situated inside the plenum of a standard evaporative condenser unit, and the evaporator is close coupled to the evaporative condenser. Single or dual phase cyclonic separators may also be housed in the plenum of the evaporative condenser.