A coolant cycle system for cooling a structure includes a two stage compressor configured to compress a coolant. The two stage compressor has a first stage with a first stage inlet and a first stage outlet and a second stage with a second stage inlet and a second stage outlet. The second stage is a high pressure stage relative to the first stage. A gas cooler has a coolant inlet fluidly connected to the second stage outlet and has a gas cooler outlet. The gas cooler outlet is fluidly connected to a heat exchanger and a fluid storage tank. The heat exchanger is configured to cool the fluid storage tank and has a heat exchanger coolant outlet fluidly connected to the second stage inlet. The fluid storage tank has a fluid storage tank outlet fluidly connected to a coolant inlet of an evaporator. A coolant outlet of the evaporator is fluidly connected to the first stage inlet of the compressor. The first stage outlet of the compressor is fluidly connected to the second stage inlet.

Provided is an indoor unit for a heat pump use apparatus, the indoor unit being a part of the heat pump use apparatus including a refrigerant circuit configured to circulate refrigerant, a heat medium circuit configured to allow a heat medium to flow through the heat medium circuit, and a heat exchanger configured to exchange heat between the refrigerant and the heat medium. The indoor unit is connectable to an outdoor unit accommodating the refrigerant circuit and the heat exchanger. The indoor unit accommodates a part of the heat medium circuit. The indoor unit includes a pressure protection device connected to the heat medium circuit, and an on-off device provided to be interposed between the heat medium circuit and the pressure protection device.

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 liquid slug reduction and charge compensator device for use in air conditioning and heat pump systems includes a housing having a cavity. The housing includes an inlet port providing an entry path into the cavity and an outlet port providing an exit path from the cavity. The housing further includes a liquid line port providing a refrigerant pathway into and out of the cavity. The liquid slug reduction and charge compensator device further includes a flash tube extending through the cavity and providing a passageway through the cavity such that a hot gas refrigerant that enters the cavity through the inlet port causes a liquid refrigerant that enters the flash tube to evaporate.

Disclosed are cascaded refrigeration systems, comprising: a plurality of refrigeration units, each refrigeration unit containing a first refrigeration circuit, each first refrigeration circuit comprising an evaporator and a heat exchanger; and a second refrigeration circuit; wherein each first circuit heat exchanger is arranged to transfer heat energy between its respective first refrigeration circuit and the second refrigeration circuit.

A liquid slug reduction and charge compensator device for use in air conditioning and heat pump systems includes a housing having a cavity. The housing includes an inlet port providing an entry path into the cavity and an outlet port providing an exit path from the cavity. The housing further includes a liquid line port providing a refrigerant pathway into and out of the cavity. The liquid slug reduction and charge compensator device further includes a flash tube extending through the cavity and providing a passageway through the cavity such that a hot gas refrigerant that enters the cavity through the inlet port causes a liquid refrigerant that enters the flash tube to evaporate.

A circulation system of an air conditioner, an air conditioner, and an air conditioner control method. The circulation system of the air conditioner includes a compressor, a first heat exchanger, a second heat exchanger, and a gas-liquid separation assembly. The gas-liquid separation assembly, together with the compressor, the first heat exchanger, and the second heat exchanger, forms a loop; the gas-liquid separation assembly includes two or more gas-liquid separators which are connected in series; the gas-liquid separation assembly is configured to perform gas-liquid separation for refrigerant. Further, two or more-staged gas-liquid separation can be performed for the refrigerant flowing back to the compressor, so that a problem that return oil containing liquid in the compressor can be effectively solved.

An apparatus includes a high side heat exchanger, a subcooler heat exchanger, a flash tank, a load, and a compressor. The high side heat exchanger removes heat from a refrigerant. The subcooler heat exchanger receives the refrigerant. The flash tank stores the refrigerant. During a first mode of operation, the load uses the refrigerant to cool a space proximate the load and the compressor compresses the refrigerant. During a second mode of operation, the subcooler heat exchanger receives the refrigerant from the flash tank, transfers heat from the refrigerant from the high side heat exchanger to the refrigerant from the flash tank and directs the refrigerant from the flash tank to the compressor. During the second mode of operation, the compressor compresses the refrigerant from the subcooler heat exchanger and directs the compressed refrigerant to the load to defrost the load.

A liquid accumulator for a heat exchange system, includes a liquid accumulator housing provided with an air inlet, an air outlet, and a liquid inlet; and a cooling heat exchanger disposed in the liquid accumulator housing, wherein the cooling heat exchanger comprises an inlet end, a main body part, and an outlet end in sequence; the inlet end of the cooling heat exchanger is connected to the air inlet on the liquid accumulator housing; and the outlet end of the cooling heat exchanger is arranged to be higher than a working liquid level of a refrigerant in the liquid accumulator.

Provided is a state analysis device and a state analyzer system that include a specific state determination unit configured to determine specific state information representing a state of refrigerant at a specific position in a refrigeration circuit and a normal region determination unit configured to determine a normal region in a state space within which the specific state information is present when an air-conditioning apparatus operates under a normal state. The state analysis device and the state analyzer system allow a display unit to display the specific state information and the normal region.