During a first cooling operation, a compressor is in an operational state, a liquid pump is in a non-operational state, and an amount of refrigerant allowing for existence of a liquid surface of the refrigerant in a refrigerant tank is accumulated in the refrigerant tank. During a second cooling operation, the compressor is in the non-operational state, the liquid pump is in the operational state, and the amount of the refrigerant allowing for the liquid surface of the refrigerant in the refrigerant tank is accumulated in the refrigerant tank.

A refrigeration system for a carbon dioxide based refrigerant fluid, wherein the refrigeration system includes a refrigerant circuit, the refrigerant circuit including a compression device, a heat rejecting heat exchanger, an ejector, a receiver, an expansion device, and a heat absorbing heat exchanger; wherein the ejector includes a primary inlet, a secondary inlet and an outlet; wherein the receiver includes an inlet, a liquid outlet and a gas outlet; wherein the ejector primary inlet is arranged to receive fluid from an outlet of the heat rejecting heat exchanger, the ejector secondary inlet is arranged to receive fluid from an outlet of the heat absorbing heat exchanger, and the ejector outlet is arranged to direct flow to the receiver inlet; wherein a suction inlet of the compression device is arranged to receive refrigerant fluid from the gas outlet of the receiver.

The purpose of the invention is to provide a control device that can calculate the lower limit of cooling water inlet temperature according to the operation status of a chiller. A control device comprises: a lower limit calculation unit that calculates the lower limit of cooling water outlet temperature, where a prescribed required temperature difference is added to the cooling water outlet temperature of a chiller, and an inlet-outlet required temperature difference, which is the difference between the cooling water outlet temperature and the cooling water inlet temperature in the chiller and which is generated according to the operation status of the chiller, and that calculates a cooling water inlet temperature lower limit calculated value for the chiller by subtracting the inlet-outlet required temperature difference from the cooling water outlet temperature lower limit value; and a lower limit value determination unit that fixes the cooling water inlet temperature lower limit calculated value as the cooling water inlet temperature lower limit value.

A heat pump system that can be selectively utilized to discharge excessive heating and cooling capacity toward secondary devices of the system to maintain operation of the heat pump system to better manage the respective temperatures associated with the fluid flows in a manner that reduces the need for cycling the heat pump system ON and OFF to attain desired fluid output temperature manipulations.

A refrigeration system includes a main refrigeration circuit for holding refrigerant fluid, the main refrigeration circuit including: a compression device 12, a heat rejecting heat exchanger 14, an expansion device 18 and a heat absorbing heat exchanger 16. In addition, the refrigeration system includes a buffer tank 20 attached to the main refrigeration circuit, with valves 22, 24 for controlling flow of refrigerant fluid between the main refrigeration circuit and the buffer tank 20. The refrigeration system is arranged such that the valves 22, 24 are controlled to transfer refrigerant fluid between the main refrigeration circuit and the buffer tank 20 based on a measure of sub-cooling in the main refrigeration circuit.

The present disclosure relates to a novel method for operating and controlling a vapor-compression cycle. The method of the present disclosure provides that a turbine-based expander in a heat pump model can achieve greater COP benefit in cooling than heating. Further, phase separation and an evaporator bypass are implemented within the turbine-based expander. Phase separation leads to successful energy recovery and compressor superheat control.

A method and apparatus for improving refrigeration and air conditioning efficiency for use with a heat exchange system having a compressor, condenser, evaporator, expansion valve, and circulating refrigerant. The apparatus includes a liquid refrigerant containing vessel having a refrigerant entrance and a refrigerant exit with the vessel positioned in the heat exchange system between the condenser and the evaporator, and means for creating a turbulent flow of liquefied refrigerant. The apparatus further preferably includes a refrigerant bypass path to sub-cool a portion of the refrigerant within the vessel; a disk positioned at the liquid refrigerant entrance to develop a low pressure area on the back side and create a turbulent flow of refrigerant entering the vessel; and a refrigerant valve incorporated into the refrigerant path downstream of the expansion valve and before the coil which develops a vortex that continues through the refrigerant coil.

A cooling system includes a second receiver that receives refrigerant from a low side heat exchanger. A pipe connects the second receiver to a first receiver. A vapor portion of the refrigerant in the first receiver can flow through the pipe to the second receiver. A compressor is used to create a pressure differential in the second receiver relative to the first receiver such that the pressure in the first receiver is greater than the pressure in the second receiver. This pressure differential effectively acts as a pump that pushes the liquid refrigerant in the first receiver towards the low side heat exchanger.

A vapor compression system includes a heat transfer system including an arrangement of components moving a refrigerant through a vapor compression cycle to condition a controlled environment and a refrigerant management system including at least one expansion device regulating an amount of the refrigerant in the vapor compression cycle. The vapor compression system also includes a controller including a processor jointly controlling the expansion device and at least one component of the heat transfer system according to a metric of performance of the vapor compression system.

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.