The application relates to a cooling system, the cooling system having: an evaporator, a first compressor, a second compressor, a cooling component, an expansion device and a line system that connects the evaporator, the first compressor, the second compressor, the cooling component and the expansion device to one another. The cooling system includes a refrigerant, wherein the refrigerant comprises carbon dioxide. The first compressor and the second compressor are arranged in series with one another. The application also relates to a corresponding laboratory instrument.

Disclosed is a CO.sub.2 based refrigeration system including a condenser for transferring heat from a CO.sub.2 refrigerant of the refrigeration system to an air stream. The system further includes a metering device downstream of the condenser and a bypass arrangement. The metering device is configured to create a pressure drop so that part of the refrigerant liquifies, when received in a supercritical state, from the condenser such that a liquid component and a flash gas component are generated. The bypass arrangement includes a valve and a bypass line to allow the refrigerant to bypass the metering device.

An air-conditioning apparatus includes a control unit performing liquid refrigerant equalization control for correcting an imbalance in liquid refrigerant amount between accumulators. The control unit includes a first liquid refrigerant equalization control unit controlling an output of a fan to perform the liquid refrigerant equalization control and a second liquid refrigerant equalization control unit controlling a frequency of a compressor to perform the liquid refrigerant equalization control. The second liquid refrigerant equalization control unit determines an increase or reduction in frequency of the compressor so that a total refrigerant circulation amount is not below a predetermined amount. When a value is within a predefined acceptable range, the control unit selects the first liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control. When the value is outside the acceptable range, the control unit selects the second liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control.

The heat source controller transmits the drive permission signal (SE) to the utilization controller when the compression element is drivable. The utilization controller opens a utilization expansion valve when heat exchange in a utilization heat exchanger is required, on condition that the utilization controller receive the drive permission signal (SE).

A refrigeration system for a temperature-controlled storage device includes a refrigeration circuit that circulates a refrigerant, a separate cooling circuit that circulates a coolant, and a controller. The refrigeration circuit includes a compressor, a condenser, an expansion device, and an evaporator. The cooling circuit includes a pump, a control valve, and a heat removing device in fluid communication with the condenser via the coolant. The controller is operatively coupled to the control valve and configured to identify a coolant temperature differential setpoint, monitor a temperature of the coolant provided to the condenser by the cooling circuit, calculate a coolant temperature differential based on the temperature of the coolant provided to the condenser, and operate the control valve to modulate a flow of the coolant through the condenser to drive the coolant temperature differential to the coolant temperature differential setpoint.

A method of operating a refrigeration and heating system (2a, 2b) comprises: circulating a refrigerant through a refrigeration circuit (4) which comprises in the direction of flow of the circulating refrigerant: at least one compressor (6a, 6b, 6c); a refrigeration circuit side (8a) of a coupling heat exchanger (8); at least one gas cooler (10); at least one expansion device (12, 14); and at least one evaporator (16); circulating a heating fluid through a heating circuit (20) which comprises a heating circuit side (8b) of the coupling heat exchanger (8) and at least one heat consumer (22); wherein the coupling heat exchanger (8) is configured for transferring heat from the circulating refrigerant to the circulating heating fluid. The method further includes increasing the temperature of the refrigerant entering the at least one gas cooler (10) in order to meet increased heating demands by allowing at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side (8b) of the coupling heat exchanger (8) bypassing the at least one heat consumer (22) or by allowing at least a portion of the refrigerant circulating through the refrigeration circuit (4) to bypass the coupling heat exchanger (8).

A gas turbine engine may include a deep heat recovery system, such as a deep heat recovery super critical carbon dioxide (sCO2) system. The deep heat recovery system may include two-stage cooling of the working fluid (such as carbon dioxide—CO2) where at least one of cooling stages is recuperative by transferring heat from the working fluid to a flow of compressed air being supplied to a combustor included in the gas turbine engine. The deep heat recovery system may operate in a supercritical cycle, or in a transcritical cycle depending on the temperature to which the working fluid is cooled during a second stage of the two-stage cooling. The second stage of the two-stage cooling includes working fluid-to-air heat rejection where the air is ambient air.

A refrigeration system includes a rotary pressure exchanger fluidly coupled to a low pressure branch and a high pressure branch. The rotary pressure exchanger is configured to receive the refrigerant at high pressure from the high pressure branch, to receive the refrigerant at low pressure from the low pressure branch, and to exchange pressure between the refrigerant at high pressure and the refrigerant at low pressure, and wherein a first exiting stream from the rotary pressure exchanger includes the refrigerant at high pressure in the supercritical state or the subcritical state and a second exiting stream from the rotary pressure exchanger includes the refrigerant at low pressure in the liquid state or the two-phase mixture of liquid and vapor.

Provided is a chiller and system that may be utilized in a supercritical fluid chromatography method, wherein a non-polar solvent may replace a portion or all of a polar solvent for the purpose of separating or extracting desired sample molecules from a combined sample/solvent stream. The system may reduce the amount of polar solvent necessary for chromatographic separation and/or extraction of desired samples. The system may incorporate a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel and a supercritical fluid cyclonic separator. The supercritical fluid chiller allows for efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps. The pressure equalizing vessel allows the use of off-the-shelf HPLC column cartridges. The system may further incorporate the use of one or more disposable cartridges containing silica gel or other suitable medium. The system may also utilize an open loop cooling circuit using fluids with a positive Joule-Thompson coefficient.

A refrigeration system includes an evaporator within which a refrigerant absorbs heat, a gas cooler/condenser within which the refrigerant rejects heat, a compressor operable to circulate the refrigerant between the evaporator and the gas cooler/condenser, a high pressure valve operable to control a pressure of the refrigerant at an outlet of the gas cooler/condenser, and a controller. The controller is configured to automatically generate a setpoint for a measured or calculated variable of the refrigeration system based on a measured temperature of the refrigerant at the outlet of the gas cooler/condenser. The setpoint is generated using a stored relationship between the measured temperature and a maximum estimated coefficient of performance (COP) that can be achieved at the measured temperature. The controller is configured to operate the high pressure valve to drive the measured or calculated variable toward the setpoint.