The present disclosure provides a composition comprising a refrigerant characterized by having a low GWP, low flammability, a COP equivalent to that of R410A, and a refrigerating capacity almost equivalent to that of R410A. Specifically, the present disclosure provides a composition comprising a refrigerant, the refrigerant comprising CO.sub.2 (R744), hexafluoropropene (FO-1216), and at least one compound A selected from the group consisting of trifluoroethylene (HFO-1123), trans-1,2-difluoroethylene [(E)-HFO-1132], cis-1,2-difluoroethylene [(Z)-HFO-1132], fluoroethylene (HFO-1141), and 3,3,3-trifluoropropyne (TFP).

A cooling system is designed to operate in two different modes. Generally, in the first mode, when parallel compression is needed, certain valves are controlled to direct gaseous refrigerant from a tank to a compressor in the system and to direct refrigerant from low side heat exchangers towards other compressors. In this manner, a compressor in the system is transitioned to be generally a parallel compressor. In the second mode, when parallel compression is not needed, the valves are controlled to return the refrigerant flow back to normal.

A cooling system implements various processes to improve efficiency in high ambient temperatures. First, the system can flood one or more low side heat exchangers in the system. Second, the system can direct a portion of vapor refrigerant from a low side heat exchanger to a flash tank rather than to a compressor. Third, the system can transfer heat from refrigerant at a compressor suction to refrigerant at the discharge of a high side heat exchanger.

A refrigeration apparatus (1) includes a heat-source-side unit (10) using a refrigerant that works in a supercritical region. The heat-source-side unit (10) includes a compression element (20) configured to compress the refrigerant, a heat-source-side heat exchanger (24), an expansion valve (26) provided downstream of the heat-source-side heat exchanger (24), a receiver (25) provided downstream of the expansion valve (26), and a control unit (101). The control unit (101) performs a first operation for evaluating the amount of the refrigerant based on a high-pressure-side pressure, on a first condition that the internal pressure of the receiver (25) be equal to or less than a supercritical pressure.

An electrochemical compressor utilizes an anion conducting layer disposed between an anode and a cathode for transporting a working fluid. The working fluid may include carbon dioxide that is dissolved in water and is partially converted to carbonic acid that is equilibrium with bicarbonate anion. An electrical potential across the anode and cathode creates a pH gradient that drives the bicarbonate anion across the anion conducting layer to the cathode, wherein it is reformed into carbon dioxide. Therefore, carbon dioxide is pumped across the anion conducting layer. The compressor may be part of a refrigeration system that pumps the working fluid in a closed loop through a condenser and an evaporator.

A heat pump system for a motor vehicle comprises at least two heat exchangers 10, 12, through which, for heating and/or cooling the motor vehicle interior, a flow is conducted, and at least two coolant circulations 14, 16 separable from one another, of which at least one is connectable, independently of the other coolant circulation, with one, two or more heat exchangers 10, 12 such that through these, in the presence of a connection with two or more heat exchangers 10, 12, a flow is successively conducted and the other coolant circulation is connectable with at least one heat exchanger 10, 12.

Cooling or refrigeration systems, and methods of operating same, are disclosed herein. In one example embodiment, such a system includes a first and second high stage circuits each including a respective heat exchanger and a respective condenser that are coupled together at least indirectly so as to allow a respective portion of a first coolant to cycle therebetween. The system also includes a low stage circuit including a heat transfer device that is coupled at least indirectly with each of the heat exchangers, so as to allow an additional portion of a second coolant to cycle between the at least one evaporator and the heat exchangers, and in a parallel manner such that, if a first one of the high stage circuits ceases operating at a desired level, then the system can continue to operate by way of a second one of the high stage circuits.

A cooling system uses P-traps to address the oil return issues that result from a vertical separation between a compressor and a heat exchanger. Generally, the vertical piping that carries the refrigerant from the compressor to the heat exchanger includes P-traps installed at various heights to capture oil in the refrigerant and to prevent that oil from flowing back to the compressor. T-connections are coupled to the P-traps to allow the oil to drain out of the P-traps. The oil may then be collected and returned to the compressor.

A refrigeration plant with a cooling circuit, comprising at least one peripheral unit having a refrigeration machine for refrigerating a storage compartment; the refrigeration machine having a heat exchanger connected to the cooling circuit for dissipating heat to a secondary fluid flowing therein; a cooling apparatus connected to the cooling circuit for cooling the secondary fluid; a control device connected to the cooling apparatus and configured to operate the cooling apparatus so as to maintain at least an operating temperature of the secondary fluid within at least a corresponding reference range or to equalize it to at least a corresponding target value.

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.