To provide a working medium for heat cycle which has less influence over the ozone layer, which has less influence over global warming and which provides a heat cycle system excellent in the cycle performance (the efficiency and the capacity), and a heat cycle system excellent in the cycle performance (the efficiency and the capacity). A working medium for heat cycle comprising 1,2-difluoroethylene is employed for a heat cycle system (such as a Rankine cycle system, a heat pump cycle system, a refrigerating cycle system 10 or a heat transport system).

A system and method for cooling a gas using a mixed refrigerant includes a compressor system and a heat exchange system, where the compressor system may include an interstage separation device or drum with no liquid outlet, a liquid outlet in fluid communication with a pump that pumps liquid forward to a high pressure separation device or a liquid outlet through which liquid flows to the heat exchanger to be subcooled. In the last situation, the subcooled liquid is expanded and combined with an expanded cold temperature stream, which is a cooled and expanded stream from the vapor side of a cold vapor separation device, and subcooled and expanded streams from liquid sides of the high pressure separation device and the cold vapor separation device, or combined with a stream formed from the subcooled streams from the liquid sides of the high pressure separation device and the cold vapor separation device after mixing and expansion, to form a primary refrigeration stream.

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.

A method for controlling a valve arrangement (12), e.g. in the form of a three way valve, in a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (6). The valve arrangement (12) is arranged to supply refrigerant to a compressor unit (2) from the gaseous outlet (11) of a receiver (7) and/or from the outlet of an evaporator (9). The vapour compression system (1) may be operated in a first mode of operation (summer mode) or in a second mode of operation (winter mode). When operated in the second mode of operation, it is determined whether or not conditions for operating the vapour compression system (1) in the first mode of operation are prevailing. If this is the case, the valve arrangement (12) is actively switched to the first mode of operation by closing a first inlet (13) towards the evaporator (7) and fully opening a second inlet (14) towards the receiver (7).

An airplane is provided. The airplane includes a pressurized volume and an air conditioning system. The pressurized volume provides a first medium. The air conditioning system includes a heat exchanger and a compressor. The heat exchanger transfers heat from a second medium to the first medium. The compressor receives the second medium. The compressor is upstream of the heat exchanger in a flow path of the second medium.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.

The present disclosure relates to the technical field of heat pumps, in particular to an air source CO.sub.2 heat pump system for preventing an evaporator from frosting by using heat of a heat regenerator. The air source CO.sub.2 heat pump system mainly includes an air source heat pump system, a regenerative heat exchange tank and a cooling pump. Through the regenerative heat exchange tank, on the one hand, the temperature drop of regenerative heat of the system is further increased and throttling loss is reduced; on the other hand, the heat generated by the regenerative temperature drop is configured for heat storage used for defrosting, and configured for overheating temperature rise.

An air conditioning apparatus uses R32 as a refrigerant, and includes a compressor, a condenser, an expansion mechanism, an evaporator, an intermediate injection channel, a suction injection channel, a switching mechanism, a branch flow channel, first and second injection opening adjustable valves, an injection heat exchanger, a refrigerant storage tank, a bypass channel, and a control part. The switching mechanism switches between an intermediate injection condition in which refrigerant flows in the intermediate injection channel, and a suction injection condition in which refrigerant flows in the suction injection channel. The branch flow channel branches from a main refrigerant channel which joins the condenser and the evaporator, and guides the refrigerant to the intermediate injection channel and the suction injection channel. The bypass channel guides a gas component of the refrigerant accumulated inside the refrigerant storage tank to the intermediate injection channel and the suction injection channel.

A system includes a flash tank and a thermal storage tank. The flash tank is configured to store refrigerant and discharge a flash gas. The thermal storage tank is fluidically coupled to the flash tank and configured, when a power outage is determined to be occurring, to receive at least a portion of the flash gas from the flash tank, and remove heat from the flash gas. When a power outage is determined not to be occurring, the thermal storage tank directs refrigerant to a compressor.

A sensor assembly is shown for sensing a crossing of the critical point in a system utilising a working fluid in a transcritical cycle passing through the critical point. A first broadband acoustic sensor is located upstream of a component and a second broadband acoustic sensor is located downstream of the component, each of which are arranged to detect high-frequency and low-frequency sounds caused by the crossing of the critical point. A flow regulation device regulates flow of working fluid through the component in response to the output of one or both of the first broadband acoustic sensor and the second broadband acoustic sensor, thereby adjusting the location of the crossing of the critical point.