An apparatus for using nitrogen within a closed loop cryogenic system is described. A cryochamber is provided that has a first nitrogen flow line with an inlet for connection to a nitrogen source and an outlet. At least one cryogenic cooling loop is provided that has a nitrogen inlet and a nitrogen outlet. The nitrogen inlet and outlet are in fluid communication with the first nitrogen flow line. The nitrogen inlet is positioned upstream of the nitrogen outlet. A heat exchanger is provided on the at least one cryogenic cooling loops through which the nitrogen passes. The heat exchanger has a fluid inlet and a fluid outlet. A turbo expander is in fluid communication with the outlet of the first nitrogen flow line and the nitrogen source. The turbo expander re-cools the nitrogen that passes through the first flow line and the at least one cryogenic cooling loop.

An object of the present invention is to provide a refrigerant composition having a reduced amount of comprehensive environmental load, in which the refrigerant composition has low GWP (direct impact on global warming is low), and has good energy efficiency (indirect impact on global warming is low) when used in a device.

The present invention provides a refrigerant composition comprising 30 to 50 mass % of difluoromethane (HFC32) and 70 to 50 mass % of 2,3,3,3-tetrafluoropropene (HFO1234yf).

An air-conditioning apparatus includes a controller which calculates a composition ratio of a refrigerant mixture using a high-pressure-side pressure of a refrigerant discharged from a compressor, a low-pressure-side pressure of a refrigerant to be sucked into the compressor, a high-pressure-side temperature of a refrigerant at an inlet side of a second expansion device in a high/low pressure bypass pipe, and a low-pressure-side temperature of a refrigerant at an outlet side of the second expansion device in the high/low pressure bypass pipe and which determines whether to open or close a bypass-channel opening/closing device.

A method for conditioning air in a test space of a test chamber which receives test material. A temperature in a range of −20° C. to +180° C. is established within the test space with a cooling device. The cooling device includes a cooling circuit with a refrigerant, a heat exchanger, a compressor, a condenser and an expansion element. An internal heat exchanger of the cooling circuit is connected to a high-pressure side of the cooling circuit upstream of the expansion element and downstream of the condenser and to a low-pressure side of the cooling circuit upstream of the compressor and downstream of the heat exchanger and is used to cool the refrigerant of the high-pressure side. A zeotropic refrigerant is used and the internal heat exchanger is used to cool the refrigerant of the high-pressure side to lower an evaporation temperature at the expansion element.

When a first temperature difference is the difference between an inlet temperature of a first refrigerant and an outlet temperature of the first refrigerant in the heat exchanger for heating, and a second temperature difference is the difference between an inlet temperature of a second refrigerant and an outlet temperature of the second refrigerant in the heat exchanger for heating, the difference between the first temperature difference and the second temperature difference is held in a predetermined value or less by controlling the opening degree of a second expansion device.

The application provides an air-conditioning system with mixed working medium, including: a compressor, and a first heat exchanger, wherein the first heat exchanger is communicated with an exhaust port of the compressor, the first heat exchanger is provided with a first flow channel communicated with a first inlet end and a second flow channel communicated with a first outlet end, and a first gas-liquid separator is further connected between the first flow channel and the second flow channel; and the first gas-liquid separator includes a first inlet, a first liquid outlet and a first gas outlet, the first inlet is communicated with the first flow channel, the first gas outlet is communicated with the second flow channel, and a liquid flowing out of the first liquid outlet is capable of being throttled and heated and then connected to a gas supplement port of the compressor for gas supplement. The application enables more high-boiling point refrigerant working medium entering the first heat exchanger to improve condensation performance, and further increases the amount of low-boiling point refrigerant working medium entering the second heat exchanger to improve evaporation performance, thereby solving the problem of poor gas supplement effect of a gas supplement system with mixed working medium, and improving the performance of the air-conditioning system.

The present invention provides a cooling system (1), comprising a receiver tank (2), an evaporator (3), a compressor (4) and a gas cooler (5), wherein the receiver tank (2) comprises a fluid inlet (6), a liquid outlet (7) and a gas outlet (8); the evaporator (3) comprises an evaporator inlet (9) and an evaporator outlet (10), the compressor (4) comprises a compressor inlet (11) and a compressor outlet (12); the gas cooler (5) comprises a cooler inlet (13) and a cooler outlet (14); and the liquid outlet (7) of the receiver tank (2) is connected to the evaporator inlet (9) via a first conduit (15), the evaporator outlet (10) is connected to the compressor inlet (11) via a second conduit (16), the compressor outlet (12) is connected to the cooler inlet (13) via a third conduit (17), and the cooler outlet (14) is connected to the fluid inlet (6) of the receiver via a fourth conduit (18), wherein at least one of the first conduit (15) and the fourth conduit (18) comprises a pressure regulator (19,25), and the gas outlet (8) of the receiver tank is connected to the evaporator inlet (9) via a fifth conduit (20) and a gas flow regulator (21,22), such that a flow of liquid refrigerant in the first conduit (15) may be controlled by operating the gas flow regulator (21,22) during use.

In accordance with the present invention refrigerant compositions are disclosed. The compositions comprise a refrigerant mixture consisting essentially of HFC-32, HFO-1234yf, and CO.sub.2. The compositions are useful as refrigerants in processes to produce cooling and heating, in methods for replacing refrigerant R-410A, and in refrigeration, air conditioning or heat pump systems. These inventive compositions match cooling capacity for R-410A within 20% with GWP less than 250 or less than 200.

The present invention relates to a refrigerant composition, including difluoromethane (HFC-32), pentafluoroethane (HFC-125), and trifluoroiodomethane (CF.sub.3I) for use in a heat exchange system, including air conditioning and refrigeration applications and in particular aspects to the use of such compositions as a replacement of the refrigerant R-410A for heating and cooling applications and to retrofitting heat exchange systems, including systems designed for use with R-410A.

An object is to provide a novel low-GWP mixed refrigerant.

Provided as a means for a solution is a composition comprising a refrigerant, the refrigerant comprising trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), 1,3,3,3-tetrafluoropropene (R1234ze), and carbon dioxide.