Provided is a composition containing a refrigerant that has a refrigerating capacity equivalent to that of widely used R404A, and a low GWP. The composition contains a refrigerant that contains difluoromethane (R32), pentafluoroethane (R125), 1,1,1-trifluoroethane (R143a), and 1,1,1,2-tetrafluoroethane (R134a) in specific concentrations.

A method for operating a cooling device, a cooling device and a test chamber having a cooling device, a temperature of at least −80° C. or lower being established at the heat exchanger by means of the cooling device having a cooling circuit comprising a refrigerant, a heat exchanger, an internal heat exchanger, a compressor, a condenser and a controllable expansion element of the cooling device, the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant of a high-pressure side of the cooling circuit being cooled by means of the internal heat exchanger, the cooling of the refrigerant of the high-pressure side by means of the internal heat exchanger being used to reduce an evaporation temperature at the expansion element, a zeotropic refrigerant being used as refrigerant, the expansion element being controlled by means of a control device of the cooling device in such a manner that the refrigerant partially freezes during an expansion at the expansion element.

A refrigerant composition comprising carbon dioxide (CO.sub.2; R-744) and from 1 to 32 weight % difluoromethane (R-32) based on the total weight of the composition is described. Also described is the use of the refrigerant composition for providing heating and cooling and a refrigeration, air-conditioning or heat pump system comprising the refrigerant composition.

A problem to be solved is to provide a composition containing a refrigerant that satisfies the following four properties: (1) a GWP of 1500 or less, (2) ASHRAE non-flammability, (3) a COP equivalent to that of R410A, and (4) a refrigerating capacity equivalent to that of R410A. As a solution to the problem, provided is a composition containing a refrigerant that contains CO.sub.2, R32, R125, and R134a, wherein when the mass % of CO.sub.2, R32, R125, and R134a based on their sum in the refrigerant is respectively x, a, b, and c, coordinates (a,b,c) in a ternary composition diagram in which 2.7≤x<6.0, and the sum of R32, R125, and R134a is (100−x) mass % fall within a triangular region surrounded by line segments that connect point E, point F, and point G, or on the line segments; or coordinates (a,b,c) in a ternary composition diagram in which 6.0≤x<9.0 fall within a triangular region surrounded by line segments that connect point E, point F, and point G, or on the line segments.

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.

A refrigerant composition, including trifluoroiodomethane (CF.sub.3I); 1,1,1,2-tetrafluoropropene (HFO-1234yf); difluoromethane (HFC-32); and carbon dioxide (CO.sub.2), for use in a heat exchange system, including refrigeration applications and in particular aspects to the use of such compositions as a replacement of the refrigerant R-404A for heating and cooling applications and to retrofitting heat exchange systems, including systems designed for use with R-404A.

The process relates to a method of using catalyzed graphene with a nanoparticle reacting agent in the refrigeration circuit of a thermal vapor compression system to improve the efficiency of the system. Specifically, the present process relates to a method of using a catalyzed graphene and nanoparticle reacting agent in the refrigeration circuit of an air conditioning, heat pump, or refrigeration system to increase the performance of the system relative to an equivalent system operating in an equivalent environment without the catalyzed graphene and nanoparticle reacting agent.

A refrigeration cycle apparatus (10) includes a refrigerant circuit (11) including a compressor (12), a heat source-side heat exchanger (13), an expansion mechanism (14), and a usage-side heat exchanger (15). In the refrigerant circuit (11), a refrigerant containing at least 1,2-difluoroethylene (HFO-1132 (E)) is sealed. At least during a predetermined operation, in at least one of the heat source-side heat exchanger (13) and the usage-side heat exchanger (15), a flow of the refrigerant and a flow of a heating medium that exchanges heating with the refrigerant are counter flows.

In an air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, high efficiency is achieved. The motor rotation rate of a compressor (100) can be changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved. In addition, an electrolytic capacitor is not required on an output side of a rectifier circuit (21), and thus an increase in the size and cost of the circuit is suppressed.

In an air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, high efficiency is achieved. In the air conditioner (1), a compressor (100, 200) can be driven without interposing a power conversion device between an AC power source (90, 190) and a motor (70, 170). Thus, it is possible to provide the air conditioner (1) that is environmentally friendly and has a relatively inexpensive configuration.