Refrigerant

A refrigerant for a cooling device comprising a cooling circuit with at least one heat exchanger, the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant being a refrigerant mixture composed of a mass fraction of carbon dioxide (CO2), a mass fraction of difluoromethane (CH2F2) and a mass fraction of at least one other component, wherein the mass fraction of carbon dioxide in the refrigerant mixture is 5 to 65 mass percent, the mass fraction of difluoromethane being up to 68 mass percent, the other component being trifluoroiodomethane (CF3I), fluoromethane (CH3F), ethane (C2H6), 1,1-difluoroethene (C2H2F2), ethene (C2H4), fluoroethene (C2H3F), ethyne (C2H2), propane (C3H8), propene (C3H6) and/or fluoroethane (CH2FCH3), said mass fraction being up to 55 mass percent.