Patent ID: 7624585

Claim:
A freezer unit comprising a refrigerant circuit on a high temperature side and a refrigerant circuit on a low temperature side to form independent closed refrigerant circuits which condense refrigerants delivered from compressors and thereafter evaporate the condensed refrigerants to achieve cooling action, and heat exchangers formed by an evaporator in the refrigerant circuit on the high temperature side and a condenser in the refrigerant circuit on the low temperature side, wherein confined in the refrigerant circuit on the low temperature side are nonazeotropic mixed refrigerants containing R245fa, R600, R404A, R508A, R14, R50 and R740 in combination at a predetermined ratio, or nonazeotropic mixed refrigerants containing R245fa, R600, R404A, R23, R14, R50 and R740 in combination at a predetermined ratio, or nonazeotropic mixed refrigerants containing R245fa, R600, R404A, R508B, R14, R50 and R740 in combination at a predetermined ratio.