Patent ID: 8826677

Claim:
A refrigeration system comprising a plurality of heat exchangers in cascade, each of said heat exchangers comprising; a flow of cold-producing liquefied methane; a high-pressure flow of a two-phase mixture of refrigerant fluids giving up its heat and including refrigerant fluids having a low normal boiling temperature; a low-presssure flow of a cold-producing two-phase mixture of said refrigerant fluids; means for expanding said cooled high-pressure flow at the outlet from said cascade and for directing at least a portion thereof to at least one refrigeration heat exchanger passing a gas including CO 2 , said heat exchanger operating in a frosting cycle; means for obtaining a liquid phase from said high-pressure flow for cooling; and means for expanding said liquid phase and directing at least a portion thereof into said at least one refrigeration heat exchanger, said heat exchanger operating in a defrosting cycle.