Low-temperature refrigeration system

A refrigeration system comprising:

• first and second refrigerant circuits each having a compressor, a condense and an evaporator, the outlet of the compressor being connected to the inlet of the condenser by a line, the outlet of the condenser being connected to the inlet of the evaporator by another line, the outlet of the evaporator being connected to the inlet of the compressor by another line, each of the refrigerant circuits being charged with an organic refrigerant,
• the evaporator of the first refrigerant circuit being divided into a plurality of evaporator portions connected together in series with respect to the flow of the refrigerant, the refrigerant of the first refrigerant circuit flowing successively into the evaporator portions,
• the condenser of the second refrigerant circuit being divided into condenser portions equal in number to the number of the evaporator portions of the first refrigerant circuit, the condenser portions being connected together in parallel with respect to the flow of the refrigerant, the refrigerant of the second refrigerant circuit being divided into volumes equal in number to the condenser portions to flow into each of them,
• the condenser portions of the second refrigerant circuit being paired with the evaporator portions of the first refrigerant circuit to provide heat exchangers, the refrigerant of the second refrigerant circuit being a mixture of refrigerants different in kind and in boiling point,
• whereby the evaporator of the second refrigerant circuit is cooled to cool the storage chamber to a cryogenic temperature. mixture of refrigerants different in kind and in boiling point, whereby the evaporator of the second refrigerant circuit is cooled to a cryogenic temperature.