Method and device for providing sub-cooling of refrigerants

A refrigeration system (1) comprising a compressor (2), a condenser (3), an expansion valve (4), an evaporator (5) and a receiver (6) of a refrigerant, the compressor (2) providing the circulation of a refrigerant, the condenser (3) being cooled by a cooling medium circulating in a heat sink circuit (30), the evaporator (5) cooling the medium of a source circuit (50), a liquid refrigerant line (7) connecting the condenser (3) to the expansion valve (4), the evaporator (5) being placed downstream from the expansion valve (4) and upstream from the compressor (2), the refrigeration system (1) providing a transfer of heat from the medium to be cooled circulating in the source circuit (50) from the evaporator (5) to the heat sink circuit (30) of the condenser (3), wherein the receiver (6) is installed in a line connected in parallel with the liquid refrigerant line (7) that directly connects the condenser (3) to the expansion valve (4), wherein the receiver is connected to the liquid refrigerant line by two conduits, a first conduit provided with a valve (61) enabling the discharge of the refrigerant to the receiver, and a second conduit provided with a valve (62) enabling the discharge of the refrigerant to the expansion valve, the refrigeration system comprising measurers connected to an electronic controller (8) that controls opening of the valve provided on the first conduit and the valve provided on the second conduit, wherein the opening of the valve provided on the first conduit enables the discharge of refrigerant to the receiver and the opening of the valve provided on the second conduit enables the discharge of the refrigerant to the expansion valve.