A refrigeration device having a closed circuit in which a flow rate of coolant is circulating is provided. The closed circuit has a condenser and a main branch provided with a reciprocating compressor inside which a defined flow rate of the coolant enters, from the main branch, at a defined suction pressure, of an evaporator and a first expansion valve that is arranged between the condenser and the evaporator. The closed circuit further has a first secondary economizer branch for a first fraction of flow rate of the coolant, the first secondary economizer branch fluidically connecting the compressor to a section of the closed circuit between the condenser and the first expansion valve, wherein the compressor has a first side inlet port for the entrance of the first fraction of coolant flow rate.