Refrigeration apparatus having a closed circuit (C) in which a flow rate (P) of coolant circulates, said closed circuit comprising at least one main branch (M) provided with at least one main compressor , at least one cooling device to cool said coolant, expansion means to expand the coolant and at least one evaporator , said closed circuit further comprising at least one secondary economizer branch for at least one fraction of flow rate (X1) of said coolant, wherein the inlet section of said at least one first secondary economizer branch is arranged in a length of said closed circuit (C) comprised between said cooling device and said expansion means and the outlet section of said at least one secondary economizer branch is arranged in proximity of the suction of said main compressor , said apparatus being characterized in that said main branch (M) further comprises at least one reciprocating compressor arranged between said evaporator and said main compressor and provided with at least one cylinder , at least one rod and at least one piston , the latter being integrally constrained to said at least one rod and translatable inside said cylinder, and in that said at least one secondary economizer branch comprises at least one control device for controlling the actuation of said at least one rod and adapted to divert at least one portion (X2) of said fraction (X1) of coolant coming from said secondary economizer branch to drive the displacement of said at least one piston and compress the coolant coming from said evaporator and contained in said cylinder, and to reintroduce said at least one portion (X2) of fraction of coolant into said secondary economizer branch during the displacement of said at least one piston in the step of suctioning the coolant coming from said evaporator, for the outflow of said at least one portion (X2) of fraction of coolant through said outlet section of said at least one secondary economizer branch , wherein said outlet section of said at least one secondary economizer branch is arranged downstream of said reciprocating compressor , said cylinder being provided with a first chamber comprising a first port for the inflow of the coolant coming from said evaporator and a second port for the outflow of the compressed coolant contained in said first chamber in order to reach said main compressor , said cylinder further comprising a second chamber fluidically separated from said first chamber by said piston and provided with at least one third port for the inflow of said portion (X2) of said at least one fraction (X1) of coolant for displacing said piston and compressing said coolant contained in said first chamber , said at least one third port being further suitable for the outflow of said portion (X2) of said fraction of coolant, at the end of the compression of the coolant contained in said first chamber , in order to reach said outlet section of said secondary economizer branch , said control device for controlling the actuation of said rod comprising at least one inflow section fluidically connected with said secondary economizer branch , at least one outflow section fluidically connected with said outlet section of said secondary economizer branch , and cut-off means switching between a first configuration (C1), wherein the fluidic connection between said inflow section and said at least one third port is allowed, for the inflow of said portion (X2) of said fraction (X1) of coolant into said second chamber , and a second configuration (C2), wherein the fluidic connection between said outflow section and said at least one third port is allowed, for the outflow of said portion (X2) of said fraction (X1) of coolant from said second chamber and the fluidic connection between said inflow section and said at least one third port is not allowed. <EOS>