A solar absorber device (2; 2'; 2"; 102; 202; 302) comprising a closed circuit arranged for the circulation of a thermovector fluid, said closed circuit comprising: - an evaporation side (4; 4'; 4"; 104; 204; 304) of said thermovector fluid, and - a condensation side (6; 6'; 6"; 106; 206; 306) of said thermovector fluid, wherein, furthermore: - the solar absorber device (2; 2'; 2"; 102; 202; 302) comprises a first and a second sheet made of metal material (S1, S2) connected to each other in correspondence of areas delimiting said closed circuit, - the evaporation side (4; 4'; 4"; 104; 204; 304) comprises a first and at least one second channel (8, 10; 108, 110; 208, 210; 308, 310) wherein said at least one second channel (10; 110; 210; 310) is in fluid communication with said first channel (8; 108; 208; 308), - said first channel (8; 108; 208; 308) is adapted to receive the thermovector fluid from said condensation side (6; 6'; 6"; 206; 306) in liquid phase and it is adapted to convey said thermovector fluid towards said at least one second channel (10; 110; 210; 310), - said at least one second channel (10; 110; 210; 310) is adapted to receive the thermovector fluid from said first channel (8; 108; 208; 308) and it is adapted to convey said thermovector fluid towards said condensation side (6; 6'; 6"; 106; 206; 306) in vapour phase, - the solar absorber device (2; 2'; 2"; 102; 202; 302) been characterized in that in said condensation side (6; 6'; 6"; 106; 206; 306) comprises a reservoir (14; 14'; 114; 214; 314) in fluid communication with said first and at least one second channels (8, 10; 108, 110; 208, 210; 308, 310) respectively in correspondence of an outflow port (16; 16'; 116A; 116B; 216; 316) and at least one inflow port (18, 18'; 118; 218; 318), and - in that said at least one second channel (10; 110; 210; 310) is in fluid communication with said reservoir (14; 14'; 114; 214; 314) by means of at least one siphon duct (20, 20'; 120; 220; 313; 320) comprising a first and a second bends (22, 24; 122, 124; 222, 224; 322, 324) arranged fluid dynamically in series. - an evaporation side (4; 4'; 4"; 104; 204; 304) of said thermovector fluid, and - a condensation side (6; 6'; 6"; 106; 206; 306) of said thermovector fluid, - the solar absorber device (2; 2'; 2"; 102; 202; 302) comprises a first and a second sheet made of metal material (S1, S2) connected to each other in correspondence of areas delimiting said closed circuit, - the evaporation side (4; 4'; 4"; 104; 204; 304) comprises a first and at least one second channel (8, 10; 108, 110; 208, 210; 308, 310) wherein said at least one second channel (10; 110; 210; 310) is in fluid communication with said first channel (8; 108; 208; 308), - said first channel (8; 108; 208; 308) is adapted to receive the thermovector fluid from said condensation side (6; 6'; 6"; 206; 306) in liquid phase and it is adapted to convey said thermovector fluid towards said at least one second channel (10; 110; 210; 310), - said at least one second channel (10; 110; 210; 310) is adapted to receive the thermovector fluid from said first channel (8; 108; 208; 308) and it is adapted to convey said thermovector fluid towards said condensation side (6; 6'; 6"; 106; 206; 306) in vapour phase, - the solar absorber device (2; 2'; 2"; 102; 202; 302) been characterized in that in said condensation side (6; 6'; 6"; 106; 206; 306) comprises a reservoir (14; 14'; 114; 214; 314) in fluid communication with said first and at least one second channels (8, 10; 108, 110; 208, 210; 308, 310) respectively in correspondence of an outflow port (16; 16'; 116A; 116B; 216; 316) and at least one inflow port (18, 18'; 118; 218; 318), and - in that said at least one second channel (10; 110; 210; 310) is in fluid communication with said reservoir (14; 14'; 114; 214; 314) by means of at least one siphon duct (20, 20'; 120; 220; 313; 320) comprising a first and a second bends (22, 24; 122, 124; 222, 224; 322, 324) arranged fluid dynamically in series.