A thermosiphon cooling device including: at least one evaporator section including at least one evaporation channel arranged to receive heat and evaporate a liquid in the at least one evaporation channel and a liquid return path for delivering condensed liquid to the at least one evaporation channel , the at least one evaporation channel and the liquid return path being formed as a single, integrated part; at least one condenser section including at least one condensing channel arranged to transfer heat from evaporated liquid to a surrounding environment to condense the evaporated liquid and a vapor supply path for delivering evaporated liquid to the at least one condensing channel , the at least one condensing channel and the vapor supply path being formed as a single, integrated part; the device being characterized by a single manifold having a vapor chamber fluidly connecting the at least one evaporation channel with the vapor supply path and a liquid chamber fluidly connecting the at least one condensing channel with the liquid return path , the vapor chamber and the liquid chamber being separated by a separation wall in the manifold , for maintaining a cyclical flow in the thermosiphon device , from the evaporation channel into the vapor chamber , into the vapor supply path , into the at least one condensing channel , into the liquid chamber , into the liquid return path , and then into the evaporation channel , wherein the at least one evaporation section is received at a corresponding opening of the manifold , wherein the at least one evaporation channel is in fluid communication with the vapor chamber and the liquid return path is in fluid communication with the liquid chamber , and the at last one condenser section is received at a corresponding opening of the manifold , wherein the at least one condensing channel is in fluid communication with the liquid chamber and the vapor supply path is in fluid communication with the vapor chamber . at least one evaporator section including at least one evaporation channel arranged to receive heat and evaporate a liquid in the at least one evaporation channel and a liquid return path for delivering condensed liquid to the at least one evaporation channel , the at least one evaporation channel and the liquid return path being formed as a single, integrated part; at least one condenser section including at least one condensing channel arranged to transfer heat from evaporated liquid to a surrounding environment to condense the evaporated liquid and a vapor supply path for delivering evaporated liquid to the at least one condensing channel , the at least one condensing channel and the vapor supply path being formed as a single, integrated part; the device being characterized by a single manifold having a vapor chamber fluidly connecting the at least one evaporation channel with the vapor supply path and a liquid chamber fluidly connecting the at least one condensing channel with the liquid return path , the vapor chamber and the liquid chamber being separated by a separation wall in the manifold , for maintaining a cyclical flow in the thermosiphon device , from the evaporation channel into the vapor chamber , into the vapor supply path , into the at least one condensing channel , into the liquid chamber , into the liquid return path , and then into the evaporation channel , wherein the at least one evaporation section is received at a corresponding opening of the manifold , wherein the at least one evaporation channel is in fluid communication with the vapor chamber and the liquid return path is in fluid communication with the liquid chamber , and the at last one condenser section is received at a corresponding opening of the manifold , wherein the at least one condensing channel is in fluid communication with the liquid chamber and the vapor supply path is in fluid communication with the vapor chamber . <EOS>