Abstract: There is disclosed a heat-transferring device comprising a buffer tank (1), a reactor vessel (2) in thermal contact with the buffer tank, wherein an active substance is held inside the reactor vessel, a burner (A), a reactor heating loop adapted to transfer heat from the burner to the active substance in the reactor vessel, a reactor cooling loop adapted to transfer heat from the active substance in the reactor vessel to the buffer tank, a volatile liquid reservoir (14) in fluid contact with the reactor vessel, an evaporator (15) in fluid contact with the volatile liquid reservoir, a volatile liquid in the volatile liquid reservoir, with the ability to be absorbed by the active substance at a first temperature and desorbed by the active substance at a higher temperature, an exhaust gas pipe (10,11,12) from the burner to the volatile liquid reservoir to heat it.