Method of recovering energy from dry ice at infra-atmospheric pressure

Method of recovering energy produced by a phase change of dry ice, said method being implemented by a device (1) comprising: an enclosure (2) containing the dry ice at an infra-atmospheric pressure; a primary energy recovery circuit (3), in which a primary heat transfer fluid circulates, passing through the enclosure (2); a suction line (7) passing through a heat exchanger (9) before coming out at one end provided with a vacuum pump (11). The method comprising the following steps: passage of the heat transfer fluid into the primary circuit (3) causing the heating and the phase changing of the dry ice into gaseous CO2 and the cooling of the heat transfer fluid; extraction of the gaseous CO2 contained in the enclosure (2) by the suction line (7); substantially continuous lowering of the pressure of the enclosure (2) to the infra-atmospheric pressure, by the vacuum pump (11); and conveyance of the gaseous CO2 extracted from the enclosure (2) into the heat exchanger (9) in which the gaseous CO2 transfers heat to a secondary heat transfer fluid circulating in a secondary circuit (14). The disclosed device and method allows improved energy recovery by more optimally exploiting the thermodynamic properties of CO2 undergoing a sublimation phase change.