Abstract: A method and system for converting thermal energy into mechanical energy and producing a flow of pressurized gas in a closed loop with a gas pressurizing unit, a heat storage unit, a cooling unit and a gas absorption unit. The gas pressurizing unit includes a tank in which a mother liquor such as a mixture of ammonia and water is vaporized to produce the pressurized gas flow. The pressure in the tank pumps the mother liquor up against gravity through a second heat storage tank which is part of the heat storage unit and to the cooling unit where the liquor is injected into a third cooled tank forming a part thereof. From the third tank the liquor flows through a microporous tube in a fourth tank forming part of the gas absorption unit where the liquor absorbs spent gas which is supplied thereto.