Abstract: A method of recovering energy by means of a cyclic thermodynamic process which is induced by means of a medium comprising at least two substances or groups of substances, one of which substances is separated from the other at a point w' defining a first thermodynamic parameter of the medium and combined with the other one of said substances at a second point w" defining second thermodynamic parameter of the medium while a differential in total pressure of the medium is maintained between the two points. The separation and combination of the two substances are induced by diffusion whereby one of the substances or groups of substances is diffused out of the other one of the substances or groups of substances at the first point and diffused into the other substances at the second point.