Abstract: A heat engine (H) has a heat input means (10) and a work output means (20). A property of a first working substance is cyclically changed in a first subsystem forming a property modulator (1). The property modulator is provided with a work transfer input means (3) and a work transfer output means (4), a heat input means (10), a heat transfer input means (5) and a heat transfer output means (6), the sum of said work transfer input and said work transfer output being equal to zero over a cycle of the heat engine. The property modulator (1) is connected to a second subsystem forming an energy converter (2) wherein said change in the property of the first working substance of the property modulator induces a corresponding change in a property of a second working substance of said energy converter.