Abstract: A closed cycle thermodynamic apparatus (10) is provided for powering a combustion machine. The apparatus (10) has a compressor (12) for compressing a working medium from a reservoir (14) at temperature T1. The temperature of the working medium increases during compression and reaches temperature T2 when leaving the compressor (12). It is then expanded in an expander (16) for turning the machine. In this manner mechanical work is extracted from the working medium. The apparatus (10) has a first heat exchanger (18) and a second heat exchanger (20) connected to the compressor (12) and the expander (16) in a closed cycle. It also has a burner (22) and a third heat exchanger (24). Air, as a Heat transfer medium, at ambient temperature T5 is induced into the second exchanger (20) to cool the working medium by receiving heat therefrom. The temperature of the working medium decreases from T4 to T1 before entering the compressor (12) for repeating the cycle.