Abstract: An energy conversion device comprising at least one thermal energy input, a plurality of energy outputs, a first modular part and a second modular part, wherein: the first modular part comprises at least a core Brayton generator; the second modular part comprises at least a heat pump module comprising at least one heat exchanger; and wherein the heat pump is integrated with the first modular part in order to share at least one heat exchanger between the first and the second modular parts, as well as set of valves and variable speed mechanical coupling and gear box. The core Brayton generator comprises an expander module and a compressor module configured to be positive displacement machines of the screw type with the expander module supplying motive power to the second modular part.