A compact energy cycle construction that utilizes a working fluid in its operation is disclosed having a compact housing of a generally cylindrical form, an orbiting scroll type expander, a central shaft which is driven by the expander, a generator having a rotor and a stator with the central shaft being mounted to the rotor for rotating the rotor relative to the stator, a pump mounted to the central shaft, an evaporator positioned between the expander and the generator and surrounding the central shaft, and the orbiting scroll type expander, the central shaft, the generator, the pump, and the evaporator being housed within the compact housing to form an integrated system operable in accordance with an energy cycle.