An energy conversion device for generating
electricity includes a
heat exchanger adapted to receive heat from a heat source. A closed magnetohydrodynamic (MHD) circuit includes a section for extracting heat from a
heat exchanger so as to raise the temperature of the flowable
electrically conductive material within the MHD circuit. The
heat exchanger includes a heat-conductive support adapted to be heated, and a heat-extracting section of the MHD circuit extracts heat from the support. The support may be a
metal plate having a sinuous
pipe arrangement in heat-conductive contact against each face, one of these
pipe arrangements being part of a circuit for heating the plate and the other
pipe arrangement being part of the MHD circuit. The heat source may be
combustion of a fuel, solar, geothermal,
chemical reaction, or
waste heat in the form of a hot gas. The heat conductive support may be a
metal tube heated, usually by a hot gas, in which case the heat-extracting section of the MHD circuit includes a
helical pipe surrounding the tube. The heat-providing means may include a lens arrangement for concentrating solar
radiation on one face of the heat exchanger plate.