Abstract: A heat transformation device which is compact and effective for recovering waste heat from one or more sources which sources may have different temperatures, comprises a closed cylinder containing a working piston made of heat conducting material and at least one impact piston which is constructed to act as a recuperator. Electromagnetic means are provided to suddenly move the impact piston when it absorbs heat from an end of the cylinder into contact with the working piston. The cylinder is filled with a low molecular weight, low density gas which has high specific heat and is preferably compressed.

Abstract: In an induction energy transfer device comprising a static power conversion circuit for producing an alternating magnetic field of ultrasonic frequency of the type wherein the static power conversion circuit includes a parallel resonant circuit which comprises a coil which also couples power across an air gap, an improvement in efficiency and power transfer is obtained by including at least two such parallel resonant circuits in the power conversion circuit, one of which resonant circuits is tuned to the third harmonic of said fundamental frequency.