U.S. patent application 20180320518 (inventor Yanming Wei, Ontario, Canada):
"A new kind of solid-liquid-solid cyclic phase change heat engine is presented with optional but highly recommended multiple cylinders aka multiple stages cascading powertrain. Unlike the traditional Rankine engine or Stirling engine, hereby the gaseous phase is prohibited, and the conventional turbine is abandoned too. Under the drive of heat flux, low expansion volume of the working Phase Change Material (PCM) replaces the high expansion volume of hot gas, and in compensation, high expansion pressure replaces the low expansion pressure of hot gas. ... Inspired by [Donald] Trump's book “the art of deal,” I audaciously make technical trade-off to combine but isolate standard hydraulic oil and PCM in a hydraulic ensemble, despite minor existence of PCM leakage, corrosion and excessive friction, which are caused by the non-ideal viscosity & fluidity."