A method and apparatus for generating power which includes a phase-change media (PCM) that expands upon cooling contained within an expandable capsule if the phase change involves solidification (if phase change is solid-solid, then capsules are not needed), a carrier liquid that does not freeze in the operating temperature range, a heat exchanger, and an engine. Alternatively, the method and apparatus can include a PCM contained within a layer next to the walls of a constant volume container, a working liquid within the container that does not freeze in the operating temperature range, a heat exchanger, and an engine. In both cases, the engine denotes a device that converts the energy in the high-pressure liquid into electrical or mechanical power.
US 8,683,803 B2
Bastawros, Ashraf F.; Chandra, Abhijit; and Shih, Tom I-Ping, "Method and apparatus for energy harvesting through phase-change induced pressure rise under cooling conditions" (2014). Aerospace Engineering Patents. 3.