US Patent 7810330 Power generation using thermal gradients maintained by phase transitions

Power is generated from an ambient environment through the use of thermodynamic engines. A thermodynamic engine is disposed in the ambient environment and converts heat provided in the form of a temperature differential to a nonheat form of energy. Conditions in the ambient environment induce a phase transition in a heat-transport medium that causes the temperature differential. The heat-transport medium is renewed by allowing inducing a reverse phase transition in the heat-transport medium, permitting the heat-transport medium to repeatedly or continuously undergo the phase transition that causes the temperature differential.