Patent ID: 8350444

Claim:
An apparatus for converting heat to electric energy, comprising: (a) a first electrode formed of a thermally and electrically conductive material; (b) a second electrode formed of a thermally and electrically conductive material, wherein the second electrode is spaced from the first electrode; (c) one or more layers of electrically polarizable material between the first and second electrodes; (d) one or more heat exchangers for removing thermal energy from or adding thermal energy to the one or more layers of electrically polarizable material; (e) a control circuit, the control circuit: thermally cycling the one or more layers of electrically polarizable material between a first temperature T 1 and a second temperature T 2 by alternately adding thermal energy to and withdrawing thermal energy from the one or more layers of electrically polarizable material using the one or more heat exchangers, wherein the electrically polarizable material exhibits spontaneous polarization at T 1 and wherein the spontaneous polarization exhibited by the electrically polarizable material at T 2 is less than the spontaneous polarization exhibited by the electrically polarizable material at T 1 ; wherein a DC poling voltage is applied to the one or more layers of electrically polarizable material such that, when the material is in a first portion of the cycle which includes the temperature T 1 , the electrically polarizable material develops an overall net spontaneous polarization and screening charges are generated on the first and second electrodes; and wherein the first and second electrodes are connected to a load such that electrical energy is output from the first and second electrodes to the load when the electrically polarizable material is in a second portion of the cycle which includes the temperature T 2 ; and wherein residual charges are left on the first and second electrodes after electrical energy is output to the load and wherein the residual charges provide the DC poling voltage for the next cycle.