Ceramatec Inc. and partner Georgia Institute of Technology are developing a modular heat engine power block for distributed CSP with an estimated efficiency higher than 50%. These generators will be most similar to thermoelectric generators, though the ion expansion engines are considerably more efficient. This project was announced on September 16, 2015 at the Solar Power International conference. Read the press release.
The modular heat engine power block, referred to as a sodium ion expansion engine, will be able to convert heat directly into electricity without moving parts. This technology is made possible by taking advantage of solid-electrolytes – materials that have previously been successfully commercialized by Ceramatec. Unlike previous versions of this technology, this approach will use multiple internal stages, resulting in more efficient conversion of heat to electricity at lower temperatures.
The key to the project’s innovation is the use of Ceramatec’s patented NaSelectTM and b-Alumina solid electrolytes, which have high sodium ion conductivities, for operation in a dual stage heat engine. The modular multi-stage sodium ion expansion heat engine has the potential to be highly efficient. This power cycle could achieve efficiency that is more than 92% of the theoretical maximum for converting heat to electricity over the operating temperatures.