Johnson thermoelectric energy converter

A Johnson thermoelectric energy converter or JTEC is a type of solid-state heat engine that uses the photodecomposition and recombination of hydrogen in a fuel cell via an approximate Ericsson cycle. It is under investigation as a viable alternative to conventional photovoltaic cells. Lonnie Johnson invented it and claims the converter exhibits an energy conversion efficiency of as much as 60% compared to the 30% efficiency typical of the best photovoltaic cells; however, this claim is at a theoretical level based on comparison with a Carnot cycle and assumes a temperature gradient of 600C. It was originally proposed for funding to the Office of Naval Research but was refused. Johnson obtained later funding by framing the engine as a hydrogen fuel cell. Johnson is collaborating with PARC on development of the engine.

Mechanism of action

The JTEC converts heat into electrical energy by compressing and expanding hydrogen gas. It operates as a closed system with no moving parts, requires no input of fuel, and creates no exhaust. The engine consists of two stages: A low-temperature compression stage and a high-temperature power stage. Each stage consists of a working fluid chamber that a copper lined membrane electrode assembly (MEA) bisects. A MEA is a proprietary ceramic proton exchange membrane (PEM) that is sandwiched between two electrodes.