A pyroelectric energy converter which employs regeneration

A single-stage regenerative pyroelectric heat engine has been built and tested. The pyroelectric engine converts heat directly into electrical energy. The efficiency of the conversion process was directly measured (the first such measurement for any pyroelectric conversion process). The measured 0.4% efficiency is 16 times larger than the so-called van der Ziel limit. Further improvements of efficiency are discussed. The engine's power density (at 0.13Hz) was 17 Watt per liter of ferroelectric material. This early progress indicates that multi-stage pyroelectric engines operating at higher frequencies may achieve 2 kW per liter with efficiencies of 10% to 20%.