Cylindrical thermoelectric generator with water heating system for high solar energy conversion efficiency

Thermoelectric generator (TEG) with water heating system, which utilizes solar energy with a high total energy conversion efficiency, is promising environmental technology for eco-housing and factories to reduce their carbon footprints. In this study, a newly developed cylindrical TEG consisting of ring-disk thermoelectric material is proposed showing that the total energy conversion efficiency is higher than that of a conventional pillar type TEG. The cylindrical TEG is implemented using high-performance CoSb3-based filled skutterudite thermoelectric materials and a unique 45Ni-55Fe electrode as the hot-side junction. The solar TEG performance is demonstrated under the real sunlight, which is concentrated by a Fresnel lens. The maximum thermoelectric efficiency of the presented solar TEG is 1.8%, with a water heating efficiency of 59% when the temperature difference across the TEG is 428 degrees C. Further improvement should be achieved by lowering the internal resistance of the TEG and increasing the average dimensionless figure of merit of the thermoelectric materials.