Concentrated solar thermal energy harvesting using Bi2Te3based thermoelectric generator

Abstract

This paper presents the harvesting of concentrated solar thermal energy using Bismuth telluride (Bi2Te3) based thermoelectric generator. An experimental setup was made which consist of Fresnel lens which concentrates the solar thermal energy and makes to fall on the 4 × 4 cm2 Bi2Te3 based thermoelectric generator hot side. Aluminum fins are provided on the other side of TEG. Openings are filled with nanoAl2O3 -OM35PCM composite material. PCM is mixed with nanoparticles to increase the thermal conductivity of PCM. Due to the temperature difference between the hot and the cold side of TEG,a voltage is generated. A greatest of 0.615 V is generated with a hot side temperature of 140 °C and cold side temperature of 44 °C in the day time. The maximum current developed by a single TEG is about 84.9 mA in the day time. During the day time, the Nano-PCM mixture changes its phase from solid to liquid and stores heat energy. During the night, heat energy stored in the nano-PCM mixture releases and its phase changes from liquid to solid. During this process, it will create a temperature difference between the top side and bottom side of the TEG resulting voltage across the TEG. The maximum voltage generated during the night is 89 mV. Thus day and night energy harvesting are obtained using thermoelectric and latent heat effects.