Experimental analysis and evaluation of a vacuum enclosed concentrated solar thermoelectric generator coupled with a spectrally selective absorber coating

Abstract

Significant research in the past decade has been focused on quantitatively and qualitatively validating potential of solar thermoelectric modules to harness electricity. In the present study, we have experimentally analysed steady-state temperature variation of a spectrally selective solar absorber coating (α = 0.954, ε = 0.13) with variation in solar irradiation flux (concentration ratios = 39, 50 and 65) using Fresnel lens and vacuum enclosure pressure (200 mbar to 900 mbar in steps of 100 mbar). It is observed that the experimental results so obtained go hand in hand with a COMSOL simulation model of the set-up. Further, we have carried out performance analysis of a solar thermoelectric generator (STEG) set-up enclosed in vacuum conditions equipped with Fresnel lens and absorber set-up coupled to Bi2Te3 thermoelectric module array electrically connected in series. The results depict a maximum power output of 0.91 W and a peak efficiency of 2.21% at a hot-side temperature of 642 K.

Keywords

• convective heat transfer
• optical concentration
• solar thermoelectric generator
• spectrally selective solar absorber coatings
• vacuum enclosure