Transient and non-uniform heat flux effect on solar thermoelectric generator with phase change material

Abstract

Transient and non-uniform heat flux from solar concentrators can affect the performance of solar thermoelectric generators, which generate electricity from concentrated solar radiation. Therefore, this paper presents a detailed three-dimensional study on the effect of transient and non-uniform heat flux on the performance of a solar thermoelectric generator (STEG). COMSOL 5.4Multiphysics software is utilized for the numerical study while the non-uniform heat flux from a compound parabolic concentrator is obtained through ray tracing simulation using Lighttools software. Varying solar radiation under typical partly cloudy weather condition is utilized. Furthermore, phase change material (PCM) is used to reduce the effect of transient and nonuniform heat flux therefore; it is positioned at the top surface of the solar thermoelectric generator.A comparison between the performance of the STEG with and without PCM is presented, and a parametric study on the effect of PCM fins and PCM height on the STEG performance is carried out. Results show that the place of PCM on the top surface of the solar thermoelectric generator is an effective approach to provide a stable electrical performance form the STEG under varying weather conditions. Furthermore, results reveal the effectiveness of the phase change material in protecting the solar thermoelectric generator under highly concentrated solar radiation. This study will provide valuable design guidance for solar thermoelectric generators under varying weather conditions and with solar concentrators, which produce non-uniform heat flux.

Analysis of thermoelectric geometry in a concentrated photovoltaic-thermoelectric under varying weather conditions

“…where is the Stefan-Boltzmann constant, is emissivity and is sky temperature which is given as [34]:…”

Comparative investigation of concentrated photovoltaic thermal-thermoelectric with nanofluid cooling

“…The combination of PV and TE enables the utilization of a larger solar spectrum because the photovoltaic utilizes the visible and ultra-violet parts of the solar spectrum whereas the thermoelectric uses the infrared part [14]. Furthermore, a TE generator is a viable clean energy technology capable of generating electricity directly from waste heat via the Seebeck effect [15][16][17][18][19]. Thermoelectric generators are small size, reliable energy converts that provide zero noise due to the absence of moving mechanical parts and they cause no damage to the environment because of zero pollution [20].…”

Advances and outlook of TE-PCM system: a review

“…The maximum output power of the R-STEG is 60%, higher than that of the typical STEG at solar intensities of 1 kW/m 2 . Maduabuchi and Shittu et al also validated the effect of PCM placed at the hot junction of STEG acting as thermal medium layer through numerical simulation [151,152]. The results demonstrate that PCM lens dramatically alleviates the adverse effect of transient and non-uniform solar radiation.…”