Performance of a Thermoelectric Generator Partially Illuminated with Highly Concentrated Light

Abdelrahman Lashin,Mohammad Al Turkestani,Mohamed Sabry

doi:10.3390/en13143627

Abstract

In order to maximize the output of concentrator Photovoltaic cells and maintain their efficiencies, the operating temperature of concentrator photovoltaic cells must be reduced. A way that could reduce such photovoltaic temperature is by thermally attaching them on top of a thermoelectric generator. A thermoelectric generator in such coupling will act as a low-cost passive-cooling subsystem, as well as a power generator for producing additional energy from the rejected photovoltaic heat. Increasing the area of the proposed photovoltaic cells relative to the thermoelectric generator’s hot-side area will result in an increase in the thermoelectric generator’s electrical output, but may also result in overheating the photovoltaic cells, hence reducing their performance. Optimization has to be performed for the photovoltaic covering percentage relative to the hot-side area in order to maximize the output of the whole coupled system. This work investigates the electrical and thermal performance of thermoelectric generators in the case of partial illumination of their hot side. Experiments have been carried out using three thermoelectric generator modules with different areas, and under two levels of concentrated illumination. The thermoelectric generator output voltage, current, and temperature have been measured, and the figure-of-merit and maximum power of the thermoelectric generator (TEG) has been calculated and demonstrated.

Highlights

It is a fact that flat-plate modules is very cheap, but its efficiency is around 23% for single junction panels, except in laboratory cells under examination
It is believed that concentrator photovoltaic cells (CPV) are superior to flat-plate ones
This will certainly reflect on the cost/watt of the Employing such concentrated solar radiation will have two effects: (1) increasing solar radiation intensity will reduce the cost of the whole system, including the PV cell and the required spaces outdoors; (2) the necessity for reducing CPV cell temperature by a passive or active cooling subsystem in order to maintain a proper output

Summary

Introduction

It is a fact that flat-plate modules is very cheap, but its efficiency is around 23% for single junction panels, except in laboratory cells under examination. A proposed CPV/TEG coupled system [11] is composed of a large area Fresnel lens for concentrating solar radiation on a solar cell that is passively cooled by thermally attaching it to the top side of a TEG unit such that it covers only part of the top of the TEG surface. A factor that will definitely reduce the whole CPV/TEG system is that the elevation in PV temperature is not accompanied by the ability of the TEG to dissipate such high temperature by converting it into electricity This will result in increasing the temperature of the PV cells to levels that greatly impair its efficiency. This work focuses on investigating the performance of a TEG under partial illumination over its top surface with different covering percentages, as well as different light intensities in the case of partial illumination

Characterization of TEG Devices

Measurement and Calculation Method

Results and Discussion

Conclusions