Energy and economic analysis of thermoelectric generator on wood fuel

Oleg Marchenko,V.A Stennikov,P Changwei,J.-Y Yoon,B Sereter,S.V Alekseenko,F.-J Lin,N.A Yusifbeyli,N.I Voropai,S.P Filippov,C Rehtanz,M Negnevitsky

doi:10.1051/e3sconf/202020903017

Abstract

The advantages of thermoelectric generator (TEG) are the absence of moving parts, reliability, long service life, the possibility of fully automatic operation without maintenance. At the same time, TEGs also have disadvantages - low efficiency and high cost. In this regard, it is advisable to use them in autonomous installations of small power, as well as in devices intended mainly for heat supply, when the low efficiency of thermal energy conversion into electrical energy does not play a role. It is the latter case that is realized in furnaces that burn biomass. In this paper, we consider the main physical effects due to which the direct conversion of thermal energy into electrical energy occurs in semiconductor thermoelements. The conjugate problem of heat and electric charge transfer with temperature-dependent properties of a semiconductor is reduced to a problem with constant properties. Based on the literature data, the boundary conditions for the TEG were selected, its sizes were optimized, current-voltage characteristics were constructed, and the maximum power and efficiency were determined. Estimates of the cost and economic efficiency of using TEG are made.

Highlights

Most technologies for using wood biomass for power supply to consumers include the stages of thermal and mechanical energy production
There are technologies that make it possible to obtain electrical energy without preliminary production mechanical energy. One of these technologies is the direct conversion of thermal energy into electrical energy in thermoelectric generators (TEG) [1, 2]
With variable properties of materials, the small value of thermoelectric effects in comparison with the heat transferred by thermal conductivity makes it possible to find a solution to the problem by the method of perturbation

Summary

Introduction

Most technologies for using wood biomass for power supply to consumers include the stages of thermal and mechanical energy production. There are technologies that make it possible to obtain electrical energy without preliminary production mechanical energy. One of these technologies is the direct conversion of thermal energy into electrical energy in thermoelectric generators (TEG) [1, 2]. It uses thermoelectric effects: a) the temperature gradient in a solid causes diffusion of the electric charge carriers (in a semiconductor – electrons and holes), i.e. electric current; b) electric current is accompanied by heat generation or absorption. The use of semiconductor materials, including those with a variable doping profile or composed of separate segments, each optimized for the corresponding temperature range, made it possible to achieve an efficiency of up to 12-15% [3]

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