Waste heat recovery from the biomass engine for effective power generation using a new array-based system

Abstract

Thermoelectric generator (TEG)-thermosyphon-based heat recovery system (HRS) for harvesting the heat from the high temperature sources is a well-known technology for power generation. However, various thermal resistances (a total of nine) are involved in the thermosyphon-based HRS between the heat sources and TEGs which generate irreversibility that ultimately reduces its performance. In this work, a new design of HRS i.e. TEG-array-based is proposed for effective power generation even at low temperatures of sustainable heat source by minimizing the thermal resistances. This TEG-array-based HRS is driven by a salt gradient thermal storage device (SGTSD) which is used for efficiently recovering and storing of sustainable waste heat generated from a biomass(renewable energy)-based engine-generator. The proposed system is experimentally studied to analyse the temperature variations in SGTSD, characteristics of sustainable waste heat temperature, and performance features of TEGs in terms of obtained electrical parameters, output power and conversion efficiency. The experimental results showed that the maximum open circuit voltage, output power and conversion efficiency of TEG are obtained as 81.62V, 7.438W and 4.63\\% respectively. With this proposed system, seven thermal resistances (out of total nine) are totally eliminated while the others two are lowered that leads to effectively transfer the energy from sustainable heat source to TEGs via minor equivalent thermal resistance of 0.01198oC/W. The proposed system is found to be capable of charging a 12 V, 80 Ah heavy-duty battery for real life applications.