Waste heat regeneration from thermoelectric generator based improved biomass cookstove (TIBC): Modelling of TEG system utilizing DC-DC converter with fuzzy logic MPPT

Abstract

Most of the people in the rural areas cook their food in traditional biomass cookstove which emits a lot of emission that leads to poor health of the women and children. This paper points out a technology that utilises a thermoelectric generator (TEG), which converts thermal energy into electrical energy directly. A TEG is a small plate made of semiconductor p-n junctions connected electrically in series and thermally in parallel. The difference in temperature produced on the hot side and cold side of the TEG is proportional to the voltage generated. The TEG is integrated into the wall of the inner combustion chamber of the biomass cookstove with the help of heat plate and the cold side of the TEG is connected to a flower-type heat sink to maintain the temperature difference. The power generated by the TEG is used to drive a 12 V DC fan which helps to keep the cold side of the TEG relatively cooler and direct the same air inside the inner combustion chamber of the cook stove through holes to increase the air-to-fuel ratio. As a result, it improves the cookstove's combustion, thereby reducing emissions and increasing thermal efficiency. For testing the efficiency of the TEGs available in the market, a hit and trial method is used by taking TEGs of different specifications and connecting them to a hot side and a cold side test bed and then finally the performance is realized. Therefore, for every different TEG, a hardware has to be made for final conclusion of the result. To eliminate the hit and trial method, the electrical characteristics of thermoelectric generator module has been analysed by modeling a TEG module in MATLAB/Simulink and implementing it with fuzzy logic control (FLC) based MPPT utilizing a DC-DC boost converter with a constant as well as variable load. This fuzzy logic-based scheme exhibits fast dynamic response and precisely tracks the maximum power point (MPP) from TEG under varying load conditions. Based on the robust performance of the obtained simulation results, the TEG module is integrated and tested in the laboratory using a thermoelectric generator based improved biomass cookstove (TIBC). The novelty lies on the concept of using MATLAB/Simulink platform by modeling the FLC based MPPT incorporating boost converter to test the performance of TEG module for its integration with TIBC and eliminating traditional hit and trial method. This TIBC is able to power the fan directly within just 2–3 min using the electricity generated by the TEG module. The maximum power generated from the TIBC is 6.25 W using a single TEG. The fan requires 1.4 W and rest of the power was used to charge auxiliary battery.