Thermodynamic studies and maximum power point tracking in thermoelectric generator–thermoelectric cooler combined system

• Thermodynamic models of TEG-TEC combined system is developed and analysed.
• Impact of MPPT in the thermoelectric generator–cooler combined system is studied.
• Improvements in the system efficiency and cooling power have been achieved.
• Optimum duty cycle of operation of the combined system has been determined.
• The effect of heat source temperature and heat transfer area is also studied.

Thermoelectric generator (TEG) operated thermoelectric cooler (TEC) is a highly compatible combination for low-cooling power application. The conventional TEG–TEC combined systems have low operating efficiency and low cooling power because maximum power output from the TEG is not fully utilized. This paper proposes and analyses the combined system with maximum power point tracking technique (MPPT) to maximize the cooling power and overall efficiency. This paper also presents the effect of TEG, TEC source temperature and the effect of heat transfer area in the performance of the combined system. The thermodynamic models of the combined system are developed in MATLAB simulink environment with temperature dependent material properties and analysed for variable operating temperatures. It has been found that, in the irreversible thermodynamic model of the combined system with MPPT, when the hot and cold side of TEG and TEC are kept at a temperature difference of 150 K and 10 K respectively, the power output of TEG increases from 20.49 W to 43.92 W, cooling power of TEC increases from 32.66 W to 46.51 W and the overall combined system efficiency increases from 2.606% to 4.375% respectively when compared with the irreversible combined system without MPPT. The characteristics improvements obtained by this practice in the combined system for the above mentioned operating conditions is also true for other range of operating temperatures. It is also been observed that the external irreversibilities decreases the cooling power and the overall system efficiency of the combined system by 36.49% and by 16.9% respectively.