Thermoelectric Generator–Integrated Solar Air Heater: A Compact Passive System

Solar air heater is a promising, economically viable, and matured technology for space heating and drying applications. One of the primary reasons for the limited usage of a solar air heater in developing countries is the unavailability of continuous electricity supply. Although the solar air heater is theoretically passive, practically electrical energy is required to achieve a steady airflow. Therefore, the unreliability of electricity forces people to rely on firewood for heat during the cold weather, which has severe effects on health and climate change. In the present work, the potential of thermoelectric generators (TEGs) to meet the electrical energy requirement of a solar air heater is studied. Two configurations, each with three different numbers of stages of TEGs, are analyzed. The effect of the integration of TEGs on the thermal performance of solar air heater is analyzed alongside the comparison between the electrical energy required by solar air heaters and electrical energy generated upon the integration of TEGs. A numerical model is developed in matlab and validated using the experimental results. One of the designs meets the electrical energy requirement of the fan in a wide operational range but lowers the process heat generation by approximately 1–6.25%. The electrical energy generated by the other design falls short of demand posed by the system in most operating range. However, the thermal energy generation is marginally higher compared to that of the conventional solar air heater.