Outdoor Performance of a Thermoelectric Heat-Pumping Solar Air Heater

Thermoelectric (TE) devices reliably convert electricity to heat (and vice versa) without moving parts. They can be integrated into solar energy devices to improve thermal energy conversion in various applications. This study aimed to experimentally investigate the improvement in the efficiency of a solar air heater (SAH) by incorporating TE modules. Eleven TEC1-12706 TE modules, with their cold sides affixed to the rear of the SAH absorber plate, were installed in the model SAH we assessed. Photovoltaic modules provided direct current to the TE modules to create a temperature difference across the surface of the TE modules. This propelled heat transmission to the air moving beneath the absorber plate as the TE modules extracted heat from the absorber plate through their cold to their hot sides. Under the same ambient conditions of 38.6°C maximum ambient temperature and maximum insolation of 380.6 W/m², this thermoelectric heat-pumping solar air heater (TE-SAH) demonstrated a notable gain in efficiency over the classic SAH, with an average efficiency of 23% compared to the latter's 18%. The maximum collector outlet temperatures were 61°C and 56.5°C, respectively. These indicated mean efficiency and outlet temperature gains of 31.5% and 8%, respectively. At an air mass flow rate of 0.013 kg/s, the TE-SAH achieved a peak efficiency of 74%, whereas the standard SAH recorded a peak efficiency of 57%. This work introduces a new strategy for enhancing the performance of SAH systems. It shows the significant improvement in efficiency that thermoelectric technology can produce when paired with a conventional SAH system.