Solar Energy, Vol.215, 131-143, 2021
Thermal performance of an evacuated tube solar collector with inserted baffles for air heating applications
The thermal performance of an evacuated tube solar air collector with inserted baffles (ETSACIB) was investigated experimentally and analytically investigated under the indoor solar thermal simulator. The effects of the operating parameters such as flow rate, inlet air temperature, baffle length and solar insolation on the thermal behaviour of ETSACIB system were analyzed. Experiments were performed different flow rates of air (100-1000 kg/h). The maximum temperature rise of 42.8 degrees C was achieved with the lowest thermal efficiency of 35.31% at the flow rate of 100 kg/h. The experimental results show that a heat transfer enhancement in terms the thermal efficiency is obtained with inserted baffle arrangements. An increase in the inlet temperature of air causes a decrease in temperature rise as well as the thermal efficiency of the collector. The results indicated that the increase in baffle length has a positive impact on temperature rise and thermal efficiency but induces higher pumping power. It is concluded that the developed evacuated tube solar air collector has sufficient potential for industrial process heating applications.