Experimental and Numerical Evaluation of Thermal Performance of Parabolic Solar Collector Using Water/Al2O3 Nano-fluid: A Case Study

Energy demand keeps growing all over the world and is contributing to climate change. So, fossil fuels must be replaced by renewable energies. Solar energy is the most accessible energy in Iran as well as in many other countries. Parabolic solar collectors appear to be a very promising technology in solar energy absorption. Meanwhile, nano-fluids are known to improve the heat transfer capabilities in comparison with ordinary pure fluids. In this work, an experimental study was applied to solar collectors using water/Al2O3 nano-fluid located in a renewable energy site of Islamic Azad university of Khomenishahr branch followed by numerical simulations. Experimental tests were conducted for 2, 3, and 4 L·min−1 flow rates with pure water and 0.1 %, 0.2 %, and 0.3 % volume fraction of nanoparticles, respectively, with the results validating the numerical simulations. The results revealed that reductions in flow rate and elevations in volume fraction led to increased outlet temperature of solar collector, inlet and outlet temperature difference in collector, tank and radiator, and improved solar collector efficiency. Also, heat transfer coefficient rose with augmenting the flow rate and volume fraction.