Paper Title
The Applications of Nanofluids in Solar Thermal Engineering System: A Review

Abstract
The shortage of fossil fuels and environmental considerations are motivated the researchers to do further research to improve utilization of solar energy. The nanofluids application is a relatively new for better performance on small change in volume and concentration, which is less than three decades old. The aim of this review paper is the nanofluids applications in solar thermal engineering systems. Therefore, it is essential to enhance the efficiency and performance of the solar thermal systems. this review paper allocated to the effects of nanofluids on the performance of solar collectors and solar water heaters, thermal energy storage, solar cells, and solar stills are reviewed. The challenges of using nanofluids in solar energy devices are also discussed.