Numerical and Experimental Investigation of an Evacuated Tube Solar Collector Performance Using Different Nanofluids

Nanofluids are highly effective in enhancing the performance of heat transfer devices due to their high thermal conductivity. Various types of nanoparticles have been utilized, making these nanofluids particularly beneficial for renewable energy applications, such as solar collectors. Evacuated tube solar collector (ETSC) is widely used in thermal applications. This paper presents a study using a mathematical model to evaluate the performance of an ETSC using different nanofluids materials under different climatic conditions in Cairo, Egypt. The mathematical model was validated through experimental tests using water as the working fluid at different flow rates, demonstrating the model's reliability. The study also compared the performance using different nanoparticles (Cu, Ag, and 〖Al〗_2 O_3) at different concentrations. The key findings showed that increasing the volume concentration of hybrid nanoparticles increased the outlet temperature, with Ag yielding the highest temperature increase, followed by Cu, and then 〖Al〗_2 O_3, across various inlet temperatures and flow rates.