Exergy Performance of a Natural Circulation Solar Collector System Using Aluminum Oxide, Copper, and Copper Oxide Nanofluids

Most of the global energy demand is related to the residential and commercial sectors. This significant share in the energy demand portfolio also shows a significant share of greenhouse gas emissions from the great cities. This is why renewable and other cleaner energy sources have been attractive in the last three decades. Solar collectors, energy storage, and photovoltaic cells are the most suitable clean technologies applicable to generate and store electricity, cooling, and heating demand in the residential sector. Due to this increasing attractiveness, much research has been done on those technologies to increase the systems' efficiency. One of the most important methods to improve these systems' performance can directly improve thermal conductivity and heat transfer. In this study, the collector is modeled in the system's fluent software and the main parameters
are estimated for different nanoparticles. Then an exergy analysis is done to find the entropy generation and exergy destruction of the system to detect the main sources of the irreversibility in the system. Also, the effect of different parameters is studied on the exergy efficiency of this system. The results show that the value of temperature generation in cold climates has been higher than in hot climates, and increasing the inflow and collecting water level has increased consumer water Temperature. Using copper nanofluids increases solar water heaters' efficiency by up to 67%, while aluminum oxide and copper oxide nanofluids have 74% and 47% efficiency, respectively.