Optimizing the efficiency of solar thermal collectors and studying the effect of particle concentration and stability using nanofluidic analysis

Abstract

The emission of greenhouse gases is widely acknowledged as the primary driver of global warming. The adoption of renewable energy sources is paramount to address the dependence on fossil fuels, which contribute significantly to this issue and account for 84.3% of current energy production. Solar thermal energy stands out as a prominent option, representing 54.1% of the world's solar energy derived from solar collectors. However, solar thermal energy encounters challenge due to the suboptimal thermal properties of the liquids used in these collectors. Incorporating particles into the liquids offers a potential solution to enhance absorption and thermal properties. Nanofluids, formed by reducing solid particles to nanoscale dimensions, provide an avenue for improvement. This study aimed to produce an Ag nanofluid through mechanical exfoliation and assess its impact on radiation absorption compared to a GO nanofluid. Under a simulated power of 1 unit, the Ag nanofluid demonstrated temperature differences of 4 to 7°C, while pure water showed no significant deviation. Moreover, the evaporation efficiency of the Ag nanofluid reached up to 40.8% for concentrations of 200 and 500 ppm, compared to 28.6% for pure water. These findings highlight the potential of Ag nanofluid as a promising option for direct absorption solar collectors, owing to its cost-effectiveness, low toxicity, and similar benefits to graphene. Incorporating nanofluids, particularly the Ag nanofluid produced through mechanical exfoliation, can significantly enhance the efficiency of direct absorption solar collectors.