On the Efficiency of Solar Radiation Conversion into Steam, Production of Clean Water, and Generation of Electrical Energy

Abstract

This study focuses on the development of a model for evaluating the efficiency of converting solar radiation into thermal energy. The efficiency coefficient is represented as a function of multiple variables, including system geometry, time, properties of the working fluid, and external parameters. The developed model is a simplified version and is applicable to systems with a stationary working fluid undergoing heating and vaporization due to solar radiation. Calculations were performed based on the model using a gold-water nanofluid. The results of the calculations demonstrated the existence of an optimal range of optical thickness and nanoparticle concentration, where the working fluid is effectively heated and vaporized. It is shown that the efficiency of systems employing nanofluids as heat transfer fluids cannot be evaluated solely based on the absolute value of the heating efficiency coefficient. However, it can be assessed through its derivative with respect to time. The faster the heating efficiency coefficient decreases over time, the more efficient the system is in terms of heating, and the sooner it reaches a steady-state condition. The developed model serves as a foundation for the advancement of more sophisticated models that allow for the evaluation of various other factors, such as complex geometries with forced fluid flow, the nature of interactions between nanoparticles and the base fluid, as well as mechanisms of solar radiation conversion into thermal energy.