Experimental investigation and computational modelling of double slope solar still integrated with eutectic phase change material

Abstract

The scarcity of potable water in many parts of the world is of primary concern and it is mainly due to the abrupt increase in population growth, environmental pollution and rapid social development. Solar desalination system associated with PCM can be one of the prominent solutions for conversion of saline water into fresh water. The main disadvantage of using the organic PCMs was that no single PCM possessed all of the favourable features required to operate the solar still in any environment. As a result, combining two or more different types of organic PCMs to create binary eutectic PCM increases the thermo-physical properties of PCM. The current research includes conduction of an experimental study to compare the energy efficiency and hourly yield of traditional and modified double slope single basin solar still integrated with binary eutectic PCM. The ANSYS FLUENT 19.2 workbench is used to create a multiphase three-dimensional CFD model of the solar still in order to compare experimental and simulation results in the atmospheric conditions of Bhopal (23.24° N, 77.40° E), India. The maximum experimental value of freshwater yield obtained at 3 PM is 0.31 kg/m2 h while the maximum yield in simulated result is 0.35 kg/m2 h with 11.4% difference in experimental and simulated results. Similarly, in case of conventional solar still there is maximum deviation of 10.3% in simulated result as compared to experimental values. The incorporation of PCM enhanced the average energy efficiency of modified solar still to 30.42%, which was greater than traditional solar still efficiency (22.21%). The experimental value of daily energy efficiency is 30.42%, whereas simulated result is 33.15%, with 9.06% difference in experimental and simulated results of modified still. The CFD analysis was carried out and the experimental results like basin temperature, glass cover temperature, water volume fraction and surface water temperature were also compared with simulation results for validation. It infers that the simulated and experimental findings are nearly identical, with negligible deviation.