A detailed thermal modeling of a passive single-slope solar still with improved accuracy

Abstract

In the present study, a comprehensive approach is introduced to model a passive single-slope solar still. This approach is a proposed combination of Nusselt and Sherwood numbers. Unlike the conventional approach of solar still modeling which assumes the mean value of top glass pane and brackish water temperatures for the humid air temperature, the present thermal modeling includes the energy balance for humid air. Hence, the thermophysical properties of humid air are more accurately determined. Furthermore, the inclusion of brackish water salinity in equations as a decisive and effective parameter helped a lot with better determination of brackish water thermophysical properties. The top glass cover, brackish water and basin liner temperatures were determined by the proposed thermal modeling approach and the four well-known models i.e. Dunkle's model, Chen et al.‘s model, Clark's model and Zheng Hongfei et al.‘s model and the results were compared with the experimental data reported in literature. It was observed that the proposed thermal modeling approach is able to predict the temperatures of all three aforementioned components with higher coefficients of correlation and lower error values. Hence, the proposed approach provided a more accurate simulation for studying the thermal behavior of passive single-slope solar stills.