Numerical modeling of a multi-storey solar still in transient mode

Abstract

Climate change has intensified the scarcity of available drinking water, posing a critical challenge to communities, particularly in rural Africa. In response to this pressing issue, our study investigates the transient behavior of a multi-storey solar still as a sustainable solution. The research focuses on harnessing the latent heat of vaporization from the first stage to heat subsequent stages, utilizing pre-heated water from a reservoir. Mathematical models for each stage were developed, and the Numerical modeling of the system was carried out using the finite-forward discretization scheme on Scilab software. Insolation data for Nsukka (Lat = 6.8567, Lon= 7.3958) were extracted from NASA-SSC Database. Results showcase the temperature distribution and distillate output at each stage. The first stage reached an optimal temperature of 325K, while the second and third stages maintained averages of 322K and 319K, respectively. Distillate outputs for the first, second, and third stages were 7.5Kg, 5.7Kg, and 3.8Kg, respectively. An overall still efficiency of 16% was achieved, hence the multi-story solar still presents a promising avenue to address the water scarcity challenges faced by vulnerable rural communities in Africa.