Computation of irradiance in a solar still by using a refined algorithm

A refined solar algorithm from the ESP-r system has been used to calculate the distribution of solar irradiation inside a basin-type solar still. In the approach, surface finish, view factors and multiple reflections are taken into consideration in the computation of the solar radiation that reaches the surface of the saline water in the distillation system. The algorithm was applied to a solar still tested at the University of Strathclyde in Glasgow (55° 52′ N, 4° 15′ W). Under the prevailing meteorological conditions, it was found that previous models overestimated the computed solar load on the saline water surface. The present modelling approach is demonstrated to exhibit a higher degree of accuracy than previous methods for irradiance distribution prediction, yielding new insights into approaches to solar still performance improvement. The modelling outcomes are presented and discussed. ► ESP-r software was used to calculate the distribution of solar irradiation inside a basin type solar still. ► Surface finish, view factors and multiple reflections were taken into consideration in this computation. ► It was found that previous models overestimated the computed solar load on the saline water surface. ► The present modelling approach exhibits a higher degree of accuracy than previous methods.