Solar Still is an ancient desalination device. It absorbed the sunlight and turned the solar energy into heat, which heated the seawater to the steam. The steam was then condensed into water which was desalinated as drinking water.

This is a picture of typical solar still.

In solar still desalination process, solar energy was applied on water evaporation. Thus the effective energy could be calculated by the amount of drinking water we collected multiplied the water evaporation enthalpy. The total energy that solar still consumed was solar energy. So the formula is:

\[Efficiency = \frac{Water Production * \Delta H}{Solar Energy}\]

My shiny app showed the solar still performances under different solar energy levels. Check the app on https://lzyempire.shinyapps.io/My-first-Shiny/

-Thanks to Zhejiang Energy R&D Institute for the Solar Still Program -Thank you for your attention