Determination of the effect of water depth on the yield of a solar still using an automatic feedwater system

Herein, the water depth in a pyramidal solar still was kept constant using an automatic feedwater system through an auxiliary tank. Six water depths ranging from 5 to 50 mm were investigated. All variables were measured continuously but were logged automatically every hour. Increasing the water depth increased the water volume, thereby increasing the thermal capacity of the solar still. Therefore, increasing water depth increases the nocturnal yield but decreases the diurnal yield. Over the whole day, lower water depths resulted in higher accumulated yields. These accumulated yields increased by 37% by decreasing the water depth by 90% from 50 mm. The desalination system can work without human intervention, improving its sustainability. Moreover, the automatic feedwater system facilitates the end-user operation processes and succeeds in maintaining a constant optimal water depth in the solar still.