Challenges and progress made toward the improvement of a multistage solar still desalination system

Abstract

The shortage of potable water has been a growing concern globally. This concern has led to the development of systems and devices that can be used to produce freshwater from seawater or any contaminated water. Solar still is one of the devices that was developed mostly for seawater purification. This device works with the principle of evaporation and condensation for freshwater production. Solar still can be categorized as single-stage or multistage depending on the design. This paper reviews briefly the various designs of multistage solar stills with stacked stages. The current work found that the evacuated system with flowing waterbed achieved the highest distillate output of 28.04 and 53.21 kg/m2/d at atmospheric pressure and 0.03 bar vacuum pressure, respectively. However, a standalone multistage system produced on average about 7.36 L/m2/d with flat plate solar collector (FPSC) and 16 L/m2/d with evacuated tube solar collector (ETSC), respectively. The approximated cost of producing distillate per gallon (CPG) ranges from 0.00182993–0.3631 $/ gal. The challenges that are associated with each design are also reviewed. Recommendations and future outlook which would guides the future researches has also been presented.