Comparative tests on the performance of solar stills enhanced by pebbles, corrugated plate and membrane distillation and construction of performance prediction model for rock type still

To improve the water production capacity of solar still (SS), realize the theoretical prediction of the enhanced SS performance, and enrich the theoretical research basis of the desalination technology of SS, this paper sets up three kinds of enhancement measures, namely, rock, corrugated plate and membrane distillation, tests the enhanced water production effect, and reveals the enhanced operation mechanism. At the same time, a per- formance prediction model of rock enhanced was established based on the body-centered cubic stacking rock technology, and the influence of rock parameters on the distillation effect was studied. The study found that the water production increment of the three enhancement measures was concentrated in the rising period of the water production of the SS, and the total water production was 6.38 %, 12.30 % and 11.63 % higher than that of the traditional basin SS, respectively. The rock or corrugated plate enhances the distillation effect by elevating the seawater temperature and its temperature difference with the cover plate, and the membrane distillation increases the total water production through the additional water production of the membrane. Moreover, the constructed model can effectively predict the characteristics of rock enhanced SS. The increase in the rock layer thickness and the decrease in the rock particle size and material heat capacity both enhance the total daily water production, but the effect of rock particle size and material is weak. Although the increase of thickness increases the water production obviously, it aggravates the fluctuation of water production.