Development and validation of a transient model for a passive solar still considering the aspect ratio of the evaporation chamber. (15th September 2022)

• Record Type: Journal Article
• Authors: Mohsenzadeh, Milad; Aye, Lu; Christopher, Philip
• Is Part Of: Solar energy. Volume 244(2022)
• Page Start: 434
• Page End: 447
• Publication Date: 2022-09-15
• Subjects: Passive solar still -- Thermal model -- Experiment -- Evaporative heat transfer coefficient -- Cavity aspect ratio; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2022.08.059
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A transient model considering chamber aspect ratio & thermal inertias is presented. The significance of considering thermal inertias in the model is explored. The effect of distillate on the transmissivity of the cover was examined. The model predictions agree with the experiments within a 5.2% deviation. The larger the aspect ratio of the chamber, the higher the daily water yield. Abstract: This article presents a transient model of a single slope single basin passive solar still. The model considers the aspect ratio of the evaporation chamber, the thermal inertia of components and the bulk water, and the salinity level. An experimental rig was designed, fabricated, and tested for various aspect ratios of the evaporation chamber. The transmissivity of the glass cover was measured during experiments and applied as an input to the model. It was found that the transmissivity is reduced by up to 21% over the day. The developed model was validated with the experimental data. The simulations and experiments were conducted in Melbourne, Australia during a summer. The model predicted outputs agree with the measured data. The predicted performance of the solar still is about 5% more than that of measured. A sensitivity analysis was conducted on the climate parameters. The simulated and measured water yield and the thermal efficiency of the solar still under a range of water depths and chamber aspect ratios are reported. A solar still with a larger aspect ratio of the evaporation chamber (shorter specific height) generates more potable water. However, the effect of lower depth of bulk water on the water yield of the system is more significant. The fabricated passive solar still generated 2.52 kg m −2 d − 1 of potable water with a thermal efficiency of 19.2% for a water depth of 0.01 m and the salinity of 3% by wt. Based on the results of the simulations, the study provides recommendations to achieve maximum performance for conventional passive solar stills.