A Comparative Study of the Multistage Solar Stills with Stacked Stages (MSS-SS)

The current work conducts a comparative study of the waterbed multistage solar still with stacked stages (MSS-SS) and the vapour-based MSS-SS. Various experimental test results obtained from the vapour-based MSS-SS are briefly discussed in comparison with the waterbed MSS-SS reported in the literature. Based on the experimental observations and tests, the stage tray requires no maintenance and upper stages can operate even when the lower stages are nonoperational. About 0.8–41.3% distillate yield dropped from the upper stages when lower stages were exposed to the atmosphere. The upper stages increased their productivity by 7.1–15.4% when the lower stages were shut off completely. The waterbed-based MSS-SS preserves and reuses thermal energy much better even during off sunshine hours than the vapour-based system. The vapour-based MSS-SS is only productive during sunshine hours, and about 97-98% of the distillate is produced during daytime. Furthermore, the vapour based was able to produce 6.3 kg/day on average on the selected days.

Performance enhancement of a single slope solar still with single basin using Fresnel lens

This paper presents an experimental study using Fresnel lens to increase the overall efficiency of the conventional Single Slope Solar Still (SSSS) with single basin. The work aims to increase the performance of single basin conventional SSSS while maintaining the simplicity and usability of the system. Especially in the rural parts of Oman, the device is very simple to use. For the present unit, the conventional single basin SSSS has been fitted with an adjustable Fresnel lens. The adjustment enables the carrying out the experiments with and without the Fresnel lens at our Institute. The equipment was constructed from simple available materials and was placed north-south during the experimentation. The Fresnel lens fitted frame once adjusted in the morning was kept at same position for the entire day without tracking. The depth of water in the basin was maintained constant at 0.02 m during the study. The distillate yield for single basin SSSS fitted with Fresnel lens is observed 3 to 3.5 times higher than the conventional. The overall efficiency of the system has also increased almost 32.19 percent over the conventional. The quality of the distillate was assessed, which was estimated to be within limits in compliance with international standards. In conclusion, Fresnel lens has significantly improved the distillate production output and overall efficiency of conventional single basin SSSS.

AUGMENTATION OF SOLAR WATER DISTILLER PERFORMANCE WITH PV/T

Recently, due to global warming and urbanization, there are many major cities that may face the challenge of day zero next decades. Obviously, water is an indispensable component for maintaining life on the earth. Although portable water is required of the hour, the quantity of available freshwater is impacted significantly by sea-level rise and pollution from industrialization. As a consequence of the global water crisis, different methods for clean water production from brackish water have been studied and developed in practice, however, the solar distillation of water is the most economical and desirable approach due to this method utilize solar energy that is the environmentally friendly and economical resource. Over the last 15 years, the impressive price drop of the photovoltaic solar collector (PV/T) makes them popular and easy to access. As a result, the employment of PV/T in solar stills is emerging as a potential device for water distillation. Therefore, in this paper, an active solar distiller combined with a photovoltaic panel has been reviewed for improvement of the distillate yield and effectiveness of solar photovoltaic. This review work presents a variety of studies on various types of solar still (for example conventional solar still (CSS), double slope solar still (DSSS), stepped solar distiller, and cascade solar still) couples with different solar water collectors (such as flat plate collector (FPC) and evacuated tubes collector (ETC)) and solar photovoltaic modules. It is obtained that the hybrid PV/T active solar still improves the distillate yield, energy efficiency, and exergy efficiency as compared to passive mode. The cooling method enhances the performance of the photovoltaic solar collector as well as the productivity of solar still. Moreover, the environmental economic estimation reveals that the solar still coupled with the PV/T mitigated considerably the amount of CO2. It can be stated that it is suitable to commercialize the hybrid PV/T active solar still for supplying not only electricity but drinking water also. Finally, this review paper also suggests the scope for the research in the future.

Productivity enhancement of stepped solar still integrated MEMS light sensors for solar tracker

Water is life, and the threat of unsustainable means of potable water supplies has led to the reviews of various renewable energy sources to create a cleaner and more efficient solution for potable water supply. The aim of this study is to present a way in which the efficiency of stepped solar still can be increased. It is to increase the efficiency of solar still by increasing the amount of time that the solar still is directly perpendicular to the sunlight. The Micro-Electro-Mechanical Systems (MEMS) light sensors for solar tracking are used to enhance the productivity. The results obtained indicate that the use of MEMS light sensors for solar tracking are used to makes a solar still to be predictable and it equally increases its efficiency in terms of distillate yield and overall performance.

Comparative Study of Tubular Solar Stills with Phase Change Material and Nano-Enhanced Phase Change Material

This study is intended to investigate and analyze the operational performances of the Conventional Tubular Solar Still (CTSS), Tubular Solar Still with Phase Change Material (TSS-PCM) and Tubular Solar Still with Nano Phase Change Material (TSS-NPCM). Paraffin wax and graphene plusparaffin wax were used in the CTSS to obtain the modified solar still models. The experimental study was carried out in the three stills to observe the operational parameters at a water depth of 1 cm. The experiment revealed that TSS-NPCM showed the best performance and the highest yield in comparison to other stills. The distillate yield from the CTSS, TSS-PCM and TSS-NPCM was noted to be 4.3, 6.0 and 7.9 kg, respectively, the daily energy efficiency of the stills was observed to be 31%, 46% and 59%, respectively, and the daily exergy efficiency of the stills was recorded to be 1.67%, 2.20% and 3.75%, respectively. As the performance of the TSS-NPCM was enhanced, the cost of freshwater yield obtained was also low in contrast to the other two types of stills.