الفهرس 
Desalination TechniquesOnly 14 pages are availabe for public view
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Abstract
Fresh water is constantly shrinking and contaminated day by day on account of
industries, agricultural and population growth. The United Nations reported that in 2050 the population of the world will be about 9 billion. This will consequently make important changes, such as water shortage. The UNICEF stated that globally more than 1.1 billion people do not have potable water and about 1000 children die daily because of diseases resulting from non potable water. Numerous people feel that they will suffer from lack of drinkable water. Problem with shortage of drinkable water needs to be solved. Two ways exist to deal with it and both are necessary to use. Firstly, water treatment should be improved where much water is wasted daily. Secondly, new sources of potable water are needed. It is obvious, regarding the percentage of salty to fresh water, that desalination is the clue.
Especially for countries that lies both on coasts and in solar zones. In this work, the overall objective is to improve the performance of basin type solar
still under Egyptian climate conditions experimentally and simulation it by using
ANSYS. For that, single slope double basin solar still [SSDBSS] and a conventional
basin type single slope solar still [SSSS] were designed, fabricated and tested at
the Faculty of Engineering, Menoufia University at Shebin El-Kom (latitude of 30.5° N - Longitude of 31° E) in Egypt. These configurations are constructed with materials that are available in the local market. Experiments were carried out during the months of June and July 2018. Both solar still configurations were operated on the same tested days to compare their performance and to determine the optimal productivity. The two tested solar still configurations were
constructed using the same basin area of 1000 mm x 1000 mm. The solar still
configurations condensing glass covers are inclined at 23° on both sides with respect to the horizontal. The base of basin, water, vapour and condensing glass cover surface temperatures as well as the ambient temperature are measured every hour. Also, the intensity of solar radiation and the distilled fresh water are recorded continuously. The effect of water depth ds /de on the performance, productivity and efficiency of
the both solar still configurations was studied. In addition, the analogy between heat and mass transfer was taking into consideration. The depth of water ds
/de in the basins was maintained at 2cm, 3cm, 4cm and 5cm after fixing the orientation of the two tested solar stills towards to south to receive the largest possible amount of solar radiation.
The combined effect of evaporative and convective internal heat transfer can be
predicted by Nu=C(Gr.Pr) n and the convective mass transfer coefficient can be determined by Sh=C’(Gr.Sc)n’ . The constants C, n, C’ and n’ for the dimensionless convective heat and mass transfer correlations were determined using linear regression analysis. It was observed that the proposed models give closed results with the experimental observation for all tested solar stills.
The new configuration solar still [SSDBSS] and equivalent water depth de of 2cm
has the highest accumulated productivity and efficiency compared to the other tested conventional basin single slope solar still and water depths ds /de
. The results indicated that the daily measured accumulated productivities for modified [SSDBSS] and conventional solar still [SSSS] were 2.855 lit/m2 and 1.785 lit/m2 , indicating increases of 59.94 % in fresh water production. Also, in this work, transient CFD simulations of the basin type single slope solar still [SSSS] and the modified single slope double basin solar still [SSDBSS] have been developed. The simulation results were compared with the available experimental data of the both tested solar stills. The amount of solar intensity (maximum discrepancy amounts to 12.7%), fresh water productivity (maximal discrepancy comes to 10.26 %) as well as water and condensing glass covers temperatures (the maximum error was estimated to be 3.5%) were in good agreement with the experimental data. The results showed that simulated and experimental daily efficiency is around 27.65% and 25%, respectively for the SSDBSS at equivalent water depth de of 2cm. while, it is around 16.79% and 15.5%
for the SSSS, respectively at the same water depth ds.