الفهرس 
CHAPTER (1) INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The high cost of traditional fuel has led the scientists to look for new sources of energy. Solar energy is the best renewable source of energy as it is free of running cost and has no pollution on the environment. So, solar distillation is a cheap way to produce fresh water. In this work, the design, construction, and performance evaluation for solar distiller with flat plate solar collector (FPSC) using gravity assisted heat pipes (Thermosyphon) and using acetone as a working fluid is presented. First, two systems of FPSC were designed, the first system was a flow water heat exchanger connected with FPSC welded to 11 thermosyphons. For this system, the effect of tilt angle of FPSC was performed from 12, 17, 20, 25 and 30 with filling ratio of thermosyphon being 80% of the evaporator volume. Measurements ware conducted from June to October 2021 at Faculty of Engineering, Menoufia University, Shebin El-Kom, Egypt, latitude 30.5 N and Longitude 31 E. The results were as follows, average effectiveness of FPSC all over the day of measurements was 73% at 12. The other average effectiveness was 69.35% for 17, 62.47% for 20, 67.14% for 25 and 66.68% for 30. So, the results showed that the best-performance angle was 12 with absorber maximum temperature of 70.36 C at 12:30 PM, and adiabatic section temperature of 60.35 C, and condensing section temperature of 42.46 C. The second system is the same FPSC welded to 11 thermosyphons but the condensing section was immersed in the basin of shaded conventional solar distiller as a thermal storage tank and the experiment was conducted with 12 tilt for FPSC. The results of the experimental work showed that maximum value of the instantaneous effectiveness is 51.7% at noon, daily accumulated stored energy of 0.937 MJ and the maximum heat transfer coefficient is 187.82 W/m2. K. This means that, a better performance is obtained for the solar distiller with thermosyphon (modified distiller) if compared with conventional solar distiller. The other experiments were carried out for studying the performance of the modified solar distiller and comparing its performance with a conventional solar distiller for the same water depths and for water depths of 2 cm and 3 cm. Thus, two experiments were carried out. First, the water basin depths were 2 cm and 9 cm for the two conventional distillers and 9 cm for the modified distiller. In the second experiment, the water depths were 3 cm and 10 cm for the two conventional distillers and 10 cm for the modified one. The accumulated productivities for conventional distiller with water depth of 2 cm, conventional distiller with water depth of 9 cm and modified distiller with water depth of 9 cm were 1.48667 (lit/day), 1.67333 (lit/day), and 1.75333 (lit/day), respectively. This means that, a daily enhancement in productivity of 12.55% and 17.93% for conventional distiller with water depth of 9 cm and modified distiller with water depth of 9 cm over conventional distiller with water depth of 2 cm; respectively, was obtained. The accumulated productivities for conventional distiller with water depth of 3 cm, conventional distiller with water depth of 10 cm and modified distiller with water depth of 10 cm were 1.49567 (lit/day), 1.340 (lit/day), and 0.885 (lit/day), respectively.
The CFD simulation for the conventional solar distiller will be presented. There are two simulation modes, the first is a steady mode and the second is a transient mode. The transient mode was used because it allows executing many calculations and leads to a real simulation of the distiller. A comparison between the experimental and simulated results of temperatures and productivity has been made. On 14th July, for conventional distiller with 2 cm water basin depth, the maximum experimental and simulated temperature for absorber plate were found 71 and 75.4 C; respectively, with enhancement of 6.19 % and for glass cover were 59 and 52.5 C with relative change of 11.02 %. Whereas the accumulated productivities were 2.5667 and 2.710 liter per day with enhancement of 5.58 %. The comparison showed a good agreement between both results, so CFD simulation is a powerful tool for conventional solar distiller analysis and can be used as an optimizing tool for this scope to compare between different solar still configurations.