الفهرس Only 14 pages are availabe for public view
 |  | from | 209 |  |  |
| | | from | 209 | | |
Abstract
Global resources of fresh water are scarce, unevenly distributed and, in many cases, may require some form of treatment and handling. These limited resources have resulted in water shortages in 88 developing countries across the world containing 50% of the world’s population. Need for purification of saline water is increasing due to an increase of population and limited supply of potable water. The standard techniques like multi stage flash, multi effect distillation, vapor compression and reverse osmosis are reliable for large capacity range of (100-50,000) m3/day of fresh water production. However, these technologies are expensive for small amounts of fresh water. Moreover, they can not be used in locations where there are limited maintenance facilities. In addition, the use of conventional energy sources to drive these technologies has a negative impact on environment. Using solar energy is a practical method for obtaining small amounts of fresh water from saline water. Solar water distillation has been a subject of great interest for several decades.
Solar desalination techniques are considered to be clean operations for producing clean water from the saline water. Egypt is considered to be one of the high insolation countries of the world. The sunshine hours are estimated to be 3600 hours/year. Also Suez-Gulf region is considered to be one of the highest insolation regions in Egypt hence the world. The average total insolation that hits this region is found to be range as 3.5 to 7.2 kWhr/m2 and this is during the year. That for some geographically reasons like nearest from the sea level, the seasonal rainfall hours almost low and the weather is always hot and dry. So it is very important to utilize this present huge energy in Egypt (Suez-Gulf) in desalination technologies (small and large sizes).
In the present work a small size of flash unit coupled with flat plate solar collector has been designed and tested in many ways, especially for producing a small amount of potable water for small groups of people. The system is designed and investigated at the Faculty of Petroleum and Mining Engineering at Suez-Egypt. The system is operated and investigated under real environmental conditions during winter and summer seasons. The theoretical study is performed to achieve some targets like:
1- Determining best configuration (based on exergetic analysis) of the examined process.
2- Investigating the system productivity and performance under real operating conditions.
3- Developing a simulation program using Mat-Lab to predict the process behavior under a wide range of operating conditions and design parameters. Deferent solar intensity models are examined, and the most reasonable one for the considered location is determined. Also the performance of multi stages (two and three stages) is developed by the simulation program.
4- Examining the system productivity enhancement using different dosages of surfactant material.