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Solar energy is one of the main promising clean energy sources in future of the world. The technology of photovoltaic systems (PV) has continuous development with many applications. So, it is generate electricity without dangerous effects in the environment. Today, photovoltaic systems are largely used in rural electrification, and grid connected system water pumping irrigation and remote check point etc. Solar cell performance decreases with increasing temperature, fundamentally owing to increased internal carrier recombination rates, caused by increased carrier concentration. Results obtained showed that from 26.6 to 42.1 % reduction in power when temperature was 47 and 40oC respectively El-Kharga Oasis has hyper-arid climate which characterizes the western desert. El-Kharga oasis climate is continental with very hot summer and extreme daily temperature ranges. July is hottest month, with daily maximum and minimum temperature of about 40.9 and 24.7oC, respectively. The maximum temperature occasionally approaches 50oC ion summer; with January being the coldest month in January. This work aimed to study and overcome the negative effects of climatic factors on the efficiency of solar panel quantities to increase the amount of pumped water to satisfy the growing crops needs. It was carried out at El-Kharga, New Valley Governorate, Egypt, which bounded by long 30 20 and 30 40 E and Lat 25 05 and 25 30 N. To increase the efficiency of photovoltaic module two experiments were conducted: 1-Shading: Five shading treatments were tested including control, black screen sheath of 63% shading; grey screen sheath of 65% shading, black screen sheath of 73% shading and white screen sheath of 65% shading. The highest current and voltage output was from the control, and all other treatments were less than the control. The white 65% came the next after the control. 2- Cooling: In this part, five treatments were investigated namely, control, coaling by water, covering by glass 3 mm thick, Greenhouses effect as covering with glass at 2 cm over the panel and coating with as olive oil. The obtained results showed that was cooling with water was the best treatment may followed coating with olive oil and then the control. The produced energy in will used for pumping irrigation water for growing crops in farms at north El-Kharga. [ABSTRACT FROM AUTHOR]

The western desert of Egypt is an area of the natural extension for agricultural, industrial, and civil activities. The expansion requires a great demand for groundwater on the western limestone plateau in the central part of Egypt. Ten groundwater samples were collected from limestone Eocene aquifer wells located in the western desert, Assiut region.to evaluate the quality of these well waters for irrigation. The area under consideration lies between latitudes 27o 7' 540" - 27o 34' 474" N and longitudes 30o 39' 487" - 30o 53' 244"E. The chemical properties of groundwater of the investigated aquifer wells were determined, such as, major ions, pH, EC, TDS, SAR, RSC, RSCB, SSP, magnesium hazard (MH), total hardness (TH) and permeability index (PI). The concentration of the cations in the groundwater of the study area is in the order of Na+ > Ca 2+ > Mg2+ > K+ and that of the anions is in the order of Cl> HCO3 2> SO4 2 .Values of the groundwater quality show that the water is suitable for the irrigation use, except the EC values of some wells that have a moderately saline water. [ABSTRACT FROM AUTHOR]