الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Recently, energy demand, global warming, ozone depletion, and environmental pollution drew a huge attention to clean alternative energy resources instead of fossil fuels. Using solar collector in heating for domestic and industrial purposes is an ideal and promising alternative to provide the required heating loads without gas emissions, hence keeping a clean environment. The objective of the present report is investigating the performance of using evacuated tube heat pipe solar collector for heating that needed for industrial and domestic purposes. The thermal performance of a heat-pipe evacuated-tube solar collector is investigated in the present study under various operating conditions and arrangements. A mathematical model for the system was developed and validated by comparing its results with experimental cases under weather conditions of Alexandria, Egypt. The effects of the inlet temperature and ambient temperatures, number of evacuated-tubes, and mass flow rate, on both the exit temperature and the collector efficiency were all considered in extensive investigations. The results showed that the collector performance was strongly affected by all the above parameters but with different manners. At certain values of the mass flow rate of the working fluid (WaterOil) and solar irradiance, the exit temperature increases with the increase in the number of series evacuated tubes reaching a specified number above which the increase in the exit temperature will be insignificant. In addition, the performance of the collector with various working fluids was tested using the validated mathematical model and the results showed that the efficiency of the collector is greatly affected by changing the heat transfer fluid through the collector with different weather conditions.