| الملخص: | People are always looking for new sources of energy to be able to meet their growing energy needs and keep pace with advanced life applications in the world. As most of the existing energy sources are at risk of depletion and expected to drain, in addition to their high cost and the negative environmental impacts resulting from using them extensively, we are now alerted to consider the potential of making use of other more sustainable sources of energy, such as the solar energy. It is an easy, effective and safe source. This study aims at evaluating three types of solar water heaters and studying the effect of wind and dust that accumulate continuously on the glass surface of these solar heaters. The work also provides suggestions to select the simple and easy way of manufacturing considering the least poor villagers with their local skills and materials. Three different types of solar heaters namely Flat Plate, Serpentine and Zigzag heaters with different forms have been designed, considering maintaining similar dimensions and the same zones exposed for the sun rays, and tested them in the same climatic conditions in Minia Province, Upper Egypt. With experiment, it is observed that Zigzag water heater is the highest in efficiency than the other two types. The experiment also shows that the dust layers accumulated on surfaces of the heaters reduce the solar heater absorption of heat and that the presence of high or reduce airflow contributes directly to heat loss, where water pipes became cooler inside, consequently, the efficiency of the solar water heater decreases by accumulating dust on the surface of the collector or increasing the wind speed targeted directly towards the collector.
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