| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 101 === Traditional fossil fuels and nuclear energy gradually be resisted under consideration for eco-awareness and safety, while renewable energy is developed positively in recent years. Since Taiwan is located in subtropical area which has sufficient sunshine, solar energy is indeed the most promising renewable energy. With the subsidy from government for installation of solar water heater systems, solar water heater has been widely used by folks. However, there are about 3.7 typhoons, in average, attack Taiwan every year, they sometimes cause damage to the solar water heater. This study investigates the structural stress response of solar collector under wind loads by finite element analysis software ANSYS 14.0.
The results show that solar collector fails due to the extreme stress of stainless steel shell which is caused by locally extreme negative pressure under loads of 60 m/s wind velocity and 135o wind incidence. It is found that the maximum stress of solar collector can be reduced by installing supports and changing the thicknesses of stainless steel shell and glass. By increasing the thickness of stainless steel shell, the maximum stress can be decreased from 100.5% to 45% of yielding strength under wind velocity 60 m/s and 135o wind incidence. The maximum stress of glass under wind velocity 80 m/s and 180o wind incidence is 66.7% of tensile strength when its thickness is decreased to 2.4 mm, and still within the safety concern. Therefore, the best thicknesses of stainless steel shell and glass are 1.4 mm and 2.4 mm. Some vendors installed supports in the middle of the bottom surface of solar collectors. But after simulation analysis, it is found that installing this support cannot reduce the maximum stress. So the locations of supports is changed to near the negative pressure region, it is found that the best arrangement of supports, by optimization analysis, can decrease the maximum stress of stainless steel shell from 100.5% to 63% of yielding strength.
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