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العنوان
Solar selective Coating Design and Implementation via Sol-Gel Technique/
المؤلف
Sabrah,Fatma Taha Abdollah
هيئة الاعداد
باحث / فاطمة طه عبدالله صبره
مشرف / ناهد المحلاوي
مناقش / ناهد عبد الحميد المحلاوي
مناقش / مديحة أحمد شعيب
تاريخ النشر
2021.
عدد الصفحات
143p.:
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
الهندسة الميكانيكية
تاريخ الإجازة
1/1/2021
مكان الإجازة
جامعة عين شمس - كلية الهندسة - ميكانيكا انتاج
الفهرس
Only 14 pages are availabe for public view

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Abstract

This thesis reports on the efforts made to research and develop solar selective coating, which is considered to be a key element of solar thermal collectors, in an attempt to highlight the importance of increasing knowledge in this field. This aim was accomplished by reading and discussing previous scientific publications relating to this field, and then choosing the solar selective coating composition and preparation method that seemed promising and preferable from several aspects, setting, and implementing a work plan, and subsequently, discussing and evaluating the findings that presented substantial conclusions served the aim of this thesis.
The present study investigates the effect of different process parameters on the optical properties of prepared solar selective surfaces made of stainless-steel sheets coated with CoCuMnOx solar selective coating, which was prepared and applied through the sol-gel dip-coating method. This is in addition to investigating the inclusion of different mass fractions of different carbon allotropes in the CoCuMnOx coating structure, besides attempts to apply carbon on top of the CoCuMnOx selective surface. Furthermore, bare stainless-steel sheets were considered to be solar selective surfaces after processing the sheets by thermal exposure and roughening their surfaces. X-ray diffraction, Scanning Electron Microscope, and Energy-dispersive X-ray were the used analysis methods to identify the phase composition, topography, and elemental composition, respectively, of some featured samples.
The performed study revealed outstanding spectral characteristics for the roughened stainless-steel sheet coated with two layers of charcoal-CoCuMnOx. A 5 wt.% of charcoal embedded in the structure of CoCuMnOx managed to surpass the plain CoCuMnOx solar selective coating with 7% higher spectral selectivity. Noting that the plain coating achieved an absorptivity of 0.906, an emissivity of 0.116, and 85% selectivity, while the developed version, which contained carbon, achieved an absorptivity of 0.964, an emissivity of 0.095, and 92% selectivity. In addition, it was found that annealing bare stainless-steel sheets with a surface roughness of 1.35 μm at 750 °C yielded a solar selective surface with an absorptivity of 0.953, an emissivity of 0.205, and 85.1% selectivity. Moreover, it was evidenced that the roughness degree of the substrate surface has a substantial potential to boost optical properties.