Optimization of operation temperatures and durations during solar thermal water splitting towards greater energy efficiencies

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Kimya Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2016

Öğrenci: EZGİ YAVUZYILMAZ

Danışman: DENİZ ÜNER

Özet:

Hydrogen production by solar thermal water splitting is an eco-friendly way of storing solar energy in chemical bonds. The most important obstacles for the viability and the commercialization of this technology are lower energy efficiencies and higher production costs compared to conventional hydrogen production ways such as steam reforming, coal gasification, and electrolysis of water. Two-step thermochemical hydrogen production by using solar energy is an alternative method to conventional hydrogen production. In this method, the thermochemical cycle consists of two sequential steps: a high temperature step where the decomposition of the redox material is driven by solar energy and a relatively moderate temperature step where oxidation of the redox material is achieved by steam fed to the reactor. However, the changes in operation temperatures and process durations lead to trade-offs between performance criteria of the reactor. Therefore, the problem of evaluating optimum values for the operation temperatures and durations have extreme significance in terms of achieving high energy efficiencies in the reactor. In this thesis, more than one solution approach is presented for the solution of the problem. Both parametric statistical analysis approach and mathematical optimization methods are adopted to find local optima for operation temperatures and durations. Several local optimum values are presented for the studied specific reactor conditions and alternative cases.  .