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Power production of photovoltaic (PV) modules is strongly depends on environmental conditions such as, solar radiation, ambient temperature and wind speed. In other words, PV operating point is changed with environmental factors. Therefore, PV power prediction is significantly important according to environmental conditions. One of the most important issues of PV power prediction is PV operating temperature estimations. While the rising PV module temperature is its short circuit current slightly increases, it causes on sharply decreases its voltage. Thus, power production decreases. This study focuses on PV temperature estimation methods such as, nominal cell operating temperature (NOCT) model, Faiman model, Ross model, King model, Muzathik model and finite differences. These methods are reviewed and compared. Influence of the wind speed on the PV module operating temperature and power production is also investigated. Finally, advantages and disadvantages of the methods are discussed. In all the models, it is reported that while the results of the NOCT, Ross and King models are close to each other’s, those of the Faiman and the remaining models are respectively overestimated and underestimated.

1.st International Conference Energy Systems Engineering
ıcese'17

Cihan Demircan Hilmi Cenk Bayrakçı Ali Kecebas Onur Vahip Güler

In this study, the optimum insulation thickness, total cost, energy saving, payback period and the environmental pollution resulting from fuel consumption for heating purposes were investigated as a case study for Ankara. Extruded polystyrene (XPS) foam, expanded polystyrene (EPS) foam and rock wool as insulation material, natural gas and coal as fuel, sandwich and externally insulated walls as wall construction types were chosen for said purpose. Life cost analysis and degree hour method was used for heating cost and optimum insulation thickness calculations, respectively. In addition, considering the work done for the province of Ankara by the Ministry of Energy and Natural Resources in 1998, some calculations and evaluations were made for the fuels used for heating purposes and their quantities. A realistic analysis was made on this side; economic and emission reduction benefits of building exterior wall insulation are shown in graphs, and the amount of emissions per capita and their reductions are proportional. Bu çalışmada, Ankara’da farklı duvar bileşenlerinin optimum yalıtım kalınlığı, toplam maliyet, enerji tasarrufu, geri ödeme süresi ve dış duvar konstrüksiyonunun ısıtma amaçlı yakıt tüketimi sonucu oluşan çevre kirliliğine etkisi incelenmiştir. Yalıtım malzemesi olarak sıkıştırılmış polistren köpük (XPS), genleştirilmiş polistren köpük (EPS) ve taş yünü, yakıt olarak doğal gaz ve kömür, duvar konstrüksiyonu olarak sandviç duvar ve dıştan yalıtımlı duvar tipleri seçilmiştir. Isıtma maliyeti hesabında ömür maliyet analiz yöntemi, optimum yalıtım kalınlığı hesabında ise derece saat yöntemi kullanılmıştır. Bu çalışmada, 1998 yılında Enerji ve Tabii Kaynaklar Bakanlığı tarafından İstanbul ili için yapılan çalışmayı dikkate alarak ısıtma amaçları ve miktarları için kullanılan yakıtlar için bazı hesaplamalar ve değerlendirmeler yapılmıştır. Bu sayede gerçekçi bir analiz yapılmış; bina dış duvar yalıtımının ekonomik ve emisyon azatlımı faydaları grafiklerle gösterilmiştir.

1.st International Conference Energy Systems Engineering
ıcese'17

Onur Vahip Güler Ali Dasdemir Mustafa Erturk Ali Kecebas