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Öğe Applicability of Thermophotovoltaic Technologies in the Iron and Steel Sectors(Wiley-V C H Verlag Gmbh, 2018) Utlu, Zafer; Parali, Ufuk; Gultekin, CagriThe theoretical potential for converting excess heat from the iron and steel sectors in Turkey into electricity by the use of thermophotovoltaic (TPV) systems is investigated and analyzed. The TPV usage in this industry is numerically investigated because this sector is in the leading position in terms of energy consumption in industrial sectors. Using the iron and steel industry waste heat energy data, it is shown that the energy conversion efficiencies of the TPV systems with the photovoltaic (PV) cell modules of In0.2Ga0.8As0.18Sb0.82 and GaSb are 7.31% and 2.04%, respectively. When using TPV systems in the Turkish iron and steel sectors for waste heat energy potential, it is calculated that 29.88MJ per year can be generated with GaSb cells, and 1.076PJ per year can be generated with In0.2Ga0.8As0.18Sb0.82 cells. Based on the results obtained from the numerical model in this study, some specific advice for the applicability and the development of the high efficiency TPV conversion systems is proposed.Öğe Application of artificial neural network model for forecast energy efficiency of the cryogenic liquefaction system in the meaning of sustainability(Inderscience Enterprises Ltd, 2021) Altintas, Elif; Tolon, Mert; Karabuga, Arif; Utlu, ZaferSustainable engineering approaches are a necessity for improving efficiency. For this reason, the artificial neural network (ANN) model is used to forecast different types of energy efficiency problems. In this paper, a comparison is made between a simple model based on ANN which gives meaningful findings in terms of thermodynamics and a model that is based on thermodynamic principles as auditing and predicting tool to forecast exergy efficiency of the system by applying different ANN architecture types with 441 data of experimental measurements obtained from liquefied nitrogen and analysed the Engineering Equation Solver (EES) program to make an exergy analysis.Öğe Examination of the liquefaction system for the use of different cryogenics in terms of thermodynamic analysis(Inderscience Enterprises Ltd, 2019) Karabuga, Arif; Utlu, Zafer; Selbas, ResatEnergy consumption in the world is increasing day by day. In addition to diversifying energy resources, it is also important to reduce energy consumption. In order to find the actual consumption of a thermodynamic system, energy efficiency as well as exergy efficiency should be done. The purpose of this study is to determine the parameters affecting the exergy efficiency of the cryogenic liquefaction unit integrated into a real cryogenic air separation unit. Cryogenic liquefaction is one of the basic processes between liquefaction methods. In addition to this process, absorption and membrane are used in methods. The main difference in the selection of these methods is the desired purity rates. Cryogenes are defined as fluids used in cryogenic cooling. In this study, five different cryogenes in the air are investigated. The energy and exergy analysis of the liquefaction unit for each cryogen is made. As a result of the study, the highest COPactual value is obtained with 0.3105 hydrogen fluid and the highest COPrev value with 0.8551 oxygen. Exergy of the system is found as 0.48 with hydrogen.Öğe Isıl sistemlerde mevcut atık ısı potansiyelinden yararlanarak termofotovoltaik yöntemlerle elektrik enerjisi üretim teknolojilerinin geliştirilmesi(2018) Utlu, ZaferGünümüzde enerji tüketiminin giderek artması, yenilenebilir enerji kaynaklarının hızla tükenmesi ve minimum girdi ile maksimum verim elde etme talebi yeni teknoloji arayışlarına hız kazandırmıştır. Atık ısıların değerlendirilmesi enerji yönünden tasarruf sağlamaktadır. Atık ısılardan elektrik üretimi gerçekleştirilerek temiz ve yenilenebilir enerji olarak mevcut elektrik üretimine katkı sağlanmaktadır. Bu yöntem, maliyet, atık ısının etkin kullanımı ve enerji tasarrufu açısından alternatif sunarken aynı zamanda sera etkisini azaltarak çevre dostu bir üretim modeli olarak kabul edilmektedir. Bu çalışmada mevcut atık ısı potansiyelinden yararlanarak termofotovoltaik enerji dönüşümü ile elektrik üretim teknolojisinin geliştirilmesi amaçlanmıştır. Literatürde termofotovoltaik enerji dönüşümü ile endüstriyel sistemlerde ve merkezi ısıtma sistemlerinde kullanılabilirliği araştırılmış ve endüstriyel sistemlerde teorik bir model geliştirilmiştir. Bu modelde, endüstriyel sistemlerdeki atık ısılar, sisteme ısı geçişi yöntemlerinden biri olan ışınım yolu ile incelenmiştir. Üretim aşamasından sonra meydana gelen atık ısı, sisteme termofotovoltaik dönüşüm ile elektrik üretimi sağlanarak geri kazandırılmıştır. Yapılan çalışmada endüstriyel ve merkezi ısıtma sistemlerinde termofotovoltaik sistemin analizi yapılmıştır. GaSb hücre yapısının tabaka kalınlıkları optimize edilmiş ve nihai örnek tasarımı Matlab programı kullanılarak hesaplanmıştır. Yapılan analizde, TPV sıcaklık grafikleri GaSb hücresi kullanılarak elde edilmiştir. Kullanılan sıcaklık parametreleri hücre sıcaklığı ve kaynak sıcaklığıdır. Bu grafiklerle enerji verimliliği, dolum faktörü, açık devre voltajının etkisi ve kısa devre akım değerleri belirlenmiştir. Ayrıca termofotovoltaik sistemin termodinamik analizi yapılarak sonuçlar sunulmuştur. Öncelikli olarak termofotovoltaik sistem üç ayrı bölgeye ayrılarak analizi yapılmıştır. Analizde sistemin her bir parçası ayrı ayrı yapılırken sistemin bütünü ayrıca ele alınmıştır. Sistem öncelikle birinci kanun analizi yapılarak değerlendirilmiştir daha sonra ikinci kanun analizi yapılmıştır. Birinci bölge ısı kaynağının ışınım ile filtrelere ulaşana kadar meydana gelen enerjinin termodinamik analizidir. İkinci bölge ise fotovoltaik sistem olarak değerlendirilen filtre, seçici- yayıcı ve fotovoltaik hücrelerin yer aldığı bölümdür. Son bölge olarak ifade edilen üçüncü bölge ise elektrik enerjisinin depolandığı kısım olarak değerlendirilmiştir. Sonuçlar formüller ve grafikler ile desteklenmiştir. Yapılan çalışmanın mevcut elektrik üretimine alternatif olması ve ileride yapılacak çalışmalara bir kaynak oluşturması amaçlanmıştırÖğe Modelling of energy and exergy analysis of ORC integrated systems in terms of sustainability by applying artificial neural network(Oxford Univ Press, 2021) Utlu, Zafer; Tolon, Mert; Karabuga, ArifThe present study focuses on the organic Rankine cycle (ORC) integrated into an evacuated tube heat pipe (ETHP), whose systems are an alternative solar energy system to low-efficiency planary collectors. In this work, a detailed thermodynamic and artificial neural network (ANN) analysis was conducted to evaluate the solar energy system. One of the key parameters of sustainable approaches focused on exergy efficiency is application of thermal engineering. In addition to this, sustainable engineering approaches nowadays are a necessity for improving the efficiency of all of the engineering research areas. For this reason, the ANN model is used to forecast different types of energy efficiency problems in thermodynamic literature. The examined system consists of two main parts such as the ETHP system and the ORC system used for thermal energy production. With this system, it is aimed to evaluate energy and exergy analysis results by the ANN method in the case of integrating the ORC system to ETHP, which is one of the planar collectors suitable for the roofs of the buildings. Within the scope of this study, the exergy efficiency was evaluated on the developed ANN algorithm. The effect rates of parameters such as pressure, temperature and ambient temperature affecting the exergy efficiency of ORC integrated ETHP were calculated. Ambient temperature was found to be the most influential parameter on exergy efficiency. The exergy efficiency of the whole system has been calculated as similar to 23.39%. The most suitable BPNN architecture for this case study is recurrent networks with dampened feedback (Jordan-Elman nets). The success rate of the developed BPNN model is 95.4%.Öğe Photovoltaic system configurations: an occupational health and safety assessment(Wiley Periodicals, Inc, 2020) Erten, Begum; Utlu, ZaferThere is an attempt to reduce CO(2)emissions caused by the use of fossil fuel worldwide and the negative consequences of global warming. Thus, renewable energy systems (RES) are an alternative for reducing fossil fuel use. In addition to being environmentally friendly, it is also important to ensure safety, reliability, and sustainability in the resources and systems used to achieve targets to reduce CO(2)emissions by increasing RES use. Solar energy systems have an important share in RES investments and their scope of use is becoming widespread. However, employment rates are also increasing. Hence, the issue of protecting employees also gains importance. Moreover, photovoltaic (PV) systems require an accurate risk management process with a holistic approach since the design phase. Therefore, occupational health and safety (OHS) studies should be seen as an integral part of the whole. In this study, regulations and standards related to OHS in PV systems have been investigated. Studies have been evaluated in terms of human health, environmental, and economic effects. Regulations vary according to countries' energy policies. Therefore, solutions are offered with national approaches to global problems. In this respect, the arrangements made at the national level have been investigated in Turkey and field observations have been made from an OHS perspective. The aim of this study is to support a holistic approach to the hazards and risks in PV systems and the sustainability of the systems. In this regard, the need for an inclusive basic guide is emphasized and a contribution is made to proactive approaches. (c) 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.Öğe Synthesis and characterization of salt-impregnated anodic aluminum oxide composites for low-grade heat storage(Springer, 2020) Yilmaz, Bengisu; Yuksel, Behiye; Orhan, Gokhan; Aydin, Devrim; Utlu, ZaferThermochemical heat storage (THS) systems have recently attracted a lot of attention in research and development. In this study, an anodic aluminum oxide (AAO) template, fabricated by a two-step anodization method, was used for the first time as the matrix material for a THS system. Different salts were studied as thermochemical materials for their suitability in low-grade heat storage application driven by solar energy for an open system. Compositions were prepared by absorbing CaCl2, MgCl2, LiCl, LiNO3 and mixtures of these salts under a vacuum in an AAO matrix. Field Emission Scanning Electron Microscopy was used to examine the morphology of the produced AAO composites. Thermal energy storage capacities of the composites were characterized using a differential scanning calorimeter. Characterization analysis showed that anodized Al plates were suitable matrix materials for THS systems, and composite sorbent prepared with a 1:1 ratio LiCl/LiNO3 salt mixture had the highest energy value among all composites, with an energy density of 468.1 kJ center dot kg(-1).
