08. İYTE Tezler / IZTECH Theses & Dissertations

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This collection of IZTECH Theses in DSpace contains selected theses and dissertations from all IZTECH departments.

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Adaptive Thermal Comfort Analysis of Historic Mosque: the Case Study of Salepçioğlu Mosque, Izmir, Turkey
(Izmir Institute of Technology, 2016-10) Bughrara, Khaled S. M.; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
Mosques differ from other types of buildings by having intermittent operation schedule. Due to five prayer times per day throughout the year, mosques are fully or partially, yet periodically, occupied. Historic mosques, possessing cultural heritage value, need to be evaluated in terms of thermal comfort. The adaptive thermal comfort method presented by ASHRAE 55 is recommended to be used to analyze thermal comfort conditions of unconditioned buildings. The aim of research is to analyze thermal comfort conditions of historic mosques throughout the year, and to conduct an adaptive comfort analysis. The selected Salepçioğlu Mosque was built in 1905 in Kemeraltı, İzmir, Turkey. The objective is to improve indoor thermal comfort levels by applicable interventions with specific attention to its heritage value. First, indoor and outdoor microclimate of Salepçioğlu Mosque was monitored from October 2014 to September 2015. The physical model of mosque was created via dynamic simulation modelling tool, DesignBuilder v4.2. The model was calibrated by comparing simulated and measured indoor air temperature within hourly error ranges defined by ASHRAE Guideline 14. Whole-year thermal comfort analysis was conducted on monthly basis by using adaptive thermal comfort model. The adaptive comfort analysis of monitoring campaign shows that the Mosque does not satisfy acceptable comfort levels. Different scenarios were applied to better comfort levels. The best improvement is obtained with underfloor heating by which discomfort hours drop into 1369 hours by 31.34%, while it was 3760 hours by 86.08% in the baseline model.
Atmospheric Effects on Short Term Wind Power Forecasting
(01. Izmir Institute of Technology, 2021) Kalay, Yüksel; Kalay, Yüksel; Bingöl, Ferhat; Bingöl, Ferhat; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
Wind power all over the world are being popularizing unlike decrease in conventional sources due to environmental issues. However, power acquired from wind is not stable during day and night, which means that intermittent due to nature of the source. Forecasting in wind power plant is very challenging compared to forecasting of production of conventional power plant. Although there are many robust and site-specific models in order to forecast wind power accurately, decrease of deviation in wind power forecasting by using statistical, physical and hybrid models is still open to new approaches. In this study, four different forecast models based numerical weather prediction (NWP) models for three different wind farms which have different atmospheric conditions are examined to improve wind farm-based power forecasting. For this purpose, wind power forecasting of the providers was categorized based on atmospheric effects, which are site temperature and turbulence. Results have been compared with real time power production from wind turbine supervisory control and data acquisition (SCADA) system. Afterwards, new method based on selecting best provider for specific condition was developed by considering atmospheric effects on power forecasting. It should be noted that the method is an engineering approach, not a new forecast model. In many cases, newly developed method has succeeded to outperform in comparison to results belonging to forecast providers. Hourly and daily wind power forecasting that have significant role in electricity market has been improved for selected wind farms by the help of an engineering approach used in this study. Same method is also implementable to another wind farm if required inputs exist.
Coupled Wake and Blockage Modelling for a Wind Farm
(Izmir Institute of Technology, 2022-10) Çam, Janset Betül; Bingöl, Ferhat; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
One of the significant reasons for the power loss in wind farms is the wake effect. Therefore, the wake effect is crucial for designing a wind farm. However, only wake modeling is not sufficient to explain power losses. Wake is the turbulent, complex, and relatively weak flow behind the wind turbine. The wake effect is not required for the front row turbines in wind farms, and the wake model cannot be applied. It is assumed that the wind farm directly encounters the free stream wind speed. However, the blockage effect, also known as the induction zone effect, is observed at the front of the wind turbines. Due to this effect, the wind farm encounters a lower wind speed than the free-stream wind speed. This situation reduces the accuracy of the Annual Energy Production (AEP) calculation in wind farms. The motivation of this study is to obtain an improved coupled wake and blockage model that converges to the accurate SCADA data of a wind farm more than the wakeonly or blockage-only models. This study applies seven wake and six blockage models to the wind farm. The similarities and differences between the coupled models and the wind farm SCADA data and their reasons are discussed.
Design and Tests of a Geothermal Dryer and Determination of Quality Parameters of Dried Product
(Izmir Institute of Technology, 2012-12) Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
Drying which is a heat and mass transfer process between the product surface and its surrounding medium and within the product is practised to enhance the storage life and reduce transportation costs of products. Olive leaves are the plants which have been used for medicinal purposes are often dried before use. Renewable energy sources such as geothermal energy can be used in drying processes as heat source besides fossil fuels. The temperature and the thermal potential of geothermal resources in Turkey is high enough to be used in drying process. In this thesis, a geothermal cabinet type drier was constructed and placed in Balcova-Narlidere geothermal field. To be able to determine drying parameters (temperature and velocity) and whose effects on drying kinetics of olive leaves and on the quality parameters of dried olive leaves (antioxidant content and phenolic content), drying experiments were carried out at three different air temperatures (40, 50 and 60 Â°C) and at three air velocities (0.5, 1, 1.5 m/s). During the experiments temperature, relative humidity and velocity of drying air was measured and recorded. Then, using the measured data drying time, drying rate, moisture ratio and effective diffusivity was determined and moisture ratio was modelled using thin-layer models. The quality parameters which are total antioxidant activity and total phenolic content were determined using spectrophotometric techniques. To evaluate the performance of the dryer, energy and exergy analyses were conducted. The drying time was determined as 240 â€“ 555 min. (4 â€“ 10) hour which is quite short comparing with open air sun drying. Optimum drying air temperature and velocity which gives the minimum total phenolic content and antioxidant loss value were determined by response surface methodology as 50 Â°C and 1 m/s, respectively. The energy utilization was found 0.3316 kW and the energy utilization ratios were found 50.36% and 7.96% for the case at drying air is re-circulated and the case at drying air was no re-circulated, respectively.
Determination of Effective Parameters for Drying of Apples
(Izmir Institute of Technology, 2007) Dikbasan, Tarık; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Drying is one of the oldest methods for the preservation of agricultural products such as fruits and vegetables. Apple has a significant share in fruit production both in the World and in Turkey. It is also an important raw material for many food products.Temperature, velocity and relative humidity of drying air are important parameters for hot air drying process. To determine the drying kinetic of agricultural products, drying and drying rate curves should be plotted.Experiments are conducted in a tunnel dryer using cubic shaped (10x10x10mm) red delicious (Malus Domestica) apple for various drying air temperature (40.1-65.3oC), velocity (1.1, 1.4, 1.9, 2.3 and 2.5 m/s) and relative humidity (4.6-20.5%) values. The temperature and relative humidity are measured and recorded every 1 min. at fan inlet, upstream and downstream of the tray, the velocity is measured only at the tunnel exit. The measured data is used to obtain drying and drying rate curves. The curves indicate that drying process takes place in the falling rate period except very short unsteady-state initial and constant rate periods. Thus, effective diffusion coefficients are calculated using the data collected during the falling rate period and the experimental data are fitted to fourteen thin layer drying models which are found in the literature. Rehydration time and colour are used as parameters for the dried apple quality.The effective diffusion coefficients are obtained within the range of 0.486x10-9 -5.63x10-9 m2/s Regarding with drying time, rehydration time and colour data, the best results are obtained at 2.5 m/s velocity, 20.5% relative humidity and a temperature range of 53.5-65.3oC under experimental conditions. Midilli and Kucuk model is the best fitted model with a minimum R2 of 0.9991 and a maximum RMSE of 0.0087976.
Development of Energy-Efficient Personalized Thermal Comfort Driven Control in Hvac Systems
(Izmir Institute of Technology, 2018-12) Turhan, Cihan; Gökçen Akkurt, Gülden; Simani, Silvio; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Increasing thermal comfort and reducing energy consumption are two main objectives of advanced HVAC control systems. Studies conducted in the last decade show that intelligent HVAC systems can geatly affect thermal comfort, health, satisfaction, and productivity of building occupants while decreasing the energey consumption. Also, personelized thermal comfort driven control of the HVAC systems is the most effective way of saving energy and maintaining thermal comfort. In this thesis, an energy-efficient personalized thermal comfort control algorithm is developed to improve HVAC control systems. The thesis presents a complete system to control algorithm which includes the deployment of wireless sensor network. First a novel control algorithm is developed to perceived comfort conditions of occupants and to save energy. Then, a prototype of the personalized thermal comfort driven controller (PTC-DC) is manufactured an tested in a case building at İzmir Institute of Technology Campus, İzmir/Turkey. The proposed control strategy is tested betwen July 3rd, 2017 and November 1st, 2018, and compared with conventional controller in terms of energey saving and boath energetic and exergetic approaches of thermal comfort. The results showed that PTC-DC satisfies neutral thermal comfort for 92% of total measurements days while AM=0 for only 6% of total measurement days for conventional controller. From energy consumption point of wiev, PTC-DC decreased energy consumption by 13.2% compared to conventional controller.
Development of holistic methodology for sustainable adaptive reuse of public heritage buildings: Dokuz Eylul gate building of Kültürpark
(01. Izmir Institute of Technology, 2024) Güleroğlu, Selin; Arsan, Zeynep Durmuş; Akkurt, Gülden Gökçen; 02.02. Department of Architecture; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
Sürdürülebilir yeniden işlevlendirmenin sağlanabilmesi için yapının yeni işlevinin karar verilmesinden iyileştirme önerilerinin kararına kadar olan tüm süreci ele alan bütüncül bir yaklaşım gerekmektedir. Bu çalışma, sosyal, ekonomik, çevresel ve tarihi değerleri bütünleştirerek sürdürülebilir yeniden işlevlendirme için bütüncül bir yöntem sunmaktadır. Çalışmada geliştirilen metodolojiye göre birinci aşama yapının yeni fonksiyonunun belirlenmesine odaklanırken, ikinci aşama ise iyileştirme önerilerinin seçimini kapsamaktadır. Aşama 1'de, çevresel sürdürülebilirlik, kültürel değer ve sosyal etki gibi kriterler göz önünde bulundurularak toplumun talepleriyle uyumu garanti altına alıp, paydaş katılımını dikkate alan Analitik Ağ Süreci (ANP) kullanılarak binanın yeni işlevinin belirlenmesi önerilmektedir. Aşama 2'de kaynak verimliliğini ve malzeme yeniden kullanımını teşvik ederken, çevresel etkiyi azaltan optimum çözümler bulmak için enerji performansı, çevresel etki ve döngüsellik potansiyeli gibi ölçütlere dayalı iyileştirme önerileri belirlenmektedir. Geliştirilen yöntem, İzmir'deki Dokuz Eylül Kapı Binası üzerinde bir vaka çalışması olarak uygulanmıştır. Birinci aşamada, bina için en uygun yeni işlev olarak sanat galerisi ve müze belirlenmiştir. Binanın enerji tüketimi önceki işlevine göre %1,5 oranında artsa da, sosyal sürdürülebilirliğe katkısı yeni işleviyle önemli ölçüde artmaktadır. İkinci aşamada, duvar, çatı ve zeminler için koyun yünü yalıtımı ve düzcam kullanımını içeren en uygun iyileştirme senaryosu belirlenmiştir. Bu kombinasyon, enerji tüketimi (10.707 kWh), Küresel Isınma Potansiyeli (143.993 kg CO2-eşdeğer) ve yüksek döngüsellik (%74) arasında bir denge sağlamaktadır. Bu çalışma, iyileştirme önlemleri ile işlev seçimini birleştiren kapsamlı bir yaklaşım sunarken, yeniden işlevlendirilen tarihi yapıları sosyal ve çevresel olarak dirençli yapılara dönüştürme potansiyelini ortaya koyarak, yeniden işlevlendirmenin sürdürülebilir kentsel gelişim için temel bir strateji olduğunu vurgulamaktadır. Anahtar Kelimeler: sürdürülebilir yeniden işlevlendirme, bütüncül metodoloji, enerji etkin tasarım, YDD, döngüsellik, toplumsal katılım
District Heting System of Iztech Campus and Its Integration To the Existing System
(Izmir Institute of Technology, 2003) Yıldırım, Nurdan; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Izmir Institute of Technology (IZTECH), founded in 1992, is the third state university of Izmir. At present IZTECH Campus has individual fuel boiler heating systems for each faculty building and the Campus is still under development. But the Campus has also a geothermal source. In 2002, 5 gradient wells were drilled. Of these, one well has a geothermal fluid of 33Â°C is obtained but the actual flowrate of the geothermal fluid has not been measured yet. The aim of this Thesis is to investigate this source whether it can be used for district heating application for IZTECH Campus. Mainly two heating system types have been considered;. Heat pump heating system (HPHS) (using a renewable energy source, geothermal energy), . Fuel boiler heating system (FBHS) (using a conventional energy source, fuel-oil). HPHS is considered as HPO type since the existing geothermal fluid temperature is low. While HPHS is considered only as district, FBHS is considered as district and individual. Each heating system is simulated using hourly outdoor temperature data. For these heating simulations, the main control parameter is the indoor temperature of the buildings. Mathematical models are derived using Matlab [16] and EES [17] programs. Various heating regime alternatives have been studied for HPHS for the various condenser outlet temperature and geothermal fluid flowrate. Consequently, the heating regime with 35Â°C condenser inlet and 45Â°C condenser outlet temperature with 120 kg/s geothermal fluid flowrate considered to be the best option. FBHSs are also simulated for various boiler set temperatures. Boiler set emperatures have been recommended by Demirdöküm [39], is the best alternative with the least fuel consumption and best indoor temperature around 20Â°C. Besides heating system simulations, piping network simulation is made using the software Pipelab [18]. The piping network of the Campus has been considered with two loops as geothermal and Campus. Each loop contains supply and return main. The location of the heat centre and the pressure loss per unit length are common design parameters for economy of the system. Therefore, several alternatives have been studied and because of the lowest investment and operational cost, Alternative 3, where the heat centre is in the middle of the Campus, is considered to be the best option with target pressure loss of 150 Pa/m. For installation type of piping network, underground (buried) pipeline installation is selected. Furthermore, economic analysis has also been done for each heating system alternative depending on investment and operational costs. For operational cost, 3 heating scenarios are considered depending on the heating period of the buildings in the Campus. According to the results of economical analyses, while heat pump district heating system (HPDHS) has the biggest investment cost with 3,040,125 US$, it has minimum operational cost. The alternatives are evaluated according to internal rate of return (IRR) method, which shows the profit of the investment. The results indicate that, the HPDHS has minimum 3.02% profit according to the fuel boiler district heating system (FBDHS) at the end of the 20-year period. The profit increases with increasing operating period of the heating systems.
The Economic Analysis of Geothermal / Absorption Cooling of a Hospital: Case Study of Dokuz Eylül University Research and Application Hospital
(Izmir Institute of Technology, 2006) Altın, Mete; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Dokuz Eylül Research and Application Hospital, founded in 1982, is located in İnciraltı Place, in Balçova. It is placed at the south of İzmir and between the İzmir-Çeşme Highway and İzmir-Çeşme Super Highway. Rather rich geothermal resources found in Balçova, provides the use of geothermal water for heating in the hospital. However, the required cooling capacity for the hospital, which is relatively massive when compared with the residents, has been supplied by conventional compression chillers. In this study, the aim is to decrease the overall annual costs incurred by cooling of the hospital by implementing an absorption cooling system, which uses geothermal fluid as the heating source. The main idea behind this implementation is that the electricity consumption of an absorption chiller is minimal when compared with a compression chiller. On the other hand, since the source that is going to be used in the system is geothermal energy, there will be an additional cost incurred by the use of geothermal fluid. So, the economic analysis that is going to be conducted involves the comparison of two alternatives, which are leaving the system as is now and implementing an absorption cooling system. To minimize the costs incurred by the implementation of an absorption cooling system, instead of supplying the full capacity of the hospital, a moderate capacity will be supplied by the absorption chillers, by using the existing compression chillers as the peaking units. Since it is not known which capacity will be suitable for the needs, several absorption cooling machines with various capacities will be examined. After comparing these mutually exclusive alternatives, the effect of the change in geothermal fluid price on the implementation of an absorption cooling system, and the break-even geothermal water price will be found. At the end, the investment worth values of the selected absorption cooling machines will be examined to decide whether to implement an absorption cooling system in the hospital or not.
Effect of Aging Electrolyte and Organic Coating Type on the Corrosion Mechanism of Tinplate
(Izmir Institute of Technology, 2019-12) Yıldırım, Koray; Kızılkaya, Ali Can; Çağlar, Başar; 03.06. Department of Energy Systems Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Market share of the can coating industry was 2 billion dollars in 2018 globally. A large portion of this market is focused on protecting valuable goods such as foods and cosmetics. Recent bans on the Bisphenol A(BPA) created a BPA-free coating demand due to the high portion of BPA based coatings in the industry such as epoxy. A conventional epoxy based (EP) can coating was compared with a new design of BPAfree polyester coating(PE). Atomic Force Microscopy(AFM), Scanning Electron Microscopy(SEM), Electron Dispersive Spectroscopy(EDX), Electrochemical Impedance Spectroscopy(EIS), Direct Current(DC) Polarization were used to investigate degradation. Industrial and model tinplate samples are compared with surface investigation methods. AFM results indicate the surface composition difference. To investigate bare tinplate corrosion, a mixture of acidic electrolyte was prepared and compared with other conventional aging electrolytes, containing mono acids. The electrolyte prepared from mixed acids was found to have the highest detinning abilities. Therefore, coated samples were aged with this mixed acid solution electrolyte. EIS results indicated that the type of electrolyte alters the corrosion mechanism, indicated by the observance of different time constants at different time scales. During immersion tests, EP based coatings showed better corrosion resistance as shown by higher impedance at low frequency, higher coating resistance and lower capacitance values. However, after sterilization, polyester coated samples showed better corrosion protective abilities (indicated by lower amount of corrosion products and higher impedance values) compared to the epoxy sample even though AFM measurements indicated that it had larger pore sizes after aging compared to epoxy sample. These results are attributed to the larger electrochemical area and higher diffusion properties of EP coatings, obtained after modelling of EIS data.
The Effect of Restoration Interventions on the Indoor Climate of Historic Buildings: Case Study of Tire Necip Paşa Library, İzmir, Turkey
(Izmir Institute of Technology, 2022-07) Çağırgan, Umut; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
Libraries are collections of recorded information which can host cultural heritage values that must be protected against mechanical, chemical and biological degradation. To prevent degradations, libraries require stable indoor climates with minimal temperature and relative humidity fluctuations and low concentrations of indoor air pollutants. Aim of the thesis is to investigate if installing a HVAC system is effective in improving the indoor climate of a historic library as a long-term preventive conservation method on the preservation of paper-based collections. Tire Necip Paşa Library in İzmir was selected as the case building which underwent restoration and a HVAC system integration in 2015. Library’s indoor climate was investigated before 2015 which allowed the comparison of pre- and post-restoration periods. Within the scope of this thesis, library was monitored at five locations between 2019-2021. 2019-2020 monitoring results were compared to pre-restoration monitoring results in terms of degradation risks and ASHRAE Chapter 23 control classes. Pre- and post-restoration indoor climates satisfied A1 and AA control classes, respectively. While there were mechanical and chemical degradation risks before restoration, no risk was observed post-restoration. There was no biological degradation risk during either periods. Additionally air pollutants were sampled during summer and winter of 2020-2021 which showed high SO2 and NO2 concentrations. Lastly the BES model of library was prepared and calibrated to investigate if existing HVAC system will continue to provide a stable indoor climate on future. The results of 2050 and 2080 simulations showed that HVAC system will struggle to provide a stable indoor climate.
Effects of Electrical Dynamic Response of Doubly Fed Induction Generator Type Wind Turbines on Their Mechanical Systems During Single and Multiple Faults
(2023) Coşgun, Mert; Karadeniz, Ziya Haktan; Altın, Müfit; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In the early stages of wind turbine technology, the focus was on the separate development of mechanical and electrical systems and research was carried out only in these areas. Today's modern wind turbine designs, which have reached megawatt sizes, continue to be more cost-effective and dependable for countries to achieve their renewable energy targets. In this direction, wind turbine research and development processes have now started to focus on both mechanical and electrical systems and their subsystem interactions. In this thesis study, it is aimed to investigate the effects of the response of electrical control systems on towers components during grid faults. A doubly fed induction generator is used for power generation and power systems including converters and control systems are modelled in MATLAB/Simulink. Simulations were designed in Simulink to test the grid-connected wind turbine model and the Fault Ride Through condition that causes voltage drops in the grid connection lines; the response of the control system and electromagnetic torque output in the relevant case were sent to the mechanical system analysis tool Horizonal Axis Wind Turbine Simulation Code 2 to observe the effects on the mechanical system. In Horizonal Axis Wind Turbine Simulation Code 2, the interaction of the main bodies against forces and limits is analyzed and the results are reported graphically. The state of the system without fault and data with the faults are analyzed comparatively. It has been observed that the reactions of the electrical power systems during grid failure influence the mechanical systems.
Electrocatalytic isopropanol oxidation for direct organic fuel cells
(01. Izmir Institute of Technology, 2024) Çetin, Yağmur; Çağlar, Başar; Şeker, Erol; 03.06. Department of Energy Systems Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Dünya üzerinde sürekli artan nüfus yoğunluğu ve buna eşlik eden enerji tüketim oranları nedeniyle, yenilenebilir enerji kaynaklarını bulma, bunları erişilebilir ve kullanıma hazır hale getirme ihtiyacı önemli konular gelmiştir. Son yıllarda, hidrojen taşıyıcıları ve yakıt hücresi sistemleri, geleneksel fosil yakıt türlerine bağlı enerji üretim sistemlerine iyi alternatifler olarak öne çıkmıştır. Bu çalışma için, hidrojen taşıyıcısı olarak izopropanol-aseton çifti seçilmiş ve reaksiyon kinetiği incelenmiştir. İzopropanolün elektrokimyasal oksidasyonu, yakıt hücresi uygulamaları ve enerji depolama cihazlarındaki önemi nedeniyle oldukça ilgi görmüştür. Bu tez içeriğinde, Pt/C, Cu/C, Pt-Cu(1:1)/C, Pt-Cu(3:1)/C ve Pt-Ru/C ticari katalizörleri kullanılarak izopropanolün elektrokimyasal oksidasyon davranışına odaklanılmıştır. Oksidasyon reaksiyonunun performansını iyileştirmeyi amaçlarken, her bir elektrokimyasal katalizörün aktivitesi, seçiciliği ve reaksiyon koşullarındaki kararlılığı farklı ortamların etkisi altında, alkali koşullarda incelenmiştir. Bu katalizörlerin elektrokimyasal performansı Döngülü Voltametri, Elektrokimyasal Empedans Spektroskopi ve Kronoamperometri analizleri ile değerlendirilmiştir. Sonuçlar, diğer Platin bazlı katalizörlere kıyasla daha yüksek katalitik aktivite ve daha düşük kinetik direnç gösteren Pt-Cu/C katalizörünün üstünlüğünü göstermektedir. Bu gelişmiş performans, Bakır'ın OH- türlerine olan güçlü afinitesine atfedilir ve bu da izopropanol oksidasyon hızını artırır ve genel elektrokimyasal aktiviteyi teşvik eder. Genel olarak, bu çalışma izopropanol elektrooksidasyonunun kinetiğine dair değerli bilgiler sağlayarak ve Pt-Cu alaşımının çeşitli elektrokimyasal sistemlerde verimli alkol oksidasyonu için umut verici bir katalizör olarak potansiyelini vurgular.
Energy and exergy analysis of renewable energy utilization in cement production
(01. Izmir Institute of Technology, 2025) Alaca, Pelin; Çağlar, Başar; Fard, Mousa Mohammadpour; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Geleneksel çimento üretim yöntemlerine kıyasla daha yeşil enerji sistemleri alternatiflerini keşfetmek için çimento üretiminin enerji ve ekserji analizi çalışılmıştır. İki farklı yeşil enerji senaryosu dikkate alınmıştır. Temel senaryo geleneksel çimento üretimidir. İlk senaryoda atık rüzgar türbini kanatlarının pirolizi ve gaz türbini çimento fabrikasına entegre edilmiştir ve elektrik ihtiyacı gaz türbini tarafından karşılanmıştır. Aynı zamanda hammadde piroliz ünitesinin katı ürününden sağlanmıştır. Bu senaryo için sıcak akımları kullanmak üzere bir ön ısıtma sistemi düşünülmüştür. İkinci senaryoda, PEM elektrolizörü de çimento fabrikasına dahil edilmiştir. Burada kömürle değiştirilmek üzere PEM elektrolizöründen hidrojen üretilmiştir. Tüm senaryoların termodinamik modellemesi Engineering Equation Solver (EES) yazılımı aracılığıyla gerçekleştirilmiştir. Temel senaryonun enerji ve ekserji verimliliği sırasıyla % 61,60 ve % 20,21 olarak bulunmuştur. Termodinamik analiz dışında, özgül enerji tüketimi (SEC) ve CO2 emisyonları hesaplanmıştır. En düşük SEC, 1704 kJ/kg olan senaryo 1 ile elde edilmiştir. CO2 emisyonları, 0,219 kg CO2/kg çimento ile senaryo 2 için minimum olarak sonuçlanmıştır. Tüm bunlar göz önüne alınarak, daha yeşil ve daha az enerji tüketen bir sistem oluşturulmaya çalışılmıştır.
Energy Efficiency in a University Building: Energy Performance Assessment of Iztech Administrative Building
(Izmir Institute of Technology, 2009) Yaman, Mustafa Can; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Energy performance of the buildings can be evaluated by measuring energy consumptions or performing simple or detailed simulation methods. In this study, IZTECH Administrative Building which is a university building, is selected as case study and energy audit is performed to evaluate energy performance of the building. Indoor conditions are recorded with dataloggers and outdoor climatic data is taken from IZTECH Meteorological Station. Fuel consumption is tracked by two flowmeters and electricity consumption is measured with three power analyzer connected to heating, cooling and lighting and general use electricity meters. Energy consumption of the building is simulated by three different methods which are TS 825 (static), CIBSE Admittance (simple dynamic) and ASHRAE Heat Balance (full dynamic) methods. Sensitivity of these methods is tested by comparing energy consumption measurements and simulations and performance improving measures are proposed. Also a hypothetical no-HVAC case is simulated. ASHRAE Heat Balance Method is determined as the most accurate model compared to measurement results and performance improving measures are simulated with this method, reduction in energy consumption and greenhouse gas emissions are observed.
Energy Efficient Retrofitting of Historical Buildings: a Case Study on the Building of Basmane Semt Merkezi-Izmir
(Izmir Institute of Technology, 2013) Şahin, Cem Doğan; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
Buildings account for 40% of total energy consumption in the European Union yet at the same time it is foreseen that they have a considerable energy saving potentials. Along with the issued energy efficiency related laws and regulations, energy efficient retrofitting applications of the existing buildings are getting increased and the new buildings are built considering the energy efficiency issues. At this point, historical buildings should be treated different than contemporary ones when energy efficient improvements matter. Therefore the specifications adding value to the historical buildings require attention and well-preservation while saving energy. The purpose of this study is to denote how the energy efficient retrofitting in historical buildings should be managed in a transdisciplinary way with a case study conducted on a historical building, Basmane Semt Merkezi-İzmir. A detailed building energy simulation tool, DesignBuilder, was used to determine the impacts of the energy efficient retrofits. The actual energy consumption of the case building was calculated obtaining the utility bills regarding electricity and heating fuel consumption. Building energy simulation tool was calibrated by comparing of the measured and simulated indoor air temperatures and total energy consumptions. The inappropriate retrofits, which contradict to the heritage and cultural values, were eliminated with an interdisciplinary approach. Later appropriates retrofits were gathered into three packages to evaluate their effects on the energy consumption. The results show that energy saving up to 41% can be obtained without damaging the heritage values. Besides, the results of combined and aggregated effects of single retrofits show considerable alterations that might cause errors in economical calculations.
Energy Performance Analysis and Materials Characterization of Aerogel Insulation Blankets
(Izmir Institute of Technology, 2022-07) Alan, Selena; Gökçen Akkurt, Gülden; Akkurt, Sedat; 03.09. Department of Materials Science and Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
İzmir Geothermal Energy Inc. is a geothermal district heating company in İzmirTurkey that circulates hot water throughout the district via a 450 km of piping system and with the help of valves, pipes, and heat exchangers. As the distance traveled by the hot water is excessively long, heat losses are common. Rock wool is used as thermal insulation material, but the performance degraded over time because of water leakage. Instead of rock wool, aerogel insulation blanket use is evaluated in this study. Rock wool and three different aerogel insulation blankets are comparatively studied to assess their structures and thermal performances in two ways: the first is the characterization of materials by various physical and chemical analysis methods in the IZTECH-Integrated Research Center. The second way is to assemble a test setup on-site and make thermal measurements on the test setup for each aerogel insulation material, rock wool, and bare pipe. Heat loss calculations were conducted by EES software. The results are compared based on each characterization and thermal performance calculation. The thermal conductivity values of the insulation materials were calculated. Nonwetting properties were also checked to understand their hygrothermal properties. Compared with bare pipe, with the 10 mm thickness, rock wool decreases heat loss by 48-52%, and with the 10 mm thickness, the aerogel insulation blankets reduce heat loss by 57-61%. Finally, while aerogel insulation blankets have a better performance, they are more expensive than rock wool.
Energy, Exergy and Enviromental Assessment of a Novel Multi-Generation System Fed by Biomass and Geothermal Energy Sources
(01. Izmir Institute of Technology, 2022-12) Şeker, Utku; Gökçen Akkurt, Gülden; Mohammadpourfard, Mousa; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Energy is the one of the critical tools that ensure the development of the countries. Since almost no country is completely energy independent, it is very important for countries to use the available energy efficiently and to produce their own energy from renewable energy sources. Multi-generation systems combine various cycles and processes to produce number of outputs and valuable market products using one or multiple energy sources as input. By creating a multi-generation system powered by renewable sources can increase system efficiency and provide some additional outputs such as hydrogen, heating, cooling, and domestic hot water. In this thesis, a novel multi-generation system consisting of a biomass gasification cycle, a double-flash geothermal cycle, an Organic Rankine Cycle and a PEM electrolyzer subsystems, is proposed to increase the efficiency and energy production from biomass and geothermal energy sources instead of using a single source for a single output. The proposed system is analyzed in terms of energy, exergy, and environmental impact point of view. By performing parametric studies for biomass flow rate, turbine inlet temperature, and single-objective optimization, effects on thermodynamic behavior and environmental impact are investigated for subsystems and overall system. The best operating conditions are determined. The findings indicate that energy efficiency of the proposed multi-generation system is 75% higher than a double-flash geothermal power plant. Based on the parametric study, biomass mass flow rate is encountered as the most significant parameter, which caused an 11.7% increase in energy efficiency, and 225% increase in environmental impact cost.
Environmental Effects of Geothermal Applications Case Study: Balçova Geothermal Field
(Izmir Institute of Technology, 2003) Çakın, Ayça; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Direct application of geothermal energy can involve a wide variety of end uses, such asspace heating and cooling, industrial applications, greenhouses, fish farming, and health spas. It uses mostly existing technology and straightforward engineering. The technology, reliability, economics and environmental acceptability of direct use applications of geothermal energy have been demonstrated throughout the world.The use of geothermal energy is the minimum waste forming type of energy in the world. Geothermal energy is also considered cheap, sustainable and environmentally friendly when compared to the other energy resources.Turkey has abundant geothermal resources because of its location. In particular, İzmir-Balçova district heating system is one example of the high temperature district heating applications in Turkey exhibiting high geothermal potential.The objective of the Thesis is threefold, namely: (a) to determine the negative and positive environmental effects of Balçova Geothermal District Heating System, (b) to find out sources of contamination if pollution exists (c) to offer a solution to protect the public health.Contamination may occur in Balçova Geothermal Field in either water phase or soil phase. Therefore, a sampling program was developed in order to monitor the alterations in water. The sampling points were chosen in a way that Balçova District Heating System production wells, groundwater wells, and the irrigation points could all be monitored.In order to investigate the contamination of the region, several parameters including physical properties such as temperature, electrical conductivity, total dissolved solids, alkalinity; non-metallic constituents such as ammonia, boron, chloride, silica, sulfate; and metals and semi metals such as calcium, magnesium, sodium, potassium etc. were determined.The results of this study showed that all of the samples had bicarbonate alkalinity. The concentrations of the parameters were not constant during the monitoring study. This may be because of the nature of geothermal fluid. During the studying period, concentrations of many heavy metals were below the limit of detection of atomic spectrometric techniques used in the study. Wells T and I did not seem to be suitable for drinking and irrigation water, respectively.In order to determine the effects of Balçova District Heating System on physical environment, noise measurements were conducted. The results of noise measurements have shown higher values than the acceptable limits of Noise Control Regulation.
Environmental Impact and Capacity Analysis of Renewable Energy Resources: Case Study of Wind Energy in Turkey
(Izmir Institute of Technology, 2016) Değirmenci, Sinem; Bingöl, Ferhat; Sofuoğlu, Sait Cemil; Bingöl, Ferhat; Sofuoğlu, Sait Cemil; 03.07. Department of Environmental Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The majority of electricity in Turkey is generated from coal and natural gas; however, renewable energy, especially wind power, is a promising energy source for Turkey. Development of new wind energy project requires complex planning process involving many social, technical, economic, environmental, political concerns and different agents such as investors, utilities, governmental agencies or social groups. To address the proper site selection, a Geographic Information System (GIS) based Multi- Criteria Decision-Making (MCDM) method has been used in previous studies. The aim of this study is to develop a GIS-based multi-criteria decision making application which can be updated by the changing regulations to identify potential sites for wind power plants in Turkey. A variety of constraints and factors were identified based on a literature review, regulations and gathered from variety of agencies. After excluding of infeasible sites, pairwise comparisons was carried out using analytic hierarchy process (AHP) as MCDM method by the study group to estimate relative importance of the criteria. The suitability map obtained from MCDM analysis was divided into four classes from the low suitable to extremely suitable area. As a final stage, decision making was carried out with the objectives by environmental impact approach. The output of this study can be used by energy planners to estimate the extent that wind energy can be developed based on public perception, administrative and environmental aspects.

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