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Öğe Atık baca gazı kullanımı ile termoelektrik jeneratörlerde elektrik üretiminin faydalı kullanımının deneysel ?ncelenmesi(2014) Özkaymak, Mehmet; Bas, Şahin; Acar, Bahadır; Yavuz, Celil; Boran, Kurtuluş; Tabak, A. Samet; Variyenli, H. İbrahimTermoelektrik jeneratörlerin çok sayıda jeneratörün birbirine seri bağlanması ile voltaj çıkış yükseltilebilmekte, paralel bağlanması ile de akım değeri artırılabilmektedir. Bu çalışmada, termoelektrik jeneratörler kullanılarak bir deney seti oluşturulmuş, jeneratörün sıcak tutulması gereken yüzeyi soba borusunda üretilen atık gaz tarafından ısıtılarak ve soğuk olan yüzeyi üzerinden su geçirilip soğutularak sıcaklık farkı ile elektrik üretimi sağlanmıştır. Burada gerilim değerleri 5,11 V ile 8,69 V arasında değiştiği görülmüştür. Debi 0,083 lt/s olduğu anda 8,69 Volt ve 1,45 Amperlik maksimum performans elde edilmiştir. Soğutma suyu debisi değiştirilerek yapılan deneylerde elektrik üretimi doğru orantılı olarak arttığı gözlemlenmiş, sonuçlar grafikler halinde sunulmuştur.Öğe Comparison of the impact of r449-a and r290 on refrigerated display cabinets using life-cycle climate performance method(2024) Demirpolat, Havva; Erten, Süleyman; Ataş, Şafak; Aktaş, Mustafa; Özkaymak, MehmetDue to the high energy consumption of refrigerated display cabinets used in supermarkets, a life cycle cooling performance analysis to increase energy efficiency and reduce environmental impacts is the main subject of this study. It also emphasizes the need for cabinets that consume less energy and provide environmentally friendly working conditions. The Life Cycle Climate Performance (LCCP) of the two refrigerants R290 and R449-A was evaluated using measured data to compare the environmental impact of the refrigerants over the entire fluid and equipment life cycle, including energy consumption. Both vapor-compressed cooling cycles were thermodynamically modeled with the parameters taken from the experiments and the efficiency of system was calculated by using the EES software. The results show that the cabinet using R290 has lower compressor power utilization. The COP of the R290 system increased by 13% compared to the R449A system. The total daily energy consumption was also significantly lower for the R290 system. The energy efficiency index provides a standardized metric that can be used to compare the performance of different cooling systems. In this study, the energy efficiency index value was 17.3 points lower for the R290 system, indicating higher energy efficiency. The energy classes are “E” for the R449-A system and “C” for the R290 system, with the R290 system two classes higher in terms of energy class labeling. The EEI value of the system with R290 refrigerant has been reduced by 33% in comparison with the system with R449A refrigerant. The system using R290 refrigerant achieved a 33% reduction in energy consumption compared to the system using R449A refrigerant. The study also assessed the life cycle climate performance of the two systems. It was found that the R449-A system emits 19032.45 kg CO2e more over its lifetime compared to the R290 system. This was attributed to the relatively high global warming potential and energy consumption of R449-A refrigerant. However, when considering safety (flammability), it was concluded that R-449A has a lower environmental impact than R-290.Öğe Doğal soğutucu akışkan kullanımında gelişmeler(2020) Demırcı, Esra; Özkaymak, Mehmet; Kosan, Meltem; Akkoç, Ahmet Eren; Aktaş, MustafaGünümüzde son zamanlarda, insanoğlu tarafından enerji sistemlerinin ısıtma ve soğutma amacıyla kullanılan sentetik soğutucu akışkanların yol açtığı hava, su, toprak kirliliği, ozon tabakasının tahribatı ve küresel ısınma gibi çevresel sorunlar yalnızca insan sağlığını tehdit etmeyip tüm canlı ve cansız türlerin yaşamlarını ve geleceğini önemli ölçüde etkilemektedir. Bu çalışmada, çevreye olan zararların minimum seviyeye indirilmesi için sentetik soğutucu akışkanlara alternatif olarak kullanılabilecek doğal soğutucu akışkanlardan (R290, R600, R717, R744 vb.) ve uygulama örneklerinden bahsedilmiştir. Doğal soğutucu akışkanların kullanımı, soğutma sistemi performans katsayısı ve sistemin teknolojik özellikleri açısından yapılan çalışmalar incelenmiştir. Elde edilen bulgular ve çıkarımlar ısıtma ve soğutma sistemi tasarımcılarına enerji verimliliği ve çevre kriterleri anlamında ışık tutacaktır.Öğe Elektrik motorlarinda uygulanan bakim yöntemlerinin incelenmesi, karşilaştirilmasi ve uzaktan erişimin kestirimci bakima etkisi(2020) Tabak, Abdülsamed; Özkaymak, MehmetSanayi devriminden günümüze kadar gelinen süreçte tüketici talepleri sürekli artmış ve bu talebi karşılamak adına üreticiler yeni arayışlar içerisine girmiştir. Buna bağlı olarak üretimdeki devamlılığın sağlanması için ekipmanlara daha fazla değer verilmiş, ekipmanlardaki arıza ve duruş istenmez hale gelmiş ve bakım yöntemlerine duyulan ilgi artmıştır. Özellikle endüstride üretimin kalbi niteliğindeki elektrik motorlarında uygulanan bakım yöntemleri ilk zamanlardan beri sürekli geliştirilmiş ve en uygun bakım yöntemi her zaman aranmıştır. Çalışmamızda sanayideki elektrik motorları üzerinde yapılan bakımlar ilkelden gelişmişe doğru sınıflandırılmış ve irdelenmiştir. Bu bakım yöntemleri hem maddi açıdan hem de birtakım avantaj/dezavantajları açısından birbirleri ile karşılaştırılarak uygulamada teknik personel için en uygun bakım yönteminin seçimi hakkında bilgi verilmiştir. Ardından, durum bazlı bakım olarak da bilinen kestirimci bakım yönteminin en yaygın kullanılan teknikleri irdelenmiştir. Bunların yanında internet ve uzaktan erişim sistemlerinin kestirimci bakıma olan katkısı incelenmiş ve bakımın önemi her açıdan ortaya konmuştur.Öğe Energy and exergy analysis of an organic rankine cycle in a biomass-based forest products manufacturing plant(2016) Eyıdoğan, Muharrem; Çanka Kılıç, Fatma; Kaya, Durmuş; Özkaymak, Mehmet; Çoban, Volkan; Çagman, SelmanIn this study, energy and exergy analysis of an organic Rankine cycle (ORC) unit was carried out at a biomass-based forest products manufacturing plant. The ORC unit is used for the production of electricity and heat, by using thermal oil as a heat source in the plant. The actual data were obtained from the ORC unit during the energy production process. Studies were realized for the energy and exergy analysis of the main components of the ORC unit, which are the evaporator, condenser, turbine, and regenerator, at two different working conditions. The effect of condenser pressure on the energy and exergy efficiencies of the system was studied in the context of this study. Under the working conditions of Case-1, the energy and exergy efficiencies were calculated as 12.59% and 33.26 %, respectively. As for Case-2, the energy and exergy efficiencies were calculated as 13.22% and 35.5%. The gradation of the exergy destructions of the components from greater to lower can be listed as evaporator, condenser, turbine, regenerator, and pump.Öğe Freeze- drying of carrot slices in diverse thicknesses(2021) Acar, Bahadır; Dagdeviren, Abdullah; Janaani, Ahmed; Roshanaei, Khandan; TaskeŞen, Edip; Ongun, Göknur K.; Özkaymak, MehmetIn this paper we dried carrots by the method of freeze-drying. The carrots had cut into slices; then\rdivided in halves. The mass looses of samples sized. The mass losses measured and recorded during the\rprocess. The sections were in 5 mm and 7 mm. Slices were dried with SCANVAC COOLSAFE. The masses of\rthe carrot slices differed also in each unit with the same mass and shape varied. Our team did the drying\rprocedures every two hours, also the experiment was applied at different temperatures. While evaluating\rthe number of carrot slices as samples for freeze-dried observed that, dried samples amount were 5\rtimes less than the number of carrots before drying. The procedure was applied to 10 different\rmathematical models using the MATLAB program. The error analysis of the models at the result made by\rusing the root-mean-square error (RMSE), chi-square (X2) and regression coefficients (R2). According to\rthe results, it was sdetermined that the results of the Page model were closer as the experimental results\rbe compared to other models. The statistical error values of samples for R2, RMSE respectively were\r0.018565707 for 5 mm and 0.019532936 for 7 mmÖğe Gaz yakıtlı bir turbo blower santralinin performans analizi(2017) Ergün, Alper; Arslan, Ümit; Özkaymak, MehmetDemir-çelik tesisleri bünyesinde birbirinden farklı birçok alt tesisi barındırmaktadır. Bu tesislerin en önemli ekipmanı demir cevherinin işlendiği yüksek fırınlardır. Bu tesise yüksek basınçta yakma havası sağlanması gerekir ve bu hava turbo blower ile sağlanmaktadır. Turbo blower temelde bir enerji santralidir ve türbin kısmına yüksek basınçta hava sağlayacak bir kompresör akuple edilmiştir. Bu çalışmada, entegre demir çelik fabrikalarında üretim sırasında atık gaz olarak ortaya çıkan yüksek fırın ve kok gazının yakıt olarak kullanıldığı bir santralin ekserji analizi yapılmıştır. Ekserji analizinde proses içindeki her bir ekipmanın ekserji yıkımları ve ekserji verimleri hesaplanmıştır. Çalışmanın sonunda sistemin toplam iyileştirme potansiyeli 54717.427 kW genel sistem verimi ise %27.6 olarak tespit edilmiştirÖğe Investigation of wind energy potential of four different sites of libya by using weibull distribution(2021) Selimli, Selçuk; Shtewı, Fauzi Ammar Ahmed; Fahed, Abdel Karim; Koymatcık, Çagıl Yaman; Özkaymak, MehmetIn this study wind energy capacity of Libyan sites are Espiaa, Msallata, Alqatrun, and Adirsiyah has been assessed with the Weibull distribution. Three different methods of Weibull distribution that are the Empirical Method of Justus (EMJ), the Graphical Method (GM), and the Maximum Likelihood Method (MLM) was used. As a result, the best velocity estimation performance has been obtained with graphical and maximum likelihood methods. The power density estimation showed that the wind power potential of Msallata is best with the value of 444.743 W/m² power density at 60 m and in Espiaa is in the second order with 414.98 W/m² potentials. Alqatrun is in the third order with the 184.134 W/m² power density and the last one is Adirsiyah with 101.201 W/m² potentials. When ordered for an elevation of 20 m, the power density of Msallata was found 418.502 W/m², 414.873 W/m² at Espiaa, 137.736 W/m² at Alqatrun, and 77.993 W/m² at Adirsiyah. The maximum power potential was determined at Msallata and the minimum at Adirsiyah. To investigate the most appropriate statistical method that provides the closest values to the real results, variance (R²), root mean square error (RMSE), mean bias error (MBE), and mean absolute error (MAE) values were calculated and assessed that at Adirsiyah, the best results were obtained with the GM method for a height of 20 m. This situation was evaluated with a calculated maximum R² of 0.9948 and minimum values of 0.0245, 0.00037 RMSE, and MAE. For Espiaa, the GM method was determined as the most appropriate method with 0.9984 R², 0.0186 RMSE, 1.23e-06 MBE, and 0.00033 MAE values. For Msallata, the EMJ method was determined as the best method with 0.9985 R², 0.0146 RMSE, 2,4e-07 MBE, and 0.00022 MAE. For 60 m altitude, the EMJ method gave the most compatible results with 0.9957 R², 0.0221 RMSE, and 0.00027 MAE values in Adirsiyah. In Alqatrun, the MLM method provided the closest results with 0.9979 R², 0.0151 RMSE, 2.63e-06 MBE, and 0.00024 MAE. The MLM method for Espiaa was determined as the most suitable method with 0.9988 R², 0.0163 RMSE, 1.21e-06 MBE, and 0.00029 MAE. For Msallta, the EMJ method was determined as the most suitable method with 0.9986 R², 0.0163 RMSE, 1.83e-07 MBE, and 0.00019 MAE.Öğe Kinetic model and effective diffusivity of frozen-dryed european blueberry (vaccinium myrtillus)(2022) Ayrıksa, Mutlucan; Acar, Bahadır; Dagdevıren, Abdullah; Roshanaeı, Khandan; Coşkun, Tuba; Ongun, Göknur K.; Özkaymak, MehmetIn current study, the freeze-drying (FD) method has been investigated. This method is the healthiest drying method that used in recent years by extending the shelf life of the products and preserving the beneficial flavors in its content. Antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antiseptic, etc., are the most emphasized role among the berries. Thus, blueberry is one of the great aspects to be a case for drying. Blueberry (Vaccinium Myrtillus), which is an opulent source of many phenolic compounds with known properties, has been determined. In the study, blueberries by the weight of 100 g and with a thickness of 5 mm were placed in the drying device, and the data were processed by observing the weight loss every two hours after being subjected to the drying process for 14 hours. 8 different kinetic drying models were applied to the acquired data using the Matlab program. As a result of the application, the estimated standard errors (RMSE), chi-square (X2), regression coefficients (R2) were calculated, error analysis was performed, R2, X2, and RMSE values were found, as 1.4686 ×10-2, 2.875×10-4 and 9.978 ×10-1. According to these results, it was determined that the most suitable model is the Page model. Also, the effective diffusivity coefficients for blueberries were calculated as 2.57665 × 10-12 m2/s.Öğe Techno-economic feasibility study of the commercial-scale oxy-cfb carbon capture system in turkey(2021) Coşkun, Tuba; Özkaymak, Mehmet; Okutan, Hasan CanOxy-fuel combustion is a promising technology for the reduction of carbon dioxide emissions, in coal-fired power plants that allowthe clean use of fossil fuels. Circulating fluidized bed (CFB) boilers are one of the power generation technologies that can use oxyfuel combustion design successfully. The purpose of this paper is to perform the techno-economic feasibility analysis of thecommercial-scale oxy-fuel combustion circulating fluidized bed (oxy-CFB) power plant generating 550 MWe net power with acarbon capture rate of 90%. So far, economic analysis of oxy-PC power plants has been studied by researchers at many reports.Nevertheless, the cost of an oxy-CFB power plant has rarely been studied.This is the first study that has used Turkish lignite(Orhaneli Coal) in an oxy-CFB carbon capture plant economic analysis. The basic economic performance indicators wereinvestigated. The Models are based on cost scaling and Discounted Cash Flow analysis. Three cases were analyzed: In the firstcase, A base scenario (air-fired CFB plant without CO2 capture) is considered and then based on this baseline scenario the otherscenarios are taken into account. The economic viability of transition from the classical air-fired CFB plant system to oxy-CFBwith CO2 capture and compression plant is evaluated. The post-combustion monoethanolamine (MEA) based CO2 capture systemis investigated as a benchmark study to compare oxy-CFB capture system performances. The main applicability parameters suchas cost of electricity (COE), levelized cost of electricity (LCOE) and the cost of CO2 capture for each case are calculated. Theobtained results indicated that 54% and 52% increase in terms of total plant cost and COE respectively in the oxy-CFB plant whencompared to air fired-CFB without carbon capture. Considering the COE, the designed oxy-CFB power plant is greater than theair-fired SC-PC (without capture) plant by more than 45% (DOE target). The efficiency penalty for oxy-CFB is 10%. Oxy-CFBplant has a net efficiency 2% point higher than amine-based CO2 capture systems. In amine-based CO2 capture system; The capitalcosts, LCOE, and cost of CO2 captured are higher than the oxy-CFB plant. The results show that the oxy-CFB power plant has alower cost for carbon capture compared to amine-based capture plant.
