Yazarlar
- Cuce, Erdem(27)
- Cuce, Pinar Mert(22)
- Tozlu, Alperen(12)
- Guclu, Tamer(10)
- Karaali, Rabi(10)
- Imamoglu, Ilyas Kays(7)
- Isik, Cem(7)
- Ongan, Serdar(7)
- Aydin, Rahman(4)
- Hırca, Tuğçe(4)
- Karaali, R.(4)
- Keven, Arzu(4)
- Özahi, Emrah(4)
- Abusoglu, Aysegul(3)
- Ceviz, Mehmet Akif(3)
- Eryılmaz Türkkan, Gökçen(3)
- Kuziboev, Bekhzod(3)
- Serencam, Uğur(3)
- Tozlu, A.(3)
- Yıldırım, Ümit(3)
- Çakir, Uǧur(3)
- Çomakli, Kemal(3)
- Abuşoǧlu, A.(2)
- Afshari, Faraz(2)
- Aloui, F(2)
- Arslantürk, Cihat(2)
- Atabani, A.E.(2)
- Ayşegül, Çokgez Kuş(2)
- Dincer, I(2)
- Erol, Şahin(2)
- Guleryuz, Didem(2)
- Güler, Cüneyt(2)
- Güngör, Osman(2)
- Jomaa, Seifeddine(2)
- Kamiloğlu, Hakan Alper(2)
- Kemal, Çomakli(2)
- Köksal, Hüseyin(2)
- Niazkar, Majid(2)
- Ozahi, Emrah(2)
- Riffat, Saffa(2)
Yayınlar
- MakaleAçık Erişim2022Scopus SJRQ2Investigation of inlet air pressure and evaporative cooling of four different cogeneration cycles
Karaali, Rabi
The objective of this study was to search the effects of the inlet air compressor pressure and evaporative cooling of four different cogeneration plants that are absorption cooling (ab), basic (bsc), air heating (airh), and air fuel heating (airfh) cogeneration systems by using the first law and the second law of thermodynamics, and the exergy analysis methods. For analysis, a program is written by the author in the FORTRAN programming language. Decreasing the atmospheric pressure or increasing the installation altitude of the plants increases the Z factor (ratio of lost exergy to useful exergy) of the four cycles about 10-13%. Also, decreasing inlet air pressure decreases the specific work about 25-28%, and the fuel energy saving ratio of the four cycles decreases about 29-30%. The method of water spray cooling of the compressor inlet air especially in the summer months, the humidity increases and the evaporative cooling can be obtained. By using this method, the ratio of lost exergy to useful exergy can be decreased for the four cycles about 0.5-2%. Also, the specific work of the four cycles can be increased about 1.2-6%.
AtıfOpenAlex4
İncele - MakaleAçık Erişim2022Scopus SJRQ3Evaluation of four different cogeneration cycles by using some criteria
Karaali, Rabi; Keven, Arzu
The purpose of this article is to evaluate four different gas turbine cogeneration cycles which are basic, absorption cooling, air heating and air fuel heating cogeneration cycles by using the most important six evaluation criteria for different excess air coefficient, different compression rates, and different compressor inlet air temperatures. These six evaluation criteria are electrical heat ratio, exergy efficiency, incremental heat rate, artificial thermal efficiency, fuel energy saving ratio, and specific fuel consumption. It is seen that the air-fuel heating cogeneration cycle is the most efficient among the cycles examined for a certain compressor compression ratio, followed by the air heating, basic, and absorption cooling cycles.
AtıfScopus20WoS18OpenAlex30İncele - MakaleAçık Erişim2022Scopus SJRQ1Techno-economic assessment of a synthetic fuel production facility by hydrogenation of CO2 captured from biogas
Tozlu, Alperen
In this study, a thermodynamic and economic analysis of a synthetic fuel production facility by utilizing the hydrogenation of CO2 captured from biogas is carried out. It is aimed to produce methanol, a synthetic fuel by hydrogenation of carbon dioxide. A PEM electrolyzer driven by grid-tie solar PV modules is used to supply the hydrogen need of methanol. The CO2 is captured from biogas produced in an actual wastewater treatment plant by a water washing unit which is a method of biogas purification. The required power which is generated by PV panels, in order to produce methanol, is found to be 2923 kW. Herein, the electricity consumption of 2875 kW, which is the main part of the total electricity generation, belongs to the PEM system. As a result of the study, the daily methanol production is found to be as 1674 kg. The electricity, hydrogen and methanol production costs are found to be $ 0.043 kWh−1, $ 3.156 kg−1, and $ 0.693 kg−1, respectively. Solar availability, methanol yield from the reactor, and PEM overpotentials are significant factors effecting the product cost. The results of the study presents feasible methanol production costs with reasonable investment requirements. Moreover, the efficiency of the cogeneration plant could be increased via enriching the biogas while emissions are reduced.
AtıfScopus34WoS32OpenAlex37İncele - MakaleAçık Erişim2022Scopus SJRQ2Estimation of soil temperatures with machine learning algorithms—Giresun and Bayburt stations in Turkey
Guleryuz, Didem
Since soil temperature (ST) is one of the most critical determinants affecting the soil’s physical and chemical properties, the studies on soil temperature estimation increase with the widespread use of deep learning and machine learning algorithms. This study estimates soil temperature at four depths for Giresun and Bayburt stations in Turkey employing the Bayesian Tuned Gaussian Process Regression (BT-GPR), Bayesian Tuned Support Vector Regression (BT-SVR), and Long Short Term Memory (LSTM) models. The stations were selected from semiarid (Bayburt station) and very humid (Giresun station) climates to compare the models’ performance and measure their applicability in different climate classes. Common meteorological indicators were determined as input parameters in the developed models, and a five-and-a-half-year daily dataset was used for all models. This paper represents a novel scheme to optimize the hyperparameters of kernel functions for GPR and SVR models using the Bayesian optimization method to expand predictive efficiency. The developed GPR and SVR models’ outputs are compared with LSTM via three statistical metrics comprising the root mean square error (RMSE), mean absolute error (MAE), and the coefficient of determination (R2). The results show that the BT-GPR model has a superior estimation ability than other developed models for the two stations. The daily ST estimation with the highest accuracy was obtained at a 5-cm depth using BT-GPR at Giresun station (RMSE = 0.0439, R2 = 0.9535, MAE = 0.0344 in the testing phase) and Bayburt station (RMSE = 0.0525, R2 = 0.9438, MAE = 0.0412 in the testing phase). These outcomes provide helpful benchmarking guidance for future soil temperature investigation at various depths across the selected regions.
AtıfScopus12WoS14OpenAlex21İncele - MakaleAçık Erişim2022Scopus SJRQ1Assessment of Climate Change Impact on Discharge of the Lakhmass Catchment (Northwest Tunisia)
Ben Nsir, Siwar; Jomaa, Seifeddine; Yıldırım, Ümit; Zhou, Xiangqian; D’Oria, Marco; Rode, Michael; Khlifi, Slaheddine
The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km². First, the Hydrologiska Byråns Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981–1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0%) and (0.53, −9.5%) for calibration (September 1982–August 1984) and validation (September 1984–August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981–2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010–2039), mid-term (2040–2069) and long-term (2070–2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5% for every +1 °C of global warming. By long-term (2070–2099) projection period, results suggested an increase in temperature with about 2.7 °C and 4 °C, and a decrease in precipitation of approximately 7.5% and 15% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5% and 36.6% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users.
AtıfScopus11WoS11OpenAlex14İncele - MakaleAçık Erişim2022Scopus SJRQ1Double adaptive power allocation strategy in electric vehicles with battery/supercapacitor hybrid energy storage system
Çorapsız, Muhammed Reşit; Kahveci, Hakan
This paper proposes a new energy management strategy (EMS) for electric vehicles (EVs) with battery/supercapacitor hybrid energy storage systems (HESS). Firstly, the battery/supercapacitor HESS configuration and obtaining the load current from the driving cycle are comprehensively explained. Secondly, fixed and adaptive frequency-based (AFB) EMS are discussed in detail. In the proposed method, the current demanded by the load is separated into low and high-frequency components with the help of an adaptive low-pass filter (A-LPF). In addition, adaptive battery current (ABC) is generated according to the supercapacitor (SC) state of charge (SoC), and a double adaptive power allocation strategy is performed. The proposed method is compared with the AFB-EMS for load currents, load powers, DC link voltages, filter cut-off frequencies, battery, and SC SoCs on the UDDS driving cycle. When the obtained results were evaluated together, it was observed that the proposed method completed the driving cycle with a higher battery SoC and realized the adaptive cut-off frequency in a narrower band.
AtıfScopus14WoS12OpenAlex14İncele - MakaleYalnız künye2022Scopus SJRQ2Applications of innovative polygonal trend analyses to precipitation series of Eastern Black Sea Basin, Turkey
Hırca, Tuğçe; Eryılmaz Türkkan, Gökçen; Niazkar, Majid
Examining historical variations of hydroclimatic variables can provide crucial information about changes of water resources in a water cycle. In this study, the Mann–Kendall (MK) and Innovative Polygon Trend Analysis (IPTA) methods were applied to 56-year precipitation data collected at 8 measuring stations. These stations are located in Eastern Black Sea Basin (EBSB), which has a significant amount of annual precipitation and hydroelectric potential in Turkey. This study has two objectives: (1) investigating possible changes in the monthly precipitation and (2) comparing the results achieved by a classical (MK) and one of the latest trend analysis methods presented in the literature (IPTA). Based on the results, MK achieved no trend for most of months, while it reached an increasing trend for March at most of the stations. Likewise, IPTA determined an increasing trend for March precipitation. However, an increasing/decreasing trend was obtained by IPTA for most of the months and stations. In other words, comparing the trend analysis results obtained by IPTA and MK indicates a significant discrepancy between the numbers of months with detected trends primarily because the former is relatively more sensitive in trend identification. To be more precise, IPTA and MK determined trends in approximately 81.25% and 12.5% of all months, respectively. Furthermore, the former identified quite the same trends in every month which the latter reported a trend. Moreover, the polygon of the mean and standard deviation graphs developed by IPTA provides a year cycle, which brings about useful information for water utility sectors and decision makers of the study area. Finally, the findings of this study contribute to a large amount of research that attempts to explore spatio-temporal variations of hydroclimatic variables around the globe not only to enhance humans’ knowledge about changes in a water cycle but also assess climate change impacts.
AtıfScopus54WoS50OpenAlex64İncele - MakaleAçık Erişim2022Scopus SJRQ2Assessment of waste-to-energy potential of ELT management: An actual case study for Erzincan
Güngör, Osman; Tozlu, Alperen; Arslantürk, Cihat
End-of-life tires (ELTs) and their decomposition are becoming a major environmental issue in the local region as a result of economic and technological challenges. Despite this, ELT management is gaining popularity as an advanced function for treating tires to obtain char, oil, and gas products using pyrolysis. The main goal of this article is to integrate data from an actual recycling plant with the activities of pyrolysis products and their physical properties in the literature. This article presents energy potentials and basic applications of pyrolysis products as well as advances in the current situation in ELT management in the world. Accordingly, an existing ELT management in Erzincan, Turkey is explained in detail by considering the available energy recovery and material treatment activities. In this plant, which has an installed power capacity of 12 MW, approximately 25 tons of pyrolytic oil, 10.7 tons of pyrolytic gas, 24 tons of carbon black and, 10.4 tons of steel are produced daily. The calorific values of carbon black and pyrolytic oil for the products leaving the pyrolysis plant are close to the values in the literature, which is promising. In the plant, the overall thermal efficiency of the system and the engine is found to be 26.34% and 51.24%, respectively. On the other hand, to supply additional power to the plant utilizing exhaust gas discharged to the atmosphere, some thermodynamic models can be developed; additionally, more rational values can be obtained through thermoeconomic and optimization.
AtıfScopus1WoS2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ1Thermoeconomic analysis of a low-temperature waste-energy assisted power and hydrogen plant at off-NG grid region
Tozlu, Alperen; Kayabasi, Erhan; Ozcan, Hasan
In this study, thermoeconomic analysis of a CO2 power cycle and PEM hydrogen system using ultra-low temperature waste heat from a milk production facility is conducted. In the transcritical CO2 cycle, low-temperature LNG evaporation is used for cooling the condenser to increase the temperature difference enabling low temperature waste heat use. In addition, a PEM electrolyzer produces hydrogen to reduce the LNG requirement at the plant. A CO2-water exchanger has been designed to recover the pasteurized water's excess heat and evaporate the CO2 using Simcenter-Flomaster software. The inlet mass flow rates and outlet temperatures of the heat exchanger were optimized by performing thermoecomic analysis, and the thermal and economic performance of the facility was examined. The power cycle has 14% higher efficiency when LNG is used as the heat sink compared to ambient temperature condensation with an electricity production cost range at 0.05–0.11 $/kWh, and the hydrogen generation cost is between $2.6–5.20 kg−1. It is found that the plant could only be economically feasible when less than 50% of the power produced is used for hydrogen generation. Consequently, the proposed system can co-generate power and on-demand hydrogen in off-NG grid regions with reasonable investment and product costs.
AtıfScopus6WoS6OpenAlex8İncele - MakaleYalnız künye2022Scopus SJRQ3Comparison of Statistical Methods to Graphical Method in Precipitation Trend Analysis, A Case Study: Coruh Basin, Turkey
Hırca, Tuğçe; Eryılmaz Türkkan, Gökçen
It is a known fact that the precipitation characteristics will become irregular as a result of climate change resulting from global warming. Trend analysis is one of the most effective methods of observing the effects of climate change on precipitation. This study compares the changes in precipitation with traditional trend analysis methods and graphical method (divided into subcategories using the Z-Score Index). Some preliminary analyzes (missing data estimation, homogeneity check, autocorrelation, and removal of the autocorrelation), which are lacking in many studies in the literature, have been performed. In this context, the monthly total precipitation data of the precipitation stations belonging to the Coruh Basin, one of the most important basins of Turkey, for the period 1972–2011 were used. As a result of the study, it was determined that all the stations’ data were homogeneous, and 92% of them were at the Class A level. While 100% trend is determined in Innovative Trend Analysis in total annual precipitation, this rate was just 40% at Mann–Kendall and Spearman's rho at 95% confidence. An increasing trend was determined in the “high” group of total spring precipitation at all stations.
AtıfScopus5WoS4OpenAlex5İncele - MakaleAçık Erişim2021Investigation of the Roughness Coefficient Effect on Open Channel Flow
Türkkan, Gokçen Eryılmaz
With the effect of global warming in our world, rising sea levels, changing seasons and degrading the ecosystem can cause floods. Preventing floods requires good planning and projecting. The effect of roughness coefficient on open channel flow was investigated with this study. The purpose of the study is to examine the flow in the channel depending on the seasonal change of vegetation cover. This study was carried out on the Sarıhan river, which is located within Bayburt province borders. The flow was simulated using different roughness coefficients. In the study, ArcGIS and Hec-GeoRAS software were used to create a numerical model. HEC-RAS software was preferred to simulate open channel flow. The froude number, velocities in the cross section, the water level and the flow area have been seen to differences with the change of the roughness coefficient. In addition, for four different roughness coefficient values calculated in the study, critical flow rates that will cause flooding in any section of Sarıhan river were determined. In this study, the importance of roughness coefficient, which changes as a result of seasonal changes, was emphasized with this model.
AtıfOpenAlex4TR Dizin3
İncele - MakaleYalnız künye2021Scopus SJRQ1Enhancing Burnability Characteristics of Low-Temperature Burnt-Cement Clinker by Recycling Phosphogypsum Wastes
Aksan, U.; Köseoglu, K.; Gökçe, H. S.
In the present study, the effect of phosphogypsum, a byproduct from the phosphoric acid production industry, on the clinkerization process was researched in order to improve the burnability of clinkers at lower burning temperatures. Raw meal samples containing phosphogypsum at 0%, 1%, 3%, and 5% by weight were burned at 1,350 degrees C, 1,400 degrees C, 1,450 degrees C, and 1,500 degrees C. The introduction of phosphogypsum reduced the presence of unbounded (free) CaO relatively up to 43%. Thus, the mineralization effect of phosphogypsum promotes lower burning temperatures. The free CaO content of the 5% phosphogypsum containing clinker decreased to 0.94% at 1,400 degrees C after 120 min of burning time. The free CaO content was found to be almost identical (0.75%) to that of industrial clinker burned in a rotary kiln at 1,500 degrees C. Due to the low free CaO content (<1%) and the burnability index (73), the recycling of phosphogypsum wastes was found to be suitable for the production of eco-efficient clinkers. The reduced energy consumption and energy-related CO2 emissions in such modified clinkers can contribute to the economic and ecological goals of the cement industry. (C) 2021 American Society of Civil Engineers.
AtıfWoS2OpenAlex3İncele - MakaleAçık Erişim2021Scopus SJRQ3Land Use Impact of Maritime Pine and Eucalypt: A Life Cycle Assessment Study
Ferreira, José; Esteves, Bruno; Ayata, Ümit; Cruz-Lopes, Luisa; Domingos, Idalina
The forestry sector in Portugal faces important challenges, resulting in an increased incidence of fires and the action of pathogens, which puts the sustainability of forest resources at risk. Due to the economic, social, and environmental importance of forests, this work assessed the land use environmental impact of maritime pine and eucalypt standing in Portuguese forests. SimaPro software was used to translate the inventory table results into land use impact category. The ILCD 2011 Midpoint+ method was chosen to assess the “land use” environmental impact that focuses on soil quality and its indicator (kg carbon deficit), which describes the changes in soil organic matter associated with land interventions. The results showed that for the first rotation time, the land use impact category per cubic meter of maritime pine is 18423 kg C deficit and 23430 kg C deficit for eucalypt, which means that the land use impact category of eucalypt is 27% higher than the impact of maritime pine.
AtıfScopus2WoS1OpenAlex1İncele - MakaleAçık Erişim2021Scopus SJRQ1Modelling of the discharge response to climate change under RCP8.5 scenario in the Alata river basin (Mersin, SE Turkey)
Yıldırım, Ümit; Güler, Cüneyt; Önol, Barış; Rode, Michael; Jomaa, Seifeddine
This study investigates the impacts of climate change on the hydrological response of a Mediterranean mesoscale catchment using a hydrological model. The effect of climate change on the discharge of the Alata River Basin in Mersin province (Turkey) was assessed under the worstcase climate change scenario (i.e., RCP8.5), using the semi-distributed, process-based hydrological model Hydrological Predictions for the Environment (HYPE). First, the model was evaluated temporally and spatially and has been shown to reproduce the measured discharge consistently. Second, the discharge was predicted under climate projections in three distinct future periods (i.e., 2021–2040, 2046–2065 and 2081–2100, reflecting the beginning, middle and end of the century, respectively). Climate change projections showed that the annual mean temperature in the Alata River Basin rises for the beginning, middle and end of the century, with about 1.35, 2.13 and 4.11 °C, respectively. Besides, the highest discharge timing seems to occur one month earlier (February instead of March) compared to the baseline period (2000–2011) in the beginning and middle of the century. The results show a decrease in precipitation and an increase in temperature in all future projections, resulting in more snowmelt and higher discharge generation in the beginning and middle of the century scenarios. However, at the end of the century, the discharge significantly decreased due to increased evapotranspiration and reduced snow depth in the upstream area. The findings of this study can help develop efficient climate change adaptation options in the Levant’s coastal areas.
AtıfScopus16OpenAlex19İncele - MakaleYalnız künye2021Scopus SJRQ2Thermodynamic feasibility analysis of a newly modified absorption power cycle running with LiBr-water
Tozlu, Alperen; Yosaf, Salem A.; Özcan, Hasan
This study thermodynamically evaluates a newly modified absorption power cycle (APC) working with Lithium Bromide–Water (LiBr-H2O) solution and compares it with the conventional Rankine, one-stage, and three-stage APC systems. An additional steam condenser is integrated to the conventional APC and part of pure water is extracted and pumped back to the high-pressure side without passing through the absorber of the cycle. In order to specify the best system parameters, parametric optimization of all configurations is evaluated. The Rankine cycle and the modified APC have better thermodynamic performances than those of the conventional and the three-stage APC at generator temperatures. The conventional APC is found to improve the cycle performance at low generator pressure. However, the efficiencies of this cycle start to decrease when generator pressure increases. In contrast, the Rankine cycle and the modified APC have larger working ranges of generator pressure.
AtıfScopus8WoS5OpenAlex7İncele - MakaleAçık Erişim2021Scopus SJRQ1Municipal solid waste-based district heating and electricity production: A case study
Tozlu, Alperen; Abusoglu, Aysegul; Ozahi, Emrah; Anvari-Moghaddam, Amjad
In this paper, municipal solid waste (MSW) based electricity production and district heating (DH) potential of Turkey are considered. Three MSW based waste-to-energy (WtE) scenarios is developed: (i) Scenario-I, a DH system integrated into a gas turbine power plant (GTPP), (ii) Scenario-II, a DH system integrated into an organic Rankine cycle (ORC), and (iii) Scenario-III, which is based solely on a DH system. As a result of the thermodynamic and thermoeconomic analyzes of these developed scenarios using an existing MSW-based cogeneration facility's actual operating data, the system with the most extended payback period (about 5 years) is found as the GTPP-DH system developed in Scenario-I, which also has the highest investment cost. On the other hand, the system with the shortest payback period (about 2 years) is found as the DH system developed in Scenario-III, which also has the lowest investment cost. Overall exergy efficiencies of the GTTP-DH, ORC-DH, and DH systems are found to be 41.86%, 16.15%, and 31.87%, respectively. When the developed WtE scenarios adapted to the pilot provinces selected from each geographical region of Turkey, it is found that the GTPP system developed in Scenario-I can increase the power generation capacity of MSW plants for each province by about 20%.
AtıfScopus16WoS15OpenAlex16İncele - MakaleAçık Erişim2021Scopus SJRQ1Thermoeconomic analysis of a hybrid cogeneration plant with use of near-surface geothermal sources in Turkey
Tozlu, Alperen; Gençaslan, Betül; Özcan, Hasan
In this study, thermodynamic and thermoeconomic analyses of systems that produce electricity and heat through the use and storage of solar energy and near-surface geothermal sources are carried out. Three different configurations, which are the organic Rankine cycle (ORC), cogeneration system (CGN) and hybrid system (HYB), are coupled to the parabolic trough collector (PTC) system. The systems are named PTC-ORC, PTC-CGN and PTC-HYB are conducted. The reference system called PTC-ORC only produces electrical energy with parabolic trough collectors and it does not have a thermal energy storage system, whereas in PTC-CGN, in addition to the cogeneration of electricity and heat, thermal energy storage is also available. Finally, thermodynamic and economic analyses are conducted in the PTC-HYB with the assistance of near-surface geothermal energy, which is widely available in Turkey. In this study, the actual data of Ankara Kızılcahamam near-surface geothermal fields are taken as the heat source for the hybrid system. These facilities, each producing 1 MW of electricity, are first optimized with the help of parametric studies, and exergoeconomic analysis is performed with respect to optimum thermal conditions. The electricity production costs of PTC-ORC, PTC-CGN and PTC-HYB are found to be 0.257 $/kWh, 0.448 $/kWh and 0.401 $/kWh, respectively. The study demonstrates that thermal energy storage brings extra costs, while near-surface geothermal sources may help decrease energy costs from renewables.
AtıfScopus15WoS13OpenAlex21İncele - MakaleAçık Erişim2021Scopus SJRQ1A comparative thermoeconomic analysis and optimization of two different combined cycles by utilizing waste heat source of an MSWPP
Ozahi, Emrah; Abusoglu, Aysegul; Tozlu, Alperen
In this paper, thermodynamic and thermoeconomic analysis as well as genetic algorithm optimization of two combined cycles, a gas turbine-organic Rankine cycle (GT-ORC) and a gas turbine-Kalina cycle (GT-KAL) are carried out. The novelty of this study is that the cycles are adapted to an actual solid waste power plant to generate additional power from the exhaust gas. Thus, the power generation capacity of the actual power plant can be raised by using the combined cycle. Due to this reason, besides the thermodynamic analysis of the cycles, thermoeconomic analyses and optimizations are also very important in order to improve the actual system capacity. The net power output of GT-ORC and GT-KAL are found to be 1.51 MW and 1.59 MW, respectively. The results obtained are seen to be reasonable when compared to the net power output of the power plant (5.66 MW). Another originality of this study is that the thermoeconomic results are improved by utilizing a multi-objective optimization method namely non-dominated sorting genetic algorithm method (NSGA-II). Thus, the two objectives, total power output and the total cost rate, at the design stage of the cycles are optimized and enhanced. Due to the optimization results, it is found that the net power output of the GT-ORC and GT-KAL are increased by 11.34% and 0.99%, respectively, while the total cost rates are decreased by 18.59% and 1.31%, respectively. GT-ORC with the net power output of 1.70 MW is seen to be more efficient as compared to GT-KAL which produces a net power output of 1.61 MW. However, the total and the capital cost rates of GT-ORC are found to be higher than those of GT-KAL.
AtıfScopus7WoS5OpenAlex11İncele - MakaleAçık Erişim2020Econometric analysis of convergence in carbon emission per capita for mena countries
Yıldız, Ümit; Boz, Fusun Celebi
In this study, it is mainly aimed to investigate whether carbon emission rates tendto converge for MENA countries. In this context, the convergence of carbonemissions per capita in MENA countries is examined for the period 1965-2014.In the study in which panel data econometric methods are applied, it is primarilyinvestigated whether there are cross-sectional dependence on the variables. Afterthe determination of cross-sectional dependency, the stationarity of the series areexamined by CADF unit root test. According to the test results, it is concludedthat the carbon emission rates series in MENA countries are stationary at I(1).The results of the study indicate that the carbon emission per capita in MENAcountries tends to converge and they are in a similar industrialization process
AtıfOpenAlex3TR Dizin2İncele - MakaleAçık Erişim2020Scopus SJRQ2Experimental investigation of effects on performance, emissions and combustion parameters of biodiesel–diesel–butanol blends in a direct-injection CI engine
Örs, İlker; Sarıkoç, Selçuk; Atabani, A.E.; Ünalan, Sebahattin
This paper aims to asses and conduct a comparative analysis of fuel properties, performance, emissions and combustion characteristics of biodiesel produced from waste cooking oil (B100) as a cheap biodiesel feedstock, along with a binary blend of biodiesel–diesel (B20) and ternary blends of biodiesel–diesel–butanol as substitutions to diesel fuel. Although biodiesel and n-butanol have some negative impacts on engine performance parameters, they generally positively affect exhaust emission parameters compared to euro diesel. B100 caused an average reduction in brake power and exhaust gas temperature of 15.16% and 1.4%, respectively, although it increased brake specific fuel consumption on average by 14.09%, at full throttle under different engine load conditions. B100 decreased CO and HC emissions and smoke opacity by 65.4%, 61.07% and 54.94%, respectively. However, CO2 and NO emissions increased by 22.3% and 23.91%, respectively. Addition of n-butanol decreased some of the fuel thermo-physical properties such as density, viscosity and flash point. The average decreases in brake power when n-butanol was added were 6.17%, 7.49% and 11%, respectively, coupled with increases in specific fuel consumption of 6.25%, 8.96% and 14.29%, respectively. The addition of n-butanol decreased exhaust gas temperatures, CO, HC, NO and smoke emissions.
AtıfScopus41WoS33OpenAlex52İncele
