Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Karaali, Rabi(10)
- Keven, Arzu(4)
- Afshari, Faraz(1)
- Atasbak, Musa(1)
- Berber, A.(1)
- Ceviz, Mehmet Akif(1)
- Cimsit, Canan(1)
- Cimşit, Canan(1)
- Cuce, Erdem(1)
- Cuce, Pinar Mert(1)
- Dagci, O.(1)
- Guclu, Tamer(1)
- Gür, Mehmet Murat(1)
- Kuş, Ayşegül Çokgez(1)
- Köksal, Hüseyin(1)
- Muratçobanoğlu, Burak(1)
- Ozturk, Ilhan Tekin(1)
- Oztürk, Ilhan Tekin(1)
- Topal, Esra Nur(1)
- Tozlu, A.(1)
- Tozlu, Alperen(1)
- Yilmaz, Metin(1)
- Yosaf, Salem A.(1)
- Yılmaz, Metin(1)
- Çakir, Uǧur(1)
- Çakmak, Bahar(1)
- Çomakli, Kemal(1)
- Özcan, Hasan(1)
- Öztekin, Erman Kadir(1)
- Şahin, Erol(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Enhanced freshwater production in prism-type solar stills using a fresnel lens system with comprehensive energy-exergy and cost analysis
Ceviz, Mehmet Akif; Köksal, Hüseyin; Afshari, Faraz; Muratçobanoğlu, Burak
This study presents the development and performance evaluation of a novel prism-type solar still integrated with a Fresnel lens concentration system designed to concentrate solar radiation on an external spiral heat exchanger. Experimental investigations were conducted under two different saline water flow rates of 0.05 and 0.1 kg/min. The performance of system was comprehensively analyzed in terms of fresh water yield, thermal efficiency, exergy efficiency, and economic viability. The heated saline water and resultant vapor were directed into the prism-shaped condensation chamber, where condensation occurred efficiently. The experimental results demonstrated that lower saline water flow rates led to higher water temperatures and enhanced evaporation rates, thereby increasing freshwater productivity. In contrast, higher flow rates resulted in greater accumulation of saline water within the basin, reducing the evaporation rate and thus lowering overall productivity. The proposed design uniquely combines geometric enhancement via a prism-shaped condensation chamber with solar concentration through a Fresnel lens, enabling a dual-effect improvement in energy absorption and condensation efficiency, an approach not previously reported in the literature for solar desalination systems. The system achieved thermal and exergy efficiencies of 22.95 and 15.50%, respectively, at a saline water flow rate of 0.05 kg/min, producing 92 g of clean water in 60 min. Furthermore, the cost analysis conducted indicated a cost of $0.2546 per liter for this scenario.
AtıfScopus1WoS2OpenAlex3
İncele - MakaleYalnız künye2026Scopus SJRQ1Experimental 4E analysis (energy-exergy-economic-environmental) of hybrid parabolic trough collector-thermoelectric generator-phase change material cogeneration system
Guclu, Tamer; Cuce, Pinar Mert; Cuce, Erdem
Hybrid solar cogeneration systems are critical for enhancing energy utilisation and mitigating the intermittency of solar resources. This study presents a comprehensive 4E (Energy-Exergy-Economic-Environmental) experimental analysis of a novel hybrid system that uniquely integrates a Parabolic Trough Collector (PTC), a small-scale steam turbine, a Thermoelectric Generator (TEG) assembly, and a Phase Change Material (PCM) thermal storage unit. The system's performance was investigated under 15 distinct operating conditions, varying initial water masses (0.1, 0.15, 0.2 kg) and operating pressures (6, 8, 10, 12, and 14 bar). Experimental results demonstrated the system's adaptive cogeneration capabilities. At 14 bar and 0.2 kg, the system achieved its maximum Solar-to-Electricity efficiency of 0.42%. At this operating condition, the highest collector thermal efficiency was 25.25% (at 6 bar), and the maximum overall energy and exergy efficiencies were 8.43% and 1.45%, respectively. A key finding was the system's adaptive electrical output: at low pressures (6 bar), the TEG acted as a crucial co-generator, supplying up to 55% of the electricity, whereas at high pressures (14 bar), the turbine dominated, accounting for 88-90% of the output. Furthermore, the study experimentally confirmed that latent heat transfer was the dominant heat transfer mechanism for the PCM, with latent heat contributing ∼445 kJ (55%) of the 805 kJ total energy stored. The thermo-economic analysis confirmed the system's viability, yielding a Simple Payback Period (Spp) of 6.9 years and a competitive Levelised Cost of Energy (LCOE) of $0.101/kWh. The system is projected to save 118.8 kg of CO2 and 660 L of water annually. The results validate the thermodynamic and economic feasibility of the integrated PTC-Turbine-TEG-PCM concept as a flexible solution for small-scale solar cogeneration.
AtıfScopus3WoS2OpenAlex6İncele - MakaleYalnız künye2026Scopus SJRQ3An exergoeconomic analysis of a wastewater treatment plant: investigation and optimization of sludge drying—a case study
Dagci, O.; Tozlu, A.; Berber, A.
The primary parameters in wastewater treatment plant applications are pollutant removal in compliance with standards and energy costs. This study conducts exergy, exergoeconomic, and optimization analyses on the Konya Wastewater Treatment Plant to enhance its energy efficiency. All assessments of the plant were based on actual operational data. Numerical calculations were executed using Engineering Equation Solver software. Exergoeconomic analyses were performed using the Specific Cost Method, while optimization calculations employed the Net Present Value approach. Thermodynamic calculations revealed that the exergy efficiency of the biogas engine was 30.8%, which increased to 39.8% when integrated into a cogeneration system. The overall exergy efficiency of the plant was calculated to be 35.3%, which rose to 58.6% when stabilized sludge was utilized as fuel. During the optimization phase, various drying systems were evaluated, and a hybrid greenhouse-solar-panel drying system was identified as the optimal model. The analyses indicated that the total cost was minimized at the maximum dryness value (70%), suggesting that the greenhouse-type drying system could achieve regional conditions. Compared to thermal and solar energy systems, hybrid systems have been observed to offer significant advantages in first-year costs. Optimization studies reveal that hybrid systems provide 41% greater cost savings in initial investment and operational expenses compared to thermal systems, and 29% greater savings compared to solar energy systems. Meeting the system's energy demand with fossil fuels results in annual emissions of 76,850 tons of CO₂ and 1500 tons of harmful pollutants, equivalent to removing 19,000 cars from traffic or preserving 7300 hectares of forest. Significant soil and ecosystem degradation also occurs. The use of solar energy substantially reduces these environmental impacts, improving air quality and conserving natural resources.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2024Scopus SJRQ3Thermoeconomic Analyses of Heat Pumps
Öztekin, Erman Kadir; Gür, Mehmet Murat; Karaali, Rabi
Recently, the rapid development of technology and the increase in energy costs and needs have made reducing the costs and efficient use of energy and exergy important. The thermoeconomic analysis method, which is the best cost analysis method of energy and exergy, gives the ways to reduce costs and increase efficiency that can be applied a facility. It has been found that the most suitable thermoeconomic solution for winter heating and summer cooling of a facility is a vertical underground source heat pump and the most high-performance working fluid that should be used is R32. If the heating is done with a ground source heat pump instead of electrical energy, 4.25 kW of heating energy will be obtained for each kW of electrical energy given for heating, since the costs are COPIP 4.25. Here the earnings increase by around 325%. In other words, heating costs decrease by around 77.5 percent, that is, from one hundred liras to 22. 5 liras.
AtıfOpenAlex4İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Energy, exergy, environmental, and enviroeconomic (4E) analysis of cascade vapor compression refrigeration systems using nanorefrigerants
Yılmaz, Metin; Cimşit, Canan; Keven, Arzu; Karaali, Rabi
The refrigerants used in traditional vapor compression refrigeration systems are harmful to the ozone layer and contribute to global warming. The demand for refrigeration is increasing because of global warming. In this study, for the first time, an energy, exergy, environmental, and enviroeconomic (4E) analysis was performed using different refrigerants and nanoparticles to reduce the energy required in low-temperature vapor compression cascade refrigeration systems and to determine more environmentally friendly nanorefrigerants. The R290 refrigerant was used for the Low-Temperature Circuit (LTC), while the High-Temperature Circuit (HTC) used RE170, R1234yf, R600, R600a, and R450A refrigerants. The nanoparticles used in the analysis were Al2O3, CNT, CuO, TiO2, ZnO, and SiO2. The R600 nanorefrigerant performed the best, whereas the R1234yf nanorefrigerant performed the worst. The results indicate that the CuO nanoparticles provided the highest performance. In addition, the results showed that the R290+R600-CuO nanorefrigerant emitted 11 % less CO2 than the pure R290+R600 refrigerant. The nanorefrigerants provide a more environmentally sustainable option because of their high efficiency and lower energy consumption than conventional refrigerants.
AtıfScopus9WoS7OpenAlex8İncele - MakaleAçık Erişim2024Scopus SJRQ1Analysis of cascade vapor compression refrigeration system using nanorefrigerants: Energy, exergy, and environmental (3E)
Yilmaz, Metin; Cimsit, Canan; Keven, Arzu; Karaali, Rabi
Nanorefrigerants are considered the most efficient heat transfer fluids for improving heat transfer properties in the refrigeration and air conditioning equipment. For the first time in this study, energy, exergy, and environmental evaluation (3E) analyses were performed by the addition of different nanoparticles to a low GWP refrigerant pair such as R290/R1233ZDE in a cascade refrigeration system. CNT, CuO, and, TiO2 nanoparticles were added to the refrigerant. The effect of nanoparticles on the cascade refrigeration system was analyzed using a model based on density changes. A detailed thermodynamic analysis was performed of the cascade refrigeration system at different evaporator temperatures and mass ratios. The power consumption of the compressor decreases as the evaporator temperature increases for all types of nanoparticles, resulting in an increase in COP values. The analyses showed that CuO nanoparticles had the highest performance. It has been observed that the energy and exergy efficiency increase as compressor work decreases with increasing mass ratios in all nanorefrigerants. In addition, the results indicated that all nanorefrigerants emit lower monthly CO2 emissions compared to the pure refrigerants. The nanorefrigerants play a crucial role in reducing energy consumption and promoting environmental protection compared to traditional refrigerants.
AtıfScopus16WoS16OpenAlex17İncele - MakaleAçık Erişim2024Scopus SJRQ3Exergetic Analyses of Detonation Engine Cogeneration Plants
Çakmak, Bahar; Karaali, Rabi
Efficiency improvements are very important in all research and technology. Detonation engines are high technology devices. In the last decades they attracted attention by many researchers. However, detonation engines for cogeneration are not researched efficiently. This article is about the detonation engines cogeneration cycles which analysed by using 1. and 2. law of thermodynamics and exergy analyses methods by the authors. The exergetic performance analyses, their advantage and disadvantages of the ZND-HRSG detonation engine cogeneration cycles were obtained. The exergetic performance analyses were done for various excess air rates to obtain the variations of the combustion exit pressures and temperatures, exergy efficiencies, electric heat rates, SFC and other parameters of their performance. Also, an optimization analysis was done for the ZND-HRSG by searching the optimum values for different excess air rates. The results showed that, the ZND-HRSG cycle have the optimum values of the performance at 1.6-1.8 of the excess air rates.
AtıfScopus1OpenAlex5
İncele - MakaleYalnız künye2023Exergetic Analyses of Hypersonic Flows
Topal, Esra Nur; Karaali, Rabi
Hypersonic devices and vehicles and hypersonic flows are very important and competitive advanced technology in science and in the World. Hypersonic technology is rapidly spreading and turning into competition in developed countries, especially in space studies and defense industry. This technology is vital for developed countries. Because of shock waves emerging in hypersonic devices during hypersonic flow, the energy and exergy destructions they cause are the most important difficulties, obstacles and problems which arise in this vital technology. To overcome these problems and difficulties, to prevent or reduce or minimize energy and exergy destruction, aerodynamic analysis and energy and exergy analysis methods are applied. The data and the results that can be guiding and useful for the calculations and the design have been obtained. In this study optimal design and optimum calculations ways of the energy and exergy destructions of hypersonic devices and instruments are discussed. It is obtained and shown that how much exergy destruction and entropy production occurs at which altitude and hypersonic velocities and also at which oblique shock angles.
AtıfScopus2İncele - MakaleAçık Erişim2023Performance Analyses of Combined Cycle Power Plants
Karaali, Rabi
In this article, different compressor pressure and different excess air rates for a gas turbine based combine cycle power plant with steam Rankine cycle as bottoming cycle were analyzed by using 1. and 2. laws of thermodynamics and exergy analyses methods to obtain the best performances of the cycle. Exergy efficiency of the cycle, net powers of the gas and steam turbines and the overall cycle, exergy loss of the components, the efficiencies of the components are obtained, compared and discussed. It was found that, increasing the compressor pressure increases exergy efficiency of cycle, gas turbine and total plant power, and the combustion chamber, the HRSG and the compressor efficiencies. However, increasing compression rates decreases steam turbine power, combustion chamber, steam turbine, and HRSG exergy losses and the gas turbine efficiency. Also, it is found that, increases in excess air ratios gives an optimum or a maximum exergy efficiency, at 2.5 excess air rate of the cycle.
AtıfScopus3OpenAlex6İncele - 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 SJRQ3Exergy analyses of two and three stage cryogenic cycles
Atasbak, Musa; Keven, Arzu; Karaali, Rabi
Cryogenics has an important influence on industry and science. In this study, optimum working conditions are obtained by applying exergy analysis and local optimization methods to two- and three-stage vapor compression cascade cryogenic cycle. The first and second laws of thermodynamics, exergy analysis, and local optimization methods are applied to the two- and three-stage cascade cryogenic cycle. By considering the needs and demands, it is possible to create new cycles by adding new devices and/or new stages to these cycles. The results of the optimum operating conditions are obtained for the two- and three-stage vapor compression cascade cryogenic cycle. It is seen that to achieve high COP values and high efficiency; it is necessary to reduce the compression ratio of the compressor as much as the fluid allows. For the two-stage cycle, the minimum total work required for cryogenic cooling is around P 7 = 2,400 kPa. The COP value is 0.30 between P 7 = 2,400 and 2,800 kPa, and the maximum exergy efficiency is obtained around 0.235. It is seen operating the first-stage compressor at high pressures increases the total losses of the entire cycle from 7,500 to 18,550 kW. The increase in total exergy losses is around 247%, and operating the first-stage compressor at high pressures increases the exergy efficiency of the entire cycle. The increase in total exergy efficiency is around 160%. When the second-stage compressor is operated at low pressure, the COP value increases by 2%, the exergy efficiency increases by 20%, and the exergy losses decrease by around 40%.
AtıfScopus6WoS3OpenAlex9İncele - 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 - MakaleYalnız künye2017Scopus SJRQ3Performance analyses of gas turbine cogeneration plants
Karaali, Rabi; Oztürk, Ilhan Tekin
In this study, some improving methods of gas turbine cogeneration cycles are applied on a simple cogeneration cycle. These methods are preheating air, preheating air and fuel, inlet air cooling by using evaporative cooling and absorption cooling. These cogeneration systems are evaluated with respect to energy efficiency (energy utilization factor), exergetic efficiency, electric and heat power, electric-heat energy rate, artificial thermal efficiency and fuel energy saving ratio and are compared with each other. In these analyses, the thermodynamic parameters such as compressing ratio, air and fuel mass ratio and compressor inlet temperatures of the cycles are used. It is concluded that these parameters can be listed from most effective to least effective as air fuel ratio, pressure ratio and compressor inlet temperature. It is also concluded that the most efficient cycle is found to be the air-fuel preheated cycle for obtaining more electric power and less heat power, and the simple cycle is the most suitable one for obtaining more heat power and less electric power.
AtıfScopus6İncele - MakaleYalnız künye2016Scopus SJRQ3Thermodynamic optimization of a zero CO2 emission cogeneration cycle
Karaali, Rabi; Ozturk, Ilhan Tekin
CO2 emissions that have the greatest negative impact on the greenhouse and the global warming that should be decreased or kept at the same rates. Today fossil fuels share 60 % of total electricity production of the world, which plays an important role on CO2 emissions. Thermal cogeneration and zero CO2 emission cycles have potential for reducing this effect. By taking into consideration the most applicable and important zero CO2 emission cycles, a new cycle is designed. Thermodynamic analyses and optimization of this cycle is studied with FORTRAN code. The optimization results of this cycle show that the maximum exergy efficiency of this new cycle is 64 %, which is 17.6 % higher than (0,544) the one for the air preheated cogeneration cycle (APHCC) and 18.7 % higher than (53,9) the absorption cooling zero CO2 emission cycle (ACZEC). In the introduced new cycle, steam and CO2 in the exhaust gases are condensed so that the condensing energy of them is regained. For that reason, the heat output and the electrical power of the introduced cycle is better than the other cogeneration cycles.
AtıfScopus3İncele - MakaleAçık Erişim2013Scopus SJRQ2Energetic and exergetic comparison of air to air and air to water heat pumps according to evaporator conditions
Çomakli, Kemal; Çakir, Uǧur; Şahin, Erol; Kuş, Ayşegül Çokgez
This paper presents an experimental energetic and exergetic comparison for a heat pump system that can be run in different modes as air to air and air to water. Components of the heat pump do not change when the running mode changes, except for the condenser. This means that some external and internal effects (like compressor type, pipe lines) that can affect the system performance will be the same for each running mode. The comparison which was made in this study demonstrates which system leads to an efficient conversion and supply of energy and exergy. In the analysis, four balance (mass, energy, entropy and exergy) equations are applied to the system for the two modes. Exergy and energy efficiency values for both systems are given, while exergy destructions in each of the systems are determined and presented. It is seen that the heat pump unit which has the highest COP value is the air to air type (3.45-3.8); second is the air to water type (3.35-3.41). The exergy efficiency of the air to air heat pump (29-32%) is higher than the exergy efficiency of the air to water type heat pump (24.1-25). Ranking of the exergy destruction rates of the two heat pump types from high to low is as follows: air to air and air to water.
AtıfScopus5OpenAlex5İncele