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This paper addresses the challenges the policymakers face concerning the EU decarbonization and total electrification roadmaps towards the Paris Agreement set forth to solve the global warming problem within the framework of a 100% renewable heating and cooling target. A new holistic model was developed based on the Rational Exergy Management Model (REMM). This model optimally solves the energy and exergy conflicts between the benefits of using widely available, low-temperature, low-exergy waste and renewable energy sources, like solar energy, and the inability of existing heating equipment, which requires higher exergy to cope with such low temperatures. In recognition of the challenges of retrofitting existing buildings in the EU stock, most of which are more than fifty years old, this study has developed a multi-pronged solution set. The first prong is the development of heating and cooling equipment with heat pipes that may be customized for supply temperatures as low as 35 °C in heating and as high as 17 °C in cooling, by which equipment oversizing is kept minimal, compared to standard equipment like conventional radiators or fan coils. It is shown that circulating pump capacity requirements are also minimized, leading to an overall reduction of CO2 emissions responsibility in terms of both direct, avoidable, and embodied terms. In this respect, a new heat pipe radiator prototype is presented, performance analyses are given, and the results are compared with a standard radiator. Comparative results show that such a new heat pipe radiator may be less than half of the weight of the conventional radiator, which needs to be oversized three times more to operate at 35 °C below the rated capacity. The application of heat pipes in renewable energy systems with the highest energy efficiency and exergy rationality establishes the second prong of the paper. A next-generation solar photo-voltaic-thermal (PVT) panel design is aimed to maximize the solar exergy utilization and minimize the exergy destruction taking place between the heating equipment. This solar panel design has an optimum power to heat ratio at low temperatures, perfectly fitting the heat pipe radiator demand. This design eliminates the onboard circulation pump, includes a phase-changing material (PCM) layer and thermoelectric generator (TEG) units for additional power generation, all sandwiched in a single panel. As a third prong, the paper introduces an optimum district sizing algorithm for minimum CO2 emissions responsibility for low-temperature heating systems by minimizing the exergy destructions. A solar prosumer house example is given addressing the three prongs with a heat pipe radiator system, next-generation solar PVT panels on the roof, and heat piped on-site thermal energy storage (TES). Results showed that total CO2 emissions responsibility is reduced by 96.8%. The results are discussed, aiming at recommendations, especially directed to policymakers, to satisfy the Paris Agreement.
Birol Kılkış; Malik Çağlar; Mert Şengül. Energy Benefits of Heat Pipe Technology for Achieving 100% Renewable Heating and Cooling for Fifth-Generation, Low-Temperature District Heating Systems. Energies 2021, 14, 5398 .
AMA StyleBirol Kılkış, Malik Çağlar, Mert Şengül. Energy Benefits of Heat Pipe Technology for Achieving 100% Renewable Heating and Cooling for Fifth-Generation, Low-Temperature District Heating Systems. Energies. 2021; 14 (17):5398.
Chicago/Turabian StyleBirol Kılkış; Malik Çağlar; Mert Şengül. 2021. "Energy Benefits of Heat Pipe Technology for Achieving 100% Renewable Heating and Cooling for Fifth-Generation, Low-Temperature District Heating Systems." Energies 14, no. 17: 5398.
Total decarbonization strategies are facing technical and environmental challenges according to the 2nd Law of Thermodynamics, such as equipment oversizing versus temperature peaking by heat pumps to accommodate low-temperature renewable and waste energy sources. As a method of this paper, the Rational Exergy Management Model (REMM) derived fourteen metrics, aiming to minimize the CO2 emissions responsibility. Two case studies are presented. One of them is a fifth-generation district energy system concept with a 250 MW design heating load of 20000 residence-equivalent apartments at a supply temperature of 35oC. Results showed that two heat pumps in a cascade achieved a 23% higher exergy utilization rate with an optimum temperature peaking to 45oC and 25% radiator oversizing. The second case study is concerned with the strategy of the Chinese government to substitute the domestic use of coal and wood with local wind turbines for electric heating to combat global warming. Five alternatives were considered; 1-Wind electricity to resistance heating, 2-Wind electricity to heat pumps, 3-Wind electricity to mini hydrogen fuel cells, 4-Wind electricity to hydrogen and micro-cogeneration, and 5-Hydrogen district systems with biogas, geothermal, and solar energy. Results showed that Case 1 has the maximum carbon footprint, whereas a custom-designed hydrogen house has the least footprint leading to about 90% CO2 emissions responsibility emanating from exergy destructions. The paper concludes that low-temperature heating either in district energy systems, in private buildings, or prosumers is both environmentally, economically, and technically feasible.
Birol Kilkis. An exergy-based minimum carbon footprint model for optimum equipment oversizing and temperature peaking in low-temperature district heating systems. Energy 2021, 236, 121339 .
AMA StyleBirol Kilkis. An exergy-based minimum carbon footprint model for optimum equipment oversizing and temperature peaking in low-temperature district heating systems. Energy. 2021; 236 ():121339.
Chicago/Turabian StyleBirol Kilkis. 2021. "An exergy-based minimum carbon footprint model for optimum equipment oversizing and temperature peaking in low-temperature district heating systems." Energy 236, no. : 121339.
This paper investigates the exergy and energy rationality of a near‐future, two‐step hydrogen production system in the Black Sea on a custom‐built hydrogen ship with 100% onboard wind, wave, and solar energy system. In the first step of this concept, hydrogen will be produced from the low‐salinity seawater by electrolysis utilizing the onboard renewable energy. Part of the hydrogen produced will be used in the second step, which is the major production step, claiming the H2S gas, which is exceptionally rich in the seawater. The hydrogen and sulfur products will be shipped by hydrogen‐powered shuttle ships to the nearby city of Sinop to blend hydrogen with the natural gas (NG) to form a hydrogen city. Thus this project presents a novel coupling of the land‐side and the sea‐side operations with renewable energy and hydrogen in an exergy‐based minimum CO2 emissions responsibilities. This on‐board H2S exploration concept for hydrogen and sulfur production is compared with the current NG explorations in the Black Sea and the use of NG on the landside. A detailed comparison of the total carbon footprint shows that NG explorations in the Black Sea will be responsible for direct and indirect‐nearly avoidable (due to exergy destructions) CO2 emissions, while the ever‐increasing H2S threat faced by all Black Sea countries will remain at an increasing rate. A new exergy‐based optimum H2S claim depth calculation and control algorithm for onboard operations have also been developed and designed, which shows that economy‐based optimization—if ever exists—will be responsible for nearly avoidable CO2 emissions, while the on‐board hydrogen production and utilization on the land side have a minimal environmental footprint. None of the earlier studies available in the literature concerning the exact harmful effects of hydrocarbons address exergy rationality. Renewable energy systems like wind turbines and solar energy systems, along with other renewable and waste energy systems like geothermal and wave energy are mostly treated individually, which are not free from large exergy destructions. Therefore, future energy plans with environmental concerns must be carried out from the source to the very last point of demand sectors. This is the specific attribute of this research. Novelty Statement None of the studies about the exact harmful effects of hydrocarbons involve exergy rationality and the consequences of this ignorance on the environment and overall energy budget and economy. Renewable energy systems like wind turbines and solar energy systems, along with other renewable and waste energy systems like geothermal and wave energy are mostly treated individually, which are not free from exergy destructions. For example, a solar photovoltaic (PV) plant generates power but releases heat back without claiming it. This unclaimed heat represents about 50% of the unit exergy of the available solar energy and leads to exergy destruction that is responsible for nearly avoidable CO2 emissions because destroyed thermal exergy has to be offset by spending additional fuel in another system, which most likely is using fossil fuels in a boiler. The term nearly precedes the word avoidable, because exergy destructions may not be completely avoided. Even solar and wind energy systems have exergy destruction components during their operation. Yet, a solar PV and heat system would be a much better choice from the exergy rationality point of view. Although the ongoing increase in the renewable shares in the energy stock, it is essential to follow where the power is used in the built environment. For example, according to Global Wind Energy Council, within the next 10 years 234 GW, within the next 30 years 1400 GW offshore wind power capacity is expected to be installed. However, these installations will never know where this electricity and how this electricity is used in an energy/exergy balance and rationality when coupled to the landside through national and international grids. Therefore, future energy plans with environmental concerns must be carried out from the source to the very last point of demand sectors. Whether off‐shore or land‐based, wind turbines just generate electric power without asking where the electricity goes and how rational it is used in the built environment. There is no control over the best way of utilizing this wind energy. Instead, hydrogen production with renewables and utilization in next‐generation fuel cells produces power and heat (pending on heat distribution tariffs for the fifth‐generation district energy systems and LowEx applications, the temperature is the best fit for LowEx applications). The interrupted and unpredictable characteristics of renewables are offset by hydrogen storage.
Birol Kılkış; Başak Kılıç Taşeli. Two‐step onboard hydrogen generation from Black Sea H 2 S reserves. International Journal of Energy Research 2021, 45, 7177 -7192.
AMA StyleBirol Kılkış, Başak Kılıç Taşeli. Two‐step onboard hydrogen generation from Black Sea H 2 S reserves. International Journal of Energy Research. 2021; 45 (5):7177-7192.
Chicago/Turabian StyleBirol Kılkış; Başak Kılıç Taşeli. 2021. "Two‐step onboard hydrogen generation from Black Sea H 2 S reserves." International Journal of Energy Research 45, no. 5: 7177-7192.
Bu makalede terminal binalarının ekserji-düzeltili yolcu başına sarf edilen enerji miktarını uçak yolculuklarında sarf edilen ekserji-düzeltili enerji ile karşılaştıran yeni ölçütler tanıtılmaktadır. Söz konusu enerji tüketimlerinin toplam CO2 salım sorumluluklarına ve küresel ısınmaya nasıl yansıdığı ise akılcı ekserji yönetim modeli (REMM) ile incelenmektedir. Bu ölçütlere göre verimsiz terminaller yolcu başına 12 ila 15 kW-h/yıl enerji tüketmektedirler. Toplamda EP olarak adlandırılan terminallerde yolcu-başı enerji, ısı, soğuk, sıcak servis suyu ve buhar gibi değişik birim ekserji kırılımlarını içermediğinden yeni ekserji-düzeltili yolcu başına enerji tanımı getirilmiştir. Böylelikle terminallerin gerçek zamanda CO2 salım sorumlulukları ve sürdürülebilir çevreye olumsuz etkileri birebir incelenebilmektedir. Yolcu-başı enerji, ekserji eş bazına getirildiğinde bu tür terminallerin birincil enerji talebi 80 ila 100 kW-h/yolcu olmaktadır. Makalede CO2 salımları yanı sıra soğutma kulelerinin ve yoğuşmalı kazanların bilinenin aksine daha fazla su buharının atmosfere salınmasından sorumlu olmaları nedeni ile sera etkilerinin fazla olduğu da göz önünde tutularak küresel ısınma ve ozon tabakası seyreltim potansiyelleri incelenmektedir. Makalede Amsterdam Schiphol ve İstanbul IGA havaalanları yeni ölçütlerle mukayese edilmektedir. This article introduces new benchmarks that compare the amount of exergy-corrected energy consumed per terminal building with the exergy-corrected energy consumed in air travel. How these energy consumptions reflect on total CO2 emission responsibilities and global warming is examined with a rational exergy management model (REMM). According to these criteria, inefficient terminals consume 12 to 15 kW-h / year energy per passenger. Since the terminals named as EP in total do not contain different unit exergy breaks such as energy per passenger, heat, cold, hot service water and steam, a new definition of exergy-corrected passenger is introduced. Thus, the responsibilities of the terminals to release CO2 in real time and their negative effects on the sustainable environment can be examined. When passenger-head energy is brought to exergy level, the primary energy demand of such terminals is 80 to 100 kW-h / passenger. In addition to CO2 emissions, the article examines global warming and ozone layer dilution potentials, considering that cooling towers and condensing boilers are responsible for the release of more water vapor into the atmosphere, contrary to what is known. In the article, Amsterdam Schiphol and Istanbul IGA airports are compared with new criteria.
Birol Kilkis. HAVAALANI TERMİNAL BİNALARINDA EKSERJİ AKILCILIĞI VE KÜRESEL ISINMA. Sürdürülebilir Havacılık Araştırmaları Dergisi 2019, 2, 29 -42.
AMA StyleBirol Kilkis. HAVAALANI TERMİNAL BİNALARINDA EKSERJİ AKILCILIĞI VE KÜRESEL ISINMA. Sürdürülebilir Havacılık Araştırmaları Dergisi. 2019; 2 (2019.2):29-42.
Chicago/Turabian StyleBirol Kilkis. 2019. "HAVAALANI TERMİNAL BİNALARINDA EKSERJİ AKILCILIĞI VE KÜRESEL ISINMA." Sürdürülebilir Havacılık Araştırmaları Dergisi 2, no. 2019.2: 29-42.
The realization of net-zero exergy districts can be supported by urbanization options for district density and the selection of building materials. This research work formulates an urbanization algorithm based on terms for the carbon dioxide emissions responsibility of districts based on energy usage and aspects of embodied energy. The combined method is implemented to scenarios that contribute to a net-zero exergy district target with 6 options for district density and the selection of building materials. Based on a case study in the province of Ankara, Turkey, the scenario in which on-site exergy production is about 9.5% of the annual exergy consumption will be responsible for about 13,731 ktonnes of carbon dioxide emissions in a timeframe of 30 years. A near net-zero exergy district based on on-site exergy production at 75% of the annual exergy consumption will have about 2967 ktonnes of carbon dioxide emissions, including embodied energy in buildings. The sensitivity analysis with 9 different combinations provides differences in trade-offs based on timeframes and scenarios. The research work has ramifications for avoiding locking-in of carbon dioxide emissions by considering an integrated approach to urban energy solutions, district density, and building materials in local decision-making processes while reaching net-zero targets in the future.
Şiir Kılkış; Birol Kılkış. An urbanization algorithm for districts with minimized emissions based on urban planning and embodied energy towards net-zero exergy targets. Energy 2019, 179, 392 -406.
AMA StyleŞiir Kılkış, Birol Kılkış. An urbanization algorithm for districts with minimized emissions based on urban planning and embodied energy towards net-zero exergy targets. Energy. 2019; 179 ():392-406.
Chicago/Turabian StyleŞiir Kılkış; Birol Kılkış. 2019. "An urbanization algorithm for districts with minimized emissions based on urban planning and embodied energy towards net-zero exergy targets." Energy 179, no. : 392-406.
The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a “hydrogen city” model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production, hydrogen storage, and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80, which is above the value of conventional district energy systems, and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 °C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200,000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.
Birol Kılkış; Şiir Kılkış. Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus. Energies 2018, 11, 1226 .
AMA StyleBirol Kılkış, Şiir Kılkış. Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus. Energies. 2018; 11 (5):1226.
Chicago/Turabian StyleBirol Kılkış; Şiir Kılkış. 2018. "Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus." Energies 11, no. 5: 1226.
Birol Kılkış; Şiir Kılkış. New exergy metrics for energy, environment, and economy nexus and optimum design model for nearly-zero exergy airport (nZEXAP) systems. Energy 2017, 140, 1329 -1349.
AMA StyleBirol Kılkış, Şiir Kılkış. New exergy metrics for energy, environment, and economy nexus and optimum design model for nearly-zero exergy airport (nZEXAP) systems. Energy. 2017; 140 ():1329-1349.
Chicago/Turabian StyleBirol Kılkış; Şiir Kılkış. 2017. "New exergy metrics for energy, environment, and economy nexus and optimum design model for nearly-zero exergy airport (nZEXAP) systems." Energy 140, no. : 1329-1349.
Şiir Kılkış; Birol Kilkis. Integrated circular economy and education model to address aspects of an energy-water-food nexus in a dairy facility and local contexts. Journal of Cleaner Production 2017, 167, 1084 -1098.
AMA StyleŞiir Kılkış, Birol Kilkis. Integrated circular economy and education model to address aspects of an energy-water-food nexus in a dairy facility and local contexts. Journal of Cleaner Production. 2017; 167 ():1084-1098.
Chicago/Turabian StyleŞiir Kılkış; Birol Kilkis. 2017. "Integrated circular economy and education model to address aspects of an energy-water-food nexus in a dairy facility and local contexts." Journal of Cleaner Production 167, no. : 1084-1098.
Birol Kilkis. Exergetic comparison of wind energy storage with ice making cycle versus mini-hydrogen economy cycle in off-grid district cooling. International Journal of Hydrogen Energy 2017, 42, 17571 -17582.
AMA StyleBirol Kilkis. Exergetic comparison of wind energy storage with ice making cycle versus mini-hydrogen economy cycle in off-grid district cooling. International Journal of Hydrogen Energy. 2017; 42 (28):17571-17582.
Chicago/Turabian StyleBirol Kilkis. 2017. "Exergetic comparison of wind energy storage with ice making cycle versus mini-hydrogen economy cycle in off-grid district cooling." International Journal of Hydrogen Energy 42, no. 28: 17571-17582.
Basak K. Taseli; Birol Kilkis. Ecological sanitation, organic animal farm, and cogeneration: Closing the loop in achieving sustainable development—A concept study with on-site biogas fueled trigeneration retrofit in a 900-bed university hospital. Energy and Buildings 2016, 129, 102 -119.
AMA StyleBasak K. Taseli, Birol Kilkis. Ecological sanitation, organic animal farm, and cogeneration: Closing the loop in achieving sustainable development—A concept study with on-site biogas fueled trigeneration retrofit in a 900-bed university hospital. Energy and Buildings. 2016; 129 ():102-119.
Chicago/Turabian StyleBasak K. Taseli; Birol Kilkis. 2016. "Ecological sanitation, organic animal farm, and cogeneration: Closing the loop in achieving sustainable development—A concept study with on-site biogas fueled trigeneration retrofit in a 900-bed university hospital." Energy and Buildings 129, no. : 102-119.
Mustafa Fatih Evren; Abuzer Özsunar; Birol Kilkis. Experimental investigation of energy-optimum radiant-convective heat transfer split for hybrid heating systems. Energy and Buildings 2016, 127, 66 -74.
AMA StyleMustafa Fatih Evren, Abuzer Özsunar, Birol Kilkis. Experimental investigation of energy-optimum radiant-convective heat transfer split for hybrid heating systems. Energy and Buildings. 2016; 127 ():66-74.
Chicago/Turabian StyleMustafa Fatih Evren; Abuzer Özsunar; Birol Kilkis. 2016. "Experimental investigation of energy-optimum radiant-convective heat transfer split for hybrid heating systems." Energy and Buildings 127, no. : 66-74.
E. Koç; T. Yavuz; B. Kılkış; O. Erol; C. Balas; Mehmet Timur Aydemir; B. Kilkiş. Numerical and experimental analysis of the twin-blade hydrofoil for hydro and wind turbine applications. Ocean Engineering 2015, 97, 12 -20.
AMA StyleE. Koç, T. Yavuz, B. Kılkış, O. Erol, C. Balas, Mehmet Timur Aydemir, B. Kilkiş. Numerical and experimental analysis of the twin-blade hydrofoil for hydro and wind turbine applications. Ocean Engineering. 2015; 97 ():12-20.
Chicago/Turabian StyleE. Koç; T. Yavuz; B. Kılkış; O. Erol; C. Balas; Mehmet Timur Aydemir; B. Kilkiş. 2015. "Numerical and experimental analysis of the twin-blade hydrofoil for hydro and wind turbine applications." Ocean Engineering 97, no. : 12-20.
T. Yavuz; E. Koç; Birol Kilkis; Ö. Erol; C. Balas; Mehmet Timur Aydemir. Performance analysis of the airfoil-slat arrangements for hydro and wind turbine applications. Renewable Energy 2015, 74, 414 -421.
AMA StyleT. Yavuz, E. Koç, Birol Kilkis, Ö. Erol, C. Balas, Mehmet Timur Aydemir. Performance analysis of the airfoil-slat arrangements for hydro and wind turbine applications. Renewable Energy. 2015; 74 ():414-421.
Chicago/Turabian StyleT. Yavuz; E. Koç; Birol Kilkis; Ö. Erol; C. Balas; Mehmet Timur Aydemir. 2015. "Performance analysis of the airfoil-slat arrangements for hydro and wind turbine applications." Renewable Energy 74, no. : 414-421.
Birol Kilkis. Energy consumption and CO2 emission responsibilities of terminal buildings: A case study for the future Istanbul International Airport. Energy and Buildings 2014, 76, 109 -118.
AMA StyleBirol Kilkis. Energy consumption and CO2 emission responsibilities of terminal buildings: A case study for the future Istanbul International Airport. Energy and Buildings. 2014; 76 ():109-118.
Chicago/Turabian StyleBirol Kilkis. 2014. "Energy consumption and CO2 emission responsibilities of terminal buildings: A case study for the future Istanbul International Airport." Energy and Buildings 76, no. : 109-118.
The concept of a hybrid system consisting of a wind turbine plant and a pumped storage hydropower plant is a promising idea with respect to a number of important factors. Wind turbine plant power output has a fluctuating and interrupted nature, and the penetration of the electrical energy to the grid usually poses problems to the steady operation of the system. Pumped storage hydropower is a mature technology in the energy storage sector. Pumped storage hydropower has advantages compared to other energy storage technologies such as CAES, batteries, etc. due to its short discharge time, high energy storage capacities, and high power output. The first objective of this study is to time-shift the power output of the wind turbine plant to the peak-demand periods by means of storage and thus realizing increase in the penetration level to the grid. The second objective is to obtain a more stable power output from the wind turbine plant that inevitably has a variable power output. A 1-year operation simulation of the hybrid system was carried out under peak tariff strategy within the scope of these two objectives. An operation simulation was also made covering only the wind turbine plant with same power output data and same demand strategy and the results were compared. Without storage, the wind turbine plant feeds 6,350.30 MW h of electrical energy into the grid; this value increases to 7,656.00 MW h for the hybrid system, and this means that there is 17.05 % increase in penetration and the system is technically applicable for the first objective. Annual stable power output ratio that shows the fulfillment of demand is approximately 72.49 % for wind turbine plant without storage, and this value is approximately 87.40 % for the hybrid system. This means that there is a 14.91 % increase and that the system is technically applicable for the second objective. This paper provides the details of the year-long analysis, draws generalized conclusions, and provides recommendations for future studies.
Kurtuluş Değer; Birol Kilkis; Tahir Yavuz. Parametric Analysis of Pumped Storage Hydropower-Coupled Wind Turbine Plants. Progress in Exergy, Energy, and the Environment 2014, 791 -803.
AMA StyleKurtuluş Değer, Birol Kilkis, Tahir Yavuz. Parametric Analysis of Pumped Storage Hydropower-Coupled Wind Turbine Plants. Progress in Exergy, Energy, and the Environment. 2014; ():791-803.
Chicago/Turabian StyleKurtuluş Değer; Birol Kilkis; Tahir Yavuz. 2014. "Parametric Analysis of Pumped Storage Hydropower-Coupled Wind Turbine Plants." Progress in Exergy, Energy, and the Environment , no. : 791-803.
Recent finding by Bond et al. (2013) about the age of the star HD 140283 (14.46 ± 0.8 Gyr) requires us to reconsider the estimates about the age of the universe, namely 13.817 ± 0.048 Gyr. Their conflicting result is analytically supported by the paper in Int. J. Exergy by Kilkis (2004). This paper, which introduced the Radiating Universe Model (RUM) with exergy flow to an infinitely-sized thermal bath at 0 K, predicted that the age of the universe is 14.885 ± 0.040 Gyr. It further calculated that Hubble constant is 65.7 km s
Birol Kilkis. An exergetic approach to the age of universe. International Journal of Exergy 2014, 15, 76 .
AMA StyleBirol Kilkis. An exergetic approach to the age of universe. International Journal of Exergy. 2014; 15 (1):76.
Chicago/Turabian StyleBirol Kilkis. 2014. "An exergetic approach to the age of universe." International Journal of Exergy 15, no. 1: 76.
Özgür Erol; Birol Kilkis. An energy source policy assessment using analytical hierarchy process. Energy Conversion and Management 2012, 63, 245 -252.
AMA StyleÖzgür Erol, Birol Kilkis. An energy source policy assessment using analytical hierarchy process. Energy Conversion and Management. 2012; 63 ():245-252.
Chicago/Turabian StyleÖzgür Erol; Birol Kilkis. 2012. "An energy source policy assessment using analytical hierarchy process." Energy Conversion and Management 63, no. : 245-252.
Birol Kilkis. Exergy metrication of radiant panel heating and cooling with heat pumps. Energy Conversion and Management 2012, 63, 218 -224.
AMA StyleBirol Kilkis. Exergy metrication of radiant panel heating and cooling with heat pumps. Energy Conversion and Management. 2012; 63 ():218-224.
Chicago/Turabian StyleBirol Kilkis. 2012. "Exergy metrication of radiant panel heating and cooling with heat pumps." Energy Conversion and Management 63, no. : 218-224.
While our planet is rapidly approaching an environmental crisis under the dominant use of depleting fossil fuels, the need for exploiting all forms of new, small carbon foot-print, renewable, and clean energy resources are increasing in the same proportion. Therefore, the need for exploring all types of clean energy resources that the world has- some of which might have not attracted sufficient attention before- is essential in order to implement sufficient, efficient, and widely use all them. In this respect, operational effectiveness of the wind and hydrokinetic turbines depend on the performance of the airfoils chosen. Using double-blade airfoils in the wind and hydrokinetic turbines, minimum wind and hydrokinetic flow velocities to produce meaningful and practical mechanical power reduces to 3- 4 m /s for wind turbines and 1-1.5 m/s or less for hydrokinetic turbines. Consequently, double-blade hydrofoils may re-define the potentials of wind power and hydrokinetic power of the countries in positive manner.
Tahir Yavuza; Birol Kilkis; Emre Koc; Ozgur Erol. Flow and Performance Characteristics of a Double-Blade Hydrofoil. Advanced Materials Research 2012, 433-440, 7218 -7222.
AMA StyleTahir Yavuza, Birol Kilkis, Emre Koc, Ozgur Erol. Flow and Performance Characteristics of a Double-Blade Hydrofoil. Advanced Materials Research. 2012; 433-440 ():7218-7222.
Chicago/Turabian StyleTahir Yavuza; Birol Kilkis; Emre Koc; Ozgur Erol. 2012. "Flow and Performance Characteristics of a Double-Blade Hydrofoil." Advanced Materials Research 433-440, no. : 7218-7222.
Operational effectiveness of the wind and hydrokinetic turbines depend on the performance of the airfoils chosen. Standard airfoils historically used for wind and hydrokinetic turbines had and have the maximum lift coefficients of about 1.3 at the stall angle of attack, which is about 12o. At these conditions, the minimum flow velocities to generate electric power are about 7 m/s and 3 m/s for wind turbine and hydrokinetic turbine, respectively. Using leading edge slat, the fluid dynamics governing the flow field eliminates the separation bubble by the injection of the high momentum fluid through the slat over the main airfoil-by meaning of the flow control delays the stall up to an angle of attack of 20o, with a maximum lift coefficient of 2.2. In this study, NACA 2415 was chosen as a representative of hydrofoils while NACA 22 and NACA 97, were chosen as slat profiles, respectively. This flow has been numerically simulated by FLUENT, employing the Realizable k-e turbulence model. In the design of the wind and hydrokinetic turbines, the performance of the airfoils presented by aerodynamics CL = f (α,δ), CD = f (α,δ) and CL/CD = f (α,δ) are the basic parameters. In this paper, optimum values of the angle of attack, slat angle and clearance space between slat and main airfoil leading to maximum lift and minimum drag, and consequently to maximum CL/CD have been numerically determined. Hence, using airfoil and hydrofoil with leading edge slat in the wind and hydrokinetic turbines, minimum wind and hydrokinetic flow velocities to produce meaningful and practical mechanical power reduces to 3-4 m /s for wind turbines and 1-1.5 m/s or less for hydrokinetic turbines. Consequently, using hydrofoil with leading edge slat may re-define the potentials of wind power and hydrokinetic power potential of the countries in the positive manner.
Tahir Yavuz; Birol Kilkis; Hurşit Akpinar; Özgur Erol. Performance Analysis of a Hydrofoil with and without Leading Edge Slat. 2011 10th International Conference on Machine Learning and Applications and Workshops 2011, 2, 281 -285.
AMA StyleTahir Yavuz, Birol Kilkis, Hurşit Akpinar, Özgur Erol. Performance Analysis of a Hydrofoil with and without Leading Edge Slat. 2011 10th International Conference on Machine Learning and Applications and Workshops. 2011; 2 ():281-285.
Chicago/Turabian StyleTahir Yavuz; Birol Kilkis; Hurşit Akpinar; Özgur Erol. 2011. "Performance Analysis of a Hydrofoil with and without Leading Edge Slat." 2011 10th International Conference on Machine Learning and Applications and Workshops 2, no. : 281-285.