Günümüzde yaygın olarak kullanılan yenilenemeyen enerji kaynaklarının (kömür, doğalgaz, petrol vb.) çevre üzerinde zararlı etkileri bulunmaktadır. Ayrıca bu tür kaynaklar kullanıldıkça tükenme ...sorunuyla karşılaşmaktadırlar. Dünyanın enerji ihtiyacını, doğaya zarar vermeden ve sürdürülebilir bir formda üretebilmek için yenilenemeyen enerji kaynakları yerine yenilenebilir enerji kaynaklarının kullanımı yaygınlaştırılmalıdır. Potansiyeli en yüksek olan yenilenebilir enerji kaynağı güneştir. Bu bağlamda güneşten enerji elde edebilmek için de güneş pilleri kullanılmaktadır. Literatürde güneş enerjisinden enerji elde edebilmek için çoğunlukla silisyum bazlı güneş pillerinin kullanıldığı belirtilmektedir. Ama bu silisyum bazlı güneş pillerinin üretimi oldukça zor ve maliyetlidir. Bu güneş pillerinin olumsuzluklarını ortadan kaldırmak için literatürde güneş pilleri üzerine çalışmaların yapıldığı görülmektedir. Bu bağlamda organik güneş pillerinden biri olan perovskit güneş pilleri üzerinde birçok araştırma yapılmıştır. Perovskit güneş pillerinin verimi, ilk üretimlerinden çok kısa bir süre sonra diğer güneş pilleri ile rekabet edebilecek seviyeye çıkmıştır. Ayrıca bu güneş pillerinin maliyeti de oldukça düşüktür. Ancak perovskit güneş pilleri üretildikten sonra kararsızlık problemleri ile karşılaşmaktadırlar. Bu makalede, güneş enerjisi ve güneş pilleri ile ilgili literatürdeki makalelerin derlemesi ve değerlendirilmesi yapılmıştır.
•We examined the current and future use of hydrogen energy.•Extensive information was given about the storage of hydrogen.•Solid state storage method is more promising than other methods.•The ...advantages and disadvantages of different hydrogen storage methods were compared.•Hydrogen energy can be used in fuel cells.
Our need for energy is constantly increasing. We consume existing oil, coal and natural gas resources in order to obtain energy. As fossil fuels are exhausted, their prices have increased and new energy sources have been sought. It is possible to meet the daily energy demand with renewable energy sources. The utilization rates of renewable energy resources are gradually increasing. The use of fossil fuels is reduced in order to reduce carbon emissions in accordance with international agreements. Therefore, the use of clean energy resources is encouraged. In this article, hydrogen energy, which is a clean energy source, has been examined. Subjects such as hydrogen sources, production, storage and transportation have been investigated from articles in the literature. The current uses of hydrogen energy, limitations in hydrogen use, future uses, future goals have been examined. In this article, studies on hydrogen energy have been gathered together and it is aimed to create a source for future articles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Due to developing aviation sector, number of aircraft in the world is increasing. Along with this development, problems such as the decrease in air quality in and around the airport also ...arise. In this study, it is tried to calculate pollutant emissions occurring in 2022 during the LTO cycles of Denizli Çardak Airport in Turkey. These calculations are based on the information obtained from ICAO Engine Emission Data Bank and flight information published by the General Directorate of State Airports Authority (GDSAA). As a result of the data obtained, 74.64 ton/year pollutants (NOx-37.148 t/y, CO-35.398 t/y and HC-2.094 t/y) were calculated for 2022 at Denizli Çardak Airport. Of all emissions, NOx accounted for 50%, CO 47% and HC 3%. In the LTO cycle, the most fuel is burned in taxi cycle and pollutant emissions produced in this cycle are greater. With a 2 min reduction in taxi time, there will be an approximate 6.8% reduction in the total emission rate in the LTO cycle. Similarly, with a 4 min reduction in taxi time, there will be a 13.72% reduction in the whole emission rate in the LTO cycle. Unlike other studies, in this study the emission rates of various engines were compared. It has been calculated that the amount of pollutant emissions produced by the new generation Boeing 737 MAX LEAP-1B powered aircraft in LTO cycle is 25% less than the amount of pollutant emissions produced by the Airbus A320 NEO LEAP-1 A powered aircraft. The biggest factor here is that the emission of CO pollutants is less. Considering the emission rates produced by these four different engines (B737-800 CFM56-7B, A320 V2500-A1, B737 MAX LEAP-1B, A320 NEO LEAP-1 A), the Airbus A320 V2500-A1 engine is a more environmentally friendly engine than the other engines.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The world’s energy demand is increasing. Wind energy plays an important role in meeting this demand. Investments in wind energy have been increasing in recent years. It can be said that the source of ...wind energy will be unlimited since there will be wind as long as there is sun. Most governments meet a large energy need by generating electricity from wind. At the end of 2019, the total amount of electricity generated from wind was 650 GW. Wind energy capacity is increasing with offshore wind pairs. Offshore wind turbines are a new field and research studies are ongoing. Wind turbines have the capacity to be installed anywhere in the world, and each government will have its own energy source. There is a problem of icing in wind power plants installed in cold climates. With this problem, efficiency in wind turbines decreases. Many methods have been found and developed in studies on icing problems. In this article, wind turbines were investigated, states’ perspectives on wind energy, developments and investments in wind energy, and the problem of icing were examined. Many articles in the literature have been reviewed and a solution to the icing problem of wind turbine blades has been sought.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
•Numerical simulation of propane and propane–hydrogen blending fuel was performed.•The effects of turbulence and radiation model on combustion were examined.•Comparison showed that RNG and P–I models ...give a better agreement with measurements.•As burner and combustor fuel, hydrogen may be considered a good alternative.
This paper presents numerical simulation results of propane, propane–hydrogen blending diffusion flames in a combustion chamber. The numerical simulations using Fluent CFD code were carried out by changing fuel blending from pure propane (100% C3H8) to propane–hydrogen blending including 90% C3H8–10% H2, 80% C3H8–20% H2, 10% C3H8–90% H2, 20% C3H8–80% H2 by volume. A two-dimensional axis-symmetric numerical model was solved to investigate the effects of the turbulence and radiation models on the combustion characteristics such as temperature, and gas concentration distributions. The combustion reaction scheme in the flame region was modeled using eddy dissipation model with global reaction scheme. The effects of two turbulence models including RNG k–ε, and Reynolds Stress Model, RSM, and two different radiation models including P–I and discrete transfer model were examined on combustion characteristics. The predictions are validated and compared with the published experimental and simulation results. Numerical results show that the velocity profiles, temperature gradients, CO2 and O2 concentrations profiles are overall agreement with published measurement and simulation results in the literature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► We examine usage of liquid hydrogen as a fuel in aircrafts. ► Engine performance is a little better for liquid hydrogen fuel than kerosene. ► Liquid hydrogen can be a potential alternative to ...kerosene as aviation fuel. ► Usage of liquid hydrogen will provide national independence for fuel supply. ► Increased production of liquid hydrogen will decrease its cost disadvantage.
Fossil-based fuels are commonly used in aircraft engines but they have a polluting effect and they cause a greenhouse effect for our world. This study reports a research about aircraft gas turbine engines which are fired by liquid hydrogen (LH2) in terms of performance and environmental aspects. Also, the performance and emissions of LH2 fueled engines are compared with those of kerosene fired aircraft engines. Same flights from Istanbul to London, and Paris to Kabul are examined to estimate the emission from a conventional aircraft as an application in aviation sector. It is shown that the amount of NOx, HC and CO emissions for traveling by a conventional aircraft for London is 78.36, 1.202 and 22.4kg, while Paris is 71.55, 1.171 and 21.63kg, and Kabul is 111.44, 1.36 and 26.11kg, respectively. For the use of liquid hydrogen as a fuel, amount of gas emissions decreases for any destination like London, Paris and Kabul. Total HC and CO emissions are going to be nearly 0kg because of lack of carbon in the fuel. Also NOx emission is lower because of wider flammability limit of LH2. Results show that the aircraft engines with LH2 have great potential for emissions reduction and engine performance parameters are a little better for LH2 fuel. It is strongly emphasized that one of the most important advantages for the use of LH2 is national independence for fuel supply. Oil cannot be extracted in every countries territory but LH2 is producible for every country and this is so important for a countries freedom.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents numerical simulation results of propane, propaneahydrogen blending diffusion flames in a combustion chamber. The numerical simulations using Fluent CFD code were carried out by ...changing fuel blending from pure propane (100% C3H8) to propaneahydrogen blending including 90% C3H8a10% H2, 80% C3H8a20% H2, 10% C3H8a90% H2, 20% C3H8a80% H2 by volume. A two-dimensional axis-symmetric numerical model was solved to investigate the effects of the turbulence and radiation models on the combustion characteristics such as temperature, and gas concentration distributions. The combustion reaction scheme in the flame region was modeled using eddy dissipation model with global reaction scheme. The effects of two turbulence models including RNG kaIm, and Reynolds Stress Model, RSM, and two different radiation models including PaI and discrete transfer model were examined on combustion characteristics. The predictions are validated and compared with the published experimental and simulation results. Numerical results show that the velocity profiles, temperature gradients, CO2 and O2 concentrations profiles are overall agreement with published measurement and simulation results in the literature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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