145 research outputs found
Investigation on boronizing effect to the cavitation behaviour of fe-materials
No full textIn this study, the effect of boronising on the cavitation behaviour of Fe-based materials was examined by means of samples made from X 165 CrMoV 12 tool steel.The cavitation behaviour was determined and evaluated qualitatively by means of SEM (Scanning Electron Microscopy) and quantitatively by means of differences in weight depending on the test duration under defined experimental conditions
THE TECHNO-ECONOMIC EVALUATION OF THE BETWEEN A GRID EXTENSION AND HYBRID RENEWABLE SYSTEMS CONSIDERING DEFERRABLE LOADS
No full textThe rapid depletion of fossil energy resources significantly increases the need for renewable energy resources (RES) in electricity production. Hybrid power systems (HPS) are a promising solution for rural electrification where grid extensions are uneconomical. This study investigated the technical, economic, and environmental aspects of on-grid or off-grid HPS performance for optimal rural electrification. In addition, the effects of different deferrable load values on grid extension distance (GE) and optimal off-grid system sizing were investigated. Sensitivity analyses were conducted to evaluate the effects of variations in solar irradiation potential, diesel fuel costs, and discount rates on optimal HPS sizing. In scenarios where the deferrable load is above 9%, the GEs were zero, while below 5%, they increased to 24.2 km. In contrast, when the diesel generator (DG) was integrated into HPS, the photovoltaic (PV) and energy storage system (ESS) capacities were reduced by half in the optimal scenarios, and it was found that the GE was zeros regardless of the deferrable load. In the case of the highest deferrable load, the NPC is 22.6% lower than when there is no deferrable load. NPC surpasses the energy cost in the grid-only condition when solar irradiation is less than 4 kWh/m2/day, and ESS cost multipliers are greater than 2. This study will help researchers find optimal electrification solutions that support hybrid renewable energy and environmentally friendly options.</p
Examining relations between physics-related personal epistemology and motivation in terms of gender
No full text0000-0003-4222-7468WOS: 000467779300010The gender gap continues to exist in physics education. The author examines the gender-related differences in the relations and strengths among personal epistemologies, motivation, and achievement in physics among Turkish high school students. Established questionnaires were used to identify students' personal epistemologies, motivations and achievement in physics. A total of 567 ninth-grade students from three high schools in Mugla Province in Turkey participated in the study. Multigroup structural equation modeling was used to determine the gender differences in the relations and strengths among personal epistemology, motivation, and achievement in physics. Results from the structural equation modeling showed that students' personal epistemologies directly predicted their motivation and indirectly their achievement in physics. Multigroup structural equation modeling analysis showed that the strength of the relations between personal epistemology and motivation varied for female and male students. Implications for future directions are discussed
Optimal sizing of grid-connected hybrid energy systems for electric vehicle charging stations considering charging demand periods and economic parameters
No full textThe development of electric vehicle (EV) technologies and the spread of EVs have made the expansion of charging infrastructure increasingly important. However, unplanned sizing of EV charging stations will have adverse technical, economic, and environmental impacts, especially on grid reliability and energy costs. This study performs a techno-economic evaluation of a solar PV-based hybrid power system considering variations in EV charging demand profiles and economic parameters. The results show that variations in demand profile and economic parameters significantly influence investment decisions. Higher inflation was most effective on peak evening demand profiles, increasing the levelized cost of energy by up to 2.2 times. Self-sufficiency can increase to 57% under grid sales constraints in the midday peak scenario. In addition, at maximum installed PV capacity, the SCR is 12% higher than in the evening peak, and curtailment is reduced by up to 4.5%. The results will expand the use of renewable energy with less grid dependency and faster achievement of zero carbon emission targets
BİRİNCİL VE ERTELENMİŞ YÜKLERİ DİKKATE ALARAK HİBRİT GÜÇ SİSTEMLERİ İÇİN OPTİMUM SİSTEM TASARIMI VE ŞEBEKE GENİŞLETMESİ
No full textOptimal Sizing and Techno-Economic Evaluation of Microgrids Based on 100% Renewable Energy Powered by Second-Life Battery
No full textThe rapid development of distributed renewable energy has made energy storage essential for demand reliability and flexible energy management. Due to the high investment costs of fresh batteries (FB), achieving a positive and efficient economy takes work. However, second-life batteries (SLB), whose capacity decreases by 20-30% after the first use, can be preferred as alternative energy storage to overcome this challenge. This paper investigates the renewable potential of shared energy storage and the feasibility of FB&SLB for prosumers. In addition, threshold points are determined by examining the financial obligations associated with an increasing share of renewables on the path to 100% renewable energy. Moreover, the impact of carbon taxes on extra CO2 reduction costs is assessed depending on the carbon quota. The results confirm the superiority of SLB, which increases throughput by 11.5% while reducing CO2 by 9.4%. Renewable fractions (RFs) above 59.2% and 87% in optimal hybrid power systems (HPS), in different climate potentials, and for low and high energy tariffs lead to costly investments. Increasing the carbon tax could reduce the cost of CO2 reduction by up to 5.2 /kg for FB at lower CO2 limits. In contrast, increasing RF from 95% to 100% would increase net present cost (NPC) by up to 122.65%. It will be more critical than ever for governments to support prosumers' financial trade-offs in the transition to clean energy
Optimization of Renewable Energy Hybrid Power Systems Under Different Penetration and Grid Tariffs
No full textThe trend towards renewable energy sources (RES) is increasing daily due to energy demand, costs, and environmental concerns. This study investigates the technical, economic, and environmental impacts of changes in energy costs and incentives on hybrid power systems (HPS). Optimization results show optimal HPSs vary between 75-200% penetration (PR) depending on grid energy tariffs and energy sales constraints (GSC). In these scenarios, the renewable fraction (RF) increased to 80%, while the excess electricity (EE) increased to 10%. On the other hand, energy tariffs and grid constraints limit the PR increase in the optimal scenarios. This reduced the RF by up to 26%, limiting the use of clean energy. Due to load mismatch and grid constraints, there was a minimal increase in RF after 200% PR. In addition, removing incentives increased the cost of energy (COE) and total net present costs (NPC) by up to 96%. The results show that grid constraints and energy tariffs directly affect the economic and environmental performance of renewable energy investments and can slow down the pace of these investments. Moreover, it has become clear that controlled incentive packages must continue to achieve zero carbon targets
EVALUATING THE EFFECTS OF DEPTH OF DISCHARGE IN MICROGRID UNDER LOWER RENEWABLE PENETRATION
No full textOPTIMAL SIZING AND OPERATION OF HYBRID POWER SYSTEMS CONSIDERING THE BATTERY CAPACITY DEGRADATION LIMITATIONS
No full textEvaluating clean energy alternatives in hybrid power systems (HPS) is critical withinsustainable development and zero-carbon policies. Considering the synchronizationissues between energy generation and consumption, determining the optimal operatingperformance of battery energy storage systems (BESS) will likely increase support andinterest in HPS investments. In this study, HPSs using shared BESSs for prosumers in acommon bus distribution network are optimally sized with a minimum cost objective ina multi-year sensitivity analysis. Most importantly, the optimal C-rate and maximumdepth of discharge (DODmax) operation are determined to match the supply-demandbalance and maximize the HPS benefit at lower end-of-life (EOL) limits. The impact ofincreases in EOL limits on the technical, economic, and environmental feasibility of HPSand BESS aging is also evaluated. At the same time, all operations are performedconsidering four different sub-degradation models using the Arrhenius strategy andRainflow Counting algorithm. The results show that increasing the C-rate reduces CO2 byup to 19% while increasing BESS equivalent cycles and cycling degradation by 28.26%and 10%, respectively. HPS performance is maximized based on optimum BESS operatingat 80% DODmax. Based on the obtained results, it is also emphasized that the impact ofBESS operating performance on HPS feasibility and aging analysis will be valuable formany stakeholders.</p
Technical, Economic and Environmental Optimization of Electric Vehicle Charging Stations Integrated Photovoltaic and Energy Storage with Different Climatic Characteristics
No full textDünya’da artan nüfus, teknolojinin hızla gelişimi ve modern yaşam şeklinin toplumu daha fazla tüketime yönlendirmesi enerjiye olan talebi artırmaktadır. Talep edilen enerjinin yaygın olarak konvansiyonel kaynaklardan karşılanması küresel ısınma başta olmak üzere birçok çevresel ve ekonomik problem oluşturmaktadır. Dahası enerji tüketim araçlarının verimliliklerinin düşük olması ve daha çok konvansiyonel kaynaklara bağımlılığı bu durumu daha da kötüleştirmektedir. Dolayısı ile özellikle fosil kaynaklı enerji tüketiminin yaklaşık %20’sine sahip içten yanmalı araçların elektrikli hale getirilmesi ve bunların enerji taleplerinin yenilenebilir enerji kaynakları (YEK) ile karşılanması çok önemlidir. Bu çalışmada elektrikli araç (EA) şarj istasyonlarının solar fotovoltaik panel (FV) ve enerji depolama sistemleri (EDS) ile entegrasyon potansiyeli araştırılmış ve teknik, ekonomik ve çevresel etkileri optimize edilmiştir. Ek olarak önerilen modelin farklı iklimsel özelliklere sahip coğrafi bölgelerdeki etkileri yapılan hassasiyet analizleri ile tespit edilmiştir. Sonuçlar birim enerji maliyetlerinin iklimsel farklılıklara bağlı olarak %21’e kadar artış gösterdiğini ve en iyi sonucun 0,046 $/kWh ile İzmir ilinde elde edildiğini göstermiştir. Kullanılamayan yenilenebilir enerji oranını azaltmak ve temiz enerji tüketimini artırmak amacıyla kullanılan EDS’ler, solar radyasyon potansiyeli düşük olan şehirlerde amortisman sürecinin proje ömrüne yaklaşmasına sebep olmuştur. Diğer taraftan FV’li hibrit modellerde amortisman süreci 7,88 yıla kadar düşmüştür. Sonuçlar FV-EDS entegreli EA şarj istasyonlarının bulundukları bölge iklim özelliklerine bağlı olarak farklı teknik, ekonomik ve çevresel etkilere sahip olabileceğini göstermiştir. Bu durumlar dikkate alınarak altyapı ve yatırımcı teşvik mekanizmalarının geliştirilmesi gerekmektedir
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