Search results for: wind energy conversion
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9605

Search results for: wind energy conversion

8045 An As-Is Analysis and Approach for Updating Building Information Models and Laser Scans

Authors: Rene Hellmuth

Abstract:

Factory planning has the task of designing products, plants, processes, organization, areas, and the construction of a factory. The requirements for factory planning and the building of a factory have changed in recent years. Regular restructuring of the factory building is becoming more important in order to maintain the competitiveness of a factory. Restrictions in new areas, shorter life cycles of product and production technology as well as a VUCA world (Volatility, Uncertainty, Complexity & Ambiguity) lead to more frequent restructuring measures within a factory. A building information model (BIM) is the planning basis for rebuilding measures and becomes an indispensable data repository to be able to react quickly to changes. Use as a planning basis for restructuring measures in factories only succeeds if the BIM model has adequate data quality. Under this aspect and the industrial requirement, three data quality factors are particularly important for this paper regarding the BIM model: up-to-dateness, completeness, and correctness. The research question is: how can a BIM model be kept up to date with required data quality and which visualization techniques can be applied in a short period of time on the construction site during conversion measures? An as-is analysis is made of how BIM models and digital factory models (including laser scans) are currently being kept up to date. Industrial companies are interviewed, and expert interviews are conducted. Subsequently, the results are evaluated, and a procedure conceived how cost-effective and timesaving updating processes can be carried out. The availability of low-cost hardware and the simplicity of the process are of importance to enable service personnel from facility mnagement to keep digital factory models (BIM models and laser scans) up to date. The approach includes the detection of changes to the building, the recording of the changing area, and the insertion into the overall digital twin. Finally, an overview of the possibilities for visualizations suitable for construction sites is compiled. An augmented reality application is created based on an updated BIM model of a factory and installed on a tablet. Conversion scenarios with costs and time expenditure are displayed. A user interface is designed in such a way that all relevant conversion information is available at a glance for the respective conversion scenario. A total of three essential research results are achieved: As-is analysis of current update processes for BIM models and laser scans, development of a time-saving and cost-effective update process and the conception and implementation of an augmented reality solution for BIM models suitable for construction sites.

Keywords: building information modeling, digital factory model, factory planning, restructuring

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8044 Numerical Study of Laminar Separation Bubble Over an Airfoil Using γ-ReθT SST Turbulence Model on Moderate Reynolds Number

Authors: Younes El Khchine, Mohammed Sriti

Abstract:

A parametric study has been conducted to analyse the flow around S809 airfoil of wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds number by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using γ-Reθt turbulence model. Two-dimensional study was conducted for the chord Reynolds number of 1×105 and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of laminar separation bubble and aerodynamic performances of wind turbine. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerate transition process and the turbulent reattachment point move closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase of the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to moves upstream to leading edge of the airfoil that causes earlier laminar separation.

Keywords: laminar separation bubble, turbulence intensity, S809 airfoil, transition model, Reynolds number

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8043 Suitable Models and Methods for the Steady-State Analysis of Multi-Energy Networks

Authors: Juan José Mesas, Luis Sainz

Abstract:

The motivation for the development of this paper lies in the need for energy networks to reduce losses, improve performance, optimize their operation and try to benefit from the interconnection capacity with other networks enabled for other energy carriers. These interconnections generate interdependencies between some energy networks and others, which requires suitable models and methods for their analysis. Traditionally, the modeling and study of energy networks have been carried out independently for each energy carrier. Thus, there are well-established models and methods for the steady-state analysis of electrical networks, gas networks, and thermal networks separately. What is intended is to extend and combine them adequately to be able to face in an integrated way the steady-state analysis of networks with multiple energy carriers. Firstly, the added value of multi-energy networks, their operation, and the basic principles that characterize them are explained. In addition, two current aspects of great relevance are exposed: the storage technologies and the coupling elements used to interconnect one energy network with another. Secondly, the characteristic equations of the different energy networks necessary to carry out the steady-state analysis are detailed. The electrical network, the natural gas network, and the thermal network of heat and cold are considered in this paper. After the presentation of the equations, a particular case of the steady-state analysis of a specific multi-energy network is studied. This network is represented graphically, the interconnections between the different energy carriers are described, their technical data are exposed and the equations that have previously been presented theoretically are formulated and developed. Finally, the two iterative numerical resolution methods considered in this paper are presented, as well as the resolution procedure and the results obtained. The pros and cons of the application of both methods are explained. It is verified that the results obtained for the electrical network (voltages in modulus and angle), the natural gas network (pressures), and the thermal network (mass flows and temperatures) are correct since they comply with the distribution, operation, consumption and technical characteristics of the multi-energy network under study.

Keywords: coupling elements, energy carriers, multi-energy networks, steady-state analysis

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8042 The Current Development and Legislation on the Acquisition and Use of Nuclear Energy in Contemporary International Law

Authors: Uche A. Nnawulezi

Abstract:

Over the past decades, the acquisition and utilization of nuclear energy have remained a standout amongst the most intractable issues which past world leaders have unsuccessfully endeavored to grapple with. This study analyzes the present advancement and enactment on the acquisition and utilization of nuclear energy in contemporary international law. It seeks to address international co-operations in the field of nuclear energy by looking at what nuclear energy is all about and how it came into being. It also seeks to address concerns expressed by a few researchers on the position of nuclear law in the most extensive domain of the law by looking at the authoritative procedure for nuclear law, system of arrangements and traditions. This study also agrees in favour of treaty on non-proliferation of nuclear weapons based on human right and humanitarian principles that are not duly moral, but also legal ones. Specifically, the past development activities on nuclear weapon and the practical system of the nuclear energy institute will be inspected. The study noted among others, former president Obama's remark on nuclear energy and Pakistan nuclear policies and its attendant outcomes. Essentially, we depended on documentary evidence and henceforth scooped a great part of the data from secondary sources. The study emphatically advocates for the adoption of absolute liability principles and setting up of a viability trust fund, all of which will help in sustaining global peace where global best practices in acquisition and use of nuclear energy will be widely accepted in the contemporary international law. Essentially, the fundamental proposals made in this paper if completely adopted, might go far in fortifying the present advancement and enactment on the application and utilization of nuclear energy and accordingly, addressing a portion of the intractable issues under international law.

Keywords: nuclear energy, international law, acquisition, development

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8041 Cellular Energy Metabolism Decreases with Age in the Trophocytes and Oenocytes of Honeybees (Apis Mellifera)

Authors: Chin-Yuan Hsu, Yu-Lung Chuang

Abstract:

The expression, concentration, and activity of mitochondrial energy-utilized molecules and cellular energy-regulated molecules decreased with age in the trophocytes and oenocytes of honeybees (Apis mellifera), but those of cellular energy-metabolized molecules is unknown. In this study, the expression, concentration, and activity of cellular energy-metabolized molecules were assayed in the trophocytes and fat cells of young and old worker bees by using the techniques of cell and biochemistry. The results showed that (i) the •-hydroxylacyl-coenzyme A dehydrogenase (HOAD) activity/citrate synthase (CS) activity ratio, non-esterified fatty acids concentrations, the expression of eukaryotic initiation factor 4E, and the expression of phosphorylated eIF4E binding protein 1 decreased with age; (ii) fat and glycogen accumulation increased with age; and (iii) the pyruvate dehydrogenase (PDH) activity/citrate synthase (CS) activity ratio was not correlated with age. These finding indicated that •-oxidation (HOAD/CS) and protein synthsis decreased with age. Glycolysis (PDH/CS) was unchanged with age. The most likely reason is that sugars are the vital food of worker bees. Taken together these data reveal that young workers have higher cellular energy metabolism than old workers and that aging results in a decline in the cellular energy metabolism in worker honeybees.

Keywords: aging, energy, honeybee, metabolism

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8040 Harnessing Earth's Electric Field and Transmission of Electricity

Authors: Vaishakh Medikeri

Abstract:

Energy in this Universe is the most basic characteristic of every particle. Since the birth of life on this planet, there has been a quest undertaken by the living beings to analyze, understand and harness the precious natural facts of the nature. In this quest, one of the greatest undertaken is the process of harnessing the naturally available energy. Scientists around the globe have discovered many ways to harness the freely available energy. But even today we speak of “Power Crisis”. Nikola Tesla once said “Nature has stored up in this universe infinite energy”. Energy is everywhere around us in unlimited quantities; all of it waiting to be harnessed by us. Here in this paper a method has been proposed to harness earth's electric field and transmit the stored electric energy using strong magnetic fields and electric fields. In this paper a new technique has been proposed to harness earth's electric field which is everywhere around the world in infinite quantities. Near the surface of the earth there is an electric field of about 120V/m. This electric field is used to charge a capacitor with high capacitance. Later the energy stored is allowed to pass through a device which converts the DC stored into AC. The AC so produced is then passed through a step down transformer to magnify the incoming current. Later the current passes through the RLC circuit. Later the current can be transmitted wirelessly using the principle of resonant inductive coupling. The proposed apparatus can be placed in most of the required places and any circuit tuned to the frequency of the transmitted current can receive the energy. The new source of renewable energy is of great importance if implemented since the apparatus is not costly and can be situated in most of the required places. And also the receiver which receives the transmitted energy is just an RLC circuit tuned to the resonant frequency of the transmitted energy. By using the proposed apparatus the energy losses can be reduced to a very large extent.

Keywords: capacitor, inductive resonant coupling, RLC circuit, transmission of electricity

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8039 Performance of Nakagami Fading Channel over Energy Detection Based Spectrum Sensing

Authors: M. Ranjeeth, S. Anuradha

Abstract:

Spectrum sensing is the main feature of cognitive radio technology. Spectrum sensing gives an idea of detecting the presence of the primary users in a licensed spectrum. In this paper we compare the theoretical results of detection probability of different fading environments like Rayleigh, Rician, Nakagami-m fading channels with the simulation results using energy detection based spectrum sensing. The numerical results are plotted as P_f Vs P_d for different SNR values, fading parameters. It is observed that Nakagami fading channel performance is better than other fading channels by using energy detection in spectrum sensing. A MATLAB simulation test bench has been implemented to know the performance of energy detection in different fading channel environment.

Keywords: spectrum sensing, energy detection, fading channels, probability of detection, probability of false alarm

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8038 Retrofitting Measures for Existing Housing Stock in Kazakhstan

Authors: S. Yessengabulov, A. Uyzbayeva

Abstract:

Residential buildings fund of Kazakhstan was built in the Soviet time about 35-60 years ago without considering energy efficiency measures. Currently, most of these buildings are in a rundown condition and fail to meet the minimum of hygienic, sanitary and comfortable living requirements. The paper aims to examine the reports of recent building energy survey activities in the country and provide a possible solution for retrofitting existing housing stock built before 1989 which could be applicable for building envelope in cold climate. Methodology also includes two-dimensional modeling of possible practical solutions and further recommendations.

Keywords: energy audit, energy efficient buildings in Kazakhstan, retrofit, two-dimensional conduction heat transfer analysis

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8037 Risk Assessment Results in Biogas Production from Agriculture Biomass

Authors: Sandija Zeverte-Rivza, Irina Pilvere, Baiba Rivza

Abstract:

The use of renewable energy sources incl. biogas has become topical in accordance with the increasing demand for energy, decrease of fossil energy resources and the efforts to reduce greenhouse gas emissions as well as to increase energy independence from the territories where fossil energy resources are available. As the technologies of biogas production from agricultural biomass develop, risk assessment and risk management become necessary for farms producing such a renewable energy. The need for risk assessments has become particularly topical when discussions on changing the biogas policy in the EU take place, which may influence the development of the sector in the future, as well as the operation of existing biogas facilities and their income level. The current article describes results of the risk assessment for farms producing biomass from agriculture biomass in Latvia, the risk assessment system included 24 risks, that affect the whole biogas production process and the obtained results showed the high significance of political and production risks.

Keywords: biogas production, risks, risk assessment, biosystems engineering

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8036 Theoretical and Numerical Investigation of a Tri-Stable Nonlinear Energy Harvesting System in Rotational Motion for Low Frequency Environment

Authors: Mei Xutao, Nakano Kimihiko

Abstract:

In order to enhance the energy harvesting efficiency, this paper presents a novel tri-stable energy harvesting system (TEHS), which is realized by the effect of magnetic force, in rotational motion to scavenge vibration energy. The device is meant to provide the power supply for wireless autonomous systems in low-frequency environment. The nonlinear TEHS is composed of the cantilever beam which is mounted on a rotating hub and partially covered by piezoelectric patch, a tip mass magnet in the end and two fixed magnets. A theoretical investigation using the Lagrangian formulation is derived to describe the motion of the energy harvesting system and the output voltage. Additionally, several numerical simulations were carried out to characterize the system under different external excitations and to validate its performance. The results demonstrated that TEHS owns a wide range of frequency of snap-through and high output voltage compared with the bi-stable energy harvesting system (BEHS). Moreover, some sets of experimental validations will be performed in the future work because the experimental setup is in the configuration now.

Keywords: piezoelectric beam, rotational motion, snap-through, tri-stable energy harvester

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8035 Effective Water Purification by Impregnated Carbon Nanotubes

Authors: Raviteja Chintala

Abstract:

Water shortage in many areas of the world have predominantly increased the demand for efficient methods involved in the production of drinking water, So purification of water invoking cost effective and efficient methods is a challenging field of research. In this regard, Reverse osmosis membrane desalination of both seawater and inland brackish water is currently being deployed in various locations around the world. In the present work an attempt is made to integrate these existing technologies with novel method, Wherein carbon nanotubes at the lab scale are prepared which further replace activated carbon tubes being used traditionally. This has proven to enhance the efficiency of the water filter, Effectively neutralising most of the organic impurities. Furthermore, This ensures the reduction in TDS. Carbon nanotubes have wide range in scope of applications such as composite reinforcements, Field emitters, Sensors, Energy storage and energy conversion devices and catalysts support phases, Because of their unusual mechanical, Electrical, Thermal and structural properties. In particular, The large specific surface area, as well as the high chemical and thermal stability, Makes carbon nanotube an attractive adsorbent in waste water treatment. Carbon nanotubes are effective in eliminating these harmful media from water as an adsorbent. In this work, Candle soot method has been incorporated for the preparation of carbon nanotubes and mixed with activated charcoal in different compositions. The effect of composition change is monitored by using TDS measuring meter. As the composition of Nano carbon increases, The TDS of the water gradually decreases. In order to enhance the life time for carbon filter, Nano tubes are provided with larger surface area.

Keywords: TDS (Total Dissolved Solids), carbon nanotubes, water, candle soot

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8034 Gasification of Groundnut Shell in an Air Bubbling Fluidized Bed Gasifier

Authors: Dharminer Singh, Sanjeev Yadav, Pravakar Mohanty

Abstract:

In this work, gasification of groundnut shell was carried out in an air bubbling fluidized bed gasifier. Atmospheric air used as gasification agent in the gasifier. The groundnut shell used for gasification was in powder form and the locally available river sand was used as bed material. Conventional charcoal was used for heating sand bed. Two cyclones were used for proper segregation of char particles and for proper cleaning and cooling the product gas. Experiments were performed on different equivalence ratio (ER) 0.3 - 0.33 by varying feeding rate 36 - 32.8 kg/h of biomass and by keeping the air flow rate constant at bed temperature between 700 °C – 800 °C. Performance of gasifier was evaluated on the basis of different parameters such as cold gas efficiency, carbon conversion efficiency (CCE), Tar and Suspended particles matter (SPM) generation, gas yield, and Higher heating value (HHV) of gas. The optimal ER value for gasification of groundnut shell (GNS) powder in an air bubbling fluidized bed gasifier was found to be 0.31. Cold gas efficiency and CCE value at optimal ER was found to be 63.7 %, and 91 %, respectively. Concentration of Tar and SPM, HHV of gas, and gas yield at optimal ER was found to be 11.88 g/Nm3, 2.38 MJ/Nm3, and 2.01m3/kg, respectively. In the product gas, concentrations of CO, CO2, CH4 and H2 were found to be 12.94%, 13.5%, 5.74% and 13.77%, respectively. At ER 0.31, it was observed that bed temperature of gasifier was in steady state for long time at 714 °C with 5 – 10 °C fluctuation.

Keywords: air bubbling fluidized bed gasifier, groundnut shell powder, equivalence ratio (ER), cold gas efficiency, carbon conversion efficiency (CCE), high heating value (HHV)

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8033 Economic Assessment of CO2-Based Methane, Methanol and Polyoxymethylene Production

Authors: Wieland Hoppe, Nadine Wachter, Stefan Bringezu

Abstract:

Carbon dioxide (CO2) utilization might be a promising way to substitute fossil raw materials like coal, oil or natural gas as carbon source of chemical production. While first life cycle assessments indicate a positive environmental performance of CO2-based process routes, a commercialization of CO2 is limited by several economic obstacles up to now. We, therefore, analyzed the economic performance of the three CO2-based chemicals methane and methanol as basic chemicals and polyoxymethylene as polymer on a cradle-to-gate basis. Our approach is oriented towards life cycle costing. The focus lies on the cost drivers of CO2-based technologies and options to stimulate a CO2-based economy by changing regulative factors. In this way, we analyze various modes of operation and give an outlook for the potentially cost-effective development in the next decades. Biogas, waste gases of a cement plant, and flue gases of a waste incineration plant are considered as CO2-sources. The energy needed to convert CO2 into hydrocarbons via electrolysis is assumed to be supplied by wind power, which is increasingly available in Germany. Economic data originates from both industrial processes and process simulations. The results indicate that CO2-based production technologies are not competitive with conventional production methods under present conditions. This is mainly due to high electricity generation costs and regulative factors like the German Renewable Energy Act (EEG). While the decrease in production costs of CO2-based chemicals might be limited in the next decades, a modification of relevant regulative factors could potentially promote an earlier commercialization.

Keywords: carbon capture and utilization (CCU), economic assessment, life cycle costing (LCC), power-to-X

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8032 The Energy Consumption by the Sector of Transport and His Impact on the Atmospheric Pollution

Authors: Mme Hamani Née Guessas Ghaniya

Abstract:

The transport is the base of the development of the exchanges and the business, being both a recognized determiner of the economic and social development. The development of the transport is in the center of the big challenges of development of countries, but it is also at the heart of big contradictions, since we integrate the environmental issues which are bound to him, in particular through the questions of energy. Indeed, the energy consumption by the sector of transport is one of bigger concerns, because it is increasing and it has a big impact on our environment. The main consequences are, the atmospheric pollution causing an increase of the greenhouse effect which causes a global warming. These global warming risks to engender a partial cast iron of polar caps so raising the level of seas, flooding the low coastal zones, certain islands and the deltas. Thus, the purpose of this communication is to present the impact of the energy consumption by the sector of transport on the air quality, showing its effect on the health and on the global warming.

Keywords: energy consumption, sector of transport, air quality, atmospheric pollution

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8031 Reducing Energy Consumption in Architectural Spaces by Optimizing Natural Light Transmission

Authors: Parisa Javid

Abstract:

In architecture, daylight contributes to humans' mental and physical well-being and reduces the consumption of fossil fuels. Accordingly, Iran's rich architecture has valuable achievements and experiences that should be recognized and introduced to the Iranian and international architecture communities. There are many ways to reduce energy consumption in buildings, but electricity accounts for a large part of that consumption. Lighting up spaces with natural light is a significant factor in reducing energy consumption and preventing electricity dissipation. Aside from being expensive, electric lighting systems cause excessive heat and physical injury (eyes). This study is based on library records and documents. Modern lighting systems are used to reduce energy consumption in the interior of a building to allow for optimal transmission of natural light. It discusses how to use natural light in architecture and the benefits of natural light in buildings. Solar energy can be used more efficiently, and electrical power can be saved in residential, administrative, commercial, and educational buildings by using new methods such as light tubes and mirror directors. Modern lighting systems, natural light, and reduced energy consumption are keywords for these systems, which quickly return their investment.

Keywords: modern lighting systems, natural light, reduced energy consumption

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8030 Efficient Use of Energy through Incorporation of a Gas Turbine in Methanol Plant

Authors: M. Azadi, N. Tahouni, M. H. Panjeshahi

Abstract:

A techno-economic evaluation for efficient use of energy in a large scale industrial plant of methanol is carried out. This assessment is based on integration of a gas turbine with an existing plant of methanol in which the outlet gas products of exothermic reactor is expanded to power generation. Also, it is decided that methanol production rate is constant through addition of power generation system to the existing methanol plant. Having incorporated a gas turbine with the existing plant, the economic results showed total investment of MUSD 16.9, energy saving of 3.6 MUSD/yr with payback period of approximately 4.7 years.

Keywords: energy saving, methanol, gas turbine, power generation

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8029 Assessing Efficiency Trends in the Indian Sugar Industry

Authors: S. P. Singh

Abstract:

This paper measures technical and scale efficiencies of 40 Indian sugar companies for the period from 2004-05 to 2013-14. The efficiencies are estimated through input-oriented DEA models using one output variable—value of output (VOP) and five input variables—capital cost (CA), employee cost (EMP), raw material (RW), energy & fuel (E&F) and other manufacturing expenses (OME). The sugar companies are classified into integrated and non-integrated categories to know which one achieves higher level of efficiency. Sources of inefficiency in the industry are identified through decomposing the overall technical efficiency (TE) into pure technical efficiency (PTE) and scale efficiency (SE). The paper also estimates input-reduction targets for relatively inefficient companies and suggests measures to improve their efficiency level. The findings reveal that the TE does not evince any trend rather it shows fluctuations across years, largely due to erratic and cyclical pattern of sugar production. Further, technical inefficiency in the industry seems to be driven more by the managerial inefficiency than the scale inefficiency, which implies that TE can be improved through better conversion of inputs into output.

Keywords: DEA, slacks, sugar industry, technical efficiency

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8028 Impact of Global Climate Change on Economy of Pakistan: How to Ensure Sustainable Food and Energy Production

Authors: Sabahat Zahra

Abstract:

The purpose of this research is to present the changing global environment and its potential impacts on sustainable food and energy production at global level, particularly in Pakistan. The food and energy related-economic sector has been subjected to negative consequences due to recent extreme changes in weather conditions, particularly in developing countries. Besides continuous modifications in weather, population is also increasing by time, therefore it is necessary to take special steps and start effective initiatives to cope with the challenges of food and energy security to fight hunger and for economic stability of country. Severe increase in temperature and heat waves has also negative impacts on food production as well as energy sustainability. Energy (in terms of electricity) consumption has grown up than the production potential of the country as a consequence of increasing warm weather. Ultimately prices gone up when there is more consumption than production. Therefore, all these aspects of climate change are interrelated with socio-economic issues. There is a need to develop long-term policies on regional and national levels for maintainable economic growth. This research presents a framework-plan and recommendations for implementation needed to mitigate the potential threats due to global climate change sustainable food and energy production under climate change in the country.

Keywords: climate changes, energy security, food security, global climate change

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8027 Energy Calculation for Excited Lithium Atom in Position Space

Authors: Khalil H. Al-Bayati, Khalid Omar Al-Baiti

Abstract:

The energy expectation value for Li-like ions systems (Li, Be+ and Be2+) hasbeen calculated and examined within the ground state (1s2sα)^2 S and the excited state (1s3sα)^2 S in position space. The partitioning technique of Hartree-Fock (H-F) has been used for existing wavefnctions.

Keywords: energy expectation value, atomic systems, ground and excited states, Hartree-Fock approximation

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8026 Research of the Activation Energy of Conductivity in P-I-N SiC Structures Fabricated by Doping with Aluminum Using the Low-Temperature Diffusion Method

Authors: Ilkham Gafurovich Atabaev, Khimmatali Nomozovich Juraev

Abstract:

The activation energy of conductivity in p-i-n SiC structures fabricated by doping with Aluminum using the new low-temperature diffusion method is investigated. In this method, diffusion is stimulated by the flux of carbon and silicon vacancies created by surface oxidation. The activation energy of conductivity in the p - layer is 0.25 eV and it is close to the ionization energy of Aluminum in 4H-SiC from 0.21 to 0.27 eV for the hexagonal and cubic positions of aluminum in the silicon sublattice for weakly doped crystals. The conductivity of the i-layer (measured in the reverse biased diode) shows 2 activation energies: 0.02 eV and 0.62 eV. Apparently, the 0.62 eV level is a deep trap level and it is a complex of Aluminum with a vacancy. According to the published data, an analogous level system (with activation energies of 0.05, 0.07, 0.09 and 0.67 eV) was observed in the ion Aluminum doped 4H-SiC samples.

Keywords: activation energy, aluminum, low temperature diffusion, SiC

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8025 Exploring the Viability of Biogas Energy Potential in South Africa

Authors: Solomon Eghosa Uhunamure, Karabo Shale

Abstract:

Biogas technology has emerged as a promising solution for sustainable development, enhancing energy security while mitigating environmental hazards. Interest in biogas for household energy is growing due to its potential to address both energy and waste management challenges. To ensure biogas production contributes meaningfully to South Africa's future energy landscape, understanding public perceptions is essential for shaping effective policy measures. A household survey revealed that lower awareness of biogas correlates with reduced social and cultural acceptance, however, after providing basic information—such as a definition, a diagram, or one of two simple messages—support for biogas increased by 10% to 15% compared to the baseline. These findings highlight the critical role of awareness in building support for biogas as a key component of South Africa's decarbonization strategy.

Keywords: awareness, barriers, biogas, environmental benefits, South Africa

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8024 Calculating All Dark Energy and Dark Matter Effects through Dynamic Gravity Theory

Authors: Sean Michael Kinney

Abstract:

In 1666, Newton created the Law of Universal Gravitation. And in 1915, Einstein improved it to incorporate factors such as time dilation and gravitational lensing. But currently, there is a problem with this “universal” law. The math doesn’t work outside the confines of our solar system. And something is missing; any evidence of what gravity actually is and how it manifests. This paper explores the notion that gravity must obey the law of conservation of energy as all other forces in this universe have been shown to do. Explaining exactly what gravity is and how it manifests itself. And looking at many different implications that would be created are explained. And finally, use the math of Dynamic gravity to calculate Dark Energy and Dark Matter effects to explain all observations without the need for exotic measures.

Keywords: dynamic gravity, gravity, dark matter, dark energy

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8023 The Impact of Undisturbed Flow Speed on the Correlation of Aerodynamic Coefficients as a Function of the Angle of Attack for the Gyroplane Body

Authors: Zbigniew Czyz, Krzysztof Skiba, Miroslaw Wendeker

Abstract:

This paper discusses the results of aerodynamic investigation of the Tajfun gyroplane body designed by a Polish company, Aviation Artur Trendak. This gyroplane has been studied as a 1:8 scale model. Scaling objects for aerodynamic investigation is an inherent procedure in any kind of designing. If scaling, the criteria of similarity need to be satisfied. The basic criteria of similarity are geometric, kinematic and dynamic. Despite the results of aerodynamic research are often reduced to aerodynamic coefficients, one should pay attention to how values of coefficients behave if certain criteria are to be satisfied. To satisfy the dynamic criterion, for example, the Reynolds number should be focused on. This is the correlation of inertial to viscous forces. With the multiplied flow speed by the specific dimension as a numerator (with a constant kinematic viscosity coefficient), flow speed in a wind tunnel research should be increased as many times as an object is decreased. The aerodynamic coefficients specified in this research depend on the real forces that act on an object, its specific dimension, medium speed and variations in its density. Rapid prototyping with a 3D printer was applied to create the research object. The research was performed with a T-1 low-speed wind tunnel (its diameter of the measurement volume is 1.5 m) and a six-element aerodynamic internal scales, WDP1, at the Institute of Aviation in Warsaw. This T-1 wind tunnel is low-speed continuous operation with open space measurement. The research covered a number of the selected speeds of undisturbed flow, i.e. V = 20, 30 and 40 m/s, corresponding to the Reynolds numbers (as referred to 1 m) Re = 1.31∙106, 1.96∙106, 2.62∙106 for the angles of attack ranging -15° ≤ α ≤ 20°. Our research resulted in basic aerodynamic characteristics and observing the impact of undisturbed flow speed on the correlation of aerodynamic coefficients as a function of the angle of attack of the gyroplane body. If the speed of undisturbed flow in the wind tunnel changes, the aerodynamic coefficients are significantly impacted. At speed from 20 m/s to 30 m/s, drag coefficient, Cx, changes by 2.4% up to 9.9%, whereas lift coefficient, Cz, changes by -25.5% up to 15.7% if the angle of attack of 0° excluded or by -25.5% up to 236.9% if the angle of attack of 0° included. Within the same speed range, the coefficient of a pitching moment, Cmy, changes by -21.1% up to 7.3% if the angles of attack -15° and -10° excluded or by -142.8% up to 618.4% if the angle of attack -15° and -10° included. These discrepancies in the coefficients of aerodynamic forces definitely need to consider while designing the aircraft. For example, if load of certain aircraft surfaces is calculated, additional correction factors definitely need to be applied. This study allows us to estimate the discrepancies in the aerodynamic forces while scaling the aircraft. This work has been financed by the Polish Ministry of Science and Higher Education.

Keywords: aerodynamics, criteria of similarity, gyroplane, research tunnel

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8022 Sustainable Production of Algae through Nutrient Recovery in the Biofuel Conversion Process

Authors: Bagnoud-Velásquez Mariluz, Damergi Eya, Grandjean Dominique, Frédéric Vogel, Ludwig Christian

Abstract:

The sustainability of algae to biofuel processes is seriously affected by the energy intensive production of fertilizers. Large amounts of nitrogen and phosphorus are required for a large-scale production resulting in many cases in a negative impact of the limited mineral resources. In order to meet the algal bioenergy opportunity it appears crucial the promotion of processes applying a nutrient recovery and/or making use of renewable sources including waste. Hydrothermal (HT) conversion is a promising and suitable technology for microalgae to generate biofuels. Besides the fact that water is used as a “green” reactant and solvent and that no biomass drying is required, the technology offers a great potential for nutrient recycling. This study evaluated the possibility to treat the water HT effluent by the growth of microalgae while producing renewable algal biomass. As already demonstrated in previous works by the authors, the HT aqueous product besides having N, P and other important nutrients, presents a small fraction of organic compounds rarely studied. Therefore, extracted heteroaromatic compounds in the HT effluent were the target of the present research; they were profiled using GC-MS and LC-MS-MS. The results indicate the presence of cyclic amides, piperazinediones, amines and their derivatives. The most prominent nitrogenous organic compounds (NOC’s) in the extracts were carefully examined by their effect on microalgae, namely 2-pyrrolidinone and β-phenylethylamine (β-PEA). These two substances were prepared at three different concentrations (10, 50 and 150 ppm). This toxicity bioassay used three different microalgae strains: Phaeodactylum tricornutum, Chlorella sorokiniana and Scenedesmus vacuolatus. The confirmed IC50 was for all cases ca. 75ppm. Experimental conditions were set up for the growth of microalgae in the aqueous phase by adjusting the nitrogen concentration (the key nutrient for algae) to fit that one established for a known commercial medium. The values of specific NOC’s were lowered at concentrations of 8.5 mg/L 2-pyrrolidinone; 1mg/L δ-valerolactam and 0.5 mg/L β-PEA. The growth with the diluted HT solution was kept constant with no inhibition evidence. An additional ongoing test is addressing the possibility to apply an integrated water cleanup step making use of the existent hydrothermal catalytic facility.

Keywords: hydrothermal process, microalgae, nitrogenous organic compounds, nutrient recovery, renewable biomass

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8021 Development of Energy Management System Based on Internet of Things Technique

Authors: Wen-Jye Shyr, Chia-Ming Lin, Hung-Yun Feng

Abstract:

The purpose of this study was to develop an energy management system for university campuses based on the Internet of Things (IoT) technique. The proposed IoT technique based on WebAccess is used via network browser Internet Explore and applies TCP/IP protocol. The case study of IoT for lighting energy usage management system was proposed. Structure of proposed IoT technique included perception layer, equipment layer, control layer, application layer and network layer.

Keywords: energy management, IoT technique, sensor, WebAccess

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8020 Flow Separation Control on an Aerofoil Using Grooves

Authors: Neel K. Shah

Abstract:

Wind tunnel tests have been performed at The University of Manchester to investigate the impact of surface grooves of a trapezoidal planform on flow separation on a symmetrical aerofoil. A spanwise array of the grooves has been applied around the maximum thickness location of the upper surface of an NACA-0015 aerofoil. The aerofoil has been tested in a two-dimensional set-up in a low-speed wind tunnel at an angle of attack (AoA) of 3° and a chord-based Reynolds number (Re) of ~2.7 x 105. A laminar separation bubble developed on the aerofoil at low AoA. It has been found that the grooves shorten the streamwise extent of the separation bubble by shedding a pair of counter-rotating vortices. However, the increase in leading-edge suction due to the shorter bubble is not significant since the creation of the grooves results in a decrease of surface curvature and an increase in blockage (increase in surface pressure). Additionally, the increased flow mixing by the grooves thickens the boundary layer near the trailing edge of the aerofoil also contributes to this limitation. As a result of these competing effects, the improvement in the pressure-lift and pressure-drag coefficients are small, i.e., by ~1.30% and ~0.30%, respectively, at 3° AoA. Crosswire anemometry shows that the grooves increase turbulence intensity and Reynolds stresses in the wake, thus indicating an increase in viscous drag.

Keywords: aerofoil flow control, flow separation, grooves, vortices

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8019 A Modular Reactor for Thermochemical Energy Storage Examination of Ettringite-Based Materials

Authors: B. Chen, F. Kuznik, M. Horgnies, K. Johannes, V. Morin, E. Gengembre

Abstract:

More attention on renewable energy has been done after the achievement of Paris Agreement against climate change. Solar-based technology is supposed to be one of the most promising green energy technologies for residential buildings since its widely thermal usage for hot water and heating. However, the seasonal mismatch between its production and consumption makes buildings need an energy storage system to improve the efficiency of renewable energy use. Indeed, there exist already different kinds of energy storage systems using sensible or latent heat. With the consideration of energy dissipation during storage and low energy density for above two methods, thermochemical energy storage is then recommended. Recently, ettringite (3CaO∙Al₂O₃∙3CaSO₄∙32H₂O) based materials have been reported as potential thermochemical storage materials because of high energy density (~500 kWh/m³), low material cost (700 €/m³) and low storage temperature (~60-70°C), compared to reported salt hydrates like SrBr₂·6H₂O (42 k€/m³, ~80°C), LaCl₃·7H₂O (38 k€/m³, ~100°C) and MgSO₄·7H₂O (5 k€/m³, ~150°C). Therefore, they have the possibility to be largely used in building sector with being coupled to normal solar panel systems. On the other side, the lack in terms of extensive examination leads to poor knowledge on their thermal properties and limit maturity of this technology. The aim of this work is to develop a modular reactor adapting to thermal characterizations of ettringite-based material particles of different sizes. The filled materials in the reactor can be self-compacted vertically to ensure hot air or humid air goes through homogenously. Additionally, quick assembly and modification of reactor, like LEGO™ plastic blocks, make it suitable to distinct thermochemical energy storage material samples with different weights (from some grams to several kilograms). In our case, quantity of stored and released energy, best work conditions and even chemical durability of ettringite-based materials have been investigated.

Keywords: dehydration, ettringite, hydration, modular reactor, thermochemical energy storage

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8018 Energy Retrofitting Application Research to Achieve Energy Efficiency in Hot-Arid Climates in Residential Buildings: A Case Study of Saudi Arabia

Authors: A. Felimban, A. Prieto, U. Knaack, T. Klein

Abstract:

This study aims to present an overview of recent research in building energy-retrofitting strategy applications and analyzing them within the context of hot arid climate regions which is in this case study represented by the Kingdom of Saudi Arabia. The main goal of this research is to do an analytical study of recent research approaches to show where the primary gap in knowledge exists and outline which possible strategies are available that can be applied in future research. Also, the paper focuses on energy retrofitting strategies at a building envelop level. The study is limited to specific measures within the hot arid climate region. Scientific articles were carefully chosen as they met the expression criteria, such as retrofitting, energy-retrofitting, hot-arid, energy efficiency, residential buildings, which helped narrow the research scope. Then the papers were explored through descriptive analysis and justified results within the Saudi context in order to draw an overview of future opportunities from the field of study for the last two decades. The conclusions of the analysis of the recent research confirmed that the field of study had a research shortage on investigating actual applications and testing of newly introduced energy efficiency applications, lack of energy cost feasibility studies and there was also a lack of public awareness. In terms of research methods, it was found that simulation software was a major instrument used in energy retrofitting application research. The main knowledge gaps that were identified included the need for certain research regarding actual application testing; energy retrofitting strategies application feasibility; the lack of research on the importance of how strategies apply first followed by the user acceptance of developed scenarios.

Keywords: energy efficiency, energy retrofitting, hot arid, Saudi Arabia

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8017 Catalytic Dehydrogenation of Formic Acid into H2/CO2 Gas: A Novel Approach

Authors: Ayman Hijazi, Witold Kwapinski, J. J. Leahy

Abstract:

Finding a sustainable alternative energy to fossil fuel is an urgent need as various environmental challenges in the world arise. Therefore, formic acid (FA) decomposition has been an attractive field that lies at the center of biomass platform, comprising a potential pool of hydrogen energy that stands as a new energy vector. Liquid FA features considerable volumetric energy density of 6.4 MJ/L and a specific energy density of 5.3 MJ/Kg that qualifies it in the prime seat as an energy source for transportation infrastructure. Additionally, the increasing research interest in FA decomposition is driven by the need of in-situ H2 production, which plays a key role in the hydrogenation reactions of biomass into higher value components. It is reported elsewhere in literature that catalytic decomposition of FA is usually performed in poorly designed setup using simple glassware under magnetic stirring, thus demanding further energy investment to retain the used catalyst. it work suggests an approach that integrates designing a novel catalyst featuring magnetic property with a robust setup that minimizes experimental & measurement discrepancies. One of the most prominent active species for dehydrogenation/hydrogenation of biomass compounds is palladium. Accordingly, we investigate the potential of engrafting palladium metal onto functionalized magnetic nanoparticles as a heterogeneous catalyst to favor the production of CO-free H2 gas from FA. Using ordinary magnet to collect the spent catalyst renders core-shell magnetic nanoparticles as the backbone of the process. Catalytic experiments were performed in a jacketed batch reactor equipped with an overhead stirrer under inert medium. Through a novel approach, FA is charged into the reactor via high-pressure positive displacement pump at steady state conditions. The produced gas (H2+CO2) was measured by connecting the gas outlet to a measuring system based on the amount of the displaced water. The novelty of this work lies in designing a very responsive catalyst, pumping consistent amount of FA into a sealed reactor running at steady state mild temperatures, and continuous gas measurement, along with collecting the used catalyst without the need for centrifugation. Catalyst characterization using TEM, XRD, SEM, and CHN elemental analyzer provided us with details of catalyst preparation and facilitated new venues to alter the nanostructure of the catalyst framework. Consequently, the introduction of amine groups has led to appreciable improvements in terms of dispersion of the doped metals and eventually attaining nearly complete conversion (100%) of FA after 7 hours. The relative importance of the process parameters such as temperature (35-85°C), stirring speed (150-450rpm), catalyst loading (50-200mgr.), and Pd doping ratio (0.75-1.80wt.%) on gas yield was assessed by a Taguchi design-of-experiment based model. Experimental results showed that operating at lower temperature range (35-50°C) yielded more gas while the catalyst loading and Pd doping wt.% were found to be the most significant factors with a P-values 0.026 & 0.031, respectively.

Keywords: formic acid decomposition, green catalysis, hydrogen, mesoporous silica, process optimization, nanoparticles

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8016 A Sustainable Energy Portfolio for Greater Kampala Metropolitan Area by the Mid-Century

Authors: Ismail Kimuli

Abstract:

With a steadfast economic development, the Greater Kampala metropolitan area (GKMA) faces increasing pressures to increasetheshare of low-carbon electricity in the energy balance, abate CO2 emissions and also restructure the transportation sector for a sustainable 2050. GKMA, is Uganda’s commercial, political, social, and industrial hub with a population of 4.1 million, contributing 60% tothe nation’s GDP and accounts for 80% of Uganda’s industrial sector.However, with the rampant anthropogenic interference that causes climate change, CO2 emissions in the metropolitan are contributing to global warming. Many economies across the globe are addressing this challengethrough development and analysis of sustainable energy portfolios.A sustainable energy portfolio is a low-carbon scenario. The study reviews the literature to establish the current energy management situation of GKMA and finds it wanting in addressing the immediate challenges associated with energy management of the metropolitan. Then, the study develops and examines a sustainable energy portfolio for GKMA using TIMES-VEDA and then presents it as an investigative low-carbon energy scenario that could propel the metropolitan sustainably towards 2050.Sustainability is plausible by optimizing the total primary energy supply, generating low-carbon electricity from hydropower and PV-solar renewables, improving heating technologies for residential & commercial sectors, and switching 90% of land passengers from road to a Kampala metro for a sustainable mid-century.

Keywords: GKMA, sustainability, TIMES-VEDA, low-carbon scenario

Procedia PDF Downloads 96