Готові списки джерел за темами / Energetic analysis at the national grid level

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Добірка наукової літератури з теми "Energetic analysis at the national grid level"

Автор: Grafiati

Опубліковано: 23 вересня 2022

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Статті в журналах з теми "Energetic analysis at the national grid level"

Duan, Chenghua, Chun Liu, Cheng Wang, and Xingye Yue. "Numerical complete solution for random genetic drift by energetic variational approach." ESAIM: Mathematical Modelling and Numerical Analysis 53, no. 2 (March 2019): 615–34. http://dx.doi.org/10.1051/m2an/2018058.

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In this paper, we focus on numerical solutions for random genetic drift problem, which is governed by a degenerated convection-dominated parabolic equation. Due to the fixation phenomenon of genes, Dirac delta singularities will develop at boundary points as time evolves. Based on an energetic variational approach (EnVarA), a balance between the maximal dissipation principle (MDP) and least action principle (LAP), we obtain the trajectory equation. In turn, a numerical scheme is proposed using a convex splitting technique, with the unique solvability (on a convex set) and the energy decay property (in time) justified at a theoretical level. Numerical examples are presented for cases of pure drift and drift with semi-selection. The remarkable advantage of this method is its ability to catch the Dirac delta singularity close to machine precision over any equidistant grid.

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Quintino, Filipe M., Nuno Nascimento, and Edgar C. Fernandes. "Aspects of Hydrogen and Biomethane Introduction in Natural Gas Infrastructure and Equipment." Hydrogen 2, no. 3 (August 10, 2021): 301–18. http://dx.doi.org/10.3390/hydrogen2030016.

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The injection of green hydrogen and biomethane is currently seen as the next step towards the decarbonization of the gas sector in several countries. However, the introduction of these gases in existent infrastructure has energetic, material and operational implications that should be carefully looked at. With regard to a fully blown green gas grid, transport and distribution will require adaptations. Furthermore, the adequate performance of end-use equipment connected to the grid must be accounted for. In this paper, a technical analysis of the energetic, material and operational aspects of hydrogen and biomethane introduction in natural gas infrastructure is performed. Impacts on gas transmission and distribution are evaluated and an interchangeability analysis, supported by one-dimensional Cantera simulations, is conducted. Existing gas infrastructure seems to be generally fit for the introduction of hydrogen and biomethane. Hydrogen content up to 20% by volume appears to be possible to accommodate in current infrastructure with only minor technical modifications. However, at the Distribution System Operator (DSO) level, the introduction of gas quality tracking systems will be required due to the distributed injection nature of hydrogen and biomethane. The different tolerances for hydrogen blending of consumers, depending on end-use equipment, may be critical during the transition period to a 100% green gas grid as there is a risk of pushing consumers off the grid.

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Rossitti, Marco, Marta Dell’Ovo, Alessandra Oppio, and Francesca Torrieri. "The Italian National Strategy for Inner Areas (SNAI): A Critical Analysis of the Indicator Grid." Sustainability 13, no. 12 (June 19, 2021): 6927. http://dx.doi.org/10.3390/su13126927.

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The National Strategy for Inner Areas (SNAI) is a public policy designed to tackle depopulation in inner areas, defined according to the distance from centers offering essential services. Such a policy’s success is crucial to address the new challenges for planning brought to light by the COVID-19 pandemic. In this sense, there is a need to adequately support its implementation by providing handy decision support tools, understanding the power balances among municipalities, and defining proper interventions. The Indicator Grid, already used by the SNAI for project areas selection, can answer this need. However, the Grid’s application to support public policy at the municipality level requires reviewing some of its features, such as the indicators’ large number and the impossibility of defining some of them at the municipal scale. Based on these premises, this paper aims at supporting inner areas policies by carrying out a critical analysis of the current SNAI Grid, aimed at improving its effectiveness. It relies on a hybrid methodology that merges qualitative data interpretations and statistical analyses. Thanks to this method, defining a parsimonious Grid by leaving its complexity and information level untouched is possible. The so-defined set of indicators can represent a valuable reference tool in pinpointing priorities for actions or selecting further territorial scopes from the SNAI perspective, even if it still brings some criticalities to be faced.

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Sun, Xiaoyan, and Wei Wei. "Intravitreal Conbercept with Grid/Focal Photocoagulation for the Treatment of Diabetic Macular Edema: A Systematic Review and Meta-Analysis." Journal of Ophthalmology 2022 (February 24, 2022): 1–9. http://dx.doi.org/10.1155/2022/2256779.

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Diabetic macular edema (DME) is the main cause of blindness in individuals with diabetes mellitus (DM). This meta-analysis compared the effectiveness and safety of macular grid/focal photocoagulation with and without conbercept in the treatment of DME. Studies were identified through systematic searches of PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure database, Wanfang Data Knowledge Service Platform, and VIP Information Resource Integration Service Platform from their earliest records to June 2021. Twelve articles involving 2600 patients with DME were included. Results showed that patients receiving conbercept with macular grid/focal photocoagulation had a statistically significant reduction in central macular thickness (CMT) over macular grid/focal photocoagulation alone at 1 month and 3 months post procedure. Compared with the control group, the combination therapy group had a significantly increased level of effectiveness and best-corrected visual acuity (BCVA) compared with the control group. The combination therapy group significantly increased the level of effectiveness and best-corrected visual acuity (BCVA) compared with the control group. Conbercept with macular grid/focal photocoagulation was more effective than macular grid/focal photocoagulation alone in terms of functional outcomes for DME treatment.

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Jędruch, Michalina, Marek Furmankiewicz, and Iwona Kaczmarek. "Spatial Analysis of Asymmetry in the Development of Tourism Infrastructure in the Borderlands: The Case of the Bystrzyckie and Orlickie Mountains." ISPRS International Journal of Geo-Information 9, no. 8 (July 26, 2020): 470. http://dx.doi.org/10.3390/ijgi9080470.

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This paper discusses the issue of analyzing the development of cross-border tourism infrastructure in the borderlands of countries with diversified administrative divisions and spatial databases, which hinders the use of national statistical units for comparative research. As an example, the ability to use the square grid and kernel density estimation methods for the analysis and spatial visualization of the level of tourism infrastructure development is studied for the Orlickie and Bystrzyckie Mountains, located in the Polish–Czech border area. To synthetically assess and compare the level of diversity, the methodology used in the Human Development Index was adapted using selected component indicators calculated for a square grid clipped to the boundaries of the area under study. This analysis enabled us to quantify the asymmetry in the development of tourism infrastructure in the borderlands via the calculation of the synthetic infrastructure development index. This index is 1.29 times higher in the Czech than in the Polish border area. However, the spatial concentration analysis of infrastructure shows that the diversity in the study area can be assessed as higher than the results using the average density indicators. This paper also discusses the benefits and problems associated with using the square grid method for the representation and analysis of heterogeneous data on tourism infrastructure in two neighboring national states.

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Dr. Sohaib Sultan. "Importance of Pre-Service Teacher Training and Need of Time to Strengthen at National Level." sjesr 3, no. 3 (September 30, 2020): 326–34. http://dx.doi.org/10.36902/sjesr-vol3-iss3-2020(326-334).

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The qualitative research had been carried on to highlight the importance of Pre-Service Teachers, Training programs in the country. It had been observing to underestimate the aforementioned subject during the last decade. For this purpose the topic was selected to carry on research to bring into limelight the importance of pre-service teachers’ training programs in the country. The document analysis was done to highlight the importance in the context of international scenario and its requirement in national grid. The recommendations were furnished accordingly.

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Zhang, Ruixiaoxiao, Meng Ni, Geoffrey Q. P. Shen, and Johnny K. W. Wong. "An analysis on the effectiveness and determinants of the wind power Feed-in-Tariff policy at China’s national-level and regional-grid-level." Sustainable Energy Technologies and Assessments 34 (August 2019): 87–96. http://dx.doi.org/10.1016/j.seta.2019.04.010.

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Sultan, Hamdy, Ahmed Diab, Oleg Kuznetsov, Ziad Ali, and Omer Abdalla. "Evaluation of the Impact of High Penetration Levels of PV Power Plants on the Capacity, Frequency and Voltage Stability of Egypt’s Unified Grid." Energies 12, no. 3 (February 11, 2019): 552. http://dx.doi.org/10.3390/en12030552.

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In this paper, the impact of integrating photovoltaic plants (PVPs) with high penetration levels into the national utility grid of Egypt is demonstrated. Load flow analysis is used to examine the grid capacity in the case of integrating the desired PVPs and computer simulations are also used to assess the upgrading of the transmission network to increase its capacity. Furthermore, the impact of increasing the output power generated from PVPs, during normal conditions, on the static voltage stability was explored. During transient conditions of operation (three-phase short circuit and outage of a large generating station), the impact of high penetration levels of PVPs on the voltage and frequency stability has been presented. Professional DIgSILENT PowerFactory simulation package was used for implementation of all simulation studies. The results of frequency stability analysis proved that the national grid could be maintained stable even when the PVPs reached a penetration level up to 3000 MW of the total generation in Egypt. Transmission network upgrading to accommodate up to 3000 MW from the proposed PV power plants by 2025 is suggested. In addition, analysis of voltage stability manifests that the dynamic behavior of the voltage depends remarkably on the short circuit capacity of the grid at the point of integrating the PVPs.

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Adnan, A. Z., M. E. Yusoff, and H. Hashim. "Analysis on the Impact of Renewable Energy to Power System Fault Level." Indonesian Journal of Electrical Engineering and Computer Science 11, no. 2 (August 1, 2018): 652. http://dx.doi.org/10.11591/ijeecs.v11.i2.pp652-657.

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Distributed Generation is generation of electricity from renewable energy resources, located closer to the customers or loads. Installation of Distributed Generation could improve voltage and power quality, mitigate voltage sags, minimize transmission system congestion, and provide more affordable capacity for utilizing renewable energy resources. However, high penetration of Distributed Generation to the existing national grid system may contribute several impacts including fault level, as well as the performance of power system protection. Monitoring of fault level is important in power system protection in order to sustain the health of power system networks. This paper investigates the impact of installing Distributed Generation to power system fault level. Three-phase symmetrical fault is simulated and analyzed for various sizes of distributed generation in IEEE 30 bus system using Power System Simulation for Engineering (PSS/E) software.<p class="MsoNormal" style="text-align: justify; text-indent: .5in;"><em><span style="font-size: 9.0pt; font-family: 'Arial','sans-serif'; color: black;">Distributed Generation is generation of electricity from renewable energy resources, located closer to the customers or loads. Installation of Distributed Generation could improve voltage and power quality, mitigate voltage sags, minimize transmission system congestion, and provide more affordable capacity for utilizing renewable energy resources. However, high penetration of Distributed Generation to the existing national grid system may contribute several impacts including fault level, as well as the performance of power system protection. Monitoring of fault level is important in power system protection in order to sustain the health of power system networks. This paper investigates the impact of installing Distributed Generation to power system fault level. Three-phase symmetrical fault is simulated and analyzed for various sizes of distributed generation in IEEE 30 bus system using Power System Simulation for Engineering (PSS/E) software.</span></em></p>

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Ren, Guizhou, Fangqing Li, Gang Liu, JianXin Ren, Yudong Liu, and Honghong Shen. "Study on the Development and Utilization of Renewable Energy in China." E3S Web of Conferences 136 (2019): 02013. http://dx.doi.org/10.1051/e3sconf/201913602013.

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With the continuous consumption of fossil energy and non-renewable, countries all over the world pay more and more attention to the use of renewable energy, among which Denmark, Japan, Germany and so on are among the best. Based on the basic national conditions and the energy development situation of our country, the utilization of renewable energy in our country is also promoted to the national strategic position. Experience shows that large-scale renewable energy access to the power grid system can not only meet the electricity demand of industrialized countries. Moreover, the safe and stable operation of the power grid can be realized by advanced technical means. Through the analysis of some advanced technology and equipment research in the development and utilization of renewable energy in foreign power grid, in order to improve the repeatability of our country, The level of development and utilization of raw energy.

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Дисертації з теми "Energetic analysis at the national grid level"

Saidi, Majdi. "Contribution à l'optimisation des systèmes hybrides de production énergétique à base de sources renouvelables." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0627.

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Cette thèse est une contribution à la conception optimale des systèmes hybrides pour la production énergétique. Les travaux proposés sont organisés en trois parties. La première partie consiste à étudier la possibilité d’intégrer des sous-réseaux constitués d’un ensemble de producteur-exploitant connectés au réseau principal. Le but est de renforcer la décentralisation de la production énergétique en tenant compte des besoins spécifiques et des disponibles de source renouvelable. Pour ce faire, l’approche consiste à optimiser le coût de l’installation, pour le producteur-exploitant, et les taux des subventions, assurées par l’état-soutien, tout en évitant la spéculation financière. La deuxième partie traite du problème de dimensionnement des systèmes hybrides par adaptation optimale de la charge, et l’approche est effectuée en deux parties. Une première partie consiste à modéliser la charge en tenant compte des contraintes spécifiques à l’exploitation. Ensuite, lors de la deuxième partie, une optimisation de la structure est effectuée en fonction du disponible énergétique. La troisième partie est consacrée au cas spécifique d’une application en nomade. Tout d’abord, il s’agit de déterminer les différentes contraintes caractéristiques à ce type d’application (sécurité énergétique, coût de la conception, etc.) et de définir les différents problèmes d’optimisation associés aux objectifs spécifiques. Ensuite, une étude de cas exprimée comme un problème d’optimisation de nature multi-objectif est énoncée. Finalement, des solutions optimales sont identifiées à travers des outils d’intelligence artificielle et de considérations liées à l’application
This thesis is a contribution to the optimal design of hybrid systems for energy production. The proposed work is organised in three parts. The first part is dedicated to an energy analysis at the level of the national electricity grid. The aim is to study the possibility of integrating sub-grids consisting of a set of producer-operators connected to the main grid. The aim is to strengthen the decentralisation of energy production, taking into account the specific needs and availability of renewable sources. To achieve this, the approach is to optimise the cost of the installation for the producer-operator and the subsidy rates provided by the supporting state, while avoiding financial speculation. The second part deals with the problem of sizing hybrid systems by optimal load adaptation, and the approach is carried out in two parts. In the first part, the load is modelled taking into account the specific constraints of the operation. Then, in the second part, an optimisation of the structure is carried out according to the available energy. To illustrate the relevance of the approach, an application to a concrete case of a company is performed. The third part is devoted to the specific case of a nomadic application. First, the different constraints characteristic of this type of application (energy security, design cost, etc.) are determined and the different optimisation problems associated with the specific objectives are defined. Then, a case study expressed as an optimisation problem of a multi-objective nature is stated. Finally, optimal solutions are identified through artificial intelligence tools and application

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Lozano, Adolfo. "Analysis of a novel thermoelectric generator in the built environment." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-4131.

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This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source.
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Тези доповідей конференцій з теми "Energetic analysis at the national grid level"

Radulescu, Bogdan Alexandru, and Victorita Radulescu. "Strategic Management and Operational Energetic Education, Opportunity for Future Small Developers and Entrepreneurs." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71102.

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Abstract Romania, as part of the EU has adopted new legislation concerning international energetic exchanges, based on the rules of cooperation. This paper illustrates some new concepts and essential steps in engineering education and beyond. International rules and their implementation at national level need to be adapted to the new financial and economic realities, quite important, especially in the actual economic pandemic context. All rules and regulations are based on the market economy interconnected to the international grids, necessary in the development of business opportunities. The second part presents the analysis of the target market segmentation, based on possible new criteria. Given the objectives of analyzing attractiveness and competitiveness, the advantages of being an educated engineer based on the selection of the strategy choice are determined. Success depends on the ability to understand and generate customers. The analysis of the strategic role of small developer management to ensure competitiveness and economic efficiency is also mentioned. All new graduates, master or doctoral students specialists in power engineering will have to deal with the new strategic objectives of investments, new legislation and trends as solutions to minimize global warming, increase energy efficiency, utilization of renewable resources, and environmental protection.

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Cardona, Fabio, Domenico Panno, and Antonio Piacentino. "Analysis of a Reciprocate Engine–Based Cogeneration Plant With High Temperature Heat Recovery for Industrial Uses." In ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/esda2012-82306.

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In consequence of the increasing awareness on the future scarcity of fossil energy sources and the global warming impact of energy conversion processes, the European Union has been planning several actions to enhance the efficiency of energy use and reduce the environmental impact. The declared goals of EU actions are synthetized in the 20-20-20 formula, consisting of an expected 20% increase of energy efficiency, a 20% contribution to the total energy supply by renewable sources and a 20% abatement of pollutant emissions. Applications of cogeneration in process industry can significantly contribute to achieve these targets. In this paper a reciprocate engine-based Combined Heat and Power (CHP) plant is presented, serving a pasta factory located in Sicily and installed by an Energy Service COmpany (ESCO) within the context of a national implementation scheme of Energy Saving Certificates (or “white certificates”). The CHP plant, with a 650 kWe capacity, currently covers a relevant fraction of the electric and high-temperature heat loads during peak hours, while it is switched off during off-peak hours because of the much lower electricity price. Heat content of flue gases is recovered by two cascaded gas-diathermic oil and diathermic oil-water heat exchangers; the superheated water obtained is then supplied to the pasta dryers. The first part of the paper provides a detailed plant description and an energetic analysis of historical performance data collected along the last two years of operation. Both the critical analysis of the lay-out and the evaluation of energy saving indicators reveal the current scheme to represent a sub-optimal solution for the particular application. In the second part of the paper a modified solution is simulated, consisting of the same CHP unit equipped with additional heat exchangers for heat recovery from the cooling water jacket circuit. The marginal energetic and economic benefits compared to the current plant setup are calculated; the results are presented in analytic and graphical form, coherently with the provisions of Directive 2004/8/EC and accounting separately for the different cost and revenues (fuel for the CHP unit and the supplementary boilers, electricity purchased from or supplied to the grid, taxes, etc.). The improved solution, designed to increase the thermal efficiency of the CHP unit by allowing a full exploitation of heat cascades, resulted to provide evident benefits and to make the CHP unit to comply with all the current legislative provisions for the assessment of highly efficient CHP plants. Margins for further improvements are also briefly discussed.

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Suo-Anttila, Ahti, K. C. Wagner, and Miles Greiner. "Analysis of Enclosure Fires Using the Isis-3D™ CFD Engineering Analysis Code." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49008.

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The Isis-3D™ computational fluid dynamics (CFD) code is currently under development for the Defense Threat Reduction Agency (DTRA) as a tool for risk assessment and engineering level analysis. It is designed to provide reasonably accurate estimates of the total heat transfer to objects from large fires under a variety of circumstances, predict the medium characteristics such as temperature and species concentration distributions, and use fairly short computer turnaround times. Isis-3D™ models liquid fuel evaporation, transport of fuel vapor, oxygen and other relevant species, reaction and heat release, and soot and other gaseous species formation, destruction, and transport. It models diffuse radiation within the fire and view factor radiation from the fire edge to nearby objects and the surroundings. One-dimensional transient sub-grid modules are also embedded into Isis-3D™. Either or both “ends” of each module are coupled to the flowing medium region, or objects within the three-dimensional medium. These modules allow the code to calculate the one-dimensional response of simple solid objects to the fire environment without affecting the computational fluid dynamics time step. The sub-grid modules can include thermal conduction, convection, momentum, mass, and species exchange. For example, they can be used to simulate the decomposition of organic materials (e.g. burning wood), the evaporation of liquid fuels, and the injection of gases, such as fire suppressants. Fast-running radiation heat transfer and chemical reaction models embedded in the code are designed to enable it to give engineering-level accurate results for large-fire heat transfer even when relatively coarse computational grids are employed. Low to medium level resolution Isis-3D™ simulations (less than 60,000 nodes) are relatively fast running and hence well suited for risk assessments, parametric scenario variations, and engineering level analyses. This paper includes comparisons of Isis-3D™ predictions to two enclosure fire experiments, the classical Steckler room fire experiments and the Sandia National Laboratories (SNL) Igloo enclosure fires. The Steckler fire experiments were steady state fires with a fixed heat input. The SNL Igloo tests were larger scale, unsteady fuel pan fires. Comparisons of the predicted temperature distributions within the enclosures for several tests are shown. A typical application of Isis-3D™ is also illustrated wherein the CO2 fire suppressant distribution within the cable room of a nuclear power plant is predicted as a function of time.

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Soares, Carlos Guedes, Ralf Weisse, Juan Carlos Carretero, and Enrique Alvarez. "A 40 Year Hindcast of Wind, Sea Level and Waves in European Waters." In ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/omae2002-28604.

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The paper describes the initial efforts in a project whose objective is to obtain a 40-year hindcast of wind, sea level and wave climatology for European waters. The 40-year global atmospheric re-analysis carried out by the National Centre for Environmental Prediction, Washington, USA (NCEP) and the National Centre for Atmospheric Research, Boulder, Colorado, USA (NCAR) will be used as forcing of limited area atmospheric models. The fine grid atmospheric fields will be used to force state-of-the-art wave models (WAM) and sea level models (HAMSOM and TELEMAC) in regional areas around Europe so as to produce climatic information on waves, sea levels, and currents in a very large extend of the European waters, including the Mediterranean, North East Atlantic and North Sea. The available satellite data, including wind, wave and sea-level data, will be collected and will be used to be compared with the hindcast results, so as to yield uncertainty measures related to the data. Statistical analysis of the produced atmospheric, sea level and wave hindcast and remote sensed data will be performed in order to provide information about the climatological trends in the European Waters and Coastal Seas.

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Cosham, Andrew, David G. Jones, Keith Armstrong, Daniel Allason, and Julian Barnett. "Analysis of Two Dense Phase Carbon Dioxide Full-Scale Fracture Propagation Tests." In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33080.

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Two full-scale fracture propagation tests have been conducted using dense phase carbon dioxide (CO2)-rich mixtures at the Spadeadam Test Site, United Kingdom (UK). The tests were conducted on behalf of National Grid Carbon, UK, as part of the COOLTRANS research programme. The semi-empirical Two Curve Model, developed by the Battelle Memorial Institute in the 1970s, is widely used to set the (pipe body) toughness requirements for pipelines transporting lean and rich natural gas. However, it has not been validated for applications involving dense phase CO2 or CO2-rich mixtures. One significant difference between the decompression behaviour of dense phase CO2 and a lean or rich gas is the very long plateau in the decompression curve. The objective of the two tests was to determine the level of ‘impurities’ that could be transported by National Grid Carbon in a 914.0 mm outside diameter, 25.4 mm wall thickness, Grade L450 pipeline, with arrest at an upper shelf Charpy V-notch impact energy (toughness) of 250 J. The level of impurities that can be transported is dependent on the saturation pressure of the mixture. Therefore, the first test was conducted at a predicted saturation pressure of 80.5 barg and the second test was conducted at a predicted saturation pressure of 73.4 barg. A running ductile fracture was successfully initiated in the initiation pipe and arrested in the test section in both of the full-scale tests. The main experimental data, including the layout of the test sections, and the decompression and timing wire data, are summarised and discussed. The results of the two full-scale fracture propagation tests demonstrate that the Two Curve Model is not (currently) applicable to liquid or dense phase CO2 or CO2-rich mixtures.

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Aliuddin, Atif M., AbdulAziz S. Alhamoud, and Samir Mekid. "System Level Design and Simulation of PV/Diesel/Battery Hybrid Power Systems for Portable Classrooms." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62128.

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This paper discusses a system level design and simulation of a portable solar powered classroom for rural areas that are not connected to the national grid. This constitutes a serious handicap to support general public utilities such as lack of proper schools and usual daily utilities. The lack of schools in such areas has lead to a lower level of educational standard as compared to urban schools. These regions are often isolated and far away from any major cities and thus have limited educational resources. Often these areas lack proper teaching facilities, which in turn discourage students from seriously pursuing education. Coincidentally these areas are exposed to a large amount of solar energy over the course of a year. This paper focuses on the utilization of this captured solar energy transformed into electricity to serve all electrical devices that equip a portable solar classroom. The load profile for this classroom was selected based on the power requirements of an average classroom and basic educational technologies. A parametric study was done using software that specializes in simulating renewable energy solutions (HOMER). Various alternatives for the same load profile are compared and a cost analysis and comparison between alternatives is presented. The practicality of the project is evaluated and a suitable Hybrid power system is presented.

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Moisseytsev, Anton, and James J. Sienicki. "Dynamic Analysis of S-CO2 Cycle Control With Coupled PDC-SAS4A/SASSYS-1 Codes." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54547.

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The ANL Plant Dynamics Code (PDC) for the analysis of supercritical carbon dioxide (S-CO2) Brayton cycle power converters has been under development at Argonne National Laboratory for several years. It is the leading state of the art capability for modeling S-CO2 cycles at the system level. The SAS4A/SASSYS-1 Liquid Metal Reactor Code System is the leading capability for modeling a SFR or LFR at the system level. The SAS4A/SASSYS-1 code combines reactor dynamics with thermal hydraulics calculations. Coupled together, the two codes allow users to carry out for the first time very detailed transient calculations of an entire plant incorporating a SFR with a S-CO2 cycle energy converter, including simulation of both design and beyond-design events. The developed coupling approach utilizes the restart capability of SAS4A/SASSYS-1 and allows the data transfer between the two codes at each time step. The coupling approach is demonstrated by carrying out S-CO2 cycle control calculations in which the entire plant follows a user-defined electrical grid demand scenario. The automatic control mechanisms on the S-CO2 cycle side allow following of the load changes in the entire 0–100% range. On the reactor side, an autonomous (i.e., no deliberate control other than startup and shutdown) operation is assumed where the reactor power is adjusted by the internal reactivity feedbacks to match the heat removal rate by the balance-of-plant.

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Pattawi, Kaleb, Prateek Munankarmi, Michael Blonsky, Jeff Maguire, Sivasathya Pradha Balamurugan, Xin Jin, and Hohyun Lee. "Sensitivity Analysis of Occupant Preferences on Energy Usage in Residential Buildings." In ASME 2021 15th International Conference on Energy Sustainability collocated with the ASME 2021 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/es2021-64053.

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Abstract Residential buildings, accounting for 37% of the total electricity consumption in the United States, are suitable for demand response (DR) programs to support effective and economical operation of the power system. A home energy management system (HEMS) enables residential buildings to participate in such programs, but it is also important for HEMS to account for occupant preferences to ensure occupant satisfaction. For example, people who prefer a higher thermal comfort level are likely to consume more energy. In this study, we used foresee™, a HEMS developed by the National Renewable Energy Lab (NREL), to perform a sensitivity analysis of occupant preferences with the following objectives: minimize utility cost, minimize carbon footprint, and maximize thermal comfort. To incorporate the preferences into the HEMS, the SMARTER method was used to derive a set of weighting factors for each objective. We performed week-long building energy simulations using a model of a home in Fort Collins, Colorado, where there is mandatory time-of-use electricity rate structure. The foresee™ HEMS was used to control the home with six different sets of occupant preferences. The study shows that occupant preferences can have a significant impact on energy consumption and is important to consider when modeling residential buildings. Results show that the HEMS could achieve energy reduction ranging from 3% to 21%, cost savings ranging from 5% to 24%, and carbon emission reduction ranging from 3% to 21%, while also maintaining a low thermal discomfort level ranging from 0.78 K-hour to 6.47 K-hour in a one-week period during winter. These outcomes quantify the impact of varying occupant preferences and will be useful in controlling the electrical grid and developing HEMS solutions.

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Petrykowski, John C. "Analysis of Fuel-Coolant Interaction Potential in Sodium Cooled Fast Reactor Safety Experiments." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54925.

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Improved utilization of nuclear fuels, burning of actinides and advancements in safety have brought about renewed interest in sodium cooled fast reactor technology. In regards to this and in light of recent events which have focused attention on new concerns involving safety, analyses have recently been performed addressing beyond design basis accident conditions for which the existence of large quantities of vaporized fuel and coolant have been postulated. Specifically, for very low probability, but highly energetic core disruptive accidents in sodium cooled fast reactors, molten and vaporized fuel in contact with coolant can bring about a fuel coolant interaction leading to transformation of a significant inventory of coolant from liquid to vaporforme, with a potential for subsequent release of fuel as aerosol from the reactor vessel due to transport of fuel fragments and fuel aerosol by the vaporized fuel and coolant. Because general statements concerning the nature of these events were largely speculative, out-of-reactor experiments were conducted in the mid 1980’s in the FAST-CRI-III facility at Oak Ridge National Laboratory to study the transport in sodium of aerosol-bearing UO2 vapor bubbles. Although codes featuring detailed multi-physics models [1] were in various stages of development at the time of program cessation, a simplified thermo-mechanical model, free of requirements for detailed thermophysical property data, has recently been developed for purposes of evaluating FAST outcomes. The model consists of a hydrodynamic module which is used to predict the movement of a pulsatile, aerosol-bearing vapor bubble through the surrounding coolant and a heat transfer module which accounts for thermal interactions as the bubble thermally radiates to the surrounding coolant. The model predictions are consistent with key experimental trends, namely: (1) significantly reduced aerosol release as the coolant level increased, (2) greatly reduced aerosol release in sodium tests compared to release levels measured in a series of baseline water tests. The consistency of these trends is discussed in terms of thermo-mechanical characteristics of the respective coolants. Specifically, the inertia of the surrounding coolant impedes bubble transport to the free surface which addresses the first point above, and, relative to the second point, bubble lifetimes are sufficiently short relative to time estimates for transit to the free-surface, due principally to the effectiveness of quenching by radiation which is particularly pronounced in the case of sodium, owing to high reflectivity values. Additionally, pool subcooling was found to have a cross-cutting influence on aerosol release. Only in tests in which pool subcooling was reduced to ∼10 Kelvin was significant aerosol release detected. For those tests, which occurred in water, measurements suggest that coolant vaporization occurred at intensities above 3000 kg/m2-s, well beyond what has generally been reported from fuel coolant interaction studies in which the coolant interactions are with molten fuel forms. This set of findings will permit a more general assessment of the implications of fuel coolant interactions on the progression of core disruptive accidents, particularly with regards to assessing probable modes of in-vessel aerosol transport within sodium cooled reactors.

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Kim, Dongsu, Heejin Cho, Rogelio Luck, and Pedro Mago. "Potential Aggregate Effects of Net-Zero Energy Homes (NZEHs) With Distributed Energy Generation on the U.S. Electrical Grid." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88359.

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This study evaluates potential aggregate effects of net-zero energy home (NZEH) implementations on the U.S. electrical grid in a simulation-based analysis. The aggregate impact of large-scale NZEH implementations on the U.S. electrical grid is evaluated through a simulation-based study of prototype residential building models with distributed photovoltaic (PV) generation systems. An EnergyPlus residential prototype building model (i.e., a multi-family low-rise apartment building) is used to determine the detailed electricity consumption of each residential building model using U.S. climate weather files. This study assumes that net-metering is available on the electrical grid so that the surplus on-site electricity generation can be fed to the electrical grid. This study also considers the impact of electrical energy storage (EES) within NZEHs to effectively use on-site generated electricity on the electrical grid. Finally, surveyed residential building permits in 2017 are used to estimate net-electricity demand profiles of NZEHs on a national scale. Results indicate that adding distributed PV systems to enable annual multi-family NZEH performance can significantly increase changes in imported and exported electricity demand from and to the electrical grid during the daytime. However, using the EES within NZEHs helps reduce the peak electricity demand during the daytime. The stored electricity in the EES can also be used during the evening time. The peak net-electricity differences on the U.S. electrical grid-level could potentially be reduced during the daytime and shifted to the evening. Comparison of hourly electricity demand profiles for the actual U.S. demand versus the calculated net-demand on a national scale indicates that the percentage differences of U.S. net-electricity demand include about 4.5% and 4.8% for the multi-family NZEH without the EES on representative winter and summer days, respectively, at a maximum point. In addition, when the EES is added within the multi-family NZEH, the peak percentage differences could be reduced to about 3.4% and 4.3% on representative winter and summer days, respectively, at a maximum point.

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