scholarly journals An Evaluation of the Mathematical Models of Energy Piles

2020 ◽  
Vol 28 (1) ◽  
pp. 44-48
Author(s):  
Jakub Oravec ◽  
Ondřej Šikula ◽  
Iva Nováková

AbstractA current trend is to reduce the energy performance of buildings by using alternative sources for heating and cooling. One of the most promising, and so far unprecedented sources of heating and cooling, is the use of energy from the earth using the thermally-activated foundation piles of a building, the so-called energy piles. The paper deals with an overview and comparison of computer-aided analytical models of energy piles. The individual analytical models are compared (categorized) from the point of view of their physical complexity, computational costs, and thus their usability for the purpose of optimizing energy-pile equipment or assessing the long-term energy efficiency of an energy pile field. Selected mathematical models were algorithmized, and the results obtained were compared with a more robust numerical solution performed using CalA 4 software.

Author(s):  
Ondřej Šikula ◽  
◽  
Richard Slávik ◽  
Jan Eliáš ◽  
Jakub Oravec ◽  
...  

Equipping the foundation piles with a liquid circuit pipeline makes it possible to use the advantageous ther-mal capacity of the soil for heating and cooling buildings at low cost. The energy performance of the energy-pile in a soil is a transient phenomenon dependent on many parameters, which could be investigate by a computational model. The contribution deals with the description and verification of a new numerical computational software based on a simplified 2D and 2D rotational symmetrical heat conduction model being developed for energy-piles modeling.


2020 ◽  
Vol 205 ◽  
pp. 05002
Author(s):  
Fatemah Behbehani ◽  
John S. McCartney

This paper focuses on the simulation of the coupled heat transfer and water flow in unsaturated soil layers surrounding a solitary energy pile undergoing heating and cooling cycles typical of a field-scale energy pile. The results indicate that heating leads to drying of the soil surrounding the energy pile, which has been shown in previous studies to result in an increase in axial capacity. During cooling, the degree of saturation was observed to recover to the value present before the start of heating initially, however, it will not recover in the following years. Which will lead to a cumulative effect after several cycles of heating and cooling. Heating and cooling cycles lead to an overall reduction in the thermal conductivity of the subsurface, reducing the heat transfer from the energy pile but also leading to greater storage of heat in the subsurface surrounding the pile.


2016 ◽  
Vol 846 ◽  
pp. 325-330
Author(s):  
Abraham Kazzaz ◽  
Itai Einav ◽  
Gwénaëlle Proust ◽  
Yi Xiang Gan

Geothermal energy piles have emerged as a cost effective and efficient solution for heating and cooling buildings through renewable energy. Although significant research effort has been dedicated to investigating the performance of these systems, the effect of ground mineralogy has received little attention. This study examines the likely performance of energy piles in dense sand with varying mineralogy. A 3D thermal discrete element model is used to determine the dry thermal conductivity of quartz, feldspar and mica rich sand. This is then used in a 2D finite element analysis to estimate the dissipation/extraction capacity of the soil surrounding a typical energy pile. A 35% increase in quartz content is predicted to result in 51% improvement in the thermal performance of a pile.


Author(s):  
William H. Avery ◽  
Chih Wu

The economic contribution that OTEC will make to the solution of the nation’s energy problems depends on its perceived merits relative to existing and alternative sources of energy and fuels. The previous chapters have shown that OTEC technology is ready for large-scale demonstrations that will provide a firm basis for commercial development. OTEC can have a large impact on U.S. energy needs by supplying liquid fuels for direct use in transportation, or for electric power production via fuel cells. Its commercial development will depend finally on political and other factors that cannot be assessed quantitatively. The national security and environmental impacts of continuing dependence on oil should receive major emphasis in decisions to implement new processes for fuel production. In this chapter we review the estimated sales prices of fuels and electric power from existing and proposed sources and compare them with OTEC prices. Actual manufacturing costs are generally unavailable and are highly dependent on the financing methods and resources of the individual producer. However, an objective comparison of the sales prices of fuels produced by proposed processes can be made by using the Mossman financial analysis method to estimate the sales price of fuel or electric power that must be charged for profitable operation. This requires only information on the plant investment, input fuel costs, and operation and maintenance costs. The sensitivity of the product costs to changes in the estimates in plant investment can then be displayed in a suitable graph. With this procedure the alternatives can be equitably compared from a uniform point of view. This includes costs of related facilities as well as the plant investment. See the discussion in Section 7.3. These costs vary with time in an unpredictable manner. Past forecasts have been in error by large factors. These costs are a small part of the total, typically a few percent of plant investment for capital-intensive projects. Environmental impact costs have usually been ignored. These items are a few percent of plant investment. State and local property taxes will be zero for sea-based OTEC systems.


2019 ◽  
pp. 22-29
Author(s):  
Н. В. Фрадкіна

The purpose and tasks of the work are to analyze the contemporary Ukrainian mass culture in terms of its value and humanistic components, as well as the importance of cultural studies and Ukrainian studies in educational disciplines for the formation of a holistic worldview of modern youth.Analysis of research and publications. Scientists repeatedly turned to the problems of the role of spirituality in the formation of society and its culture. This problem is highlighted in the publications by O. Losev, V. Lytvyn, D. Likhachev, S. Avierintsev, M. Zakovych, I. Stepanenko and E. Kostyshyn.Experts see the main negative impact of mass culture on the quality approach, which determines mass culture through the market, because mass culture, from our point of view, is everything that is sold and used in mass demand.One of the most interesting studies on this issue was the work by the representatives of Frankfurt School M. Horkheimer and T. Adorno «Dialectics of Enlightenment» (1947), devoted to a detailed analysis of mass culture. Propaganda at all socio-cultural levels in the form is similar in both totalitarian and democratic countries. It is connected, according to the authors, with the direction of European enlightenment. The tendency to unify people is a manifestation of the influence of mass culture, from cinema to pop. Mass culture is a phenomenon whose existence is associated with commerce (accumulation in any form – this is the main feature of education), in general, the fact that it exists in this form is related to the direction of the history of civilization.Modern mass culture, with its externally attractive and easily assimilated ideas and symbols, appealing to the trends of modern fashion, becomes a standard of prestigious consumption, does not require intense reflection, allows you to relax, distract, not teach, but entertains, preaches hedonism as the main spiritual value. And as a consequence, there are socio-cultural risks: an active rejection of other people, which leads to the formation of indifference; cruelty as a character trait; increase of violent and mercenary crime; increase in the number of alcohol and drug addicts; anti-patriotism; indifference to the values of the family and as a result of social orphanhood and prostitution.Conclusions, perspectives of research. Thus, we can conclude that modern Ukrainian education is predominantly formed by the values of mass culture. Namely, according to the «Dialectic» by Horkheimer and Adorno, «semi-enlightenment becomes an objective spirit» of our modern society.It is concluded that only high-quality education can create the opposite of the onset of mass culture and the destruction of spirituality in our society. It is proved that only by realizing the importance of cultivating disciplines in the educational process and the spiritual upbringing of the nation, through educational reforms, humanitarian knowledge will gradually return to student audiences.Formation of youth occurs under the influence of social environment, culture, education and self-education. The optimal combination of these factors determines both the process of socialization itself and how successful it will be. In this context, one can see the leading role of education and upbringing. It turns out that the main task of modern education is to spread its influence on the development of spiritual culture of the individual, which eventually becomes a solid foundation for the formation of the individual. Such a subject requires both philosophical and humanitarian approaches in further integrated interdisciplinary research, since the availability of such research will provide the theoretical foundation for truly modern educational and personal development.


2020 ◽  
Vol 29 (4) ◽  
pp. 556-563
Author(s):  
Adam Burley

This is a personal and reflective piece written from a clinician's point of view on the influence that the developing awareness around the consequences of childhood adversity has had upon the discussions, thinking and practice across the areas in which they are working. It seeks to argue that the increased understanding and recognition of the potential impact of early adversity can not only enhance and deepen the understanding of an individual's difficulties, but can serve to inform how services respond in a way that takes account of this. It suggests that the research and literature on childhood adversity can offer a route map away from a model of mental health that focuses predominantly on the individual as the sole source of interest.


2020 ◽  

BACKGROUND: This paper deals with territorial distribution of the alcohol and drug addictions mortality at a level of the districts of the Slovak Republic. AIM: The aim of the paper is to explore the relations within the administrative territorial division of the Slovak Republic, that is, between the individual districts and hence, to reveal possibly hidden relation in alcohol and drug mortality. METHODS: The analysis is divided and executed into the two fragments – one belongs to the female sex, the other one belongs to the male sex. The standardised mortality rate is computed according to a sequence of the mathematical relations. The Euclidean distance is employed to compute the similarity within each pair of a whole data set. The cluster analysis examines is performed. The clusters are created by means of the mutual distances of the districts. The data is collected from the database of the Statistical Office of the Slovak Republic for all the districts of the Slovak Republic. The covered time span begins in the year 1996 and ends in the year 2015. RESULTS: The most substantial point is that the Slovak Republic possesses the regional disparities in a field of mortality expressed by the standardised mortality rate computed particularly for the diagnoses assigned to the alcohol and drug addictions at a considerably high level. However, the female sex and the male sex have the different outcome. The Bratislava III District keeps absolutely the most extreme position. It forms an own cluster for the both sexes too. The Topoľčany District bears a similar extreme position from a point of view of the male sex. All the Bratislava districts keep their mutual notable dissimilarity. Contrariwise, evaluation of a development of the regional disparities among the districts looks like notably heterogeneously. CONCLUSIONS: There are considerable regional discrepancies throughout the districts of the Slovak Republic. Hence, it is necessary to create a common platform how to proceed with the solution of this issue.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1080
Author(s):  
Mamdooh Alwetaishi ◽  
Omrane Benjeddou

The concern regarding local responsive building design has gained more attention globally as of late. This is due to the issue of the rapid increase in energy consumption in buildings for the purpose of heating and cooling. This has become a crucial issue in educational buildings and especially in schools. The major issue in school buildings in Saudi Arabia is that they are a form of prototype school building design (PSBD). As a result, if there is any concern in the design stage and in relation to the selection of building materials, this will spread throughout the region. In addition to that, the design is repeated regardless of the climate variation within the kingdom of Saudi Arabia. This research will focus on the influence of the window to wall ratio on the energy load in various orientations and different climatic regions. The research will use the energy computer tool TAS Environmental Design Solution Limited (EDSL) to calculate the energy load as well as solar gain. During the visit to the sample schools, a globe thermometer will be used to monitor the globe temperature in the classrooms. This research introduces a framework to assist architects and engineers in selecting the proper window to wall ratio (WWR) in each direction within the same building based on adequate natural light with a minimum reliance on energy load. For ultimate WWR for energy performance and daylight, the WWR should range from 20% to 30%, depending on orientation, in order to provide the optimal daylight factor combined with building energy efficiency. This ratio can be slightly greater in higher altitude locations.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1986
Author(s):  
Andreas Koenig ◽  
Julius Schmidtke ◽  
Leonie Schmohl ◽  
Sibylle Schneider-Feyrer ◽  
Martin Rosentritt ◽  
...  

The performance of dental resin-based composites (RBCs) heavily depends on the characteristic properties of the individual filler fraction. As specific information regarding the properties of the filler fraction is often missing, the current study aims to characterize the filler fractions of several contemporary computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs from a material science point of view. The filler fractions of seven commercially available CAD/CAM RBCs featuring different translucency variants were analysed using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Micro-X-ray Computed Tomography (µXCT), Thermogravimetric Analysis (TG) and X-ray Diffractometry (XRD). All CAD/CAM RBCs investigated included midifill hybrid type filler fractions, and the size of the individual particles was clearly larger than the individual specifications of the manufacturer. The fillers in Shofu Block HC featured a sphericity of ≈0.8, while it was <0.7 in all other RBCs. All RBCs featured only X-ray amorphous phases. However, in Lava Ultimate, zircon crystals with low crystallinity were detected. In some CAD/CAM RBCs, inhomogeneities (X-ray opaque fillers or pores) with a size <80 µm were identified, but the effects were minor in relation to the total volume (<0.01 vol.%). The characteristic parameters of the filler fraction in RBCs are essential for the interpretation of the individual material’s mechanical and optical properties.


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