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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Systémy TZB v objektech se spotřebou energie blízkou nule / Systems of technical equipment in almost zero energy House

Bukovjanová, Eva January 2013 (has links)
The aim of this thesis is the design and building services systems in buildings with energy close to zero. The thesis 2 variants were designed heating and DHW. In variant 2 is considered with the photovoltaic system to generate electricity that is used up mainly in the building. It is part of the thesis experiment, whose aim was to monitor and evaluate the structure of electricity consumption in the residential unit.
62

Návrh řízení průtoku teplovodním výměníkem solárního systému / Design of flowrate control of solar system

Popov, Petr January 2008 (has links)
Problems of heating of supply water by solar energy are described in this paper. In term of these works was designed and realized attenuate prototype of solar system. There was realized measurements of the temperatures on this prototype and on the basis of these measurements was identified system parameters. Creation of compute simulation of solar system was the further step of this paper. The compute simulation was verified on the basis of comparing of final temperatures with experimental prototype. The design of control algorithm of flow of liquid through the solar system to reach the maximum effect of system is programme of this paper. Simulations of control algorithms are make in environment of MATLAB SIMULINK.
63

Vysokoteplotní zásobník energie s celoročním provozem ve spojení se solárním systémem / High temperature energy reservoir with year-round operation in conjunction with a solar system

Hoc, Pavel January 2017 (has links)
In this thesis I deal with the issue of stand-alone solar system development. This system ensures the supply of all the energy needed for a reference house. It consists of a solar concentrator and a heat reservoir. I used mathematical models to solve this issue. The calculations showed, that the concentration of solar radiation into the heat reservoir can usually achieve 69 % efficiency. The efficiency can be even higher when using a very reflective materials of the solar concentrator. In this thesis, the thermal reservoir is described and its improvements are suggested based on the optimization calculations. Thanks to knowledge gained during solving this issue, a prototype of the stand-alone solar system is going to be built. All findings will be experimentally verified with this prototype.
64

Lois d’échelles et propriétés statistiques multifractales de la topographie des planètes / Scaling laws and multifractal statistical properties of planetary topography

Landais, François 24 November 2017 (has links)
Au cours des 20 dernières années, le développement des méthodes de télédétection et le succès des missions spatiales ont considérablement enrichi nos connaissances sur les surfaces planétaires révélant une immense diversité de morphologies. Etant le reflet de l'interaction et de la compétition entre des processus géologiques dont les modalités sont variables d'un corps à l'autre, elles sont largement étudiées pour retracer l'histoire géologique des planètes telluriques. En particulier, des informations précieuses sur la nature des processus et sur les lois générales qui contrôlent la formation et l'évolution des paysages sont enregistrées dans le champ topographique qui peut être analysé en tant que champ statistique. Nous rapportons dans cette thèse les résultats d'une étude comparative des propriétés statistiques de la topographie des principaux corps du système solaire en nous appuyant sur le volume croissant de données altimétriques et photogrammétriques. Notre approche est centrée sur la notion de loi d'échelle qui vise à caractériser les symétries du champ en traduisant le caractère auto-similaire des surfaces naturelles : les détails d'une surface ressemblent en général à des versions réduites de l'ensemble. Nous mettons en oeuvre plusieurs méthodes d'analyse de données dites «multifractales» pour dégager le meilleur modèle statistique capable de décrire la topographie dans différents contexte et proposons de nouveaux indicateurs de rugosité à l'échelle globale, régionale et locale. Nous montrons qu'en dépit de leur diversité, les surfaces du système solaire respectent des lois statistiques similaires que nous explicitons. En particulier nous montrons que la distribution globale des pentes d'un corps respecte en général des lois multifractales pour les échelles supérieures à 10-20km et présente une structure statistique différente pour les échelles inférieures. Enfin nous proposons une méthode pour générer des topographies synthétique sphériques dont le propriétés statistiques sont similaires aux topographie planétaire du système solaire. / Over the past 20 years, the development of remote sensing methods and the success of space missions have considerably enriched our knowledge of planetary surfaces revealing an immense diversity of morphologies. Being the reflection of the interaction and the competition between geological processes whose modalities are variable from one body to the other, they are widely studied to trace the geological history of the telluric planets. In particular, precise information on the nature of processes and general laws controlling the formation and evolution of landscapes is recorded in the topographic field which can be analyzed as a statistical field. We report in this thesis the results of a comparative study of the statistical properties of the topography of the main bodies of the solar system based on the increasing volume of altimetric and photogrammetric data. Our approach focuses on the notion of scaling law which aims to characterize the symmetries of the field by translating the self-similar nature of natural surfaces: the details of a surface generally look like reduced versions of the whole. We use several methods of analyzing so-called "multifractal" to derive the best statistical model capable of describing the topography in different contexts and propose new indicators of roughness at the global, regional and local scale. We show that in spite of their diversity, the surface of the solar system respects similar statistical laws. In particular, we show that the overall distribution of the slopes of a body generally respects multifractal laws for scales greater than 10-20 km and presents a different statistical structure for the lower scales. Finally, we propose a method for generating spherical synthetic topographies whose statistical properties are similar to the topographies in the solar system.
65

Feasibility Study of Chemical Energy Storage for an Energy Efficient Commercial Office Space

Maritz, Kerry-Leigh January 2019 (has links)
Shifting the load demand of a commercial office space to utilise off peak tariffs would lead to cost savings as power is cheaper at this time. To achieve this shift, chemical energy storage was considered using Lead Acid batteries, Lithium-ion batteries and Advance Lead Acid batteries. The output of these storage types is electricity. Current costs of storage do not support the option of reducing peak demand by adding chemical storage, as electricity from the grid is cheaper over the storage project life. A levelised cost analysis was completed and lithium-ion batteries proved to be the outright best choice for chemical storage in commercial office spaces. Town buildings were analysed and assessed for energy savings in order to reduce overall load demand. Incorporating chemical storage as a viable option was assessed based on cost. Heating, Cooling and lighting proved to be the highest load demands in the buildings. Cost savings in buildings can be better met by increasing the efficiency in buildings, rather than by reducing the cost by shifting the purchase of electricity from peak to off-peak tariffs. More suitable options to chemical energy storage would be to replace standard lights with energy efficient variations, installing an air heat pump to heat the space and ice thermal storage to cool the space. The use of a solar thermosyphon will meet the demand for heated water. Solar energy generation was assessed as an alternative as off-peak electricity stored using chemical storage proved to be too costly. A 50kW system would be suitably sized when peak sun hours were above the local areas average. Net metering could be used to offset costs during the winter months, when the peak sun hours fall below the average.
66

Zpracování projektu tepelného solárního systému / Project of the solar heating system

Ullmann, Walter January 2011 (has links)
The diploma thesis studies the elaboration of project about thermal solar systém for all- season service. The aim of the work was to make a proportioning, choosing the right parts and calculating the economic and ecologic balance.
67

Electrification of valve system / Elkonvertering av ventilsystem

Nordqvist, Mathias, Svensson, Olle January 2019 (has links)
This report is going to investigate the possibility to save energy by converting a valve opening mechanism in a waste disposal system from a pneumatic system to an electric system. To power the system, which mainly consists of an electric actuator and a valve control module, a solar panel system was designed. The valve system was controlled by the lightweight messaging protocol MQTT. To be able to choose an electric actuator the needed force was measured and data regarding maximal stroke was taken from the data sheet of the existing setup. For developing an optimal solar panel system a program was written in Google Spreadsheet. The program takes input regarding power, cycles, solar panel system specifications and environmental factors. The output from the program is energy consumption for the system, specification for solar charger, solar panel setup and charge data. The result was that the solar panel system needed to consists of four 12 V VRLA batteries with a capacity of 90 Ah each and four solar panels with a rated power of 300 W each. The solar charger must be able to handle 900 W and provide an output current of 25,5 A to fulfil the demands. The new electric actuator will consume four times less energy than the old pneumatic actuator. Most of the energy savings are consequences of reduced energy consumption at idle of the system. A demonstarator was built to test the system. / Den här rapporten kommer att undersöka möjligheten att spara energi genom att konvertera ett ventilöppningsmekanism i ett avfallshanteringssystem från ett pneumatiskt system till ett elektriskt system. För att driva systemet, som främst består av en elektrisk aktuator och en ventil styrenhet, ska ett solcellssystem designas. Ventilsystemet ska styras med hjälp lättviktsmeddelandeprotokollet MQTT. För att kunna välja en aktuator mättes den behövda kraften och data angående maximal slaglängd togs från databladet på den nuvarande konstruktionen. För att utveckla ett optimalt solcellssystem skrevs ett program i Google Kalkylark. Programmet använder energi, cykler, solcellssystem och miljöfaktorer som indata. Som utdata ges energiförbrukning hos systemet, specifikation för solcellsregulator, solpaneler och laddningsdata. Resultatet var att det solcellssystem som behövs bestå av fyra 12 V VRLA batterier med en kapacitet på 90 Ah var och fyra solpaneler med en nominell effekt på 300 W vardera. Solcellssregulatorn behöver kunna hantera 900 W och generera en ström på 25,5 A. Den nya elektriska aktuatorn kommer förbruka fyra gånger så lite energi jämfört med den gamla pneumatiska aktuatorn. Den största delen av energibesparingarna är en konsekvens av minskad energiförbrukning av systemet i vila. En prototyp byggdes för att testa systemet.
68

The Thermodynamics of Planetary Engineering on the Planet Mars

Barsoum, Christopher 01 May 2014 (has links)
Mars is a potentially habitable planet given the appropriate planetary engineering efforts. In order to create a habitable environment, the planet must be terraformed, creating quasi-Earth conditions. Benchmarks for minimum acceptable survivable human conditions were set by observing atmospheric pressures and temperatures here on Earth that humans are known to exist in. By observing a positive feedback reaction, it is shown how the sublimation of the volatile southern polar ice cap on Mars can increase global temperatures and pressures to the benchmarks set for minimum acceptable survivable human conditions. Given the degree of uncertainty, utilization of pressure scale heights and the Martin extreme terrain were used to show how less than desirable conditions can still produce results where these benchmarks can be met. Methods for obtaining enough energy to sublimate the southern polar ice cap were reviewed in detail. A new method of using dark, carbonaceous Martian moon material to alter the overall average albedo of the polar ice cap is proposed. Such a method would increase Martian energy efficiency. It is shown that by covering roughly 10% of the Martian polar ice cap with dark carbonaceous material, this required energy can be obtained. Overall contributions include utilization of pressure scale heights at various suggested settlement sites, as well as polar albedo altering as a method of planetary engineering. This project serves as a foundational work for long term solar system exploration and settlement.
69

Maya Eclipses: Modern Data, The Triple Tritos And The Double Tzolkin

Beck, William Earl 01 January 2007 (has links)
The Eclipse Table, on pages 51-58, of the Dresden Codex has long fascinated Maya scholars. Researchers use the mean-value method of 173.3 days to determine nodal passage that is the place where eclipses can occur. These studies rely on Oppolzer's Eclipse Canon and Schram's Moon Phase Tables to verify eclipse occurrences. The newer canons of Jean Meeus and Bao-Lin Liu use decimal accuracy. What would be the effect of modern astronomical data on the previous studies and the Maya Eclipse Table? The study utilizes a general view of eclipses that includes eclipses not visible to the Maya. Lunar eclipses are also included. This inquiry differs from previous studies by calculating the Maya dates of eclipses instead of nodal passage. The eclipse dates are analyzed using the three eclipse seasons, of the 520 days, which is the Double Tzolkin or twice the Sacred Calendar of the Maya. A simulation of the Eclipse Table, using the 59-day calendar, is created to test modern data against the Dresden Table. The length of the Table is the Triple Tritos of 405 lunations. The use of the Tritos instead of the Saros suggests the Table is independent of Western Astronomy. Advanced Astronomy is not needed to produce this Table; a list of eclipses could produce this table. The result of this inquiry will be to create a facsimile of the Eclipse Table, which can be compared to the Eclipse Table to test the structure, function and purpose of the Table.
70

Towards a Chemical Taxonomy of Comets: Infrared Spectroscopic Methods for Quantitative Measurements of Cometary Water (With an Independent Chapter on Mars Polar Science)

Bonev, Boncho P. January 2005 (has links)
No description available.

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