Tesis sobre el tema "Shallow geothermal energy system"
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Bowers, Jr George Allen. "Ground-Source Bridge Deck Deicing and Integrated Shallow Geothermal Energy Harvesting Systems". Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/78777.
Texto completoPh. D.
Ninikas, Konstantinos. "Opportunities for renewable heat energy from shallow geothermal sources". Thesis, Glasgow Caledonian University, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.726798.
Texto completoCaulk, Robert Alexander. "Evaluation of Key Geomechanical Aspects of Shallow and Deep Geothermal Energy". ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/396.
Texto completoHähnlein, Stefanie [Verfasser] y Peter [Akademischer Betreuer] Grathwohl. "Shallow geothermal energy - sustainability and legal situation / Stefanie Hähnlein ; Betreuer: Peter Grathwohl". Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1162897236/34.
Texto completoHähnlein, Stefanie Verfasser] y Peter [Akademischer Betreuer] [Grathwohl. "Shallow geothermal energy - sustainability and legal situation / Stefanie Hähnlein ; Betreuer: Peter Grathwohl". Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1162897236/34.
Texto completoErceg, Ivan P. "Mathematical Analysis of a Geothermal System". Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1225138202.
Texto completoHein, Philipp Sebastian. "On the efficient and sustainable utilisation of shallow geothermal energy by using borehole heat exchangers". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232226.
Texto completoIm Rahmen der Energiewende nimmt die Geothermie eine besondere Rolle in der thermische Gebäudeversorgung ein. Die zunehmende, intensive Nutzung oberflächennaher geothermischer Ressourcen erhöht die Gefahr der übermäßigen thermischen Ausbeutung des Untergrundes und stellt damit eine wachsende Herausforderung für die Nachhaltigkeit und Sicherheit solcher Systeme dar. Zur Erschließung oberflächennaher geothermischer Energie wird insbesondere die etablierte Technologie Erdwärmesonden-gekoppelter Wärmepumpen eingesetzt. Aufgrund der daran beteiligten komplexen physikalischen Prozesse erweisen sich numerische Modelle als leistungsfähiges Werkzeug zur Erweiterung des Prozessverständnisses und Unterstützung des Planungs- und Auslegungsprozesses. Zudem können Simulationen zum Management thermischer Ressourcen im Untergrund sowie zur Planung und politischen Entscheidungsfindung auf städtischen und regionalen Maßstäben beitragen. Im Rahmen dieser Arbeit wurde, basierend auf dem sogenannten ”dual-continuum approach” und unter Berücksichtigung des Einflusses der Wärmepumpe, ein erweitertes gekoppeltes numerisches Modell zur Abbildung der in Erdwärmesonden und dem Untergrund stattfindenden Strömungs- und Wärmetransportprozesse entwickelt. Das Modell ist in der Lage, alle relevanten Einflussfaktoren zu berücksichtigen. Neben den Temperaturfeldern im Untergrund und der Erdwärmesonde werden die Effizienz und damit der Stromverbrauch der Wärmepumpe simuliert. Damit können sowohl die Betriebskosten als auch der äquivalente CO 2 -Ausstoß abgeschätzt werden. Das Modell wurde validiert und in einer Reihe numerischer Studien eingesetzt. Zuerst wurde eine umfassende Sensitivitätsanalyse zur Effizienz und Nachhaltigkeit entsprechender Anlagen durchgeführt. Weiterhin wird ein Verfahren zur Quantifizierung des technisch nutzbaren, oberflächennahen geothermischen Potentials vorgestellt und anhand einer Fallstudie für die Stadt Köln demonstriert, gefolgt von einer Diskussion der Ergebnisse
Pomerancevs, Juris. "Geothermal function integration in ice rinks with CO2 refrigeration system". Thesis, KTH, Tillämpad termodynamik och kylteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-273166.
Texto completoIshallar är energikrävande industriella applikationer. En typisk ishall i Sverige använder cirka 1000 MWh / säsong. Ett toppmodernt ishallsystem kan använda mindre än 500 MWh / säsong, vilket indikerar stora förbättringsmöjligheter. Enligt flera undersökningar har CO2-kylsystem med värmeåtervinning visat sig vara energieffektivt och kostnadseffektivt i ishallar.För att ytterligare förbättra effektiviteten kan geotermisk funktion läggas till. Syftet med denna studie är att utvärdera den geotermiska funktionen ur ett tekno-ekonomiskt perspektiv för en typisk ishall i Sverige. En modellering av flera scenarier har utförts. Resultaten antyder att CO2-kylsystem med 2-steg värmeåtervinning, om det uppgraderas med geotermisk funktion, kan spara mellan 1,7 och 6,8% energi årligen. I bästa fall antyder denna studie att den geotermiska funktionen skulle betala tillbaka om 16,4 år.
Atkinson, Trevor Alex. "Geochemical Characterization of the Mountain Home Geothermal System". DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4599.
Texto completoStrandberg, Christoffer. "Geoenergilösning för DN-huset". Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227599.
Texto completoFreundt, Florian [Verfasser] y Werner [Akademischer Betreuer] Aeschbach. "Application of Helium Isotopes in Shallow Groundwaters for Geothermal Energy Exploration in the Upper Rhine Graben / Florian Freundt ; Betreuer: Werner Aeschbach". Heidelberg : Universitätsbibliothek Heidelberg, 2017. http://d-nb.info/1178009033/34.
Texto completoFisher, Kevin Perry. "A case study to identify and evaluate the pricing policy for geothermal energy in the San Bernardino Municipal Geothermal District heating system". CSUSB ScholarWorks, 1989. https://scholarworks.lib.csusb.edu/etd-project/532.
Texto completoCorr, Mandi Lee. "Renewable energy in Montana system applications and technlogy /". [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-04212009-123850/unrestricted/Mandi_Corr_Thesis.pdf.
Texto completoIlisei, Gheorghe. "Numerical analysis using simulations for a geothermal heat pump system. : Case study: modelling an energy efficient house". Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29101.
Texto completoThe presentation was made via Skype due to the programme being online based
Alshareef, Ahmed Shehab. "Technology Assessment Model of Developing Geothermal Energy Resources for Supporting Electrical System: the Case for Oregon". PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3515.
Texto completoYekoladio, Peni Junior. "Thermodynamic optimization of sustainable energy system : application to the optimal design of heat exchangers for geothermal power systems". Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/31615.
Texto completoDissertation (MEng)--University of Pretoria, 2013.
Mechanical and Aeronautical Engineering
unrestricted
Eriksson, Douglas. "Investigation of the energy saving potential for an office building complex : A study on the viability of an on-site combined heat- and power supply system". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-39888.
Texto completoGross, Paul A. II. "Commercial Program Development for a Ground Loop Geothermal System: Energy Loads, GUI, Turbulent Flow, Heat Pump Model and Grid Study". Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1324258915.
Texto completoFredriksson, Victor y Bane Gluhajic. "Heating systems in small houses : A comparison between geothermal heating and district heating". Thesis, KTH, Byggteknik och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-253799.
Texto completoFjärrvärme och bergvärme är idag två etablerade värmesystem som ofta ställs mot varandra. Syftet med det här arbetet är att redogöra vilka faktorer som påverkar valet av värmesystem under projekteringsstadiet och vilka kostnaderna som finns för respektive system. I arbetet har en typisk husmodel tagits fram och använts som grund för jämförelsen av båda systemen. Jämförelsen har dels gjorts i form av energiberäkningar i energiberäkningsprogrammet BV2 där värmebehov och myndighetskrav på energiprestanda har jämförts i olika geografiska områden i Sverige. Vidare har kostnadsberäkningar genomförts utifrån energiberäkningarnas resultat där investeringskostnader och årliga kostnader har ställts mot varandra. Resultatet av arbetet visar hur måttet på energiprestanda skiljer sig från den faktiska mängden köpt energi på grund ut av geografiska förhållanden. I de södra delarna i Sverige där den geografiska korrigeringsfaktorn understiger 0 straffas konsumenter genom att primärenergitalet höjs, till skillnad mot de norra delarna där primärenergitalet istället sänks. Utifrån kostnadsberäkningarna kan man dra slutsatsen att fjärrvärme, när den finns tillgänglig, är mer ekonomiskt fördelaktigt på kort sikt. Bergvärme å andra sidan är ett mer lönsamt alternativ på lång sikt.
Alghamdi, Jamal Khaled. "CFD Simulation Methodology for Ground-Coupled Ventilation System". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35736.
Texto completoMaster of Science
Chavarria, Dana, Rubi Ramos y Carlos Raymundo. "Development of a hybrid heating system based on geothermal–photovoltaic energy to reduce the impact of frosts on inhabitants of rural areas in the ring of fire, southern Peru". Springer Science and Business Media Deutschland GmbH, 2019. http://hdl.handle.net/10757/656249.
Texto completoThe recent climate change has forced people to live in extreme conditions, either excessive heat or cold, implying that they must adapt to survive in these situations. However, there are people who, because of their geographical condition and lack of resources, lack the means and tools to combat these climate changes. The context of this study is provided in a rural town located in the Arequipa region (Peru), whose inhabitants have to fight against frosts of up to −20 °C in an area without electricity. A viable solution to this problem is found through the design and implementation of a heating system using geothermal and photovoltaic energy, which are resources found in the area, according to a report of the Ministry of Energy and Mines. This study analyzes and researches the geographical and meteorological conditions of the region, for validating, through theory and simulations, whether the proposed system can supply the thermal energy required to maintain the indoor temperature at a minimum of 15 °C under extreme conditions. The system is designed after analyzing the best technological options and techniques currently available in the context studied for its ultimate financing and establishing guidelines and indicators for monitoring results.
Charoenvisal, Kongkun. "Energy Performance and Economic Evaluations of the Geothermal Heat Pump System used in the KnowledgeWorks I and II Buildings, Blacksburg, Virginia". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/33942.
Texto completoIn collaboration with the Virginia Tech Corporate Research Center, Inc., this research studies the energy consumption and cost benefits of the Geothermal Heat Pump System that has been integrated and operated in the KnowledgeWorks I and II buildings located on the Virginia Tech campus.
The purpose of this thesis is to understand the energy and cost benefits of the Geothermal Heat Pumps System when compared to the conventional package variable air volume (VAV) with hot water coil heating and air-source heat pump systems using computer simulation and statistical models. The quantitative methods of building energy performance and life-cycle cost analyses are applied to evaluate the results of simulation models, the in-situ monitoring data, and the associated documents. This understanding can be expanded to the higher level of architectural systems integration.
Master of Science
Hein, Philipp Sebastian [Verfasser], Olaf [Akademischer Betreuer] Kolditz, Haibing [Akademischer Betreuer] Shao, Anke [Akademischer Betreuer] Bucher, Olaf [Gutachter] Kolditz, Peter [Gutachter] Bayer y Stephan [Gutachter] Schönfelder. "On the efficient and sustainable utilisation of shallow geothermal energy by using borehole heat exchangers / Philipp Sebastian Hein ; Gutachter: Olaf Kolditz, Peter Bayer, Stephan Schönfelder ; Olaf Kolditz, Haibing Shao, Anke Bucher". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1151047023/34.
Texto completoHein, Philipp Sebastian [Verfasser], Olaf [Akademischer Betreuer] Kolditz, Haibing Akademischer Betreuer] Shao, Anke [Akademischer Betreuer] Bucher, Olaf [Gutachter] Kolditz, Peter [Gutachter] [Bayer y Stephan [Gutachter] Schönfelder. "On the efficient and sustainable utilisation of shallow geothermal energy by using borehole heat exchangers / Philipp Sebastian Hein ; Gutachter: Olaf Kolditz, Peter Bayer, Stephan Schönfelder ; Olaf Kolditz, Haibing Shao, Anke Bucher". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1151047023/34.
Texto completoAlfadil, Mohammad Omar. "Design Tool for a Ground-Coupled Ventilation System". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100604.
Texto completoDoctor of Philosophy
Jakubovič, Artiom. "Gyvenamųjų namų šildymo geotermine energija problemos". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20090617_183259-02356.
Texto completoThe main problems that are solved in this thesis are tailored with heat pumps longtime efficiency. The borehole heat exchanger was selected as a variable of a heat pump system. This means that efficiency of the heat pump depends from the temperature of heat carrier inside soil heat exchanger. First part of this thesis represents information about geothermal energy and ways of using it. Definition about shallow geothermal energy is made. The examples of heat pump heat exchangers are given. The practical part of the thesis contains analysis of the simulation models for soil heat exchangers. According to this analysis, selection of the simulation tool is made for further modeling. The simulations of three different heat exchangers types are made. Modeling results show heat carrier’s mean monthly temperatures during time period of 25 years. Using these temperatures the heat pump’s mean monthly coefficient of performance is defined. Using coefficients of performance the calculation of electric power demand is made. Economic analysis is made. The analysis results showed that the most efficient vertical borehole heat exchanger is one heat exchanger with two U-pipes, in terms of conditions that had been used in this thesis.
Eslami, Hossein. "Comportement thermo-hydromécanique des sols au voisinage des géo-structures énergétiques". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0263/document.
Texto completoEnergy geostructures involve providing a direct heat exchange with the ground through integrated systems in the foundations or geotechnical structures. The incorporation of heat exchangers in geostructures produces a cyclic variation of the temperature in the adjacent soil. Therefore, there are important scientific questions about the effect of temperature variations on hydro-mechanical soil parameters in general, and particularly for sensitive clay soils. The main objective of this thesis is to improve the understanding and the quantification of the impact of temperature variation on the bearing capacity of geothermal piles. Currently, the design of the bearing capacity of deep foundations is based on the results of in situ penetrometer and pressuremeter tests. Herein, experimental methods are developed to carry out these tests in laboratory conditions. Mini-penetrometer tests were carried out on samples compacted at different initial states and subjected to temperature variations ranging from 1 to 70 °C. The results showed a significant change in the studied parameters: the cone resistance (qc) and the friction sleeve resistance (fs) for an illitic material compacted on the dry side of the compaction curve. Mini-pressuremeter tests performed on the same illitic compacted soil in a thermo-regulated metric scale container, showed a decrease in creep pressure (pf) and limit pressure (pl) with increasing temperature, while the variation of pressuremeter modulus (EM) is less pronounced. The results showed a quasi-reversibility of the effect of a heating cycle through the temperature range tested, while the effect of a cooling cycle was only partially reversible. In the case of several thermal cycles, the first cycle induced more important parameter variations than the subsequent cycles, and at the end of the experimentation. Further analysis of the evolution of the thermal properties (thermal conductivity (λ), heat capacity (Cv) and thermal diffusivity (D)) within heating and cooling process as a function of soil water content and dry density showed an increase of these parameters with the increase of initial values of w and ρd, and an increase of λ in the dry side of the compaction curve with increasing temperature from 1 to 70 °C. In summary, for the energy piles driven in the clay soils, some modifications in the bearing capacity have to be taken into account due to the variation of the hydro-mechanical parameters of the soil induced by thermal cycles
Badenes, Badenes Borja. "Optimización teórico-experimental de sondas de calor para intercambio geotérmico (SGE) según condiciones hidrogeológicas, características geométricas y propiedades de sus materiales". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/160477.
Texto completo[CA] Un dels majors reptes per al mercat de bombes de calor geotèrmiques és l'alt cost associat a la perforació dels bescanviadors de calor geotèrmics. Aconseguir uns bescanviadors de calor geotèrmics més eficients reduiria aquest cost, ja que seria necessària una menor longitud de bescanviador per a obtenir les mateixes temperatures de treball en ell (mateixa eficiència de la bomba de calor). L'eficiència tèrmica d'un bescanviador de calor geotèrmic està caracteritzada per la seva resistència tèrmica. Aquesta resistència tèrmica depèn d'una sèrie d'elements entre els quals es troben: propietats i cabal del fluid que recorre el bescanviador de calor, diàmetre de la perforació geotèrmica, geometria i materials de la canonada del bescanviador de calor i les propietats del material de farciment de la perforació (grouting). Com més gran sigui la resistència tèrmica del bescanviador de calor, menor serà la calor transferida entre el fluid termòfor i el terreny, traduint-se en una necessitat major de longitud de bescanviador enterrat. Per tant, és necessari una reducció d'aquest paràmetre al mínim possible. En conseqüència, l'objectiu principal d'aquesta Tesi Doctoral consisteix en, a partir d'un model analític comprensiu de quantificació de l'impacte dels paràmetres anteriors, realitzar un estudi detallat per a analitzar la seva influència combinada en la resistència tèrmica del bescanviador geotèrmic, però també examinant aquest efecte en altres plans, com a costos econòmics d'execució del bescanviador i d'explotació (consum elèctric de la bomba de calor i costos de bombament).
[EN] One of the biggest challenges for the ground source heat pump market is the high cost associated with drilling geothermal borehole heat exchangers. Achieving more efficient geothermal heat exchangers would reduce this cost, since a shorter exchanger length would be required to obtain the same working temperatures in it (same efficiency of the heat pump). The thermal efficiency of a geothermal heat exchanger is characterized by its borehole thermal resistance. This borehole thermal resistance depends on a number of parameters, mainly: properties and flow rate of the working fluid that flows through the borehole heat exchanger, diameter of the geothermal borehole, geometry and materials of the heat exchanger pipe and the properties of the borehole grouting material. The higher thermal resistance of the heat exchanger, the less heat is transferred between the heat carrier fluid and the ground, resulting in an increased requirement for the length of the buried heat exchanger. Consequently, it is essential to reduce this parameter to the minimum possible. Therefore, the main objective of this Ph. Doctoral Thesis is to carry out, based on a comprehensive analytical model of quantification of the impact of the above mentioned parameters, a detailed study to analyze their combined influence on the thermal resistance of the geothermal borehole, but also exploring this effect in other less researched areas, such as economic costs of running the exchanger and operating it (electricity consumption of the heat pump and associated pumping costs).
This research has received funding from the European Union’s Horizon 2020 Research and Innovation program under grant agreement No [657982], [727583] and [792355].
Badenes Badenes, B. (2020). Optimización teórico-experimental de sondas de calor para intercambio geotérmico (SGE) según condiciones hidrogeológicas, características geométricas y propiedades de sus materiales [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/160477
TESIS
Pitron, Jiří. "Možnosti využití alternativních decentralizovaných zdrojů energie". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220682.
Texto completoÖhlund, Martin. "Ekonomisk Optimering av Systemtemperaturer i Radiatorsystem". Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-176210.
Texto completoThe choice of temperatures in heating systems has long been a question for debate in Sweden. For the design engineer, the choice of system temperatures in a heating system has a decisive impact on the cost and in order to stay competitive on the market it is crucial to design the heating system as cost effective as possible. Historically the system temperature in Swedish heating systems has been 80/60 but today we see that the most common temperatures are 55/45. During the 1960´s Östen Sandberg became the leading advocate for a new type of heating system using a low flow principle (LF) for heat distribution. The LF principle requires a larger temperatur difference between the supply and return temperatures for the adequate heating. Advocates of the LF principle claims that large energy savings are possible if an exsisting high flow heating system (HF) undergoes an adjustment to a LF heating system. The question is how accurate is this claim? This article shows many advantages with the nowadays common 55/45-HFsystem. A 55/45-HFsystem has relatively low investment costs in comparison with other types of heating systems. Another advantage is the fact that the 55/45-HFsystem is compatible with both district heating and geothermal heat pump heating systems which makes this radiator system suitable as a standardized system. The most economical radiator system is the 80/60-HFsystem, which has a lower investment cost for both radiators and piping in comparison with a 55/45-HFsystem. The claim that LFsystems and the associated LF principle could result in a reduced energy cost for the heating system was not supported. This article shows that the energy savings that comes from the LF principle is negligible in comparison with the heating systems total energy cost. The LF principle could however reduce the risk of an uneven heating distribution in the building due to a more unpredictable regulation of the flow through the radiators. LFsystem disadvantage is an general overall larger investment cost in comparison with a HFsystem.
Condemarin, Valverde Roberto Carlos y Gonzales Jesús Alessandro Alvarado. "Guía de aplicación de cimentaciones termoactivas para fomentar el aprovechamiento de energía geotérmica de baja entalpia en edificaciones". Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/655251.
Texto completoThe use of renewable energies is rare in the country, so it is important that the technologies associated with the use of this type of resources be disseminated. Surface geothermal energy is a resource that can be used practically throughout the earth's crust, it does not provide a high amount of energy but it does have applications that reduce CO2 production (by heating systems) and energy consumption. The research analyzes low enthalpy geothermal systems, specifically thermoactive foundations, which consist of incorporating the heat exchanger in the foundation structure, this together with the heat pump and the distribution system constitutes an important use of shallow geothermal energy in building heating systems. To develop thermoactive foundations it is necessary to carry out previous studies such as a study of the geotechnical and thermal characteristics of the soil, hydrogeology and geology.
Tesis
Tang, Fu-Jiao. "Investigation numérique sur l'échangeur de chaleur installé dans des sols peu profonds". Thesis, Strasbourg, 2019. https://publication-theses.unistra.fr/public/theses_doctorat/2019/TANG_Fujiao_2019_ED269.pdf.
Texto completoShallow geothermal energy is an energy that can help humanity to reach the goal of sustainable development. Ground-Coupled Heat Pump system is traditionally used to benefit this energy. As a main element of the system, ground heat exchanger performance directly influences its energy efficiency. The shallow ground heat exchangers are normally installed in soils, which show high heterogeneity of hydrothermal properties along the soil profiles. The main objective of this project is identifying how ground heat exchanger behaves in the soil. In summary, the following investigations were conducted: the first is introducing hydrothermal transfer in the numerical modeling of Borehole Heat Exchanger installed at a site in Alsace region (France); the second is identifying the factors influencing the performance of a shallow Borehole Heat Exchanger installed in soils; the third is conducting sensitive analysis of Thermal Response Tests for Borehole Heat Exchanger installed in soils; the fourth is identifying the performance difference of a numerical simulation model with Neumann and Dirichlet boundaries on the ground surface for a Horizontal Ground Heat Exchanger
Fabbri, Julius. "Contributo di dati di gravità nella valutazione del vulcanismo CAMP in Africa Nord-Occidentale". Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10927.
Texto completoLa domanda alla base di questa ricerca è stata se il metodo della gravimetria satellitare possa essere utilizzato per seguire le unità geologiche anche in luoghi difficilmente accessibili. L’obiettivo di questa ricerca è di verificare se le missioni satellitari di nuova generazione permettano di identificare la più grande delle province ignee della Terra (Bertrand et al., 2013), nota come CAMP (Central Atlantic Magmatic Province) in Africa nord-occidentale. Oltre alle motivazioni scientifiche, una possibile applicazione è l’esplorazione di risorse minerarie e lo sfruttamento di energia geotermica. Tale provincia ignea è una LIP (Large Igneous Province) che si estende in Nord e Sud America, Atlantico, Europa ed Africa (istituita in Marzoli et al. 1999). Essa si è sviluppata a seguito della frammentazione del super-continente Pangea al limite Triassico-Giurassico, ca. 200 Ma fa. A causa probabilmente del riscaldamento globale del mantello e/o dalla convezione dello stesso innescata da dislivelli di blocchi litosferici, dai dicchi-sorgente si produssero i cosiddetti basalti da flusso e si verificò un intenso vulcanismo con imponenti colate laviche tali da suggerire a taluni ricercatori che gli elementi volatili presenti nel magma abbiano contribuito ad aumentare i gas serra con conseguenze nel clima globale e nelle estinzioni di massa. I depositi in esame sono costituiti da lave, tholeiti continentali, doleriti, basalti e gabbri. Ciò che rimane di questa attività vulcanica sono dicchi singoli o in sciami, batoliti, sill, colate laviche e plateau basaltici (nei fondali oceanici). L’Africa nord-occidentale è costituita principalmente da un cratone composto da rocce molto antiche dell’Archeano (3000-2500 Ma). Esso emerge a nord nello scudo Reguibat e, a sud, la dorsale dell’Uomo o del Leone (Lucazeau et al., 1991). Il cratone è circondato dalle zone di geosutura (greenstone e cinture mobili) associate al cosiddetto evento termo-tettonico Pan-Africano, verificatosi ca. 650 Ma fa con l’assemblaggio del continente africano da blocchi crostali più piccoli. Nelle Mauritanidi affiora il basamento ercinico (ca. 350 Ma) mentre negli Atlas e nelle Magrebidi prevalgono rocce più recenti connesse all’orogenesi alpina (0-150 Ma). Al centro del cratone si trova il bacino paleozoico Taoudenni che riempie una vasta area depressa. Tutto il territorio in esame è caratterizzato da una forte presenza di rocce metamorfiche dense e magmatiche di ogni età, con presenza di più di un “punto caldo” che potrebbe essere definito un terreno igneo (Bryan et al. (2008) con più LIP spesso sovrapposte o limitrofe. Mediamente, tutte queste rocce magmatiche e metamorfiche hanno una densità di 3000 kg/m3 (Kröner, 1977 ), maggiore di quella della crosta standard e dei sedimenti. Particolare attenzione è stata dedicata ad un lineamento tettonico noto come Pelusium Megashare System (PMS) che attraversa tutta l’Africa nord-occidentale (Neev et al., 1982) chiaramente visibile in tutte le immagini satellitari di Google Earth ma che è riportato solo in pochissime pubblicazioni. Per la prima volta in questa tesi si ipotizza un collegamento tra la CAMP e PMS. La gravimetria satellitare consente di rilevare variazioni di densità nella crosta terrestre. Ove vi sono rocce più dense, il segnale rilevato (detto anomalia gravimetrica) è positivo e viceversa. La gravimetria da satellite si è rivelata un valido strumento per identificare le aree con surplus di massa. La risposta all’interrogativo iniziale è dunque affermativa anche se, da quanto esposto, risulta difficile o impossibile associare ad un certo segnale positivo una data LIP. L’elaborazione dei segnali è avvenuta partendo dai dati del satellite GOCE (ultima generazione, a un’orbita di 250 km ma già ammarato) e GRACE (obsoleto ma tuttora in orbita a ca. 450 km). I dati utilizzati sono dei modelli del campo di gravità terrestre che contengono i coefficienti di Stokes per lo sviluppo in armoniche sferiche del potenziale. I modelli utilizzati sono l’EGM2008 (comprendente anche dati di terra, con risoluzione massima 10 km se sviluppato al massimo ordine di 2159) e GOCO TIM R4 (con una risoluzione massima di 80 km, la migliore mai ottenuta da dati satellitari globali). Il modello EGM2008 è stato sviluppato fino all’ordine e grado 720 per eliminare dati spuri (Pavlis, 2012) e, in tal modo, ha permesso di raggiungere una risoluzione di ca. 27 km se si considera metà lunghezza d’onda. Dopo il controllo della qualità dei dati, essi sono stati elaborati nel seguente modo, come esposto nei capitoli 2, 3 e 4. Ai dati grezzi sono state applicate tre riduzioni per sottrarre gli effetti di gravità indesiderati che mascherano il segnale cercato più debole. È stato sottratto l’effetto di gravità della topografia, dei sedimenti e dell’interfaccia crosta-mantello (ICM). Partendo dall’anomalia “in aria libera” (FA), è stata quindi ottenuta l’anomalia di Bouguer (BA) e la BA corretta per i sedimenti. Poi, calcolata la Moho (ICM) isostatica, si è prodotto il residuo isostatico corretto per i sedimenti. I campi elaborati sono la gravità gz (espressa in milli Gal, mGal) ed il gradiente Tzz (misurato in Eötvös, E). Sono state usate le risoluzioni di 0.5° e di 0.05°, computati ad una quota di 4000 m s.l. m perché maggiore del più altro rilievo montuoso dell’area. Dopo aver modellato dei casi a geometria semplice (cap. 6) si è passati alla modellizzazione di tre casi reali. I tre siti scelti per l’approfondimento sono: Tindouf (Algeria), Taoudenni (Mali), Timbuktu (Mali). Nel bacino di Tindouf un sill doleritico CAMP è annesso al suo probabile dicco-sorgente reso evidente dalla gravimetria che identifica bene anche una vicina miniera di Ferro. Nel bacino Taoudenni, le due anomalie principali suggeriscono la presenza di cumuliti magmatici spessi una dozzina di chilometri e connessi con la superficie attraverso dicchi obliqui. Il sito presso Timbuktu è trattato nel dettaglio perché al di sotto del vicino lago Faguibine è stata rivelata un’intrusione magmatica lunga ca. 250 km. In superficie vi sono evidenze di magmatismo (per es. fumarole) tali da preoccupare le popolazioni locali (El Abbass et al., 1993). Tra i risultati inaspettati, si ricorda il forte segnale gravimetrico generato dalle peridotiti in Marocco ed un’importante anomalia (80 mGal) nel Grand Erg Occidental (Algeria) al di sotto del Sahara che sembrerebbe essere causata da un corpo denso lungo ca. 600 km.
The question behind this research was whether the method of satellite gravimetry can be used to follow the geological units even in inaccessible places. The goal of this research is to verify if the new generation of satellite missions serve to identify the largest of the Earth's igneous provinces (Bertrand et al., 2013), known as CAMP (Central Atlantic Magmatic Province) in Northwest Africa . Besides the scientific reasons, a possible application is the exploration of mineral resources and the exploitation of geothermal energy. This is an igneous province (LIP Large Igneous Provinces) that extends throughout North and South America, the Atlantic Ocean, Europe and Africa (established in Marzoli et al. 1999). It developed as a result of the fragmentation of the super-continent Pangea at Triassic-Jurassic limit, ca. 200 My ago. Probably because of mantel global warming and/or its convection triggered by differences in thickness of lithospheric blocks, from source-dikes were produced the so-called continental flow basalts (CFB) and there was an intense volcanism with massive lava flows that this would suggest to certain researchers volatile elements present in the magma have contributed to increasing greenhouse gases with consequences in the global climate and mass extinctions. The deposits in question consist of lavas, tholeites continental dolerites, basalts and gabbros. What remains of this volcanic activity are individual dykes or in swarms, batholiths, sills, lava flows and basaltic plateau (in the ocean). The north-western Africa consists mainly of a craton made of most ancient rocks dell'Archean (3000-2500 Ma). It emerges in the shield Reguibat north and on the south, the Man or the Lion shield (Lucazeau et al., 1991). The craton is surrounded by areas of geosutura (greenstone belts and mobile belts) associated with the so-called Pan-African thermo-tectonic event, occurred ca. 650 Ma ago with the assembly of the African continent by smaller crustal blocks. Mauritanides emerges in the Hercynian basement (ca. 350 Ma) while in the Atlas and Magrebides prevail younger rocks (Alpine orogenesis, 0-150 Ma). At the center of the craton is the Paleozoic basin Taoudenni that fills a large area depressed. All the territory concerned is characterized by a strong presence of dense magmatic and metamorphic rocks of all ages, with the presence of more than a "hot spot" that could be called “igneous terrane” (Bryan et al. (2008) with more LIPs overlapping or adjacent. On average, these igneous and metamorphic rocks have a density of 3000 kg / m3 (Kröner, 1977), greater than that of the standard crust and the sediments. Particular attention was dedicated to a tectonic lineament known as Pelusium Megashare System (PMS) that runs through the north-western Africa (Neev et al., 1982) clearly visible in all the satellite images of Google Earth but is reported only in very few publications. For the first time this thesis suggests a link between CAMP and PMS. Satellite gravimetry can detect density variations in the Earth's crust. Where there are rocks denser, the detected signal (called gravity anomaly) is positive and vice versa. The gravimetry by satellite has proved a valuable tool to identify areas with surplus Mass. The initial response to the question is therefore affirmative although, from the above, it is difficult or impossible to associate a positive signal a date LIP. Signals processing occurred from the data of the GOCE satellite (last generation, in an orbit of 250 km, mission already finished) and GRACE (obsolete but still in orbit at ca. 450 km). The data used are the models of the Earth's gravity field containing the coefficients of Stokes for the development of potential in spherical harmonics. The models used are the EGM2008 (also including land data, with a maximum resolution 10 km if developed to the maximum order of 2159) and TIM GOCO R4 (with a maximum resolution of 80 km, the best ever obtained by global satellite data). The model EGM2008 has been developed up to the order and degree 720 to remove spurious data (Pavlis, 2012) and, thus, allowed to reach a resolution of ca. 27 km considering half wavelength. After quality control of the data, they were processed in the following flowchart, as discussed in Chapters 2, 3 and 4. Raw data were processed applying three reductions to subtract the effects of gravity that mask the signal. It was reduced by the effect of gravity of the topography, sediment and crust-mantle interface (CMI). Starting by the anomaly "free air" (FA), was thus obtained the Bouguer anomaly (BA) and BA correct for sediment. Then, once calculated the isostatic Moho (CMI), has produced the sediment-corrected-isostatic residual. The fields processed are gravity gz (in milli Gal, mGal) and gradient tzz (measured in Eötvös, E). It has been used the resolutions of 0.5 ° and 0.05 °, computed at an altitude of 4000 m a.s.l., higher of mountains in the area. After mng cases with simple geometry (ch. 6) we moved to the modeling of three real case histories. The three sites chosen for the study are: Tindouf (Algeria), Taoudenni (Mali), Timbuktu (Mali). In the basin of Tindouf a CAMP doleritic sill is attached to its likely source source-dyke evident by gravimetry that identifies well a nearby mine of Iron. In the Taoudenni basin, the two main anomalies suggest the presence of magmatic cumulites a dozen kilometers thick and connected with the surface through oblique dikes. The site at Timbuktu is discussed in detail because in the nearby lake Faguibine was revealed a magmatic intrusion long ca. 250 km. On the surface there is evidence of magmatism (e.g. Fumaroles) such that worry local populations (El Abbass et al., 1993) .Among the unexpected results, please note the strong signal generated by gravimetric peridotites in Morocco and a major anomaly (80 mGal) in the Grand Erg Occidental (Algeria) below the Sahara that would seem to be caused by a dense body ca. 600 km long.
XXVI Ciclo
1972
Lin, Ting-Yi y 林庭毅. "Shallow Geothermal Energy Applied to Air Conditioning System Cooling". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vr4376.
Texto completo國立臺灣大學
機械工程學研究所
105
Traditional air-conditioning cooling systems usually use cooling tower to dissipate condense heat into outdoor air. However, the outdoor temperature and humidity, which vary over time, limit the cooling performance of cooling tower. Furthermore, the use of cooling tower has many disadvantages such as noise, vibration, and also providing a proper environment for bacteria breeding. Therefore, the aim of this thesis is to replace cooling tower system with a new cooling system—the shallow geothermal cooling system. This new cooling system dissipates condense heat into the shallow ground. Because of having a relatively small temperature variation, the shallow ground can be a stable heat sink for air-conditioning cooling.In this study, we used two types of shallow geothermal cooling system: groundwater borehole and raft foundation water. According to the experiment results, the groundwater cooling system could stably cool the condenser and reached thermal equilibrium state, but the temperature of raft foundation water was continuously rising during operation. Therefore, the groundwater cooling system can be a proper alternative for replacing cooling tower system. On the other hands, the raft foundation water cooling system could be another choice through optimized operating method.
Weng, Sheng-Yang y 翁聖揚. "The simulation and analysis of energy saving EAHE system using shallow geothermal energy". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/c44e2g.
Texto completo國立臺灣大學
機械工程學研究所
107
The earth air heat exchanger (EAHE) is a low-energy ventilation technique using the stable temperature of earth. In the past decade, many experimental studies deal with the performance evaluation of EAHE system worldwide; however, in Taiwan these kinds of researches are still uncommon. This research focus on the performance of soil-based EAHE and water-based EAHE using numerical methods. Soil-based EAHE includes 4 PVC air pipes each with 52.95m in length, 0.15m in diameter and buried 4.7m beneath ground surface. Its arranged ventilation is 3150 CMH, working 9 a.m. to 9 p.m. Water-based EAHE consists of 3 PVC air pipes each with 75m in length, 0.15m in diameter and buried 9.5m underground. Its arranged ventilation is 990 CMH, working 9 a.m. to 9 p.m. This research uses ANSYS Fluent for simulating various system status over time. Initial conditions are ventilation, seasonal introduced air temperatures and seasonal introduced air humidity. After simulation, EAHE system’s seasonal outlet temperature, outlet humidity, heat transfer rates, temperature distributions in raft foundation water and soil of 2 meters around air pipes can be generated. Through heat transfer rates, seasonal energy saving efficiency can be recognized, such as cooling load in summer and heating load in winter, as well as the percentage of latent heat transfer rates through the examination of humidity difference. This analysis benefits future applications for selecting suitable areas to adjust and improve the energy saving efficiency of EAHE systems. By analyzing raft foundation water temperature distribution, the range of water affected by EAHE and its most efficient operating period can be recognized to maintain stable water temperature and its heat transfer rate for preserving EAHE’s energy saving efficiency. Through analyzing surrounding soil temperature distribution, the range and extent of soil affected by EAHE can be realized. Selecting suitable soil allows soil to maintain its stable temperature, heat transfer rates and its self-recovering ability to sustain EAHE’s energy saving efficiency. From simulation results, the influence of pipe materials, such as stainless steel, copper, aluminum and PVC on the performance of EAHE can be known, thus suitable pipe materials can be determined. From temperature distribution of introduced air within air pipes, effective length for regulating can be discerned for future applications. Besides, although increasing airflow velocities promotes heat transfer rates, heat exchange time between introduced air and air pipes also decreases. Therefore, through simulation, the optimal airflow velocities are discovered. Airflow velocities of 2m/s, 5 m/s, 9 m/s and 12 m/s are considered in this research. Finally, the influence of water temperature 21℃, 23℃, 25℃ and water storage of full, 0.75-full, half-full on the performance of EAHE and recovery during shut down period is discussed. By the simulation with mentioned settings, systems’ seasonal air regulation, energy saving efficiency, efficient operating period, influence of pipe materials, effective length, affected range of surrounding soil and water, suitable soil types, appropriate airflow velocities, the influence of water temperature and water storage can be acknowledged.
Chen, Yung-Nan y 陳勇男. "A Study of Household or Commercial Heat Pump System with Shallow Geothermal Energy". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/42251856223799183602.
Texto completo國立臺灣大學
機械工程學研究所
105
A Study of Household or Commercial Heat Pump System with Shallow Geothermal Energy By Yung-Nan Chen Master Degree of Engineering, Department of Mechanical Engineering National Taiwan University July 2016 Adviser:Sih-Li Chen, Ph.D. The purpose of this study is to test a geothermal heat pump system with two apply ways, which includes raft foundation water energy and groundwater energy. For shallow geothermal energy which temperature is lower than outdoor air in summer and higher in the winter. With this property, we want to replace the traditional heating and cooling equipment by geothermal heat pump system. In the application of raft foundation water energy and groundwater energy we via six different mode to combine heat pump system with geothermal energy for heating and cooling purpose. For groundwater energy, we used Multi-U type Borehole Heat Exchangers (MUBHEs), made of PVC material tubes to exchange heat from the evaporator or condenser of heat pump. Through experiment, we want to realize the advantages and disadvantages for this two different ways in using shallow geothermal energy. At the same time, we will compare the efficiency and cost with commonly heating and cooling household equipment in Taiwan. According to the experiment, the heating mode with raft foundation water, a high efficiency in COP 4.3 is present. And the cooling mode with raft foundation water has cooling efficiency in COP 4 with providing refrigerating capacity 18 kW. Besides, the dual mode that heating and cooling simultaneously, can provide high efficiency when operating heat pump system in right situation. In the study of these experiment, we will compare two apply modes of geothermal energy and conclusion experimental analysis, find the way to improve design to reach more high efficiency. Keywords : Shallow Geothermal Energy, Heat pump, Multi-U type Borehole Heat Exchangers, raft foundation water
Chang, Chia-Hao y 張家豪. "Measurement and Analysis of Adsorption Chillers System combined with Solar Thermal Energy and Shallow Geothermal Energy". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9z8t8z.
Texto completo國立臺灣大學
機械工程學研究所
107
When the world began to promote energy conservation issues, the energy-saving benefits of air-conditioning systems are valued by many countries. The proportion of power consumption for energy dissipation is huge. Taiwan is hot in summer. The demand for air conditioning is great, which not only cost a lot, but also cause greatly environmental burden with carbon emissions. If it can directly use solar energy as a source of heat for air conditioners and use shallow geothermal energy to cooling, this way will greatly reduce power consumption and make air conditioners more energy efficient and environmentally friendly. This study use different parameters way to explore the performance of adsorption chillers combined with solar thermal energy and shallow geothermal energy . The COP of the adsorption chiller achieve 0.51 under the operating conditions, of 70 °C regenerative temperature, 22°C cooling water temperature, and 13~15 °C cold water temperature. Under the average radiation amount is about 860 W/m2, the thermal efficiency of the solar collector is about 0.6 and the overall system performance coefficient is about 0.31. It is estimated that use shallow geothermal energy instead of cooling tower system can save 44.6 m3 of water in summer. And it uses less 1.08 kW than cooling tower system.
Hu, Jiun-Wei y 胡鈞維. "Application of Hybrid Solar-wind Power Systems and Shallow Geothermal Systems to Net-zero Energy Plant Factory". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/26687679485352107010.
Texto completo國立臺灣大學
機械工程學研究所
103
Plant factory refers to a closed or semi-closed high-quality growing system for vegetables. The system cultivates vegetables through artificial control of water, light, temperature, moisture, and carbon dioxide concentration, so it requires high initial construction and operation costs. The operation costs are mainly due to the electricity consumption of lighting and air-conditioning. Past research have done much work on reducing plant factory’s electricity consumption, however, little have considered replacing traditional air-conditioning system with renewable energy or constructing an power system for plant factory. This research innovated a new method to build up net-zero plant factory (NZPF) - by combining mat foundation heat exchanger (MFHE) system and stand-alone hybrid solar-wind (SASW) power system. Performance prediction was conducted by ANSYS Icepak - a novel computational fluid dynamic (CFD) simulation software, including: two cooling models (basement model and plant factory model), three cooling designs, of four seasons. Both parts’ performance tests were anticipated to be accomplished yearend. First part’s prediction results demonstrated that cooling capacities were identical in both traditional air-conditioning system and mat foundation heat exchanger system. Namely, the latter’s energy conservation benefits analysis displayed that: (1) power consumption of air-conditioning system can be reduced by low-power water cooling apparatus, (2) basement model (indoor environment global cooling model) can achieve its energy conservation efficiency up to 93.5% (3) plant factory model (local cooling model) can achieve its energy conservation efficiency to 23.4% (with jointed fan coil) and up to 79.7% (with forced convection with cooling fan). Temperature simulation data in this study is predictive to a NZPF’s environment temperature, laying foundation to future experiments. Finally, solar-wind power system’s performance test and its experimental data is shown in the end of chapter 4. The net-zero energy plant factory’s cost-benefit analysis presented its payback period as 16.6 years.
Fang, Shih-Da y 方士達. "Investigation of Raft Foundation Water Shallow Geothermal Energy". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5qbtt2.
Texto completo國立臺灣大學
機械工程學研究所
105
Most traditional air-conditioning systems use cooling towers to dissipate heat from cooling water to ambient air, which not only consumes lots of energy but also increases urban heat island effect. This thesis aims to investigate the application of raft foundation water shallow geothermal energy. By theoretically establishing a mathematical model and comparing it with experimental results, the possibility of replacing cooling towers with raft foundation system was evaluated. First, a model for predicting the temperature variation of raft foundation water was created and analyzed. The result showed good agreement between the predicted value and the experimental data, with an average error of 3%. However, during the time when fresh water was poured into raft foundation, due to the increasing non-uniformity of water temperature, the error went up to 10%, but still within acceptable range. Second, considering stratified phenomenon, a model based on analysis of multiple control volumes was created to predict the temperature variation within a huge water storage tank. The simulation results indicated the tank could receive cooling load of approximately 960 kW with little variation of water temperature when the flow rate of incoming tap water was 10 times as large as that of the circulation water. Through heat transfer analysis, this research showed the heat dissipation rate from raft foundation water to surrounding soil was affected by the relatively high thermal resistance in soil, hence the cooling rate was not that fast compared with the former research. In addition, the thermal resistance calculated by empirical correlations was validated through CFD simulation, with only 2% relative error. Also, it was found that the heat transfer rate through the air enclosure on top of the raft foundation water was increased due to natural convection mechanism. As a result, more attention should be paid to determine whether or not this amount of heat dissipation would have significant impact on the residential quality. Finally, through energy saving assessment, it was shown that the usage of raft foundation water thermal energy could save up to 21% electricity and reduce carbon dioxide emissions by 29,066 kg per year ; and the usage of water storage tank system could save up to 24.6% electricity and reduce carbon dioxide emissions by 183,874 kg per year.
Hsu, Chien-Yeh y 徐千曄. "The Performance Analysis of Earth-Air Heat Exchangers Using Shallow Geothermal Energy". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/44488296539795587787.
Texto completo國立臺灣大學
機械工程學研究所
105
The earth air heat exchanger (EAHE) is a low-energy ventilation technique using the stable temperature of the earth. In the past decade, many experimental studies deal with the performance evaluation of EAHE system worldwide; however, in Taiwan these kinds of in-situ applications are still not available. This thesis presents a systemic approach to the analysis of two EAHE systems with different heat transfer media: water and soil. The soil-based systems were studied by means of long-term monitoring in Nantou, Taiwan, and analytical simulation. The experimental setup for the soil-based EAHE consists of seven parallel PVC pipes with 50m length and 0.25m diameter, buried at 3m depth beneath the ground surface, and a centrifugal fan with airflow rate of 6800m3/h. The operating strategy is to turn on the fan at 11:00 and turn off at 13:00. The results demonstrate that the annual acceptable cooling potential of soil-based earth-air heat exchanger may lower than the heating potential, but the midday intermittent operating can reach the maximum use of the cooling potential. The maximum total heat transfer rate ranged from -15 kW for heating, humidify, to about 40 kW for cooling, or dehumidify, during the period from May 2015 to January 2016. This thesis also develops an analytical model counting into the time delay effect and air humidity ratio. Through the analytical investigation, it was concluding that the effect of operating duration and latent heat exchange on performance is significant because they influence not only the temperature changes with time but also the exchange coefficient of soil. Intending to calculate the effect, dimensionless correlations were developed. Furthermore, to develop alternative efficient heat transfer media of earth air heat exchanger, an investigation for water-based system was also conducted in this thesis by an in-situ experiment in Yilan, Taiwan. The objective for the water-based EAHE consists of four air pipes with 40m length, 0.2m diameter, immersed in the water-filled raft foundation of a three stories building. A centrifugal fan with airflow rate of 1460 m3/h circulating the air into the system. The investigation shows that the cooling potential of the water beneath a building of 1.3m during spring season was close to that of ground soil at 2 m depth or deeper. The effect of changing the media around the air pipe of EAHE is significant. In addition, a suitable treatment of the ground surface is also important to avoid extra heat added into the water in the foundation. The in-situ experiment in three selected dates showed the air temperature could be dampened close to the average water temperature in the foundation. The ability of dehumidification was around 1.5 kg/hour and 2.8 kg/hour during hot season, and the averages of total heat transfer rate in hot weather was 3.36kW and 3.66kW, which was approximately equal to 1RT. In order to carry out the dimensioning of water-based EAHE, an analytical model was developed. Finally, the thermal and economic comparison between water and soil EAHE was presented, indicating that the water-based EAHE costs less than the soil-based one. The evaluated ROI periods are 4 years for water-based EAHE and 5 years for soil-based EAHE. The initial costs have huge effect on the ROI period, therefore an appropriate dimensioning was recommended in real application.
Chang, Jui-Ho y 張瑞和. "Adjusting indoor ambient temperature by shallow geothermal energy of building raft foundation". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9qte6n.
Texto completo國立高雄師範大學
工業科技教育學系
107
In response to the continued warming of the global climate, Taiwan should be for highly dependent on energy imports.It is an urgent and imperative task for us to implement the policy of green building which is friendly to the earth and protects the environment in high-energy-consuming metropolitan buildings.The underground middle layer basically has the characteristics of constant temperature. Shallow geothermal energy or Earth-Air Heat Exchanger Systems can be used to import into buildings to improve the hot summer and cold winter, but also reduce the carbon footprint of buildings.In this study, numerical evaluation and simulation of raft foundation secondary utilization are carried out based on foreign cases and literature collection, and computational simulation is carried out by using CFD (Computational Fluid Dynamics) software.The results of simulation show that, in the summer, the external air of 35℃ is fed into the pipeline of the raft foundation space at the speed of 2 meters per second by a fan for heat exchange, and the temperature is reduced by 5.5℃ ~ 7.5℃. On the other hand, in winter, the external air of 15℃ is fed into the pipeline in the same way, to obtain 1.6℃ ~ 3.3℃ warming.It is concluded that the raft foundation space, which is located in the thermostatic layer and takes into account the structure, can be utilized to make full use of the stable shallow geothermal energy all the year round so as to make the indoor of the whole building cool in summer and warm in winter.It is suggested that architects should make good use of this geothermal resource to create low energy consumption design plans for buildings and generate efficient energy-saving houses.
Chang, Hao-Wei y 張皓崴. "The Thermal Analysis and Optimization of Nutrient Film Technique with Shallow Geothermal Energy". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/njesyn.
Texto completo國立臺灣大學
機械工程學研究所
105
Temperature of Nutrient Film Technique(NFT) is one of the types of Hydroponics. As compared to other Hydroponics, it can be controlled by temperature. The purpose of this study is to derive the mathematical model by heat transfer analysis, and the model can be used to predict the changes of the temperature with different operating and environmental conditions. This study used MATLAB to simulate the changes of the temperature of NFT during the summer time based on Steady State, Incompressible Flow, Navier-Stokes equations, and Thermal Resistance Analysis. According to the results of numerical analysis, with 35 °C ambient temperature and 40 °C the top of the planting tube, if we only change the input water temperature and its flow rate, the temperature of the water in the planting tube can reach the target temperature (15 ~ 24 °C), but the temperature of the air in the planting tube cannot reach the target temperature. Therefore, we need to change the parameters of hardware to optimize the design. This study used Taguchi Method and Gray Relation Analysis to approach the optimum parametric combination, with the considering of the temperature of NFT and the power consumption. The parameters include cooling method of heat pump, volume flow rate of water, wide of planting tube, temperature of inlet water of planting tube, and slope of planting tube. The result show, cooling method of heat pump with Shallow Geothermal Energy, volume flow rate of water of 2 (L/min), wide of planting tube of 0.06 (m), temperature of inlet water of planting tube of 16 (°C), and slope of planting tube of 4 % is the best in all level for system. According to the results of optimization, the highest temperature of water of inside planting tube of 21.66 (°C) can be reduced to 17.87 (°C), the highest temperature of air of inside planting tube of 30.65 (°C) can be reduced to 25.14 (°C), and power consumption of planting tube can save 53%. Shallow Geothermal Energy accounts for 43% of the contribution in the saving energy. According to the results of simulating operation, it''s payback period is 5 months, and it can reduce carbon emission by 1,000 (kg) monthly.
Lin, Chia-Yu y 林家瑜. "Numerical Simulation of Shallow Geothermal Energy with fractal U-type ground coil heat exchangers". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/94p7u9.
Texto completo淡江大學
航空太空工程學系碩士班
106
In the generation of ever-changing technology, the use of energy is increasing. Green buildings, smart grids, etc. are all required to use electricity. This study will focus on the analysis of the thermal performance of drilling U-tube soil heat exchangers and try to change the shapes and material of the pipes, then find out ways to increase the efficiency of the soil heat exchanger. The project will use the commercial software ANSYS Fluent to create geometric shapes and meshes, and use the Fluent solver to perform simulation calculations. Finally, the results will be imported into Tecplot for analysis and discussion. We maintain the cross-sectional area of the U-tube for fractal structures and change the material of the tube wall for better heat dissipation. According to the analysis of the simulation results, fractal star pipes have the lowest outlet temperatures in both the PVC material and the carbon steel material. And the star tube increasing the most heat transfer efficiency from the carbon steel material. The round pipe which use the carbon steel pipe, which the outlet temperature has been lower than the star tube using PVC material. So we can change the tube’s material to reduce the temperature in the tube except to the reference mentioned in the use of different backfill material.
Lu, Wen-Tien y 盧文添. "Performance Analysis of District Geothermal Energy Cogeneration System". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/z3jfj6.
Texto completo國立臺北科技大學
能源與冷凍空調工程系碩士班
97
Due to the limited indigenous resources in Taiwan, most energy resource are relied and imported from other countries. In addition, people are aware of carbon dioxide reducing and also the importance of clean renewable energy. With the inefficiency of the traditional fossil fuel systems and the pollutant emission, we need to look for any clean energetic system. Traditional refrigeration and air-conditioning are vapor compression refrigeration cycle that not only causes an enormous amount of electrical energy but leads to ozone-depleting and the global warming by releasing synthetic refrigerant substances. The reason why we need to seek the alternative refrigerant or even other energy lies in driven refrigeration and air-conditioning system. Because of the abundance of natural geothermal resources in Taiwan, the thesis presents mainly on(1)Using low temperature geothermal energy to drive LiBr/H2O absorption system and analyze the performances of it. Furthermore, this thesis compares primary energy ratio (PER) and carbon dioxide emission of the various energy-driven absorption systems.(2)Using high temperature geothermal energy to drive district cogeneration system that provides thermal energy, electricity and cooling energy to the residence of the region. Analyze the geothermal energy cogeneration system with thermodynamic first and second laws, showing the analysis of the energy losses and efficiency of each subsystem and entire cogeneration system. Therefore, the results of this research can be used to improve the further systematical performance and achieve optimum of district geothermal energy cogeneration system.
Hein, Philipp Sebastian. "On the efficient and sustainable utilisation of shallow geothermal energy by using borehole heat exchangers". Doctoral thesis, 2016. https://tud.qucosa.de/id/qucosa%3A30732.
Texto completoIm Rahmen der Energiewende nimmt die Geothermie eine besondere Rolle in der thermische Gebäudeversorgung ein. Die zunehmende, intensive Nutzung oberflächennaher geothermischer Ressourcen erhöht die Gefahr der übermäßigen thermischen Ausbeutung des Untergrundes und stellt damit eine wachsende Herausforderung für die Nachhaltigkeit und Sicherheit solcher Systeme dar. Zur Erschließung oberflächennaher geothermischer Energie wird insbesondere die etablierte Technologie Erdwärmesonden-gekoppelter Wärmepumpen eingesetzt. Aufgrund der daran beteiligten komplexen physikalischen Prozesse erweisen sich numerische Modelle als leistungsfähiges Werkzeug zur Erweiterung des Prozessverständnisses und Unterstützung des Planungs- und Auslegungsprozesses. Zudem können Simulationen zum Management thermischer Ressourcen im Untergrund sowie zur Planung und politischen Entscheidungsfindung auf städtischen und regionalen Maßstäben beitragen. Im Rahmen dieser Arbeit wurde, basierend auf dem sogenannten ”dual-continuum approach” und unter Berücksichtigung des Einflusses der Wärmepumpe, ein erweitertes gekoppeltes numerisches Modell zur Abbildung der in Erdwärmesonden und dem Untergrund stattfindenden Strömungs- und Wärmetransportprozesse entwickelt. Das Modell ist in der Lage, alle relevanten Einflussfaktoren zu berücksichtigen. Neben den Temperaturfeldern im Untergrund und der Erdwärmesonde werden die Effizienz und damit der Stromverbrauch der Wärmepumpe simuliert. Damit können sowohl die Betriebskosten als auch der äquivalente CO 2 -Ausstoß abgeschätzt werden. Das Modell wurde validiert und in einer Reihe numerischer Studien eingesetzt. Zuerst wurde eine umfassende Sensitivitätsanalyse zur Effizienz und Nachhaltigkeit entsprechender Anlagen durchgeführt. Weiterhin wird ein Verfahren zur Quantifizierung des technisch nutzbaren, oberflächennahen geothermischen Potentials vorgestellt und anhand einer Fallstudie für die Stadt Köln demonstriert, gefolgt von einer Diskussion der Ergebnisse.
Ganguly, Sayantan. "Analytical and Numerical Modeling for Heat Transport in a Geothermal Reservoir due to Cold Water Injection". Thesis, 2014. http://etd.iisc.ernet.in/handle/2005/2994.
Texto completoKung, Chung-Kuan y 龔仲寬. "Simulation of Energy Consumption and Optimization Control of Geothermal Heat pump System". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/02490080801515725522.
Texto completo國立臺灣大學
機械工程學研究所
100
The purpose of this dissertation is to investigate the optimal design of geothermal heat pump. This dissertation experimentally and mathematically investigates the performance of the geothermal heat pump system which consists of a heat pump and a borehole heat exchanger. Furthermore, optimal method for analyzing the cost influences of the life cycle of the system were developed based on different operation strategies and the capacity of the equipment (combination of heat pumps and borehole heat exchangers). For the performance of the heat pump system, the comparison between the mathematical modeling and the experimental approaches are identical. The relation of correlation R2 is about 0.9867. On the contrary, the capability of the borehole heat exchangers was investigated. The variation of the water temperature inside the cylindrical tube and the outlet water temperature in the spiral pipe were solved by using the thermal resistance method. The result shows that the error of the temperature for spiral pipe outlet and water temperature inside the cylindrical tube with compare to the mathematical model is 0.31% and 3.12%. While in the optimum design, it compares the performances of four updating rules of the particle swarm optimization (PSO) through applying five mathematic problems. The linear-decayed inertia weight method is favorable for this study because stability of solutions can be obtained. This dissertation also developed a solution for the discrete problem of the on-off system in the water pump and heat pump by using PSO with Roulette Wheel Method. Finally a case study was conducted. The geothermal heat pump system was developed in a factory in order to obtain the optimization. The primary parameters include the turn-off states of heat pump and water pump, the heat pump capacity, the UA of heat exchanger, the initial cold and heat water temperature and the capacity of cold and heat tank. The results indicated that the cost of life cycle of the geothermal heat pump system can be reduced by NT 1,446,552, the ratio of energy saving is 56.23%. The energy consumption decrement is 965,756 kJ/day, the ratio of energy saving is 46.50% and the reduction of CO2 emissions is 167 kg/day for a period of 10 years which compare to the conventional boiler combined with chiller.
Leitão, João André Monteiro Martins. "Estudo do potencial de aproveitamento de energia geotérmica de baixa entalpia em Portugal Continental". Master's thesis, 2014. http://hdl.handle.net/10316/38754.
Texto completoO aquecimento global, associado à elevada dependência nos combustíveis fósseis e ao crescente consumo energético, provocou situações dramáticas e impactes ambientais, bem como impactes socio-económicos. No sentido de inverter este cenário surgiram as energias renováveis para produção de energia eléctrica e para reduzir a dependência do petróleo, do carvão, etc., os quais são altamente poluentes e estão nos limites das suas reservas. Neste contexto surge o estudo da Energia Geotérmica. Esta energia, que se encontra no subsolo, tem-se afirmado como uma das alternativas, mas com fraco crescimento, quando comparado com outras energias renováveis. O aproveitamento da energia geotérmica, quer seja de alta entalpia, para produção de energia eléctrica, de baixa entalpia para usos directos ou de muito baixa entalpia para climatização de edifícios, tornase solução evidente, eficaz e rentável face a energias renováveis como a solar ou a eólica, uma vez que pode ser utilizada em continuidade. A energia geotérmica é já bastante usada mundialmente, mas ainda requer incentivos para um maior desenvolvimento em muitos países. No nosso país, apenas na ilha de S. Miguel nos Açores há produção de electricidade de forma significativa através da energia geotérmica, e no Continente basicamente apenas há aproveitamentos dos pólos termais para efeitos de climatização. Este estado insípido de Portugal na utilização da Energia Geotérmica, exige um grande impulso, principalmente a Energia Geotérmica de Baixa Entalpia e de Muito Baixa Entalpia, para que possam ter um papel de destaque no contributo para o mix energético nacional. Com esta dissertação pretende-se contribuir para a divulgação da Energia Geotérmica de Baixa Entalpia e de Muito Baixa Entalpia como alternativa sólida às energias primárias para produção de energia eléctrica, aquecimento e climatização de edifícios.
The Earth global warming, associated with the high dependence on fossil fuels and the ever growing energy consumption, caused dramatic situations and environmental impacts, as well as socio-economic impacts. To reverse this scenario, the use of renewable energy for production must be considered in order to reduce the dependence on oil, coal, etc, which are highly polluting and are within the limits of its reserves. In this context, the study of Geothermal Energy emerges. This energy contained in the Earth underground has established itself as one of the alternatives, but with a feeble growth up to now, when compared with other renewable energy. The use of geothermal energy, whether it be High-Enthalpy, for production of electrical energy, Low- Enthalpy, for direct uses, or Very Low Enthalpy, for buildings air conditioning, becomes an obvious, efficient and cost effective solution, compared to renewable energy such as solar or wind, since it can be used in continuity. Geothermal energy is already widely used worldwide, but it still requires incentives for greater development in many countries. In Portugal, there is electricity production only in the S. Miguel Island in the Azores, and in the Continent there is only exploitation of thermal poles. This insipid state of Portugal in concerning the use of geothermal energy requires a big boost, especially Energy Low and Very Low Enthalpy Geothermal, so that they can have a major role in contributing to the national energy mix. This dissertation aims at contributing for spreading the Geothermal Energy of Low and Very Low Enthalpy as a solid alternative to the primary energies for the production of electricity, heating and cooling of buildings.
Chang, He-Chien y 張合謙. "Investigate of Geothermal Energy Applications and Assisted Air-Conditioning System Energy-A Case Study of Taiwan Sea Gaia Spring Hotel". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/wf3j96.
Texto completo國立臺北科技大學
建築與都市設計研究所
100
As we know, the nature resources in Taiwan is not sufficient, geothermal energy is one of important nature energy. So far 26 famous geothermal places were developed and used in Taiwan. Geothermal energy can be used to generate power, warm up the air condition system, and heat the water; as well as develop the tourism of spring water for leisure and other multiple functions. The operation of air condition unit is occupied 30% of energy consumption in the building equipment. To analyze different parts of the operation of air condition, main power station is occupied 60% sharing, water pump is 11%, air condition box and indoor fan is 13% and others is 16%. Using geothermal energy to assist air condition system will reduce the power consumption on the start of main station and decrease the energy exhaustion. Comparing with traditional air condition, geothermal energy can save the energy, prolong the time of maintenance, extend the life cycle of air condition system and reduce the cost for operation. The thesis is a study of geothermal energy application to assist air-conditioning system to save energy-a case study of Taiwan Sea Gaia Spring Hotel, using spring water with the temperature 90℃~100℃ to assist main power station of air condition, to discuss the possibility to save main power station energy consumption and reduce the energy exhaustion.
Bauer, Johanna Frederike. "On the significance and predictability of geological parameters in the exploration for geothermal energy". Thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E3D2-2.
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