Les systèmes géothermiques de surface extraient l’énergie du sol via un fluide caloporteur circulant dans un échangeur pour une profondeur ne dépassant pas 200 m. Deux typologies d’échangeurs sont généralement utilisées : les systèmes avec échangeurs verticaux, principalement affectés par les conditions géologiques ; et les échangeurs horizontaux, plus proches de la surface du sol, impactés essentiellement par les conditions climatiques. Dans le sol, les échanges thermiques sont majoritairement des transferts de chaleur par conduction. Ainsi, les propriétés thermo-physiques du sol influencent la quantité d’énergie extraite par les échangeurs. Afin de quantifier les propriétés thermo-physiques d’un sol sous l’influence des conditions géologiques et climatiques, deux dispositifs expérimentaux sont élaborés, conçus, instrumentés et validés au sein de notre laboratoire. Les résultats expérimentaux enrichissent les connaissances scientifiques sur le comportement hydrique d’un sol soumis à des événements pluvieux et l’impact de la contrainte verticale sur les propriétés thermo-physiques d’un sol. De plus, une étude numérique, à partir d’une modélisation 2D par éléments finis d’un échangeur airsol, évalue les performances énergétiques de ce dernier en fonction de différentes humidifications du sol et différents scénarios de pluie. Les résultats numériques révèlent ainsi l’intérêt d’utiliser un sol d’enrobage très humide pour accroître significativement les performances énergétiques d’un échangeur air-sol. / Surface geothermal systems extract energy from the ground via a fluid circulating in an exchanger at a depth not exceeding 200 m. Two typologies of exchangers are generally used: systems with vertical exchangers, mainly affected by geological conditions; and horizontal exchangers, closer to the surface of ground, impacted mainly by weather conditions. Thermal exchanges in the soil are mainly conduction heat transfers. Thus, thermo-physical properties of soil influence, mostly, energy extracted by exchangers. In order to quantify influence of geological and meteorological conditions on thermo-physical properties of soil, two experimental devices are developed, designed, instrumented and validated. The experimental results provide more appropriate scientific knowledge on hydric behavior of a soil subjected to rain events and influence of compactness on thermal properties of soil. In addition, one numerical study, based on a finite element 2D modeling of an earth-air heat exchanger, evaluates their energy performance under different soil moisture conditions and rain scenarios thus revealing the utility of water to significantly improve its performance.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-08-04T17:48:21Z No. of bitstreams: 1 Genyr Kappler_.pdf: 7040737 bytes, checksum: b8f3c862e305815a08af95dead0bbfd5 (MD5) / Made available in DSpace on 2016-08-04T17:48:21Z (GMT). No. of bitstreams: 1 Genyr Kappler_.pdf: 7040737 bytes, checksum: b8f3c862e305815a08af95dead0bbfd5 (MD5) Previous issue date: 2016-04-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPERGS - Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul / A energia é considerada a espinha dorsal da economia moderna, e seu consumo se intensifica nas sociedades emergentes a medida que sua qualidade de vida melhora. O atual cenário energético global indica que as fontes convencionais de energia estão se esgotando, evidenciando a importância em se explorar e viabilizar fontes renováveis para suprir a demanda futura. A climatização de ambientes é responsável por uma grande parcela deste consumo de energia, e sistemas bioclimáticos, que utilizam a geotermia e a energia solar fotovoltaica, são alternativas adequadas e ainda pouco explorada para suprimir a necessidade do uso de condicionadores de ar. O solo tem, em certa profundidade, temperatura equivalente à temperatura média anual local. Várias iniciativas têm buscado fazer uso deste recurso através do sistema de troca térmica por dutos enterrados, onde o fluido de troca térmica é o ar, e mais recentemente surgiram estudos com o uso da água como fluido de troca térmica. Neste trabalho é apresentada uma análise experimental que avalia o desempenho de um sistema terra-água-ar, alimentado por energia solar fotovoltaica, para climatização de edificações. O sistema proposto utiliza a estabilidade térmica do solo pelo uso de um reservatório de água (WT) em certa profundidade, que opera como fonte ou dissipador de energia térmica reduzindo a variação da temperatura no interior das edifícações. Um protótipo foi construído e é essencialmente constituído por: um ambiente climatizado (AC) com volume de 0,6 m3, um fan coil; um reservatório (WT) com volume de 0,38 m3, com o fundo enterrado a 2 m abaixo da superfície do solo; e, uma bomba de água. Verificou-se que o sistema proposto manteve a sua temperatura constante e em conformidade com a norma ASHRAE 55 2004 para ambientes naturalmente condicionados, com a temperatura no AC em torno de 23,6 ℃ enquanto a temperatura do ar ambiente variou de 18,8 °C a 29,4 °C, sendo que a temperatura do solo era 21 °C. Para uma taxa de 119 W de calor adicionado no AC, a taxa de remoção de calor no fan coil foi de 98,6 W. Com base nos dados experimentais, o sistema foi validado e a profundidade e tamanho ideais do reservatório de água foram determinados para uma aplicação em escala real. Para o local experimentado foi determinada que a profundidade ideal, com o solo na temperatura constante equivalente a média anual de 18 °C, é entre 6 e 9 m. Um sistema de geração de energia elétrica fotovoltaica foi proposto para alimentar o sistema experimental terra -água-ar. / Energy is considered the backbone of the modern economy and its consumption intensifies in emerging societies as their quality of life improves. The current global energy scenario indicates that conventional energy resources are depleting, highlighting the importance of exploring and enable renewable resources to meet future energy demand. Buildings’ HVAC is responsible for a large portion of domestic energy consumption, and bioclimatic systems, that use geothermal energy and solar photovoltaic, are suitable and still little explored alternatives to eliminate the need for the use of air conditioners. The temperature of soil at a certain depth is equivalent to the local average yearly temperature. Various initiatives have sought to make use of this resource through Earth-Air-Heat-Exchange system, where the fluid used for heat transfer is air, and only recently emerged studies making use of water as a heat transfer fluid. This paper presents an experimental analysis that evaluates the performance of an earth-water-air system powered by photovoltaic solar energy, for conditioning the air of buildings. The proposed system uses the thermal stability of the soil, through the use of a water tank (WT) at a certain depth, which operates as a source or sink for thermal energy thus reducing the temperature variation inside the buildings. A prototype was built and is essentially made up of an air-conditioned environment (AC) with 0.6 m3 volume, one fan coil, a reservoir (WT) with a volume of 0.38 m3, buried with the bottom at 2 m below the ground surface, and a water pump. It was found that the proposed system has kept AC's temperature constant and in agreement with ASHRAE Standard 55 2004 for naturally conditioned environment, with the temperature around 23.6 ℃. The ambient air temperature varied from 18.8 °C to 29.4 °C and the soil temperature was 21 °C. For a 119 W incoming heat rate on the AC, the heat removal rate in the fan coil was 98.6 W. Based on the experimental data, the system has been validated and the optimal depth and size of the water reservoir were determined for an application in real scale. For the analysed site it was determined that the optimum depth to reach the soil at a constant temperature equivalent to the yearly average of 18 °C is between 6 to 9 m. A photovoltaic power generation system is proposed for the earth-water-air experimental system.

Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes that exist in the development of different geo-resources (e.g. deep geothermal and shale gas) affect the fracture response (i.e. aperture and permeability), which in turn influences the reservoir production. The main goal of this study was to experimentally evaluate the impact of THMC processes on the response of rock specimens relevant for deep geothermal and shale gas formations. The effects of THMC processes were investigated on: (i) success of the hydraulic fracturing/hydro-shearing mechanism during stimulation stage, and (ii) closure of the created network of fractures during production stage. The elastic, cyclic, creep, and failure characteristics of different intact reservoir rocks in both short- and long-term were investigated to evaluate their response in stimulation stage. In addition, a series of flow tests on fractured reservoir cores were conducted to evaluate how THMC processes affect fracture response subjected to different stress levels, temperatures, composition of injected fluid, and injection rate. Moreover, the sensitivity of ultrasonic signatures (i.e. velocity, amplitude, attenuation, and time-frequency content) to (i) microstructural changes in the intact rocks, and (ii) flow-induced alterations of aperture/permeability in the fractured rocks were investigated. Analysis of hydraulic data, chemical composition of the effluent, ultrasonic signatures, and X-Ray micro-CT and SEM images, provided invaluable information that facilitated interpretation of the effects of coupled THMC processes on fracture response.

Afin de cartographier la structure souterraine des volcans et détecter des ressources géothermiques de haute température, on utilise souvent l’imagerie de résistivité électrique. La résistivité électrique des volcans est affectée par plusieurs facteurs: volume et salinité de l’eau interstitielle, abondance de minéraux conducteurs, température de la roche et présence de magma. Ce travail de thèse tente de contraindre l'interprétation des structures de résistivité électrique autour des volcans actifs, afin de développer des outils innovants pour l'exploration des ressources géothermiques. La contribution des minéraux conducteurs est au cœur de la thèse: conducteurs ioniques solides (minéraux argileux, en particulier la smectite) ou semi-conducteurs électroniques (pyrite, oxydes de fer), mais l’influence de la porosité, de la salinité, de la température et de la présence de magma est aussi étudiée. La thèse utilise le volcan Krafla comme terrain d’étude pour affiner les interprétations des structures de résistivité électriques, du fait de la disponibilité de carottes, de données, de bibliographie et d’infrastructure. La smectite et la pyrite sont formées par altération hydrothermale des roches volcaniques et témoignent ainsi des convections hydrothermales. Les oxydes de fer en revanche sont plutôt formés lors de la cristallisation du magma et sont dissous lors des circulations hydrothermales. La contribution de la smectite à la conductivité électrique de roches volcaniques, saturées en eau à différentes salinités, est d'abord étudiée en laboratoire (à température ambiante) par spectroscopie d’impédance électrique « résistivité complexe ». Des variations non linéaires de la conductivité électrique à 1 kHz avec la salinité sont observées et discutées. La conduction interfoliaire est suggérée comme un mécanisme important par lequel la smectite conduit le courant électrique. L'influence de la pyrite et des oxydes de fer sur les effets de polarisation provoquée est ensuite analysée en utilisant l'angle de phase de l'impédance, qui dépend de la fréquence. Un angle de phase maximal supérieur à 20 mrad est attribué à la pyrite si la roche est conductrice et aux oxydes de fer si la roche est résistive. L'angle de phase maximal augmente d'environ 22 mrad pour chaque pourcent de pyrite ou d'oxyde de fer. Ces résultats de laboratoire en domaine fréquentiel sont appliqués à l’interprétation de tomographies de résistivité complexe sur le terrain en domaine temporel. Smectite, pyrite et oxydes de fer ont pu être identifiés jusqu'à 200 m de profondeur. La température in-situ, plus élevées qu’en laboratoire, semble augmenter la conductivité de la smectite. De manière générale, la tomographie de résistivité complexe est recommandée comme méthode complémentaire aux sondages électromagnétiques pour l'exploration géothermique. / Electromagnetic soundings are widely used to image the underground structure of volcanoes and look for hightemperature geothermal resources. The electrical resistivity of volcanoes is affected by several characteristics of rocks: volume and salinity of pore fluid, abundance of conductive minerals, rock temperature and presence of magma. This thesis aims at improving the interpretation of electrical resistivity structures around active volcanoes, in order to develop innovative tools for the assessment of geothermal resources. I focus on conductive minerals, which can either be solid ionic conductors (clay minerals, in particular smectite) or electronic semi-conductors (pyrite and iron-oxides), but I also investigate the effects of porosity, salinity, temperature and presence of magma. I use Krafla volcano as a laboratory area, where extensive literature, borehole data, core samples, surface soundings and infrastructures are available. Smectite and pyrite are formed upon hydrothermal alteration of volcanic rocks and thus witness hydrothermal convection. On the other hand, iron-oxides are mostly formed during the primary crystallization of magma and dissolved by hydrothermal fluids. The contribution of smectite to the electrical conductivity of volcanic rocks saturated with pore water at different salinity is first investigated in the laboratory (room temperature) by electrical impedance spectroscopy “complex resistivity”. Non-linear variations of the conductivity at 1 kHz with salinity are observed and discussed. Interfoliar conduction is suggested as an important mechanism by which smectite conducts electrical current. The influence of pyrite and iron-oxides on induced polarization effects is then analyzed, using the frequency-dependent phase-angle of the impedance. A maximum phase-angle higher than 20 mrad is attributed to pyrite if the rock is conductive and to ironoxides if the rock is resistive. The maximum phase-angle increases by about 22 mrad for each additional per cent of pyrite or iron-oxide. These laboratory frequency-domain findings are partly upscaled to interpret field time-domain complex resistivity tomography at Krafla: smectite, pyrite and iron-oxides can be identified down to 200 m. The in-situ temperature, higher than in laboratory conditions, appears to significantly increase the conductivity associated to smectite. In general, time-domain complex resistivity measurements are recommended as a complementary method to electromagnetic soundings for geothermal exploration.

Reasons like increases in the price and demand of energy in the last years, growing interest and support in the renewable energy resources, development of social environmental consciousness, interest in using domestic resources, having legal regulations has promoted the interest in the electricity production from geothermal energy. For the effective and productive use of existing resources, important data of geothermal regions are obtained with well tests. Well tests are the studies which starts while the well is drilling, continues after the well completion during the process of operation planning with optimum performance suitable to geothermal source and presents continuation also in the operation stage as required for the dynamic structure of geothermal systems. In Aydin Kuyucak Pamuk&ouml / ren region three wells are drilled, achieved results are positive. At AP1 well only CO2 emission is present, no test is done for this well. With the tests for AP2 and AP3 wells temperature, pressure and production values are determined. By the results of these tests, it is determined that this region will be one of the important fields in the West Anatolian Region with current temperature and production rate. In this study, the geothermal energy recoverable from this region is calculated with volume method of geothermal resource assessment. Monte Carlo simulation technique is used with an add-in software program @RISK to Microsoft EXCEL. Electrical power capacity of Aydin-Pamuk&ouml / ren geothermal field is determined as 45.2 MW with 90 % probability. The most likely electrical power value was found to be 78.75 MW with a probability of 69 %. The number of wells required are 10 for a production capacity of 200 t/hr and 7 for a production capacity of 300 t/hr at each well head.

ABSTRACT APPLICATION OF NON-MARKET ECONOMIC VALUATION METHOD TO VALUE THE ENVIRONMENTAL BENEFITS OF GEOTHERMAL ENERGY IN MONETARY TERMS: A CASE STUDY IN YOZGAT PROVINCE Horasanli, Erol M.Sc., Department of Environmental Engineering Supervisor: Assist. Prof. Dr. Emre ALP December 2010, 100 pages Determining environmental economic benefits of geothermal energy is difficult since there is no market for all environmental goods and services related to it. In order to determine and measure the market price of non-market goods and services, non-market valuation methods are used. Since intangible benefits do not have monetary values, non-market valuation techniques are applied to estimate them. Non-market valuation methods are important tools for policy makers in the cost and benefit analysis and environmental impact assessment process to aid their final decision. In this study, the Contingent Valuation Method (CVM) was used to determine the environmental benefits of using geothermal energy for house heating instead of fossil fuels and natural gas in Yozgat (center). The willingness to pay for geothermal energy of the Yozgat residents was determined and underlying motivations to use geothermal energy were assessed. The results showed that the mean willingness to pay (WTP) for the usage of geothermal energy in house heating to increase air quality and mitigate the effects v of climate change is $50/person/month. The results also showed that respondents know the importance of the climate changes and they believe that geothermal energy usage will affect the mitigation of climate changes positively. The geothermal energy investment in the region will amortize itself in 3 years. Therefore, in the feasibility studies, geothermal energy investment seems feasible. During the regression analyses, climate change and air pollution parameters were the most significant parameters for the calculation of mean WTP. Since, decrease in air pollution using geothermal energy, will also mitigate the effect of climate changes, during the geothermal investment in the region, training activities and campaigns should be carried to cover the issues of climate change and global warming to emphasis that geothermal energy will serve for multi-dimensional environmental problems.

Numerical analysis of multi-field problems in porous and fractured media is an important subject for various geotechnical engineering tasks such as the management of geo-resources (e.g. engineering of geothermal, oil and gas reservoirs) as well as waste management. For practical usage, e.g. for geothermal, simulation tools are required which take into account both coupled thermo-hydro-mechanical (THM) processes and the uncertainty of geological data, i.e. the model parametrization. For modeling fractured rocks, equivalent porous medium or multiple continuum model approaches are often only the way currently due to difficulty to handle geomechanical discontinuities. However, they are not applicable for prediction of flow and transport in subsurface systems where a few fractures dominates the system behavior. Thus modeling coupled problems in discretely fractured porous media is desirable for more precise analysis. The subject of this work is developing a framework of the finite element method (FEM) for modeling coupled THM problems in discretely fractured and non-fractured porous media including thermal water flow, advective-diffusive heat transport, and thermoporoelasticity. Pre-existing fractures are considered. Systems of discretely fractured porous media can be considered as a problem of interacted multiple domains, i.e. porous medium domain and discrete fracture domain, for hydraulic and transport processes, and a discontinuous problem for mechanical processes. The FEM is required to take into account both kinds of the problems. In addition, this work includes developing a methodology for the data uncertainty using the FEM model and investigating the uncertainty impacts on evaluating coupled THM processes. All the necessary code developments in this work has been carried out with a scientific open source project OpenGeoSys (OGS). In this work, fluid flow and heat transport problems in interactive multiple domains are solved assuming continuity of filed variables (pressure and temperature) over the two domains. The assumption is reasonable if there are no infill materials in fractures. The method has been successfully applied for several numerical examples, e.g. modeling three-dimensional coupled flow and heat transport processes in discretely fractured porous media at the Gross Schoenebck geothermal site (Germany), and three-dimensional coupled THM processes in porous media at the Urach Spa geothermal site (Germany). To solve the mechanically discontinuous problems, lower-dimensional interface elements (LIEs) with local enrichments have been developed for coupled problems in a domain including pre-existing fractures. The method permits the possibility of using existing flow simulators and having an identical mesh for both processes. It enables us to formulate the coupled problems in monolithic scheme for robust computation. Moreover, it gives an advantage in practice that one can use existing standard FEM codes for groundwater flow and easily make a coupling computation between mechanical and hydraulic processes. Example of a 2D fluid injection problem into a single fracture demonstrated that the proposed method can produce results in strong agreement with semi-analytical solutions. An uncertainty analysis of THM coupled processes has been studied for a typical geothermal reservoir in crystalline rock based on the Monte-Carlo method. Fracture and matrix are treated conceptually as an equivalent porous medium, and the model is applied to available data from the Urach Spa and Falkenberg sites (Germany). Reservoir parameters are considered as spatially random variables and their realizations are generated using conditional Gaussian simulation. Two reservoir modes (undisturbed and stimulated) are considered to construct a stochastic model for permeability distribution. We found that the most significant factors in the analysis are permeability and heat capacity. The study demonstrates the importance of taking parameter uncertainties into account for geothermal reservoir evaluation in order to assess the viability of numerical modeling.

Die Broschüre ist im Projekt TransGeoTherm entstanden und bietet Bauherren, Planungsbüros, Behörden und interessierten Bürgern in der sächsisch-polnischen Neiße-Region eine Anleitung zur Nutzung der oberflächennahen Geothermie. Inhalt sind Informationen zum rechtlichen und planerischen Rahmen, zu verschienenen Technologien und der Funktionsweise von Erdwärmeanlagen, zu den Anforderungen an Bauausführung und Betrieb sowie Karten zur Erdwärmenutzung. Enthalten sind auch die hydrogeologischen und wasserrechtlichen Kriterien zur Beurteilung der Genehmigungsfähigkeit sowie die für die Antragsstellung erforderlichen Formulare. / W niniejszej broszurze informacyjnej opisano sposoby wykorzystania energii geotermalnej ze szczególnym uwzględnieniem gruntowych pomp ciepła oraz określono podstawy prawne i zalecany plan czynności technicznych podczas ich instalacji. Podsumowując działania zrealizowane w ramach projektu TransGeoTherm oraz nabyte w jego efekcie doświadczenia, należy stwierdzić, że jest on istotnym świadectwem społecznej akceptacji nowych technologii i wzrastającego wykorzystania potencjału energii geotermalnej w Polsce i Saksonii oraz efektywnej współpracy instytucji z obu stron granicy polsko-niemieckiej.

Erdwärme ist eine regenerative Energieform und durch ihre vergleichsweise leichte Erschließbarkeit auch im privaten Bereich für die Energieversorgung einsetzbar. Das Merkblatt gibt einen Überblick über die Nutzung der im Grundwasser gespeicherten Wärme mit Grundwasserwärmepumpenanlagen. Diese Anlagen stellen eine Möglichkeit dar, oberflächennahe Geothermie zu nutzen. Dazu werden die hydrologischen und hydrogeologischen Aspekte sowie die Anforderungen an Planung, Bau und Betrieb dieser Anlagen dargestellt. Die Ausführungen des Merkblattes gelten sowohl für kleine Anlagen bis 30 Kilowatt Heizleistung als auch für große Anlagen (>30 Kilowatt). Es richtet sich vorrangig an Bauherren und Betreiber, Planungsfirmen, Behörden, aber auch an die interessierte Öffentlichkeit.

Die Broschüre ist im Projekt TransGeoTherm entstanden und bietet Bauherren, Planungsbüros, Behörden und interessierten Bürgern in der sächsisch-polnischen Neiße-Region eine Anleitung zur Nutzung der oberflächennahen Geothermie. Inhalt sind Informationen zum rechtlichen und planerischen Rahmen, zu verschienenen Technologien und der Funktionsweise von Erdwärmeanlagen, zu den Anforderungen an Bauausführung und Betrieb sowie Karten zur Erdwärmenutzung. Enthalten sind auch die hydrogeologischen und wasserrechtlichen Kriterien zur Beurteilung der Genehmigungsfähigkeit sowie die für die Antragsstellung erforderlichen Formulare. / W niniejszej broszurze informacyjnej opisano sposoby wykorzystania energii geotermalnej ze szczególnym uwzględnieniem gruntowych pomp ciepła oraz określono podstawy prawne i zalecany plan czynności technicznych podczas ich instalacji. Podsumowując działania zrealizowane w ramach projektu TransGeoTherm oraz nabyte w jego efekcie doświadczenia, należy stwierdzić, że jest on istotnym świadectwem społecznej akceptacji nowych technologii i wzrastającego wykorzystania potencjału energii geotermalnej w Polsce i Saksonii oraz efektywnej współpracy instytucji z obu stron granicy polsko-niemieckiej.