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1
Richter, Marcus, Christian Huber, Katrin Reinhardt, Hendrik Wachmann, and Axel Gerschel. "Geothermienutzung in sächsischen Gartenbaubetrieben." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-165045.
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Die Broschüre beschreibt Möglichkeiten der Wärmeversorgung von sächsischen Gartenbaubetrieben mit Geothermie in Abhängigkeit von geologischen Standortfaktoren und Betriebsstrukturen/ Nutzungskonzepten.
Ziel des Projektes war, für die Beheizung von Gewächshäusern den Einsatz von Geothermie zur Grundlastversorgung zu untersuchen. Hervorzuheben ist hierbei die Verknüpfung der geologischen/geothermisch und gärtnereitechnischen Komponente. Die Ergebnisse zeigen, welches geothermische System die wirtschaftlichste Variante für Gewächshäuser und deren Nutzung ist.
Das Projekt stellt eine Entscheidungsgrundlage für die Nutzung von Geothermie in sächsischen Gartenbaubetrieben dar.
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Sharma, Prajesh. "Potential of Geothermal Energy in India." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40524.
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In this research paper, review of world geothermal energy production and their capacity is shown. Here, a research is conducted to know the potential and possibility of geothermal energy in India. All the geothermal province with their geographical locations are shown and a brief calculation is conducted in order to show the potential of the particular province. As India is having the low temperature geothermal fields, binary geothermal plants are used for this analysis and results are calculated by using R134a as a working fluid at different temperatures. The results are sufficient to prove the potential of geothermal energy in India. Importance of Ground Source Heat Pump (GSHP) and power savings by its contribution over traditional heating and cooling methods is shown statistically. 9 different states of India are divided by their climatic condition, severe winter and moderate winter to calculate the heat demand in those states. Also, for the cold demands these states are considered to be same as per the climatic situation in summer. Then, comparison is done between GSHP and the traditional heating and cooling systems. The result shows the drastic power saving by using GSHP for space heating as well as cooling, over electric heater and air conditioner respectively.
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Hand, Theodore Wayne. "Hydrogen Production Using Geothermal Energy." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/39.
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With an ever-increasing need to find alternative fuels to curb the use of oil in the world, many sources have been identified as alternative fuels. One of these sources is hydrogen. Hydrogen can be produced through an electro-chemical process. The objective of this report is to model an electrochemical process and determine gains and or losses in efficiency of the process by increasing or decreasing the temperature of the feed water. In order to make the process environmentally conscience, electricity from a geothermal plant will be used to power the electrolyzer. Using the renewable energy makes the process of producing hydrogen carbon free. Water considerations and a model of a geothermal plant were incorporated to achieve the objectives. The data show that there are optimal operating characteristics for electrolyzers. There is a 17% increase in efficiency by increasing the temperature from 20ºC to 80ºC. The greater the temperature the higher the efficiencies, but there are trade-offs with the required currents.
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Clarke, Joshua. "Optimal design of geothermal power plants." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3472.
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The optimal design of geothermal power plants across the entire spectrum of meaningful geothermal brine temperatures and climates is investigated, while accounting for vital real-world constraints that are typically ignored in the existing literature. The constrained design space of both double-flash and binary geothermal power plants is visualized, and it is seen that inclusion of real-world constraints is vital to determining the optimal feasible design of a geothermal power plant. The effect of varying condenser temperature on optimum plant performance and optimal design specifications is analyzed. It is shown that condenser temperature has a significant effect on optimal plant design as well. The optimum specific work output and corresponding optimal design of geothermal power plants across the entire range of brine temperatures and condenser temperatures is illustrated and tabulated, allowing a scientifically sound assessment of both feasibility and appropriate plant design under any set of conditions. The performance of genetic algorithms and particle swarm optimization are compared with respect to the constrained, non-linear, simulation-based optimization of a prototypical geothermal power plant, and particle swarm optimization is shown to perform significantly better than genetic algorithms. The Pareto-optimal front of specific work output and specific heat exchanger area is visualized and tabulated for binary and double-flash plants across the full range of potential geothermal brine inlet conditions and climates, allowing investigation of the specific trade-offs required between specific work output and specific heat exchanger area. In addition to the novel data, this dissertation research illustrates the development and use of a sophisticated analysis tool, based on multi-objective particle swarm optimization, for the optimal design of geothermal power plants.
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Vahland, Sören. "Analysis of Parabolic Trough Solar Energy Integration into Different Geothermal Power Generation Concepts." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129093.
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The change in climate as a consequence of anthropogenic activities is a subject ofmajor concerns. In order to reduce the amount of greenhouse gas emissions inthe atmosphere, the utilization of renewable, fossil-free power generationapplications becomes inevitable. Geothermal and solar energy play a major rolein covering the increased demand for renewable energy sources of today’s andfuture’s society. A special focus hereby lies on the Concentrating Solar Powertechnologies and different geothermal concepts. The costs for producingelectricity through Concentrating Solar Power and therefore Parabolic Trough Collectorsas well as geothermal conversion technologies are still comparatively high. Inorder to minimize these expenses and maximize the cycle’s efficiency, thepossible synergies of a hybridization of these two technologies becomeapparent. This thesis therefore investigates the thermodynamic and economicbenefits and drawbacks of this combination from a global perspective. For that,a Parabolic Trough Collector system is combined with the geothermal conversionconcepts of Direct Steam, Single and Double Flash, Organic Rankine as well asKalina Cycles. The solar integrations under investigation are Superheat,Preheat and Superheat & Reheat of the geothermal fluid. The thermodynamicanalysis focuses on the thermal and utilization efficiencies, as well as therequired Parabolic Trough Collector area. The results indicate that in the caseof the Superheat and Superheat & Reheat setup, the thermal efficiency canbe improved for all geothermal concepts in comparison to their correspondinggeothermal stand-alone case. The Preheat cases, with the major contributionfrom solar energy, are not able to improve the cycle’s thermal efficiencyrelative to the reference setup. From an exergy perspective the findings varysignificantly depending on the applied boundary conditions. Still, almost allcases were able to improve the cycle’s performance compared to the referencecase. For the economic evaluation, the capital investment costs and thelevelized costs of electricity are studied. The capital costs increasesignificantly when adding solar energy to the geothermal cycle. The levelizedelectricity costs could not be lowered for any hybridization case compared tothe reference only-geothermal configurations. The prices vary between20.04 €/MWh and 373.42 €/MWh. When conducting a sensitivity analysison the solar system price and the annual mean irradiance, the Kalina Superheatand Superheat & Reheat, as well as the Organic Rankine Preheathybridizations become cost competitive relative to the reference cases.Concluding, it is important to remark, that even if the hybridization of the ParabolicTrough and the different geothermal concepts makes sense from a thermodynamicperspective, the decisive levelized costs of electricity could not be improved.It is, however, possible that these costs can be further reduced under speciallocal conditions, making the addition of Parabolic Trough solar heat tospecific geothermal concepts favorable.
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Gradeen, Rachael. "Utilizing geothermal heat and membrane distillation for sustainable greenhouse horticulture in Alberta, Canada: a multi-criteria analysis." Thesis, Uppsala universitet, Naturresurser och hållbar utveckling, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413513.
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Growing populations are contributing to resource scarcity, making it ever more important for governments to address resource challenges in a holistic and integrated manner. Energy, water and food are examples of these critical resources, and the province of Alberta in Canada faces an interesting opportunity to tackle all three in tandem. Alberta struggles with food insecurity, with one in ten households affected on an annual basis. The province has the additional issue of an abating fossil fuel-based energy sector. Retrofitting oil and gas wells to harness geothermal heat is a possible initiative that encourages an energy transition and boasts lesser environmental impacts. Further, combining geothermal heat with agricultural greenhouse production and thermally driven water filtration systems has the potential to reduce food insecurity and water scarcity in the province. The system thus handles all three food, energy and water security at once. As such, this report compares the overall sustainability of a conventional, natural gas-burning greenhouse against a novel, geothermally-heated greenhouse featuring thermally driven water filtration (membrane distillation) technology. The area of study is constrained to the greenhouse-rich region in Alberta between Edmonton and Red Deer that also has a high accessibility to geothermal heat. The comparison is conducted through a multi-criteria analysis following economic, social and environmental objectives, and is analyzed using quantitative data, scientific literature and surveys. The results indicate that the novel greenhouse exhibits a higher score as compared to the conventional greenhouse, implying that it is the preferred option on economic, social and environmental bases. The results are in keeping with economic and technical feasibility reports, though they shed new light on the social and environmental aspects – which were under-studied in the province. The geothermally-heated greenhouse system with membrane distillation acts as a holistic solution that targets energy, water and food issues in tandem, while contributing to Canada’s Sustainable Development Goals. The novel greenhouse is an avenue of exploration and development by policy-makers, greenhouse operators and researchers interested in attaining sustainable agriculture in Alberta, Canada.
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Lloyd, Caleb Charles. "A Low Temperature Differential Stirling Engine for Power Generation." Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/2916.
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There are many sources of free energy available in the form of heat that is often simply wasted for want of an effective way to convert it into useful energy such as electricity. The aim of this research project is to design and build a low temperature differential Stirling engine capable of generating electric power from heat sources such as waste hot water or geothermal springs.
The engine that has been developed is a research prototype model of a new type of design featuring a rotating displacer which is actuated by a pair of stepper motors. The rotating displacer design enables the use of readily available and comparatively cheap and robust steam pipe as the housing for the engine, and it also avoids problems associated with sealing and heat exchange that would be present in a large engine of a more traditional configuration. Owing to the fact that this engine is a research prototype, it has the ability to have some of its critical operating parameters such as phase angle and stroke length adjusted to investigate the effects on performance. When the next phase of development takes place most of these parameters will be fixed at the optimum values which will make manufacture cheaper and easier.
Unfortunately, construction of the prototype engine has not been completed at the time of writing so no power producing results have been achieved; however thorough results are presented on the operation of the control system for the stepper motors which actuate the displacer. Additionally, after a thorough history and background of Stirling engines was researched, the understanding gained of how these engines work has enabled a design process to take place which has hopefully led to a successful design. Analysis of various aspects of the engine have been carried out and results look promising for the engine to produce around 500 Watts of electrical power output whilst running on hot water up to around 90°C.
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Rehn, Alexander W. (Alexander William). "Nanoengineered surfaces for improvements in energy systems : application to concentrated solar and geothermal power plants." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76971.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 140-148).
The main drawback to renewable energy systems is the higher cost of production compared to competitors such as fossil fuels. Thus, there is a need to increase the efficiency of renewable energy systems in an effort to make them more cost competitive. In this study, the use of nanosurfaces is evaluated for its benefits in improving the efficiency of a concentrated solar tower power system by increasing the energy retained by the receiver surface, and for reducing the fouling on geothermal heat exchangers. The samples tested for the solar receiver application were Inconel 617, Inconel 617 with a 150 nm layer of platinum, Inconel 617 with a 150 nm layer of platinum and a 550 nm layer of nickel oxide, oxidized nickel, and silicon carbide. The experimental results indicated that the platinum was an ineffective diffusion barrier, nickel oxide displays solar selective properties, and silicon carbide would be the best choice for a surface among the samples tested. This indicates that at the operating temperatures for this receiver at 700 °C, a black body surface is more effective than a practical solar selective surface. The nanosurfaces tested for the antifouling application in geothermal systems were subjected to chemistry conditions similar to that in a Dry Cooling Tower at a geothermal plant in Larderello, Italy. Each sample's performance was measured by determining each samples weight change and surface characterization after exposure in an experimental loop. The best performing coatings, all of which showed negligible weight gain, were the Curran 1000 coating from Curran International, the Curran 1000 coating with nanographene, and the Curralon coating with PTFE. Upon further analysis, the Curran 1000 with nanographene was identified as the most promising coating option.
by Alexander W. Rehn.
S.M.
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Corr, 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.
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Yekoladio, 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.
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The present work addresses the thermodynamic optimization of small binary-cycle geothermal power plants. The optimization process and entropy generation minimization analysis were performed to minimize the overall exergy loss of the power plant, and the irreversibilities associated with heat transfer and fluid friction caused by the system components. The effect of the geothermal resource temperature to impact on the cycle power output was studied, and it was found that the maximum cycle power output increases exponentially with the geothermal resource temperature. In addition, an optimal turbine inlet temperature was determined, and observed to increase almost linearly with the increase in the geothermal heat source. Furthermore, a coaxial geothermal heat exchanger was modeled and sized for minimum pumping power and maximum extracted heat energy. The geofluid circulation flow rate was also optimized, subject to a nearly linear increase in geothermal gradient. In both limits of the fully turbulent and laminar fully-developed flows, a nearly identical diameter ratio of the coaxial pipes was determined irrespective of the flow regime, whereas the optimal geofluid mass flow rate increased exponentially with the Reynolds number. SeveORCs were observed to yield maximum cycle power output. The addition of an IHE and/or an Oral organic Rankine Cycles were also considered as part of the study. The basic types of the FOH improved significantly the effectiveness of the conversion of the available geothermal energy into useful work, and increased the thermal efficiency of the geothermal power plant. Therefore, the regenerative ORCs were preferred for high-grade geothermal heat. In addition, a performance analysis of several organic fluids was conducted under saturation temperature and subcritical pressure operating conditions of the turbine. Organic fluids with higher boiling point temperature, such as n-pentane, were recommended for the basic type of ORCs, whereas those with lower vapour specific heat capacity, such as butane, were more suitable for the regenerative ORCs.Dissertation (MEng)--University of Pretoria, 2013.
Mechanical and Aeronautical Engineering
unrestricted
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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.
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The building stock in the European Union accounts for over 40% of final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive (EPBD) and Energy Efficiency Directive (EED). In this study, a simulation model of an office-building complex utilizing district heating was created using transient simulation software TRNSYS. The model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. The system designs were comprised of a geothermal energy system in combination with a PV-system and electricity storage. It was concluded that the systems were sufficient in maintaining an adequate indoor climate. Furthermore, the investments were ascertained as profitable and resulted in a decreased building specific energy demand.
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Luermann, Július. "Návrh Kalinova cyklu a určení hlavních rozměrů jeho tepelné turbiny pro geotermální elektrárnu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230161.
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This master’s thesis analyses Kalina cycle, a power cycle where ammonia – water solution is used as a working fluid. The first part of this study introduces us to the Kalina cycle, presents its advantages and disadvantages, characteristics of the working fluid and its applications. Second section concerns with the method of cycle design and describes the calculation model made in this thesis. The calculation model is attached in a separate .XLSM file. The third part shows calculation of the cycle for given parameters, determination of cycle efficiency and main proportions of the thermal turbine. In the conclusion are the interpretations of the calculations results.
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Žostautas, Mauricijus. "Pastato aprūpinimas šiluma šilumos siurbliu su šiluminiu poliumi." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120726_163216-10722.
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Baigiamajame magistro darbe nagrinėjamas pastato, aprūpinimas šiluma šilumos siurbliu su šiluminiais poliais. Yra apžvelgtos esamos giliosios bei sekliosios geoterminės energijos panaudojimo panaudojimo galimybės Lietuvoje. Aprašytos prielaidos ir supaprastinimai šiluminių polių skaičiavimui, aprašytos skaičiavimo metodikos. Atlikti šiluminių polių skaičiavimai, naudojantis penkiomis metodikomis. Aprašytas pasirinktas pastatas, apskaičiuoti atitvarų šiluminiai rodikliai, nustatyta pastatui reikalinga šiluminė galia. Naudojantis „Design builder“ modeliavimo programa sukurtas pastato modelis ir apskaičiuoti pastato šilumos bei vėsos poreikiai metų laikotarpiu. Pagal nustatytus poreikius modeliavimo programa „EED“ sumodeliuoti šildymo vėsinimo ciklai dvidešimt penkeriems metams į priekį. Sistema palyginta su baziniu šilumos šaltiniu. Išnagrinėjus gautus rezultatus pateikiamos rekomendacijos bei baigiamojo darbo išvados. Darbą sudaro 11 dalių: įvadas, geoterminės energijos panaudojimo galimybės Lietuvoje, šilumos siurblių tipai, šiluminių polių skaičiavimo metodikos bei skaičiavimai, nagrinėjamo pastato aprašymas, pastato šiluminės galios skaičiavimas, pastato šilumos/vėsos poreikių modeliavimas „Design builder“ programa, šiluminių polių skaičiavimas „EED“ programa, nagrinėjamos sistemos palyginimas su baziniu šilumos šaltiniu, rekomendacijos, išvados ir literatūros sąrašas. Darbo apimtis 68 p. teksto be priedų, 49 iliustr., 16 lent., 29 literatūros šaltiniai.The final master thesis presents analysis of heat supply to the building using a heat pump with energy piles. There is an overview of shallow and deep geothermal energy utilization current possibilities in Lithuania. The assumptions and simplifications of the calculation for the energy piles are described as well as the calculation methodology. Calculations of the energy piles are performed, using five methods. The chosen building is described, thermal performance of partitions are calculated and the building heating capacity is calculated. . Using the "Design Builder" building simulation program a model was generated and the calculations of annual heating and cooling demand are performed. According to the demand of building using simulation program "EED" heating /cooling cycles are calculated of twenty-five years ahead. The system was compared with the basic heat source. After analyzing all results conclusions are given. Thesis consists of 11 parts: introduction, overview of geothermal energy resources usage posibilities in Lithuania, types of heat pumps, calculation methods and calculations of energy piles, description of the building data, calculation of building heating system power, simulation of heat /cooling demand of the building with "Design Builder" program, calculation of energy piles with "EED" modeling program, Comparison of the system with the basic source of heat, recommendations, conclusions and references, Volume of the thesis 68 p. of the text... [to full text]
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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.
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Pagrindinės šiame darbe sprendžiamos problemos yra susijusios su efektyviu ilgalaikiu šilumos siurblių eksploatavimu. Šilumos siurblio sistemos kintamuoju priimamas gruntinis šilumokaitis. Tai reiškia, kad šilumos siurblio efektyvumas priklausys nuo šilumnešio temperatūros gruntiniame šilumokaityje. Pirmoje darbo dalyje pateikiama informacija apie geoterminę energiją bei jos naudojimo būdus. Apibrėžiama seklioji geoterminė energija. Pateikiamos šilumos siurblių šilumokaičių schemos. Praktinėje darbo dalyje pateikiama gruntinių šilumokaičių modeliavimo metodų analizė bei pasirenkamas metodas tolimesniam modeliavimui. Modeliuojami trijų skirtingų tipų vertikalūs gruntiniai šilumokaičiai. Modeliavimo rezultatas: šilumnešio vidutinės mėnesinės temperatūros 25 metų laikotarpiui. Pagal temperatūras nustatomas šilumos siurblio vidutinis mėnesinis efektyvumo koeficientas. Naudojant efektyvumo koeficientus apskaičiuojamas elektros energijos poreikis. Atliekama ekonominė analizė. Analizės rezultatai parodė, kad efektyviausias vertikalus gruntinis šilumokaitis, prie darbe priimtų modeliavimo sąlygų, yra viengubas gruntinis šilumokaitis su dviem U-formos vamzdžiais.The 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.
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Hoegel, Benedikt. "Thermodynamics-based design of stirling engines for low-temperature heat sources." Thesis, University of Canterbury. Mechanical Engineering, 2014. http://hdl.handle.net/10092/9344.
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Large amounts of energy from heat sources such as waste-eat and geothermal energy are available worldwide but their potential for useful power-generation is largely untapped. This is because they are relatively low temperature difference (LTD) sources, in the range from 100 to 200 °C, and it is thermodynamically diffcult, for theoretical and practical reasons, to extract useful work at these temperatures. This work explores the suitability of a Stirling engine (SE) to exploit these heat sources. Elsewhere much work has been done to optimise Stirling engines for high temperature heat sources, but little is known about suitable engine layouts, and their optimal design and operational aspects at lower temperature differences. With the reduced temperature difference, changes from conventional engine designs become necessary and robust solutions for this novel application have to be identified.
This has been achieved in four major steps: identification of a suitable engine type; thermodynamic optimisation of operating and engine parameters; optimisation of mechanical efficiency; and the development of conceptual designs for the engine and its components informed by the preceding analysis. For the optimisation of engine and operating parameters a model was set up in the commercial Stirling software package, Sage, which also has been validated in this thesis; suitable parameter combinations have been identified.
This work makes key contributions in several areas. This first is the identification of methods for better simulating the thermodynamic behaviour of these engines. At low temperature differences the performance of Stirling engines is very sensitive to losses by fluid friction (and thus frequency), adiabatic temperature rise during compression, and the heat transfer from and to the surroundings. Consequently the usual isothermal analytical approaches produce results that can be misleading. It is necessary to use a non-isothermal approach, and the work shows how this may be achieved.
A second contribution is the identification of the important design variables and their causal effects on system performance. The primary design variable is engine layout. For an engine having inherently low efficiency due to the low temperature difference it is important to choose the engine layout that provides the highest power density possible in order to minimise engine size and to save costs. From this analysis the double-acting alpha-type configuration has been identified as being the most suitable, as opposed to the beta or gamma configurations. An-other key design variable is working fluid, and the results identify helium and hydrogen as suitable, and air and nitrogen as unsuitable. Frequency and phase angle are other design variables, and the work identifies favourable values. A sensitivity analysis identifies the phase angle, regenerator porosity, and temperature levels as the most sensitive parameters for power and efficiency. It has also been shown that the compression work in low-temperature difference Stirling engines is of similar magnitude as the expansion work. By compounding suitable working spaces on one piston the net forces on the piston rod can be reduced significantly. In double-acting alpha-engines this can be achieved by choosing the Siemens as opposed to the Franchot arrangement. As a result friction and piston seal leakage which are two important loss mechanisms are reduced significantly and longevity and mechanical efficiency is enhanced. Design implications are identified for various components, including pistons, seals, heat exchangers, regenerator, power extraction, and crankcase. The peculiarities of the heat source are also taken into account in these design recommendations.
A third key contribution is the extraction of novel insights from the modelling process. For the heat exchangers it has been shown that the hot and cold heat exchangers can be identical in their design without any negative impact on performance for the low-temperature difference situation. In comparison the high temperature applications invariably require different materials and designs for the two heat exchangers. Also, frequency and phase angle are found to be quite different (lower frequency and higher phase angle) from the optimum parameters found in high temperature engines. Contrary to common belief the role of dead volume has been found to play a crucial and not necessary detrimental role at low temperature differentials.
Taken together, the work is positioned at the intersection of thermodynamic analysis and engineering design, for the challenging area of Stirling engines at low temperature differences. The work extracts thermodynamic insights and extends these into design implications. Together these help create a robust theoretical and design foundation for further research and development in the important area of energy recovery.
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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.
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The thesis concerns of the possibility by using alternative decentralized sources of energy. The first chapter describes current energy situation in the Czech Republic and consideration of future electrical energy consumption and the coverage by the renewable sources. Another part of this chapter describes each types of renewable energy with their advantages and disadvantages related to the Czech Republic. In the second chapter are introduced inputs which are appropriate for the plan of energetic system. The following theoretical chapter deals with each types of alternative energy sources using renewable source including the possibility of the installation and plan for the building. These alternative sources are sorted out by the way of using renewable sources of energy. The theoretical-practical fourth chapter concerns of the heating by the heat pump. For the detailed description was chosen the heat pump which is currently denote as appropriate alternative source of heat in household. With appropriate plan, which the thesis deals with, is this alternative source considered as proper investment. In the last chapter was assembled programme for creating models of energetic flux and calculation for the plan of heating by the heating pump air/water. This model is taken for concrete buildings related to exact outdoor temperature from previous years in concrete locality. In the end was realized validation of the software with the real measurement in concrete building.
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Fernandes, Felipe Teixeira. "Aumento da eficiência de painéis fotovoltaicos com esfriamento por energia geotérmica e aquecimento de água." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/8541.
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This thesis deals with the increased efficiency of photovoltaic panels (PVs) through
cooling the cells by geothermal energy and water heating. Initially, a photovoltaic modeling is
made proposing an equation to obtain the maximum power point considering the variations of
solar radiation and cell temperature. Initially, it is proposed a PV modeling for obtaining the
maximum power point (MPP) as a function of solar radiation and temperature of the cells by
the PV 5-parameter model. Thus, the determination of the PV MPP, which depends only on
the internal parameters, can be made with greater precision. Water circulation by a pipe that
passes through the thermal reservoir is used to cool the PV. This is complemented by cooling
hoses buried underground to exchange geothermal avoiding the saturation of the heat
exchange between PV and water circulation, increasing the PV efficiency. After studies on the
constitution of the soil, the technical characteristics of the tubes for circulating water,
hydraulic pump and heat exchanger installed after PV, economic analysis and a set of two
PVs were mounted with and without the heat exchangers to verify the gains in power and
performance. The experiments were made with two PVs operating in MPP, proving that the
MPP and the performance increase with decreasing temperature as the modeling performed.
During the experiments, the underground temperature varied slightly, avoiding the heat
exchange saturation. The main contributions include the PV modeling to obtain the MPP with
a single iteration, the use of geothermal energy without heat pump and residential heat load
reduction by use of heated water circulation in PVs.Esta dissertação trata do aumento da eficiência de painéis fotovoltaicos (PVs) através do esfriamento das células por energia geotérmica e aquecimento de água. Inicialmente, é proposto um equacionamento para obtenção do ponto de máxima potência (MPP) de PVs em função da radiação solar e da temperatura das células, considerando o modelo PV de cinco parâmetros. Assim, a determinação do MPP, que depende somente dos parâmetros internos, pode ser feita com maior precisão. Para esfriar o PV, utilizou-se a circulação de água numa canalização que passa por reservatório térmico. Este esfriamento é complementado por mangueiras enterradas no subsolo para troca de energia geotérmica evitando a saturação da troca de calor entre PV e água de circulação, aumentando a eficiência do PV. Após estudos sobre a constituição do solo, características técnicas dos tubos para a circulação de água, bomba hidráulica e trocadores de calor instalados atrás do PV, foi feita a análise econômica e montagem de um sistema com dois PVs, sendo um deles em conjunto com os trocadores de calor e outro sem para verificar os ganhos de potência e rendimento. Experimentos foram realizados com os dois PVs operando em MPP, onde se comprova que o MPP e o rendimento aumentam com a diminuição da temperatura conforme a modelagem realizada. Durante os experimentos, o subsolo sofreu pouca variação térmica de modo a evitar a saturação da troca de calor. Dentre as principais contribuições destacam-se a modelagem para obtenção do MPP de PVs com uma única iteração, viabilização do uso de energia geotérmica sem bombeamento de calor e redução de carga térmica residencial pelo aproveitamento da água aquecida no PV.
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Vacek, Tomáš. "Posouzení možnosti připojení kogenerační výrobny 138 MW v Prostějově." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219083.
Full textAbstract:
The goal of this project is to test the possibility to connect the Cogenerational generation of power 138 MW (still in the development stage) to the control room 110 kV in Prostejov production. This merge would product the electrical energy as well as the heat energy for all local area. In this dissertation we will be considering the solution of the steady state (stationary state) of system with the voltage level of 110kV, as well as the influence of the generation of power on this system, there by the suggesting a connection. The Congenerational production indicates higher effectiveness in the transformation of energy during primary production process due to the production of heat energy as well as the electrical energy from the primary power sources. In our country, as well as around the world, commonly used fuels are fossil fuels- coal, crude oil, and gas. As the demand for energy grows, those supplies are slowly running out. Not to mention that those fuels have a negative environmental impact. They are a source of carbon, which causes damage to the atmosphere and leads to global warming. Power plants which do not produce carbon are much safer for the environment, and much more productive. However, the residue of this energy is challenging to dispose of. Nuclear energy has common attributes with renewing the sources of energies that are extremely friendly to our environment. Nuclear power plants also produce enough energy and with the usage of Fourth generation reactors, they will be able to recycle the nuclear fuels. Today, more importance is put on renewing sources which are more gentle for the environment. In the near future, CEZ Company, the largest producer of electric energy is planning to use water energy. Water energy comes from water plants or dams. Other ecological forms of energy include geothermal and solar energies. These two types of energy are not as applicable for our geographical position. Geothermal energy is commonly used on islands where there is an abundance of natural hot springs. The most discussed source of energy is bioenergy. It uses natural wood sources, recycled wood products, and applies bioenergy as a main source for thermal power plants.
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Louda, David. "Hodnocení investičního záměru - Geotermální elektrárna." Master's thesis, Vysoká škola ekonomická v Praze, 2013. http://www.nusl.cz/ntk/nusl-199503.
Full textAbstract:
The aim of this master's thesis is to create a project of a small power plant in the Czech republic, which would be powered by geothermal energy as a renewable energy source. Followed by evaluation of economic effectiveness and return of that investment. For which I use known methods for evaluation and investment decision making.
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Philip, Rhondel Devyn A., and 朗道•菲利浦. "Rethinking the Energy Future of St. Kitts based on The Geothermal Power." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/uruav9.
Full textAbstract:
碩士國立中央大學
國際永續發展碩士在職專班
106
The islands of the Caribbean, despite their large amounts of readily available renewable energy resources, including solar energy, wind power, geothermal energy, and biomass, face many challenges to their energy sectors as they are still heavily dependent and rely on imported fossil fuel for their energy production. Small island developing states such as the federation of St. Kitts and Nevis, receive subsidies from the government but economically this cannot be seen as a long term solution. A long term and much greater economic solution would be to decrease the dependency of imported fossil fuel by diversifying the energy mix with the introduction of renewable energy technologies, thus creating long term energy security which has been the top agenda for Caribbean leaders. The main goal of this thesis is to analyse the energy sector of St. Kitts and demonstrate how we can achieve energy security by implementing the use of geothermal energy as our renewable energy technology to cover baseload. With geothermal there is the added advantage of it being a god source of energy with practically no harmful emissions, exceptionally constant source of energy doesn’t depend on the climate, high efficiency with little to no maintenance. There are moderately large areas of steaming ground in the crater of Mount Liamuiga, as well as thermal springs along the western shoreline. The pre-feasibility assessment of the proposed geothermal power plant is evaluated using RETScreen simulation software, through the performance of an energy production analysis, financial analysis and greenhouse gas (GHG) emissions analysis. An annual electricity generation of roughly 183,700 MWh with an energy production of 22 MW were the initial results obtained, this is about 51% of electricity installation capacity of present St. Kitts. The net present value (NPV) which should have a positive value, internal rate of return (IRR) which should be equal or greater than the discount rate, simple payback period (SPP) which measures the time it takes to recover the initial investment, benefit-cost ratio (B/C) which should be greater than 1 and energy production cost (EPC) which could be used calculate the avoided cost of energy for the project to break even where used as financial indicators which gave profitably indications for the development of the geothermal power plant project. The sensitivity analysis shows the most sensitive variable affecting profitability and as the initial cost of the plant decreases with a feed in tariff of USD 0.078 per kWh the project will be highly attractive financially and economically. This study also performs an environmental GHG emissions analysis and it is found that some 48,562 tons of CO2 per year, which equivalent to without consuming 112,935 barrels of crude oil.
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Kampa, Kyle Benjamin. "An energy return on investment for a geothermal power plant on the Texas Gulf Coast." 2013. http://hdl.handle.net/2152/21768.
Full textAbstract:
This thesis examines the energy return on investment (EROI) of a model 3 MW hybrid gas-geothermal plant on the Texas Gulf Coast. The model plant uses a design similar to the DOE Pleasant Bayou No. 2 test geothermal plant, and uses a gas engine to harness entrained methane and an Organic Rankine Cycle turbine to harness thermal energy from hot brines. The indirect energy cost was calculated using the Carnegie Mellon University Economic Input-Output Life Environmental Life Cycle Analysis (EIO-LCA) model. The EROI of the plant using the 1997 EIO-LCA energy data is 12.40, and the EROI of the plant using 2002 EIO-LCA energy data is 14.18. Sensitivity analysis was run to determine how the plant parameters affect the EROI. A literature review of the EROI of different power sources shows that the EROI of the hybrid geothermal plant is greater than the EROI of flash steam geothermal and solar, but is lower than the EROI of dry steam geothermal, wind power, nuclear, coal, gas, and hydroelectric plants. An analysis of the EROI to financial return on investment (FROI) shows that the FROI for a hybrid geothermal plant could be competitive with wind and solar as a viable renewable resource in the Texas electricity market.text
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Bouey, Christopher. "The Power of Water: Using a Thermal Bathing Resort to Maximize the Potential of Geothermal Power Production." 2012. http://hdl.handle.net/10222/15167.
Full textAbstract:
In 2011, Calgary, Alberta based Borealis Geopower bought the geothermal rights to the
Canoe Reach arm of Kinbasket Lake, near Valemount, British Columbia. New to Canada,
a pilot project of a 2 megawatt geothermal power facility will begin within the next five
years. The project is a positive addition to the area, as it is a non-polluting energy source
with an effluent of clean hot water. This thesis proposes a maximization of this energy
source by combining the power facility with an education center and bathing facility. Included in this bathing experience are ancillary cabins and paths to promote the users’
interaction and enjoyment of the project and landscape. Finally, this thesis develops a material strategy, choreographing the visitors’ experience of the geothermal resource within the site’s mountainous topography.
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Hu, Jiun-Wei, and 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.
Full textAbstract:
碩士國立臺灣大學
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.
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"Erdwärmesonden." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-39846.
Full textAbstract:
Im Freistaat Sachsen werden 7.500 Gebäude mit Erdwärme klimatisiert. Genutzt wird die Wärme aus der Tiefe vor allem bei Ein- und Mehrfamilienhäusern zur Heizung und Warmwasserbereitung. Bei Planung und Bau von Erdwärmeanlagen sind Aspekte der Qualitätssicherung und rechtliche Vorgaben zu beachten.
Interessierten Bürgern, Planern und Bohrfirmen werden u. a. folgende Fragen beantwortet:
- Welche Nutzungsformen der Erdwärme gibt es?
- Welche Qualitätsanforderungen, Richtlinien und
Gesetze sind einzuhalten?
- Wie wird eine Anlage richtig geplant?
- Wo und wie werden Bohrungen bei Behörden
beantragt?
Die Informationsbroschüre erscheint in 3. Auflage und ersetzt den Leitfaden für Erdwärmesonden.
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"Erdwärmesonden." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-154493.
Full textAbstract:
Im Freistaat Sachsen werden ca. 11.000 Gebäude mit Erdwärme klimatisiert. Genutzt wird die Wärme aus der Tiefe vor allem bei Ein- und Mehrfamilienhäusern zur Heizung und Warmwasserbereitung. Bei Planung und Bau von Erdwärmeanlagen sind Aspekte der Qualitätssicherung und rechtliche Vorgaben zu beachten.
Interessierten Bürgern, Planern und Bohrfirmen werden u. a. folgende Fragen beantwortet:
Welche Nutzungsformen der Erdwärme gibt es?
Welche Qualitätsanforderungen, Richtlinien und Gesetze sind einzuhalten?
Wie wird eine Anlage richtig geplant?
Wo und wie werden Bohrungen bei Behörden beantragt?