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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Identifikace tepelné vodivosti a tepelné kapacity stavebních látek metodou „Hot Wire Method“ / Identification of Thermal Conductivity and Thermal Capacity of Building Materials by the "Hot Wire Method"

Průša, David January 2019 (has links)
This aim of task deals with study of heat dissipation mechanisms and the description of physical phenomena, which is accompanied by non-stationary measurement of thermal characteristics by the method "hot-wire method". In particular, we observe the coefficient of thermal conductivity and its dependence on various variables such as the temperature of the measured sample, its moisture state, the volume of the sample and its porosity. The above mentioned findings are used for the invention of the measuring device of a nonstationary gauge, which is based on regular heating and is dedicated to measuring the thermal conductivity coefficient and the heat capacity by the "hot-wire method" method. In the last part of the thesis is verified functionality of the proposed measuring device, the suitability of the created algorithm for the processing of the measured data and the evaluation of the results was verified. The reproducibility of the measurements was verified and the measured results were compared with the measurement methods, which are commonly used. the influence of humidity on the coefficient of thermal conductivity.
22

Technologie znovuvyužití odpadních vod v místě potřeby / Technologies of reuse of wastewater in place of need

Podhrázský, Martin January 2020 (has links)
Final thesis is focusing on possibilities hidden in the potential of wastewaters in sewers. The goal of this thesis is to present technologies and experiences with water reclamation and with heat recovery systems using wastewaters as a source of heat energy. The theoretical part is divided in two main topics. The first topic is focused on bringing important knowledge and experiences with designing and operating decentralized sewer mining systems, which are, due to less favourable environmental conditions, largely applicated and developed in countries such as Australia, California, etc. The second topic is focusing on heat recovery from sewage water and possibilities of heating and cooling buildings. A possibility of using heat energy from sewage for heating and cooling a swimming pool building located in Brno, Czech Republic was assessed in the last part of this thesis. As a source of wastewater was considered a sewer main located near the pool building. Payback periods and economical effectivity of investing into wastewater heat recovery system was compared with centralized heat supply system, which is a very common source of heat energy in Czech Republic.
23

Optimalizace instalace kogenerační jednotky v rodinném domě / Optimizing installation of cogeneration units in family house

Novotný, Jan January 2009 (has links)
The work deals with usage of heat energy from cogeneration unit in a family house. It is focused especially on the use for family house's heating and warming of service water. Optimalization is made on existing cogeneration units. In this work we will handle with two types of cogeneration units of different capacities. From the beginning we concern in current situation and the possibilities of regulation. Further we deal with the possible ways of optimalization of winter and summer running and with the costs for these optimalizations.
24

Kogenerační jednotky pro RD – hodnocení a simulace / The Cogeneration Units for Family House - Evaluation and Simulation

Martynek, Václav January 2013 (has links)
Master’s thesis deals with cogeneration units of low power that are used for heating of buildings and to cover the heat demand of small industrial enterprises. The introductory chapters are focusing on clarifying the principles of combined heat and power (CHP) as well as on the basic advantages and important indicators of CHP. The thesis presents a brief overview of cogeneration devices by type of primary units and also provides an overview of cogeneration units suitable for family houses that are currently available on the market. The text describes how to install and connect the cogeneration unit. The fourth chapter includes description of elemental thermal processes and possibility of heat transfer. The fifth chapter describes the thermal circuit model and calculation efficiency of a cogeneration unit. Thermal circuit consists of a cogeneration unit and a multivalent tank for hot water heating system and potable hot water system. The object of master’s thesis is to create a model of thermal circuit cogeneration units in a simulation program and a graphical user interface, that will allow a simple way to evaluate the operation of the cogeneration unit when changing the input parameters.
25

低レベル熱源からの化学的冷熱生成に関する基礎研究

松田, 仁樹, 板谷, 義紀, 渡辺, 藤雄 03 1900 (has links)
科学研究費補助金 研究種目:基盤研究(B)(2) 課題番号:08458123 研究代表者:松田 仁樹 研究期間:1996-1997年度
26

Posouzení možnosti připojení kogenerační výrobny 138 MW v Prostějově / The assessment of connectivity 138 MW combined heat and power plant in Prostějov

Vacek, Tomáš January 2011 (has links)
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.
27

Geothermie: Ansätze zur Nutzung regenerativer Energiequellen in der DDR

Eichkorn, Florian 15 September 2015 (has links)
Ende der 1970er Jahre sah sich die SED in der DDR gezwungen angesichts hoher Auslandsverschuldung und gestiegener Importpreise für fossile Energieträger stärker in heimische Energiequellen und rationellere Energieanwendung zu investieren. In diesem Kontext und um Anschluss an die internationale Entwicklung zu halten wurde Ende der 1970er und in den 1980er Jahren die Nutzung oberflächennaher und tiefer Geothermie gefördert. Im Rahmen dieser Arbeit wird neben einer chronologischen Darstellung der Geothermieförderung in der DDR eine Einordnung in deren Energiepolitik, der Wärmeversorgung und der Förderung anderer erneuerbarer Energien geleistet. Aufgrund des geringen historischen Forschungsstandes zur Geothermie und der Wärmeversorgung in der DDR allgemein wurde dieser Arbeit ein explorativer Ansatz zugrunde gelegt. Als Quellenbasis dienten unter anderem Artikel aus wissenschaftlichen Zeitschriften der DDR und verschiedene Archivbestände. Ende der 1970er Jahre bis 1983 versuchte die SED den Einsatz von Wärmepumpen für die Wärmeversorgung zu fördern. Obwohl zahlreiche Pilotprojekte wie die Wärmepumpenheizzentrale Dresden fertiggestellt wurden stießen die politischen Planvorgaben auf materielle Engpässe und wenig Nachfrage in der Wärmeversorgung. Nach der abrupten Reduzierung der Zielvorgaben für die Wärmepumpenförderung wurde ab 1984 mit besonderem politischem Interesse die Tiefengeothermie gefördert und hierfür der Spezialbetrieb VEB Geothermie Neubrandenburg gegründet. Von den geplanten Anlagen zur Versorgung von Wohngebieten mit insgesamt 110 MW thermischer Leistung konnten bis zum Ende der DDR tiefengeothermische Heizzentralen in Waren, Neubrandenburg und Prenzlau fertiggestellt werden, was 22% der geplanten Leistung entsprach. Somit scheiterte auch das Großprojekt einer geothermischen Wärmeversorgung von Schwerin. Grund waren unter anderem übersteigerte Planvorgaben, der materielle Mangel in der Wirtschaft der DDR und nicht ausreichende Erfahrungen mit der jungen Technologie.:1. Einleitung 3 2. Energiepolitik in der DDR 7 2.1 Energiepolitik der SED 7 2.2 Regenerative Energiequellen in der Energiepolitik 9 3. Erdwärme in der Energiewirtschaft der DDR 13 3.1 Akteure der Energiewirtschaft 13 3.2 Wärmeversorgung 15 3.3 Nutzung regenerativer Energiequellen 18 4. Oberflächennahe und tiefe Geothermie 22 4.2 Wärmepumpen zur Nutzung von Umweltwärme 22 4.2.1 Wärmepumpen für die rationelle Energieanwendung 22 4.2.2 Fallbeispiel Wärmepumpen-Heizzentrale Dresden 28 4.2.3 Vorzeitiges Ende der Wärmepumpenförderung 33 4.3 Tiefengeothermie im Norden der DDR 35 4.3.1 Hohe Erwartungen an die Tiefengeothermie 35 4.3.2 Grenzen der Leistungsfähigkeit des VEB Geothermie 41 5. Zusammenfassung 48 Literatur 51 Archivalische Quellen 54 Abbildungs- und Tabellenverzeichnis 56 Abkürzungsverzeichnis 57 Physikalisch-technischer Anhang 58 / At the end of the 1970s the socialist party of the GDR was forced by high debts in foreign currency and risen import prices for fossil fuels to invest in indigenous energy sources and more rational energy applications. In this context and to take pace with the international development the SED began at the end of the 1970s and during the 1980s to support the use of geothermal heating. This thesis consists of a chronological representation of the geothermal energy support in the GDR and contextualizes East German energy policy, heat supply and use of other renewable energy sources. Historical sources consist to the main extent on archive material and scientific papers from the GDR. Until 1983 the SED tried to promote the application of heat pumps for heat supply. Even though several pilot projects like the heat pump station in Dresden were successfully erected, the political plan targets collided with material short supply and low demand in the heating business. After the sudden reduction of the political targets concerning heat pumps, special political interest was given to geothermal energy in higher depths since 1984. Therefore a special company the VEB Geothermie Neubrandenburg was founded. From the planned stations for heat supply of residential areas with a total power of 110 MW only 22% were actually finished until the end of the GDR in 1990. Those stations were located in Waren, Neubrandenburg and Prenzlau in the northern part of East Germany. Consequently failed the major project of a geothermal heat supply of the city of Schwerin. Reasons were excessive plan targets, the material short supply in the East German economy and a lack of experiences in the young technology.:1. Einleitung 3 2. Energiepolitik in der DDR 7 2.1 Energiepolitik der SED 7 2.2 Regenerative Energiequellen in der Energiepolitik 9 3. Erdwärme in der Energiewirtschaft der DDR 13 3.1 Akteure der Energiewirtschaft 13 3.2 Wärmeversorgung 15 3.3 Nutzung regenerativer Energiequellen 18 4. Oberflächennahe und tiefe Geothermie 22 4.2 Wärmepumpen zur Nutzung von Umweltwärme 22 4.2.1 Wärmepumpen für die rationelle Energieanwendung 22 4.2.2 Fallbeispiel Wärmepumpen-Heizzentrale Dresden 28 4.2.3 Vorzeitiges Ende der Wärmepumpenförderung 33 4.3 Tiefengeothermie im Norden der DDR 35 4.3.1 Hohe Erwartungen an die Tiefengeothermie 35 4.3.2 Grenzen der Leistungsfähigkeit des VEB Geothermie 41 5. Zusammenfassung 48 Literatur 51 Archivalische Quellen 54 Abbildungs- und Tabellenverzeichnis 56 Abkürzungsverzeichnis 57 Physikalisch-technischer Anhang 58
28

LCC VÄRMESYSTEM X- En livscykelkostnadsstudie av fyra värmesystem utifrån småhus med varierande storlek, energibehov och geografisk placering. : LCC HEATING SYSTEM X- A life cycle cost study of four heating systems based on residential houses with varying size,energy requirements and geographical locations.

Eriksson, Martin, Ngea Chit, Pyo January 2024 (has links)
För småhusägare finns ekonomiska incitament till att sänka det årliga energibehovet för värme och tappvarmvattenberedning, då det utgör huvudparten av det totala årliga energibehovet för bostäder i Sverige. Valet av värmesystem är därför ett viktigt då det kan medföra mer eller mindre gynnsamma ekonomiska konsekvenser sett över längre tidsperioder,då den mängd köpt energi som systemet kräver kan medföra besparingar som viktas mot den ekonomiska investeringen av systemet.Syftet med denna studie har därför varit att skapa ett referensunderlag över fyra olika värmesystem med jämförelser mot småhus av olika storlek, geografisk placering samt olikaisoleringsstandard, där det eller de mest ekonomiskt gynnsamma värmesystemen, sett över en 50-årsperiod, kan utläsas utifrån dessa parametrar.De småhus som studien har jämfört har bestått av enplanshus med tre antagna areor, 89,7/120/150,3 m2. Dessa har jämförts för Malmö, Stockholm, Sundsvall samt Luleå, varpå varje area har innefattat tre olika antagna genomsnittliga värmegenomgångskoefficienter, Umedelvärden. Studien har genomförts med energiberäkningar enligt gradtimmemetoden, och den ekonomiska analysen genom beräknade livscykelkostnader, LCC, för de olika systemkonstellationerna. Fyra värmesystem har undersökts: Fjärrvärme, bergvärmepump, luft-vattenvärmepump samt frånluftsvärmepump. Frånluftsvärmepumpen har inkorporerats som ett FX-ventilationssystem, frånluftsventilation med värmeåtervinning. De övriga tre systemen har för studien kombinerats med ett FTX-ventilationssystem, från- och tilluftsventilation med värmeåtervinning.Resultaten har påvisat att FTX-system, i jämförelse med FX-system, sänker för samtliga studerade byggnader i Malmö det årliga värmeenergibehovet, den energi som måste tillsättas byggnaden, med 36–71%, medan det i Luleå sänks med 32–61%. Den årliga energianskaffningen, den energi som måste köpas för att värmesystemen skall generera erfordrad värmeenergi och tappvarmvattenberedning, är genomgående lägst för systemkonstellationen bergvärmepump i kombination med FTX. Den systemkonstellationenmed studiens genomgående högsta andel köpt energi, är fjärrvärme i kombination med FTX.Vid jämförelse av livscykelkostnader, LCC, har påvisats att fjärrvärme i kombination med FTX är mest ekonomiskt gynnsam endast då det årliga behovet av köpt energi är mycket litet, och att det vid högre behov istället blir det dyraste alternativet. Frånluftsvärmepump utgör ett ekonomiskt gynnsamt alternativ vid majoriteten av analyserade fall, tack vare lägre investeringskostnader som väger upp de högre värmeenergibehov som ventilationstypen medför. Bergvärme i kombination med FTX, utgör det dyraste alternativet i de flesta fall därdet årliga behovet av köpt energi är lågt, men påvisar ekonomisk gynnsamhet vid höga energibehov. Luft-vattenvärmepump i kombination med FTX, är relativt likvärdig bergvärmepump men har ej påvisats vara det billigaste alternativet i något studerat fall. Vid jämförelse mellan frånluftsvärmepump och bergvärmepump i kombination med FTX, har påvisats att för studiens samtliga analyserade objekt är den största prisskillnaden, utslaget på 50 år, mindre än 1.800 kr/år.Utifrån de parametrar som presenterats, har påvisats genomförbarhet i att skapa ett referensunderlag över optimal gynnsamhet för värme- och ventilationssystem hos småhus, vilket avläses utifrån husets storlek, U-medelvärde samt geografiska placering. / For homeowners, there are economic incentives to reduce the annual energy demand for heating and domestic hot water preparation, as these constitute the main part of the total annual energy demand for houses in Sweden. The choice of heating system is therefore important as it can have more or less favorable economic consequences over longer periods of time, as the amount of purchased energy required by the system can lead to savings that weigh against the economic investment in the system. The purpose of this study has therefore been to create a reference framework for four different heating systems, comparing them across houses of different sizes, geographical locations, and insulation standards, to identify the most economically beneficial heating systems over a 50-year period, that can be interpreted based on these parameters. The houses compared in the study were single-story houses with three assumed sizes: 89.7/120/150.3 m². They have been compared in Malmö, Stockholm, Sundsvall and Luleå, with each size having three different assumed average thermal transmittance values, average U-values. The study was conducted using energy calculations based on the degree-hour method, and the economic analysis was performed using calculated life cycle costs, LCC, for the different system configurations. Four heating systems were investigated: district heating, geothermal heat pump, air-to-water heat pump, and exhaust air heat pump. The exhaust air heat pump was incorporated as an MEVHR ventilation system, mechanical exhaust air ventilation with heat recovery, while the other three systems were combined with an HRVventilation system, mechanical exhaust and supply air ventilation with heat recovery. The results have shown that HRV systems, compared to MEVHR systems, reduce the annual heating energy demand, the amount of energy that must be supplied to the building, for all studied buildings in Malmö by 36-71%, while in Luleå it is reduced by 32-61%. The annual energy procurement, the amount of energy that must be purchased for the heating systems to generate the required heating energy and domestic hot water preparation, is consistently lowest for the geothermal heat pump system combined with the HRV. The system configuration with the highest proportion of purchased energy throughout the study is district heating combined with HRV. When comparing life cycle costs, LCC, it was found that district heating combined with HRVis the most economically beneficial system only when the annual demand for purchased energy is very low, and becomes the most expensive option at higher demands. The exhaust air heat pump is a cost-effective option in the majority of analyzed cases, thanks to lower investment costs that offset the higher heating energy demand induced by this type of ventilation. Geothermal heat pump combined with the HRV is the most expensive option in most cases when the annual demand for purchased energy is low but shows economic advantages at high energy demands. The air-to-water heat pump combined with the HRV is relatively similar to the geothermal heat pump but has not been shown to be the cheapest option in any of the studied cases. When comparing the exhaust air heat pump with the geothermal heat pump combined with the HRV, it is found that for all objects analyzed in the study, the largest price difference is, averaged over 50 years, less than 1,800 SEK/year. Based on the presented parameters, the feasibility of creating a reference framework for the cost-effectiveness of heating and ventilation systems in houses has been demonstrated, which can be assessed based on the house size, U-value, and geographical location.
29

Studie snížení energetické náročnosti bytového domu / Study of energy consumption reduction of block of flats

Svoboda, Lukáš January 2014 (has links)
The goal of the thesis is firstly to get all the information about the initial state of solved block of flats, which is located on the street Merhautova 76/954 in Brno – Černá pole, in terms of constructions, energy consumption and initial state of heating system. In the second part of the thesis, where are discussed the possibilities of reduction of energy consumption, variant drafts of reduction of energy consumption and their financial costs and the choice of optimal variant. Third part deals with assement of solved block of flats in terms of sustainable built environment by using tool to rate buildings in terms of sustainable built environment - SBToolCZ, evaluation of possibility to use renewables. In the end are written summaries and recommendations.

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