Dans le contexte énergétique actuel, le développement de l'énergie solaire passe par son développement à grande échelle en milieu urbain. Les solutions actives et intégrées telles que les double-façades photovoltaïques permettent d'une part d'envisager une valorisation de la chaleur et d'autre part de valoriser l'enveloppe des bâtiments en tant que surface de captation. De plus, cette configuration limite la perte de rendement et l'accélération du vieillissement liées à la surchauffe des cellules. En effet, les composants photovoltaïques sont séparés du bâtiment par une lame d'air et la convection naturelle développée dans cet espace favorise l'évacuation de la chaleur absorbée par les panneaux. Cependant, le comportement global d'une double-façade photovoltaïque est très complexe et encore mal compris. Cette thèse se focalise sur l'expérimentation du phénomène de la convection naturelle. Un banc d'essais, développé dans le cadre de la thèse de Daverat, modélise la double-façade par un canal vertical avec chauffage pariétal. Le fluide d'étude est de l'eau afin de s'affranchir du rayonnement entre parois et d'étudier le couplage conduction-convection. Le banc d'essais est constitué d'un canal vertical de 65cm de haut, chauffé à une densité de flux uniforme, plongé dans une cellule de 1,5m de haut remplie d'eau. L'écoulement est observé par des mesures de densité de flux de chaleur, de température pariétale et de vitesse, ces dernières étant réalisées par vélocimétrie par images de particules et par vélocimétrie laser Doppler. Deux configurations de chauffage sont étudiées : symétrique et asymétrique. Pour l'étude de la configuration avec un chauffage symétrique, les données expérimentales issues du travail de thèse de Daverat sont analysées par une approche zonale. Un découpage du canal est proposé et une analyse des ordres de grandeur permet de comprendre les observations expérimentales. Ainsi, cette analyse se focalise sur le transfert thermique aux parois, l'évolution de la pression dans le canal et sur les fluctuations, en particulier, sur l'évaluation du terme croisé du tenseur de Reynolds. La configuration d'un chauffage asymétrique est étudiée expérimentalement pour la phase de démarrage et le régime stationnaire. Pour la phase de démarrage, la caractérisation des premières heures à partir de la mise en chauffage de la paroi est réalisée en termes de température pariétale, de vitesse et de comportement bi-/tri-dimensionnel de l'écoulement. Un écoulement de retour de grande échelle est mis en évidence. L'impact de la stratification thermique externe du canal est également étudié. Pour le régime stationnaire, les analyses sont réalisées sur des données pour lesquels le régime est considéré établi. Les comportements thermique et dynamique sont étudiés et mettent en évidence deux états distincts. Des écoulements de retour sont également observés. Enfin, les influences du nombre de Prandtl et de l'écartement du canal sont discutées. / Under the current energy context, the development of solar energy goes through its large scale development, especially in urban areas. Active and integrated solutions, such as photovoltaic double-skins, allow both the heat recovery for building needs and the exploitation of building envelope as collecting surface. Furthermore, this configuration limits the efficiency loss and the acceleration of ageing process due to overheating of the solar cells. Indeed, in this configuration, the photovoltaic panels are separated from the building by an air channel and the thermally driven flow that develops in the channel helps to evacuate the heat absorbed by the panels. However, the global behaviour of the photovoltaic double-skin is complex and not yet fully understood. This study is part of a scientific project on multi-scale modelling and experimentation of BIPV components. It focuses on the experimentation of the natural convection phenomenon in double-façades. An experimental apparatus developed during C. Daverat's thesis models the double-façade by a vertical channel with wall heating. The working fluid is water so as to avoid radiative heat transfer between walls. The experimental apparatus consists of a 65 cm high vertical channel, with isoflux heating, immersed in a 1.5 m high water tank. The fluid flow is instrumented with measurements of heat flux, wall temperature and velocity. The velocity measurements are made by Particle Image Velocimetry and Laser Doppler Velocimetry. Two heating configurations are studied: symmetrical (same heat flux is imposed on both walls) and asymmetrical (only one wall is heated, the other one being adiabatic). For the study with symmetrical heating configuration, experimental data from Daverat's thesis are analysed by a zonal approach. The channel is split into several zones and a scaling analysis is conducted in order to explain experimental observations. Thus, the study focuses on heat transfer, pressure evolution in the channel and fluctuations, in particular, the evaluation of the maximum Reynolds stress. The asymmetrical configuration is studied for the transient regime and the steady regime. For the transient regime, early stage (first hours) is characterised in terms of wall temperature, velocity and two- or three-dimensional flow behaviour. A large-scale reversal flow is observed. The impact of external thermal stratification is also studied. For the steady regime, thermal and dynamic behaviours are studied and two different states are distinguished and characterised. Reversal flows are also observed. Finally, the influence of the Prandtl number and the channel width is discussed.

The diploma thesis deals with elaboration of project solar thermal and photovoltaic solar systems for all-season service. The theoretical part focuses on the general description of the solar thermal and photovoltaic systems, legislation of renewable sources in the Czech Republic and the status of photovoltaics in the Czech Republic. The experimental part deals with the design of measures for energy saving by using solar energy systems. These measures are proposed for construction of houses in Podolí u Brna, especially on extra-family house. The aim of the work is to make a proportioning, choosing the right parts and calculating the economic and ecologic balance. Finally, thesis gives recommendations for further action in saving energy in houses in Podolí u Brna.

The aim of this thesis is to describe the advantages of simultaneous utilization of photovoltaic and wind electricity in an autonomous system, supplying the household with electricity without connection to the electrical grid. The most used methods of connecting photovoltaic modules and wind generators to chemical batteries are discussed. Several maximum power point tracking methods and their properties are described. A block schematic diagram of an autonomous off-grid system utilizing chemical accumulators is proposed. The system also contains an inverter producing standard mains voltage 230 VAC to supply common household appliances. A Quasi-Square Wave converter topology was chosen for all three power converters. An experimental 180 W output power QSW converter with one controllable switch was designed, simulated with Pspice, manufactured and tested to verify the efficiency of the topology. Excellent agreement was found between predicted and measured efficiency at full output power. Efficiency for reliable operation varies between 89% and 92,2% at full power and depends mainly power inductor and MOSFET used. After successful evaluation of QSW topology, the power converters for the main system were designed. Because of higher power, the converters were designed as four-phase, whereas each phase contains two controllable switches to boost efficiency mainly in low-power area. The most critical and difficult part of the project was to design the mixed-signal control sections for the converters to ensure proper switching of two controllable MOSFETs in each phase. For user interactivity, main control board with graphic LC display, Ethernet module and SD memory card slot was also manufactured.

The thesis is focused on cogeneration units on vegetable oil. The first chapter contains basic information about the production, supply and consumption of electric energy in the Czech Republic and about renewable energy sources. The following chapter is devoted to possibilities of use oil kinds of phytomass in the Czech Republic, or products made from them. Next chapter is mentioned on legislation allowing the use of used cooking oils for energy purposes. It contains a summary of the laws and regulations and options regarding subsidies for electric and heat power. The main objective of these chapters is to explain the issue of the establishment and operation of cogeneration units on vegetable oil. The following chapters are devoted to the design and study of simultaneously operated cogeneration unit on the vegetable oil with a combustion engine and the calculation of economic operation running. The reason of study is to evaluation, which on based of the input values and calculation methods determine the economic efficiency of the project cogeneration unit on vegetable oil under mode purchase price and mode green bonus. Appreciation is also given to the overall legal review and responsibilities of cogeneration units on vegetable oil.

The thesis deals with energy intensity of a low energy office building. In the thesis, em-phasis is put especially on the calculation of energy consumption for heating (cooling). The energy intensity of the building is determined and evaluated by four methods of calculation, which are compared with a valid certificate of energy performance of the building, which arose at the time of its construction. In the experimental part of the the-sis, the energy intensity of the building is compared to the actual energy consumption obtained by two experimental measurements in heating season 2012/2013. (The building is operating partly only). Different methods of solutions and valid legal regulations are elaborated in detail in the first part of the thesis.

South Africa is in the critical process of determining the profile of its power composition for the next 30 years and beyond. From the IRP2010 it seems that too much emphasis is placed on renewable energy, coal and other technologies and too little on nuclear power. In the revision of the IRP2010, the renewable portion of the energy composition has been increased substantially from 11.4 to 17.8GW, where nuclear remains on 9.6GW (DME, 2011). The purpose of this research is to investigate and compare power-generating technologies. The investigation of the different technologies is corroborated through modelling the IRP2010 planned energy mix efficiency, as well as a proposed energy mix. These models will be built using Microsoft Excel. Topics not investigated are socio-economic impacts and politics around nuclear energy in South Africa. The main finding of the research is that nuclear power is the best option for base load energy in order to meet South Africa‟s growing demand for electricity. It has the highest load factor, longest economic life, best safety record, adheres to the Kyoto protocol, uses the least fresh water and is economically competitive. It addresses all the concerns stipulated in the IRP2010 and the technology also offers benefits outside the electricity industry, such as the mining, medical, agriculture and research sectors. This versatile, reliable and powerful technology holds great benefits and has the potential to uplift the quality of life for the whole South African nation. / MSc (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015

South Africa is in the critical process of determining the profile of its power composition for the next 30 years and beyond. From the IRP2010 it seems that too much emphasis is placed on renewable energy, coal and other technologies and too little on nuclear power. In the revision of the IRP2010, the renewable portion of the energy composition has been increased substantially from 11.4 to 17.8GW, where nuclear remains on 9.6GW (DME, 2011). The purpose of this research is to investigate and compare power-generating technologies. The investigation of the different technologies is corroborated through modelling the IRP2010 planned energy mix efficiency, as well as a proposed energy mix. These models will be built using Microsoft Excel. Topics not investigated are socio-economic impacts and politics around nuclear energy in South Africa. The main finding of the research is that nuclear power is the best option for base load energy in order to meet South Africa‟s growing demand for electricity. It has the highest load factor, longest economic life, best safety record, adheres to the Kyoto protocol, uses the least fresh water and is economically competitive. It addresses all the concerns stipulated in the IRP2010 and the technology also offers benefits outside the electricity industry, such as the mining, medical, agriculture and research sectors. This versatile, reliable and powerful technology holds great benefits and has the potential to uplift the quality of life for the whole South African nation. / MSc (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015

Using chilled water within South African gold mines is paramount to the purpose of extracting gold ore efficiently. Using water for cooling, drilling and sweeping and the release of underground fissure water causes the accumulation of vast amounts of water in underground dams. Deep mines use cascading pump systems for dewatering, which is an electrical energy intensive dewatering method. Due to the recent equalisation of demand to generation capacity of electrical energy in South Africa, various methods towards demand side reduction have been implemented. With the introduction of a time-of-use (TOU) tariff structure by Eskom, the implementation of projects that shift load from peak TOU times to times of the day when electrical energy is less expensive has increased. To enable load shifting on mine dewatering pumps, preparation before and recovery after peak TOU is needed for effective results. This induces a preparation- and comeback load in the standard TOU. With an annual increase in TOU tariffs and the rate of increase of standard TOU being greater than that of the peak TOU, a reduction in electrical energy consumption before and after peak TOU is needed. To enable this, a step-by-step control technique was developed to promote the shifting of load from standard- to off-peak TOU, while still realising a full load shift from peak TOU. This technique entails dynamic control ranges of underground dam levels as opposed to the conventional constant control range method. Two case studies were used to test the developed technique. Results indicated significant additional financial savings when compared to conventional control methods. Additional savings of R1,096,056.65 and R579,394.27 per annum were respectively achieved for both case studies. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

The Abstract The main objectives of the presented thesis - The Assessment of Environmental Impacts of Representative Renewable Energy Technologies in the Czech Republic were complex assessment of representative renewable energy technologies within different criterions, assessment of their greenhouse gas mitigation effectiveness and evaluation of usefulness of financial incentives aimed on renewable electricity in the Czech Republic in the period 2005-2010. Thereafter representative technologies were compared with nuclear and best available techniques coal-fired power plants in order to determine the best convenient electricity generating technology. Wind, photovoltaic, small hydro-electricity and geothermal power plants were appraised in particular. The thesis was based on partial analysis and meta-analysis aiming on particular aspects and the entire life cycles of the technologies was taken under consideration. The basic methodology framework of life-cycle assessment, which was useful for a comparison of different electricity-generating technologies, was applied within the thesis. The key input data were gathered via meta-analysis. The database GEMIS 4.81, reports by Energy regulatory office, European statistics office, International energy agency and Czech hydrometeorology institute were used to acquire...

With the adoption of the Act on Promotion of Use of Renewable Energy Resources in 2005, the Czech Republic took a significant step forward to examine the economic field of energy in general in light of environmental and climate protection. With this act, the Czech Republic followed the example of other European Union member states in asserting the goal of reducing greenhouse gas emissions and seeking alternative energy resources in the spirit of the Kyoto Protocol obligations. The goal of this Master's thesis is to present and logically analyze the relevant legal legislation concerning renewable resources passed in the Czech law. The emphasis of this analysis of the Act No. 180/2005 Sb. on the Promotion of the Use of Renewable Energy Resources in the context of energy law, whereby the attention is placed on promotion of energy production, those in the Czech Republic represent two alternative schemes: "feed-in tariff" and "green bonus certificates." With the broad definition of renewable energy resources in the introduction, this thesis comprises a basic overview of this comprehensive legal problem. This thesis consists of five separate chapters, which are closely related.