Heating of low-energy houses

Domy s nízkou potrebou energie na vykurovanie sa stávajú čoraz viac bežnými. Táto práca popisuje možnosti a jednotlivé spôsoby vykurovania nízkoenergetických domov. Ďalej sa venuje konkrétnym zdrojom energie, ich dostupnosti a vplyvu na životné prostredie. Práca obsahuje aj konkrétny návrh vykurovania do modelového domu.Low-energy houses are becoming more common and requested. This work describes possibilities and various ways of space heating in such houses. It also analyses specific energy sources, their availability as well as an environmental impact. The work includes a design of heating for a display low-energy house.

Hydrogen production

Diplomová práca sa zaoberá elektrolýzou vody so zameraním na pulzovú elektrolýzu. V teoretickej časti venuje pozornosť najprv vodíku, jeho vlastnostiam, využitiu a skladovaniu. Ďalej podáva analýzu rôznych spôsobov generovania vodíka. Podrobne rozoberá elektrolýzu vody, jej energetickú a chemickú bilanciu, účinnosť elektrolýzy a možnosti zvyšovania jej účinnosti. Následne popisuje pulzovú elektrolýzu. Navrhuje laboratórne zariadenie na jednosmernú a pulzovú výrobu vodíka. Experimentálne overuje teoretické predpoklady. Podáva výsledky merania, ich porovnanie a zhodnotenie. Poukazuje na prínos tohto spôsobu elektrolýzy, ktorým je zvýšenie efektivity. Navrhuje využitie a ďalší výskum v tejto oblasti.The thesis deals with water electrolysis focusing in particular on pulse electrolysis. The theoretical part characterizes hydrogen and its properties as well as the ways of its use and storage. It also analysis various methods of hydrogen generation. It examines in details water electrolysis and its energetic and chemical balance. There is also an evaluation of water electrolysis efficiency and its improvement followed by pulse electrolysis description. Laboratory equipment for direct current and pulsed direct current hydrogen production are suggested. Theoretical expectations are tested experimentally. Finally the thesis presents the results of measurements, compares and summarizes the data. It points out the contribution of this type of electrolysis with its effectiveness. It proposes uses of electrolysis and the subsequent research.

Influence of temperature on the production and size distribution of fine particles released from beech wood samples

This study deals with laboratory investigation of fine particulate matter production over controlled heating of beech wood samples in the atmosphere with 21% of oxygen. From carried out measurements follow that majority of emitted fine particles is in the range 40 nm to 500 nm. The peak number of particles is between 100 nm an 300 nm. The mass concentration of produced particulate matter increases proportionally with increasing size of the sample. The number of particles is increasing too, but not proportionally. In the second step, the samples in form of sawdust, bark and heartwood were analyzed from the view of particulate matter production. Obtained results are strongly influenced by actual combustion conditions that significantly differ between wood samples forms. It is not easy to find any clear trend between temperature and size distribution of produced particles. From the general view, the bark produces higher number concentration of ultrafine particles in comparison with heartwood and sawdust sam

Particulate Matter Produced by Micro-Scale Biomass Combustion in an Oxygen-Lean Atmosphere

This article extends earlier research by the authors that was devoted to the experimental evaluation of ultra-fine particles produced by the laboratory combustion of beechwood samples. These particles can have severe influence on human health. The current paper presents a parametrical study carried out to assess the influence of the composition of the atmosphere and the temperature on the production of ultra-fine particles during the micro-scale combustion process. The paper presents a laboratory procedure that incorporate the thermogravimetric analysis (TGA) and detailed monitoring of the size distribution of the produced fine particles. The study utilises the laboratory scale identification of the formation and growth of the fine particles during the temperature increase of beech wood samples. It also compares the particle emissions produced by beech heartwood and beech bark. The size of the emitted particles is very strongly influenced by the concentration of light volatiles released from the heated wood sample. From the experimental study, decreasing oxygen content in the atmosphere generally results in higher particulate matter (PM) production

Impact of Operation Parameters on Fine Combustion Particles Concentration in the Flue Gas of Biomass Boilers

This work deals with the impact of operating parameters on fine combustion particles formation in the flue gas of biomass combustion device. The research part of the work describes the properties of fine particles, its basic division, impact on human health and the environment. The basic knowledge of the influence of biomass combustion process on fine particles production up to 1 µm in size is summarized. The main part describes the experimental setup for evaluating the size distribution of fine particles. The following section describes the experimental setup with measured results for various combustion parameters in laboratory combustion, automatic boilers, as well as in the manual wood-burning combustion device. The main parameters which were tested were combustion temperature, oxygen amount, type of fuel and geometry of the burned biomass. The impact of individual parameters on the formation of the fine particles is evaluated. The final part of the thesis summarizes the ways in which it is possible to significantly influence the emissions of fine particles by the appropriate choice of combustion operating parameters

Influence of temperature on the production and size distribution of fine particles released from beech wood samples

Fine particles generated from laboratory biomass combustion are discussed in this study. The approach combines the thermogravimetric analysis during thermal decomposition of beech wood sample with detailed monitoring of the size distribution of fine particles produced. Thermogravimetric analysis (TGA) allows monitoring the exact temperature influence of a small fuel sample (wood) according to the desired schedule. The cool aerosol stream leaving TGA enters a Scanning Mobility Particle Sizer (SMPS) where the particle size fractions are separated. The monodisperse aerosol is counted by the condensation particle counter (CPC). The parametrical study was carried out to assess the influence of composition, size and surface of the wood sample on the production and size distribution of ultrafine particle