National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
Transient temperature field of the shallow subsurface and its sources
Dědeček, Petr ; Šafanda, Jan (advisor) ; Hokr, Milan (referee) ; Majorowicz, Jacek (referee)
Long-term air and ground temperature series and repeated temperature logs from several boreholes in Czech Republic, Slovenia and Portugal were processed to distinguish and describe possible sources of transient signals in subsurface temperature field. Two methods for estimation of the soil and bedrock thermal diffusivity from long-term temperature records are presented and compared. Results proved that on the annual time scale the convective heat transfer did not contribute significantly to the temperature-time variations monitored in the uppermost 10-m depth zone and that the influence of moisture changes on subsurface temperature field noticeably appears only in upper 5 cm of soil. Using 3D numerical modelling a direct human impact on the subsurface temperature warming was proved and contributions of individual anthropogenic structures to this change were evaluated. It made it possible to split the transient component of the present-day temperature depth profiles into the climatic and anthropogenic signals.
Thermal relations leading to the formation of gaseous phase within the ice covering lakes and ponds
Hrubá, Jolana ; Kletetschka, Günther (advisor) ; Dědeček, Petr (referee)
When cutting an ice from lakes and ponds gaseous phase displays often ubiquitous bubble textures along the ice thickness. The occurrence of bubbles (enclosures filled with the gas) in ice relates to a content of the dissolved gas in the lake/pond water prior to freezing over the surface. When water freezes, dissolved gases are rejected and redistributed at the ice-water interface, depending on the saturation ratio between the gas and water. If the concentration of dissolved gases surpasses a critical value (as freezing progresses), the water at the interface becomes supersaturated, and gas bubbles nucleate and grow to a visible size along the interface. The bubbles generated at the ice-water interface are either incorporated into the ice crystal as the ice-water interface advances, thus forming gas pores in the ice, or released from the interface. If there is incorporation or release is determined by several factors. The bubbles nucleated at the advancing ice-water interface may be characterized by concentration, shape, and size, which depend on growth rate of ice, the amount of gases dissolved in water, and the particulate content of water. This work focused on the relation between growth rates of the ice and the occurrence of bubbles in the pond ice. I monitored the temperature of the ice formed...
State-of-the-art and perspectives of geothermal energy utilization in Iceland
Pantůčková, Klára ; Dědeček, Petr (advisor) ; Jiráková, Hana (referee)
This thesis focuses mainly on the Iceland area and deals with the geographical and geological conditions within the context of geothermal energy. The thesis also focuses on history of Iceland, past and current utilization, tries to summarize basic types of acquisition and evaluates advantages and disadvantages of geothermal energy. The end of the thesis focuses on the latest projects, which interfere in the nearest future. Especially, the thesis is concerned with the IDDP project, which aims to drill into unknown conditions close to the magma chamber.
Specification of the geothermic model in the environs of several selected boreholes
Čápová, Lucie ; Dědeček, Petr (advisor) ; Procházka, Martin (referee)
With the advances in research of the Hot Dry Rock environment and Enhanced Geothermal Systems, geothermal energy is soon going to compete with other unconventional energy resources in Europe where Germany and France are pushing the research ahead. In the Czech Republic, the geothermal exploration borehole drilled in Litoměřice in 2006 - 2007 provided information that contributed greatly to the understanding of geothermic conditions in the country. In addition to Litoměřice, two other areas have been recently subject to geothermal exploration: Semily and Liberec. These three areas have been studied in detail in this Master's thesis to assess their geothermal potential. Information on the geology of the selected areas was gathered from numerous scientific papers and reports and was compared with information from geological maps and boreholes. On the basis of this information, geological sections of the area of Litoměřice and Semily were compiled. Drill core samples from five boreholes from the geological units in the areas under investigation were collected and measured using the Lippmann & Rauen Thermal Conductivity Scanner. Thermal conductivity of geological units inferred in the basement but not intersected in the boreholes was estimated on the basis of values presented in literature. Finally,...
Thermal logging data analysis in the area of Ohárecký Lineament
Schinkmann, Jakub ; Kobr, Miroslav (advisor) ; Dědeček, Petr (referee)
Jakub Schinkman - abstract The object of the thesis was a detailed processing of the available temperature logging data from the area of Ohře lineament. The Ohře lineament is known by its characteristic temperature manifestations. Based on a comprehensive selection of thermometric logs and using the results of other logging methods were selected a total of 281 wells suitable for the construction of temperature maps. The parts of the work are maps of geothermal gradient and temperature sections across the Ohře lineament. Based on these summary maps, 6 smaller areas with anomalous temperature signs were selected for detailed analysis. Anomalies and trends in geothermal gradient were then compared with some other geophysical features. The work provides not only detailed processing of the collected thermometric data, but also shows the different possibilities of visualization and try to understand the problems of heat transfer in the upper parts of the earth's crust.
Report on the geothermal research in borehole GTPVLT-1 (Litoměřice) - appendix
Šafanda, Jan ; Dědeček, Petr ; Krešl, Milan ; Čermák, Vladimír
The report provides detailed information about geothermal research in borehole GTPVLT-1 in the Czech Republic together with all graphic outputs. It includes (i) repeated temperature logs during and after the borehole drilling, (ii) measurements of thermal conductivity and diffusivity of the encountered rock samples, (iii) measurements of radioactive isotopes content of uranium, thorium and potassium in the encountered rock samples and calculation of their radiogenic heat production, (iv) determination of the terrestrial heat flow in the borehole and (v) prognosis of temperature expected down to the depth of 5 km.
Report on the geothermal research in borehole GTPVLT-1 (Litoměřice)
Šafanda, Jan ; Dědeček, Petr ; Krešl, Milan ; Čermák, Vladimír
The report provides information about geothermal research in borehole GTPVLT-1 in the Czech Republic, which included (i) repeated temperature logs during and after the borehole drilling, (ii) measurements of thermal conductivity and diffusivity of the encountered rock samples, (iii) measurements of radioactive isotopes content of uranium, thorium and potassium in the encountered rock samples and calculation of their radiogenic heat production, (iv) determination of the terrestrial heat flow in the borehole and (v) prognosis of temperature expected down to the depth of 5 km.

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