Vpliv fizikalnih parametrov in hidrogeoloških razmer na toplotne lastnosti sedimentov : doktorska disertacija

Adrinek, Simona (author), Brenčič, Mihael (mentor), Singh, Rao Martand (comentor), Janža, Mitja (comentor)

Za trajnostno rabo nizkotemperaturnega geotermalnega vira je temeljnega pomena poznavanje zakonitosti prenosa toplote in geoloških značilnosti v okolici načrtovane rabe odprtega geotermalnega sistema. Na mikroskopskem nivoju je osnova pri načrtovanju pravilna opredelitev vpliva fizikalnih parametrov sedimenta. To so mineralna sestava, poroznost, nasičenost, gostota in zrnavost. Na makroskopski ravni je pomembno opredeliti tudi hidrogeološke razmere, kot je prisotnost toka podzemne vode, hidravlična prepustnost in disperzivnost. Kakšen je vpliv fizikalnih parametrov in hidrogeoloških razmer na toplotno prevodnost sedimentov in prenos toplote? Je pravilna določitev toplotne prevodnosti matriksa sedimenta pomembna pri analitičnem in numeričnem modelu za porazdelitev temperature v okolici odprtega geotermalnega sistema? To so vprašanja, ki lahko, pravilno zastavljena, pomembno prispevajo k preučevanju prenosa toplote na območju medzrnskega vodonosnika Murske Sobote. V doktorski nalogi smo na mikroskopski ravni preučevali povezavo med fizikalnimi in toplotnimi parametri sedimenta, ki lahko vplivajo na rabo plitve geotermalne energije. S postavitvijo analitičnega in numeričnega modela toka podzemne vode in prenosa toplote v izbranem vodonosniku smo lahko te povezave preučevali na makroskopski ravni. Na podlagi dveh nizov laboratorijskih podatkov smo definirali ustrezne analitične modele toplotne prevodnosti, ločene za posamezne tipe sedimentov in natančno določili toplotno prevodnost matriksa sedimenta. S pomočjo dvoletnega niza terenskih meritev na območju Murske Sobote smo lahko ovrednotili vpliv izbranih fizikalnih parametrov, izmerjenih v laboratoriju, z vplivom izbranih fizikalnih in hidrogeoloških parametrov, določenih v naravnih razmerah, na porazdelitev temperature podzemne vode. Ugotovili smo, da je na obravnavanem območju najpomembnejši parameter, ki vpliva na porazdelitev temperature podzemne vode v bližini odprtih geotermalnih sistemov, hidravlična prevodnost. Toplotni parametri, merjeni v laboratoriju, na makroskopski ravni niso imeli pomembnega vpliva na temperaturo podzemne vode.

• Language: English
• Keywords: doctoral thesis, geology, Built environment, shallow geothermal energy, thermal conductivity, physical parameter, analytical model, numerical model, thermal plume
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FGG - Faculty of Civil and Geodetic Engineering; NTF - Faculty of Natural Sciences and Engineering
• Place of publishing: LJubljana
• Publisher: [S. Adrinek]
• Year: 2023
• Number of pages: XXVIII, 161 str.
• PID: 20.500.12556/RUL-153022-a6e025b1-d9e7-c02f-753b-5ecb299d1fda
• UDC: 551.3(043.3)
• COBISS.SI-ID: 177411331
• Publication date in RUL: 14.12.2023

ADRINEK, Simona, 2023, Vpliv fizikalnih parametrov in hidrogeoloških razmer na toplotne lastnosti sedimentov : doktorska disertacija [online]. Doctoral dissertation. LJubljana : S. Adrinek. [Accessed 11 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=153022

Secondary language

• Language: Slovenian
• Title: Impact of physical parameters and hydrogeological conditions on the thermal properties of sediments : doctoral dissertation

Abstract

For the sustainable use of low-temperature geothermal resources, it is essential to understand heat transfer in the geological environment of the planned geothermal system. At the microscopic level, correct identification of the influence of the physical parameters of the sediments including mineral composition, porosity, water content, density and grain size distribution is required. But also at the macroscopic level, hydrological conditions such as the presence of groundwater, hydraulic conductivity and dispersivity are the initial parameters that need to be considered. What influence do the physical parameters of the sediments and the hydrogeological conditions have on the thermal properties of the sediments and heat transfer? Is the correct determination of matrix thermal conductivity important for the analytical and numerical models that define the temperature distribution of groundwater in the vicinity of an open-loop systems? If properly addressed, these questions can make an important contribution to the understanding of heat transport in the studied intergranular aquifer of Murska Sobota. In this dissertation, we studied at the microscopic the relationship between the physical parameters and thermal properties of the sediment, that influence the potential for the use of low-temperature geothermal resources. By establishing the analytical and numerical model of groundwater flow and heat transfer in a selected shallow aquifer, we were able to study these relationships on a macroscopic level. Based on two sets of samples with parameters determined in the laboratory, we were able to define appropriate analytical thermal conductivity models based on different sediment types and accurately determine the matrix thermal conductivity. Based on 2-years field observations in NE Slovenia, we were able to evaluate the influence of the physical parameters measured in the laboratory compared to the influence of the individual parameters on the temperature distribution including natural conditions. We found out that in our study area, the most important parameter influencing groundwater temperature distribution around open-loop systems is hydraulic conductivity. The thermal parameters measured in the laboratory, did not have a significant influence on the groundwater temperature at the macroscopic level.

• Keywords: disertacije, geologija, Grajeno okolje, plitva geotermalna energija, toplotna prevodnost, fizikalni parametri, analitični modeli, numerčni modeli, toplotni oblaki