EXPLOITATION OF LOW TEMPERATURE GEOTHERMAL RESOURCES WITH HIGH TEMPERATURE HEAT PUMP FOR DISTRICT HEATING

Doktorska disertacija je razdeljena na dva sklopa. Prvi sklop zajema pregled nizkotemperaturnih geotermalnih virov in porabe geotermalne energije v Sloveniji. Razvit je matematični model enostavne, cenene in hitre izvedbe temperaturne karotaže v geotermalnih vrtinah, ki služi za oceno razpoložljive geotermalne energije in rezerv, kot tudi za definiranje mehanizma dinamike fluidov v vrtini. V drugem sklopu je opisan sistem ogrevanja z geotermalno energijo na osnovi določil Zakona o rudarstvu (Ur. list RS, št. 98/2001-UPB1 in 68/2008). Mineralno surovino- geotermični energetski vir je namreč možno po določilih Zakona o rudarstvu izkoriščati tako, da se le-ta po odvzemu toplote vrača v nahajališče. Iskali smo rešitev, kako koristno uporabiti potencial geotermalne vode po odvzemu toplote v toplotnih prenosnikih. Za klasično radiatorsko ogrevanje ta energetski potencial ni primeren, ker na območju lendavskega sistema daljinskega ogrevanja nismo našli ustrezno velikega porabnika s talnim gretjem. Edina možnost, ki se je ponujala, je bila razviti inovativno visoko temperaturno črpalko velike moči (>250 kW), ki v svetu do tega trenutka še ni obstajala. Zaradi tega smo v podjetju Nafta-geoterm d.o.o. Lendava skupaj z raziskovalci FKKT pridobili projekt EUREKA z naslovom HTH Pump (High Temperature Heat Pump), ki je dal odgovor na vprašanje, kako neposredno odpadno geotermalno vodo s temperaturo višjo od 40 °C uporabiti za segretje vode v radiatorskem sistemu na temperaturo do 80 °C.The PhD dissertation is divided into two sections. The first section includes an overview of low temperature geothermal resources and the consumption of geothermal energy in Slovenia. A mathematical model is developed of a simple, cheap and rapid implementation of temperature measurements in geothermal wells, which serves as an assessment of geothermal energy and reserves, as well as for defining mechanisms of the fluids dynamic in the well. In the second section the heating system with geothermal energy is described on the basis of the provisions of the Mining Law (Official Journal RS, No. 98/2001-UPB1 and 68/2008). Mineral raw material-geothermal energy resource can be exploited under the provision of the Mining Law in such a way that after the heat is extracted the resource is returned into the layer. We searched for a solution on how to utilize the potential of geothermal water after removal of heat in heat exchangers. For classic radiator heating, this energy potential is not suitable because in the area of the Lendava district heating system we could not find a corresponding large client with floor heating. The only option available was to develop an innovative high temperature pump with large capabilities (>250 kW) which up until this moment did not exist world wide. Because of this we have together with the company Nafta-Geoterm d.o.o. Lendava and the researchers FKKT acquired the project EUREKA titled HTH Pump (High Temperature Heat Pump), which answered the question of how to directly use the waste geothermal water with a temperature higher than 40 ºC to heat water in the radiator system up to 80 ºC