Thermodynamic foundations for geothermal energy production : master’s thesis

Analizirani su važni termodinamički parametri za proizvodnju geotermalne energije iz niskotemperaturnih ležišta koja prevladavaju u Republici Hrvatskoj. Optimalna proizvodnja za takva ležišta podrazumijeva korištenje binarnog ciklusa. Za optimalno iskorištenje binarnog ciklusa važan je odabir radnog fluida koji ovisi o temperaturi geotermalnog fluida na ušću bušotine. Za sam odabir termodinamički povoljnog radnog fluida važni su i drugi faktori. Ove faktore i termodinamičke uvjete zadovoljava radni fluid izobutan koji se najčešće koristi u postojećim geotermalnim postrojenjima. Eksergetska snaga i termodinamička iskoristivost binarnog ciklusa direktno su ovisni o temperaturi geotermalnog fluida na ulazu i izlazu iz izmjenjivača topline, a eksergetska snaga proporcionala je i protoku geotermalnog fluida. Napravljen je proračun energije i snage mogućeg binarnog postrojenja za proizvodnju električne i toplinske energije iz vodenog okruženja naftnog polja Beničanci. Određeno je vrijeme izotermne proizvodnje tog ležišta i analiza osjetljivosti temperature u geotermalnom ležištu.Abstract: Important thermodynamic parameters for production of geothermal energy from low temperature deposits which prevail in the Republic of Croatia were analyzed. Optimal production for these deposits implies the use of the binary cycle. The choice of working liquid, which depends on the temperature of the geothermal fluid at the estuary of the borehole, is important for the optimal exploitation of the binary cycle. Other factors are also important for the choice of a thermodynamic favorable working liquid. Isobutane, a working liquid which suits these factors and thermodynamic conditions is most often used in existing geothermal facilities. Exergic power and thermodynamic efficiency of the binary cycle are directly dependent on the temperature of the geothermal liquid at the entrance and exit of the heat exchanger, and the exergic power is proportional to the flow of the geothermal liquid. An analysis of the energy and the power of potential binary facility for the production of electrical and thermal energy from the water environment of the oilfield Beničanci was made. The time of the isothermal production of this deposit and the analysis of the temperatural susceptability in the geothermal deposit were determined