| Summary: | RES Master´s Thesis Verkefnið er unnið í tengslum við Háskóla Íslands og Háskólann á Akureyri Iceland is in first place in the world for direct use of geothermal energy per capita. The largest use of low temperature geothermal energy is for space heating in large districts of towns. The water sent to consumers in Akureyri town in north Iceland is a mix of hot geothermal water and water returning from users’ radiators. The goal of this work is to optimize the supply temperature to the district heating distribution network, in order to minimize the amount of water extracted from geothermal fields. First the district heating system in Akureyri is described. Information on utilized geothermal fields, distribution system and equipment such as pumps, storage tanks, pipelines, etc. is presented. It is explained how the system is controlled. The second part is a case study. Operational optimization of Naustahverfi’s district heating system is performed. A running curve for supply water temperature at the pumping station is designed and a mathematical model for this optimization is used. The choice is a macroscopic model that lumps the system into one equivalent user. Data on the supply water temperature and flow as well as outdoor temperature, provided by Norðurorka Company, is used for the simulation. A curve representing the lowest geothermal water consumption is found. The work reveals and addresses the limitations of a macroscopic model. It shows how the problem can be solved in case of unsuitability of part of the data and points out the need to modify the existing theory to include snow melting installations.
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