Geothermal energy has significant potential in Tuscany, Italy and Hungary due to their geothermal gradients. In Tuscany, the two main areas of exploitation are Larderello and Monte Amiata. In Hungary, geothermal gradients reach 6°C/100m. The document discusses three geothermal energy projects: 1) A geothermal heat pump system simulation for a building in Tuscany, 2) An energy/exergy analysis of a dry steam power plant in Larderello using EES software, 3) A study of a small binary cycle power plant for Hungary using EES software and comparing results to previous studies. Geothermal energy can be used for district heating

1. Geothermalenergy Short Presentation on Geothermal Energy Potential in the twoEuropeanregions: Tuscany and Hungary Luca Madiai Università degli Studi di Firenze Dipartimento di Filologia Moderna – Area Ugro-finnica

2. Geothermalenergy Introduction Basis History Geothermalresources Utilizationtechnologies Projects

3. Introduction Renewableenergy Unlimited Constant No air pollution No CO2emissions Extractionisrelatively cheap

4. Geothermalenergybasis The 99% of the volume of earth is warmer than 1000 °C, and only 0.1% is lower than 100 °C Geothermal gradient: towards the interior of the earth the temperature rises Earth gradient has an average of 3°C/100 m (in Hungary it reaches 6°C/100 m)

5. History First use of the thermal waters were mainly for medical, household and recreational purposes. In ancient time the geothermal water could be directly used with a pipe systems. The Roman hot springs were used for eyes and skin treatment, while in Pompei were used also to heat buildings. Thermalbath in Pompei Roman thermalbath (Naples)

6. history In 19th century, the development of technology has allowed the discovery and exploration of groundwater resources. Tuscany geothermal energy was used initially for the production of boron and ammonium compounds. The heat production was of secondary importance. The electricity production began in 1904 thanks to the work of Prince PieroGinori Conti and in 1913 the first plant in Larderello had 250 kW installed. Today the complex of Larderello has a power of more than 600 MW and development programs expected to increase the power to 880 MW In France from 1960 more than 200.000 apartments are heated by geothermal water

7. History VilmosZsigmondy (miningengineer) wanted tofindthermal water in Városliget (Pest) His work wasvery risky, expensive and full of difficulties. At the time no one believed it was possible tofindthermal water in Pest. In 1878 Zsigmondycompleted the well (970 m – the deepest in the world) Thatwell can produce 1200 m3of 73.8 °C thermal water everyday Thankstohis work Széchenyi bathwasbuilt in 1913 VilmosZsigmondy (1821-1888) –Mining engineer

8. Geotermikus Energia Magyarországon In Hungary the average geothermal gradient ranges between 5-7 °C/100 m, while the world's average value is 1.5-2 °C/100 m At depth of 1000 meters the temperature can reach or even exceed 60 °C. Currently, geothermal power is 0.28 percent of total energy in our country. In Hungary there is no electricity production from geothermal resources, while the largest producers - the U.S. and the Philippines - produce in a year from 2 to 2000 MW

9. Geothermalenergy in tuscany Two main areas of geothermal exploitation: Larderello (632 MW – dry steam) pressure (4-7 MPa) and temperature (300-350°C) Monte Amiata (79 MW –water dominated)

10. Geothermalenergyusage Today, geothermal energy is used in several areas: In agriculture: heating of greenhouses Direct district heating Thermal baths Heating and cooling with geothermal heat pump Power generation In my work I dealtwith 3 differentprojects: Geothermalheatpumpsystems Dry steampowerplant Binarycyclepowerplant

11. Geothermalheatpumpsystems Geothermalheatpump (GHP) consists in a inverse cyclethatuses the groundas low temperature source (insteadofexternal air) The groundhasanaverage temperature around 10°C, and itdoesnotvarysignificantlywith the seasons With GHP systemsispossibletoheat(max 50 °C) and coolbuildingsonlyusingelectricity There are two kind of GSHP: open loop and closed loop (in this case antifreeze must be used)

12. Electricity production with dry steam Dry steamisextractedfrom a production well Dry steamdirectlyexpands in turbine and a generatorproduceselectricalenergy The turbine outlet steamhastobecooled in a water condenser or in a coolingtower The cooledsteam can bere-injected in the subsoil

13. Electricity production with hot water The geothermal water heats up a secondaryfluid in the heatexchager Geothermal water temperature can be in the range 80-150 °C The secondaryfluidexpands in turbine and follow a normalrankinecycle (ORC) The secondaryfluidhas a lowerboling temperature than water Secondaryfluid can beeitherrefrigerant or hydrocarbon

14. Project 1 : Geothermalheatpump A simulation model has been created in order to study the behavior of the system in the long term The model includes a building, a storage tank, a heat pump, and a borehole heat exchanger The model can simulate weather conditions and can be used to compare different configurations and external parameters The software used was TRNSYS

15. Project 2: Dry steampowerplant A dry steampowerplantforLarderellohasbeenstudied A complete energy and exergy analysisof the system hasbeenperformedusing EES software The system works in steady state and severalsemplificationsweremade Constantexternalconditionshasbeenassumed (averageambient temperature and humidity)

16. Project 3: binarycyclepowerplant A smallbinarycycleplantforHungaryhasbeenstudiedusing EES software The resoultshasbeencomparedtopreviousstudies Severalconfigurations are possible and fewofthemhavebeenconsidered

17. Thanksforyourattention ! Furthermore information can be found in my thesis Luca Madiai luca.madiai@gmail.com