A novel renewable system supplying energy and water to the island of Pantelleria

In this paper a thermoeconomic analysis of a novel hybrid Renewable Polygeneration System connected to a district heating and cooling network is presented. The plant is powered simultaneously by solar and geothermal energy and capable to supply electricity, desalinated water, heat and cooling energy. System layout includes a Parabolic Through Collector (PTC) field, geothermal wells, an Organic Rankine Cycle (ORC) unit and a Multi-Effect Desalination (MED) system. A model of a typical building of Pantelleria urban area and a heating and cooling system based on fan coils have been modelled and linked to the plant model in TRNSYS environment. A detailed system control has been implemented in the model in order to prevent any heat dissipation, to match the appropriate operation temperature levels in each component, to avoid a too low temperature of geothermal fluid rejected in the wells and to give priority to space heating and cooling process. A 1-year dynamic simulation has been performed and results have been analyzed on daily, monthly and yearly basis. System is characterized by good performances with an SPB equal to 8.42 and it is perfectly capable to cover the energy demands of a small community, with a large surplus of electric energy. Moreover, the plant is potentially capable to cover the fresh water demand of the entire Pantelleria island.