Some Considerations On The Output Power Optimization In Artificial Geothermal Systems

Geothermal energy is a practically renewable energy source, first exploited for power at Lardarello in Italy. World-wide installed capacity grew slowly until the so called energy crisis in 1973, which caused a rapid increase in prospecting, in the development of specialized technology, and in the number of commissioned geothermal plants. The aim of this paper is to use a finite-time thermodynamic approach for the analysis of a Rankine cycle of the secondary closed system of a dry geothermal field plant. Heat source and heat sink are assumed of finite capacity, as happens in reality. Besides the thermal irreversibilities, due to the finite temperature differences between the system and the two heat reservoirs, also the mechanical irreversibilities in the expander are taken approximately into account, contrary to what it is usually done by the various authors.