A design strategy based on a multidisciplinary approach for a sustainable design of ORC power plants is proposed. The design of a geothermal plant is discussed, with reference to a case study about a geothermal area in Tuscany, in which a geothermal reservoir at 120 °C is estimated to be available at about 500 m of depth. A qualitative model of the reservoir under specific production/reinjection conditions is discussed. Numerical simulation of geothermal reservoirs is considered an important interacting issue, also to synthesize the data and different scenarios studied. Three factors are fundamental: the maximum energy production, in the perspective of a sustainable exploitation strategy (definition of wells depth and siting, fluid rates extracted/reinjected); the chemical characterization of the fluid (to define the minimum reinjection temperature in order to prevent scaling phenomena); the definition of a reinjection strategy (flow rates, number and depths of reinjection wells and distances between them). Key results are the temperature and pressure profiles and stored energy reduction in the reservoir during plant lifetime. A power plant output range of 250-500 kW is considered in order to keep the temperature decrease in the reservoir in a range of 5-10 °C during the expected life of the plant. The case study can be seen also as a general value example to discuss how the sustainability of the medium-low temperature geothermal resource makes the design strategy of these plants different with respect to the other renewable source based power plants.
Design strategy of geothermal plants for water dominant medium-low temperature reservoirs based on sustainability issues
Franco, Alessandro;Vaccaro, Maurizio
2012-01-01
Abstract
A design strategy based on a multidisciplinary approach for a sustainable design of ORC power plants is proposed. The design of a geothermal plant is discussed, with reference to a case study about a geothermal area in Tuscany, in which a geothermal reservoir at 120 °C is estimated to be available at about 500 m of depth. A qualitative model of the reservoir under specific production/reinjection conditions is discussed. Numerical simulation of geothermal reservoirs is considered an important interacting issue, also to synthesize the data and different scenarios studied. Three factors are fundamental: the maximum energy production, in the perspective of a sustainable exploitation strategy (definition of wells depth and siting, fluid rates extracted/reinjected); the chemical characterization of the fluid (to define the minimum reinjection temperature in order to prevent scaling phenomena); the definition of a reinjection strategy (flow rates, number and depths of reinjection wells and distances between them). Key results are the temperature and pressure profiles and stored energy reduction in the reservoir during plant lifetime. A power plant output range of 250-500 kW is considered in order to keep the temperature decrease in the reservoir in a range of 5-10 °C during the expected life of the plant. The case study can be seen also as a general value example to discuss how the sustainability of the medium-low temperature geothermal resource makes the design strategy of these plants different with respect to the other renewable source based power plants.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.