TOWARD A SUSTAINABLE OPTIMISATION OF VERY LOW ENTHALPY GEOTHERMAL PLANT. CONFIGURATION EFFICIENCY AND ENVIRONMENTAL ASSESMENT

A key issue in a sustainable use of very low enthalpy geothermal systems is their interaction with the environmental. The aim of present work is to focus on it emphasising the drawbacks on designing. The results obtained in “CasaEnergia” project represent the starting point of the actual work [1]. The “CasaEnergia” project was devoted to the optimisation of the efficiency of geothermal plant in residential buildings in order to preserve the energy source as well as the environment [2]. First step was the minimisation of the building energy needs with the purpose to obtain a building unit with the minimum environmental impact. In designing practice the attention is only paid to satisfy the energy needs considering the possible decreasing performance in time in a plant oversizing corresponding in a possible overexploitation of the resources. The open loop geothermal plant are the more impacting. Thus, the study has mainly been devoted to a Aquifer Thermal Energy Storage (ATES) plant technology and compared to the most used technologies like Vertical Geothermal probes and the direct use of groundwater in open loop system.