G.TES – Pilot Plant for Seasonal Ground Energy Storage in Italy

The energy savings market is very dynamic with many companies already operating in the area, mostly private. Italy in this field is behind Northern European countries and the U.S. and that is why the market is undergoing exponential growth and is extremely promising. The share of potential customers identified by AG3 is essentially composed of those who intend to make interventions in the medium to large geothermal plans. The clientele is local (especially initially) and national level. These are mainly plant companies, engineering firms, construction companies, public administrators and private. Ground Storage is considered a powerful solution for supplying thermal energy for H&C of buildings. The Project has tackled the development of this technology in order to enhance the current status of the technology and integrate those systems into buildings together with other energy solutions considered in the project. Ground Storage can mainly supply thermal energy to be used for H&C of the buildings and SHW covering the energy demand of buildings by means of extract or inject heat in the ground. The behavior of the ground in those systems is considered as a thermal reservoir, and, subsequently the thermal characteristics of the ground will determine the efficiency of the geothermal systems. In spite of other heat pump geothermal mature techniques, heat storage is already far from large use in commercial, residential or agricultural application for cooling or heating. Experience in Canada and North Europe justify the interest of create new experience in south Europe and alpine regions. In G.TES, the solar thermal system converts sunlight into usable energy. For this purpose the energy produced by the collectors is at first delivered to a solar control station. The control station brings together the solar heat and the heat of the combined heat and power station. In addition it controls and adjusts the heat supply. Hot water being produced by a solar thermal system and not being required immediately, will be directed to the buffer storage and the hot water storage tank. The hot water storage tank has two functions: short-term heat storage facility and transfer station to the borehole thermal energy storage. Ground Energy Storage can be implemented in different ways depending on the ground conditions. The University of Turin, also thanks to a contribution of Interreg UE funds (Alcotra-Innovation), set up a test field at the campus of Grugliasco in which this method is being tested at real scale. Apart from direct measurements "below" and "above" ground (temperature sensors and heat flux) are performing geophysical measurements of electrical type in 2 dimensions to quantify the changes in temperature during controlled experiments of recovery and heat emission. The measure are targeted to the determination of the physical parameters of the soil, to the quantification of the storable heat but also to impact on the environment. Also numerical modeling using commercial and scientific software are planned, to improve the inputs parameters thanks to back analysis. This experimentation will allow in the near future the sizing of the first seasonal storage facility of thermal energy in the ground in Italy.