Improving Thermal Efficiency of horizontal ground heat exchangers

Since heating and cooling demands constitute almost 50% of the final energy demand in Europe, the development of geothermal energy systems and especially very shallow geothermal solutions, reveals a huge potential in providing thermal energy for residential and tertiary buildings, thanks also to its local availability, manageability and flexibility. ITER Project (Improving Thermal Efficiency of horizontal ground heat exchangers) is a project (http://iter-geo.eu/) funded by European Commission under the Marie Skłodowska Curie Fellowship Programme (Horizon 2014-2020) focused on improving heat transfer efficiency of existing shallow geothermal systems. The overall aim of ITER is to ensure the sustainability of ground coupled heating-cooling systems and especially the horizontal ground heat exchangers systems. Key challenges are to enhance the heat transfer of the ground surrounding the pipes creating thermally enhanced backfilling material (TEBM) suitable for horizontal systems; to assess the performance and the environmental impacts of new promising technological solutions as helix systems with and without TEBM; to monitor the results over time through direct measurements and numerical simulation, in order to understand the heat pollution effect in the surrounding environment. Thermal laboratory measurements and in situ monitoring of existing and duly installed horizontal systems will be provided by close cooperation between host institutions and non-academic partners. A test site was realized in Eltersdorf, near Erlangen (Germany): 5 Helix horizontal probes (3m length) were installed at a depth of 0.6 m below the ground level and the trenches were filled in with 5 different materials, ranging from natural material as fine sand (0-1 mm) till commercial products, that will be analyzed also in laboratory. This paper present the preliminary results obtained during the first months of research activity