Shallow Geothermal Energy for existing buildings – overview and status of project GEO4CIVHIC

A major obstacle to decarbonisation in the building sector is the comparably low share of new construction, and the specific problems encountered when supplying heat and/or cold from renewable energies (RES) to existing and in particular older/historical, buildings. Without a solution to the problem of RES in refurbishment, however, the decarbonisation of the building stock will simply take too long. Shallow geothermal technologies have contributed substantially to decarbonisation in new construction. However, for a wider deployment in existing buildings, particularly in historical ones, the technologies need further development and innovative ideas must be tested and brought to the market. Within the EU-funded project GEO4CIVHIC a survey was done to identify and understand all other possible barriers to install Borehole Heat Exchangers (BHE) in existing building environment, be they technical or socio-economic, and the project partners work on suggestions for suitable solutions. Based upon this survey, the further work addressed two principal barriers, which are construction of ground heat exchangers under constrained site conditions, and adaption of heat pumps and other components to older heating/cooling systems. A specific emphasis is given to historic buildings, i.e. those dating from before the mid of the 20th century, including listed buildings, where the constraints are even more severe. Development work is done to provide technical solutions for overcoming these barriers, e.g. with novel drilling tools and enhanced heat pumps. Several demonstration cases are undertaken to test the solutions found (4 real sites in Belgium, Ireland, Italy and Malta, and 12 “virtual” sites, where theoretical case studies for renovation with borehole heat exchangers are performed on real, existing buildings). The COVID 19 pandemic hampered drastically the project timeline, resulting in delays of more than one and a half years. At the time of writing this abstract, two real demonstration cases are finished and started operation (Belgium and Italy), while the other two are scheduled to be operational by July 2022. This paper gives an overview of the project, the rationale behind it, and the findings of the initial survey of barriers. It presents the experiences with less invasive, less costly and quicker drilling and installation methods for borehole heat exchangers (BHE), as developed within the project and tested both in the real demonstration sites and in dedicated test fields at some of the project partners. First results of monitoring and results from the "virtual" sites are presented. Other papers within the project also submitted to EGC 2022 address specific aspect in more detail, and are referenced in this overview paper.