Long-term measurements of energy geostructures at the Taborstrasse metro station in Vienna

Abstract

For nearly twenty years, four metro stations within Vienna's U2 line extension opended 2008 have successfully utilized energy geostructures for heating and cooling. The Taborstraße station, which utilizes thermo-active diaphragm walls, piles, slabs, and tunnel sections, serves as a primary case study for this technology, supported by an extensive monitoring dataset. This paper evaluates the energy performance of the whole station using energy geostructures by comparing in-situ energy measurements against initial design simulations. The results indicate that while annual heating consumption aligns closely with original forecasts, the actual cooling demand remains significantly below predicted levels, revealing a substantial untapped thermal capacity in the infrastructure. Furthermore, the study identifies external influences on system performance, such as a notable decrease in heating energy during the 2022/23 season linked to socio-economic energy-saving measures rather than technical constraints. Ultimately, these long-term results confirm that integrated energy geostructures provide a robust and scalable solution for urban infrastructure, offering critical benchmarks for the design and optimization of future geothermal energy systems in urban environments.