Parallel Session A-8: Geothermal energy - Chair: Luis Bandeira Neto

According to Dutch legislation the drinking water temperature should be lower than 25°C at the tap to meet legionella prevention. In order to assess the impact of heat sources like heat transport pipes on the temperature in adjacent drinking water pipelines a soil temperature model was developed. This coupled micro-climate and heat transport model relates atmospheric conditions to the temperature distribution in the sub-surface. The model is validated by a number of field tests in the Dutch city district Kralingen. The validated model is used here to predict the drinking water temperature in transport, primary and secondary networks.

Energy geostructures could play a key role towards the Paris agreement goal. However, so far applications have been related to new tunnelling projects, whereas possibilities of implementation on existing tunnels have not yet been explored. This abstract will focus on an example of thermal retrofitting of an existing tunnel, namely the Piedicastello tunnel (Trento, Italy). The retrofitting solution will imply drilling radial borehole heat exchangers (rBHEs) along several tunnel cross sections. To understand the influence of two design parameters, the rBHEs length and the interaxis distance, a 3D coupled FE numerical model was built and results are illustrated.

Energy tunnel is a new type of geothermal exchanger in ground source heat pump systems due to their technical and cost improvements over traditional borehole geothermal exchangers. An in situ full scale study using the thermal response and thermal performance tests (TRT and TPT) is performed to investigate the factors affecting the heat exchange capacity in Badaling Energy Tunnel of Beijing Zhangjiakou High speed Railway. This paper analyzes the influences of constant heating power, inlet water temperature, air temperature in tunnel, circulating water flow velocity, operation mode, and pipe connection on the heat exchange capacity of the energy tunnel.

Geothermal piles, also known as energy piles, use low grade heat energy from the shallow earth surface to heat and cool buildings. Reliability analysis of geotechnical structures has become increasingly important due to uncertainties in the geotechnical engineering field. In this study, ultimate group capacity and reliability analysis of energy pile was determined. The reliability index was calculated using the first order reliability method and two soft computing models, Random Forest and Extreme Gradient Boosting were developed to predict the ultimate group capacity . The XGBM model was best for designing and and reliability analysis of energy pile the energy.

A CSM-Energywall pilot has been setup in Amstelveen. The experimental setup and research goals are described in this paper.

This paper studies the effect of climate change on the behaviour of thermo-active diaphragm walls. This study also considers the modelling methodology and compares a more simplified model where thermal loads are applied to the structure only, with modelling of atmospheric temperatures. The findings demonstrate the importance of modelling atmospheric temperatures in capturing the behaviour of thermo-active diaphragm walls and also demonstrates the importance of action on climate change. Large differences in temperature between thermal cycles increase lateral displacements as well as internal stresses linearly over the long term.