Erdwärmenutzung im Eisenbahntunnelbau – Simulation und Wirtschaftlichkeitsberechnung

Oberhauser, A.1, Adam, D.2
1 Wissenschaftlicher Mitarbeiter am Institut für Eisenbahnwesen, Verkehrswirtschaft und Seilbahnen, TU Wien, Wien
2 Ingenieurkonsulent für Bauingenieurwesen, Universitätsdozent am Institut für Grundbau und Bodenmechanik der TU Wien

The usage of geothermal heat by the means of railway infrastructure is a relatively new method to tap renewable energy sources.

A research project at the Department of Railway Engineering, Transport Economics and Ropeways at Vienna University of Technology in cooperation with the Department of Soil Mechanics and Geotechnical Enginering and the Atlas Copco MAI Ltd. deals with the development of structural elements for tunnelling, which can also be used as heat absorbers. Therefore, numerical calculations were necessary, in order to examine the proper geometry for an optimal performance of the system.

The transferred energy was simulated in 2D as well as in 3D by the means of COMSOL. This happened by multiphysics coupling of the fluid flow calculation of the absorber medium with the heat transfer by convection and conduction.

Furthermore a COMSOL- subsytem was included into a Simulink model. The connection of both programs allowes the simulation of the whole plant during the year and to monitor the energy performance.

The calculation of cost reduction by the usage of geothermal heat is an important contribution to a “geothermal design tool” for plant development. By considering the specific boundary conditions for every customer, the optimal layout for the system can be designed. Therefore it is possible to calculate amortization periods for the plant and to find an optimal solution for both operator and customer of geothermal heat.