Geothermal Field Tests with Forced Groundwater Flow

Abstract

Currently our Institute is performing a research program supported by the Federal Ministry of Economics and Technology (BMWi). Main objective of this research program titled “experimental investigation for the verification of a finite-element-multiphase-model for heat transport processes in ground” is to analyze the subsoil as a three-phases-model with separated consideration of conduction, convection and their subsequent interaction. Therefore extensive experimental laboratory tests as well as experimental field tests are currently conducted at the Technical University Darmstadt. Geothermal Response Tests (GRT) as well as Enhanced Geothermal Response Tests (EGRT) are performed in different geological and hydro geological conditions. With help of pumping wells unequal surrounding hydraulic heads are set to borehole heat exchangers to monitor the performance of GRTs and EGRTs depending on the forced groundwater flow velocities and to investigate the types of heat transport processes separately. The results of field tests with different measuring units each performed with different heating durations and heating power, different forced groundwater flows as well as at different seasons are compared to each other and back analyzed with numerical methods.