An experimental apparatus for the study of low enthalpy geothermal energy

This work has the goal to present an experimental apparatus designed for the study of the energy exchange that takes place between a geothermal probe and the surrounding environment, at low enthalpy conditions. The experimental apparatus (installed in a thermostatic chamber inside the Geotechnical Engineering Laboratory of the University of Padua) has a volume of about 1m3 and is crossed by a copper thermal probe. The thermal probe is served by a closed hydraulic circuit. The flow rate and the fluid temperature, through the thermal probe, are imposed. Inside the granular material (Risetta del Brenta), that fills up the experimental apparatus, 24 high precision temperature sensors are properly distributed. The experimental apparatus can be saturated with water and a filtration motion can be realized using a second hydraulic circuit. The first part of this work is dedicated to an introduction to the basic theory useful for the processing carried out, and to a detailed description of the physical model. Subsequently a test is taken into consideration, carried out in the absence of intergranular water. The fundamental properties of the obtained acquisitions are described, the reliability of its behavior and the validity of the initial hypothesis are verified. At last, the power of the thermal probe is estimated and the temperature field, generated by the latter, inside the control volume is described.