The LOCIE has two test platforms for studying heat transfers in the near underground in the presence of geothermal exchangers.
The bench for studying geothermal baskets in real conditions is composed of a set of 5 geothermal baskets of 1m diameter, buried between 1 and 3 m deep, instrumented with temperature probes and connected to a water-to-water heat pump of 4 kW power. This device allows the study of the influence of the nature of the soil and the distance between baskets, of the soil's freezing point and of the mode of solicitation.
This bench has been equipped with electrodes in order to be able to study the evolution of the temperature and humidity of the soil disturbed by a sampling or in heat injection through a geothermal basket.
The bench for the study of geothermal baskets under controlled conditions consists of an insulated tank thermally guarded on its side wall. The tank is filled with a model soil (calibrated silica sand). The upper and lower surfaces of the sand are respectively subjected to imposed temperature conditions reproducing the usual limit conditions. This device reproduces at 1/10th scale the temperature and humidity conditions encountered in the sub-surface. It also allows the reproduction of precipitation and the presence of a stagnant water table whose level is fixed.
The sand is instrumented with thermocouples and humidity measurements. Electrodes are also implanted in order to study the thermo-hydric evolution of the soil over time. Three thermostatic baths are used to thermally control the tank and the geothermal basket implanted inside it.