Fig. 7From: Temperature sensor module for groundwater flow detection around borehole heat exchangersTemperature sensor module (TSM) with three temperature sensor (4) ring levels. The TSM is mounted via the yellow spacers (5) to the inlet and outlet tubes of the BHE. The TSM main tube (red) is 1 m long. The blue spacers (2) ensure a constant distance between the inner (red) and the outer tubes (gray) and thus between the inner and outer ring temperature sensors (4)Back to article page