A flexible sealing tube is described that is adapted to be installed in and extend along a bore in the ground for use in a system for exchanging of energy with the ground. The flexible sealing tube has a first tube end to be installed at an inner part of said bore, and the flexible sealing tube is closed in the first tube end. The flexible sealing tube also has a first channel and a second channel extending in a longitudinal direction (L) of the flexible sealing tube, the first and second channels being in fluid connection with each other. The first and second channels are formed by the flexible sealing tube.