Abstract: A direct transfer of heat is done with the dry hot rock or rock of any other kind working with a thermal fluid in a closed circuit.By means of sounding pipes (1) provided with internal fluid conducting pipes (3) or graduated lengths introduced in perforations made in the rock, the thermal exchange zones between two specific pipes are sequentially selected, leaving the remaining zones recovering heat from the geothermal deposit. Changing to other zones of the exploitation by means of the combination of the corresponding pipes thus obtains a practically continuous heat extraction process.The extracted heat is collected in a heat exchanger and/or accumulator tank (7).