Abstract: A geothermal well is provided including a first tube including at least one opening in a first depth; a second tube having a closed bottom in a second depth; and a third tube having a closed bottom in a third depth. The first tube is inside the second tube, which is inside the third tube, wherein the first tube has at least one opening in fluid communication with a first interspace between the first tube and the second tube; wherein the third depth and the first depth are smaller than the second depth. Through-holes are formed in the second tube above the bottom of the third tube, which allow fluid communication between the first interspace and a second interspace between the second tube and the third tube. A first sealing element and a heat insulating material are disposed in the first interspace above the through-holes.