Abstract: To provide a geothermal heat exchanger with high thermal efficiency, which can reduce heat loss to a non-geothermal zone when high-temperature liquid heated in the deep underground is transported to the ground. The geothermal heat exchanger of the present invention includes a liquid transport pipe provided with a liquid lowering pipe to which a heat exchange liquid which is pressurized and supplied, a liquid raising pipe which is disposed on the inside or outside side of the liquid lowering pipe and raises the heat exchange liquid which is descended to the geothermal zone, moved from the lower part and composed of the high-temperature liquid generated by which heat from the geothermal zone is supplied, and an outer thermal insulation layer which is provided on a part or the whole of the outside of the liquid transport pipe at least from the ground surface to the geothermal zone.

Abstract: To provide a geothermal heat exchanger with high thermal efficiency, which can reduce heat loss to a non-geothermal zone when high-temperature liquid heated in the deep underground is transported to the ground. The geothermal heat exchanger of the present invention includes a liquid transport pipe provided with a liquid lowering pipe to which a heat exchange liquid which is pressurized and supplied, a liquid raising pipe which is disposed on the inside or outside side of the liquid lowering pipe and raises the heat exchange liquid which is descended to the geothermal zone, moved from the lower part and composed of the high-temperature liquid generated by which heat from the geothermal zone is supplied, and an outer thermal insulation layer which is provided on a part or the whole of the outside of the liquid transport pipe at least from the ground surface to the geothermal zone.