Abstract: A geothermal system including a multitube vertically-sealed underground heat-exchanger includes: a geothermal well formed by vertically excavating a foundation; a heat pump which is arranged in the foundation, and which includes a circulating pump; and a connection tube, an auxiliary facility, and a multitube vertically-sealed underground heat-exchanger which are buried and installed in the geothermal well, and which are connected to the heat pump such that a thermal fluid thermally restored in the geothermal well is supplied to the heat pump through the circulating pump, and the thermal fluid that has undergone heat exchange in the heat pump is recovered back to the geothermal well and thermally restored therein.

Abstract: A geothermal system includes: at least two geothermal holes (1) formed in the ground; a return water circulation tube (10) for returning underground water of the geothermal holes; a water collection and supply well (20) for collecting and then supplying the underground water returned by the return water circulation tube; at least one heat pump (30) for generating heat for cooling and heating, by using, as a heat source, the heat of the underground water supplied by the water collection and supply well; and a supply tube (40) which is an underground water supply means for supplying, to the geothermal holes, the underground water that supplied heat to the heat pump.