UNDERGROUND HEAT UTILIZATION SYSTEM AND UNDERGROUND HEAT UTILIZATION METHOD

PROBLEM TO BE SOLVED: To provide an underground heat utilization system capable of suppressing deterioration of water injection efficiency in returning pumped storage water to a well.SOLUTION: An underground heat utilization system 10 includes: a water pumping well 20 and a water injection well 30; a pipe 13 whose both ends are immersed into storage water of the water pumping well 20 and water injection well 30 so as to connect the water pumping well 20 and the water injection well 30; a pump 21 and pump 31 respectively provided in the water pumping well 20 and water injection well 30, and configured to pump storage water through the pipe 13; a valve 25 and valve 35 respectively provided on pressurization sides of the pump 21 in the water pumping well 20 and the pump 31 in the water injection well 30; and a heat exchanger 14 configured to exchange heat between itself and the pipe 13.SELECTED DRAWING: Figure 1 【課題】くみ上げた貯水を井戸へ戻す時の注水効率の低下を抑制する地中熱利用システムを提供する。【解決手段】地中熱利用システム１０は、揚水井戸２０及び注水井戸３０と、揚水井戸２０及び注水井戸３０を接続するように、揚水井戸２０及び注水井戸３０の貯水に両端が浸漬された配管１３と、揚水井戸２０、注水井戸３０内にそれぞれ設けられ、配管１３を介して貯水をくみ上げるポンプ２１、ポンプ３１と、揚水井戸２０内におけるポンプ２１、注水井戸３０内におけるポンプ３１の加圧側にそれぞれ設けられた弁２５、弁３５と、配管１３と熱交換する熱交換器１４と、を備える。【選択図】図１