| 摘要 |
PROBLEM TO BE SOLVED: To provide an underground heat utilization system capable of improving a collected heat quantity per unit length of a spiral heat collection tube with a relatively simple configuration.SOLUTION: An underground heat utilization system 10 using an underground heat exchanger 12 constituted by a spiral heat collection tube is provided. The underground heat exchanger 12 comprises natural convection acceleration means 18, including a straight tube 14 extending vertically; and a spiral tube 16 communicating with a lower end 14a of this straight tube 14, and arranged spirally around this straight tube 14 at an interval kept from the straight tube 14, for achieving natural convection of underground water W around the spiral tube 16 by generating a temperature difference of the underground water W between an upper portion and a lower portion. |
