| 摘要 |
PROBLEM TO BE SOLVED: To enhance a heat transfer rate on an inner surface of a tubular wall of an outer tube with a bottom, to improve a heat exchange performance and to collect or radiate (thermally store) a large heat by generating a turbulence in a flow of an antifreeze solution (heating medium). SOLUTION: In the circulating geothermal heat utilizing apparatus, a tube axis C2 of an inner tube 4 with an open bottom is formed in a zigzag state obtained by continuing an eccentric portion eccentrically deviated in a direction opposite to a vertical tube axis C1 in one vertical plane passing an axis C1 of an outer tube 2 with a bottom and a concentric portion concentric with the axis C1, and a plurality of bent portions 10 formed in a zigzag manner in a direction of the axis C1 to the tube 4 are provided at an equal interval over the entire length. A flowing velocity of an antifreeze solution (heating medium) flowing through an annular gap 3 is changed by the plurality of the portions 10 so that a turbulence takes place in the flow of the solution. Thus, a heat transfer rate of the inner surface of the tube 2 with the bottom is enhanced to improve heat exchange performance, and a large heat can be collected or radiated (thermally stored).
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