| 摘要 |
<p>An underground cavity, 6000 m or more below surface level, which may be natural or man made, is for geothermic energy storage. It may be round, oval, or rectangular in section. A vertical double walled plunge tube can be used for heat distribution and air circulation. Temperatures of 300 deg.C can be achieved. Heat is extracted from the large area of the sides of the cavity, based on the system of the main patent. This surface area is at least 100 times larger than that of the tube, to ensure that cooling down of the sides is not excessive. For temperatures under 100 deg.C, water can be used as an energy exchange medium.</p> |
