SOIL HEAT EXCHANGER AND A METHOD FOR ACHIEVING SUCH A HEAT EXCHANGER

摘要

The invention relates to a soil heat exchanger comprising at least one deep, cylindrical hole (1) in the soil and a heat transferring liquid circulating in a closed system with a central, heat-insulated leg (2) and a surrounding outer leg (3) in the soil hole. The outer leg (3) should make a good thermal contact with the wall of the soil hole (1), which up to now has been difficult to achieve with respect to the difficulty in feeding down the outer leg without being damaged. A solution is obtained according to the invention consisting in that the outer leg (3) is manufactured with a stable condition in which it is radially retracted. It is further designed such, that when the two legs (2, 3) are fed down into the soil hole in the end position the outer leg can be influenced to be radially expanded by water fed down under pressure in channels (12) of the outer leg.