The principle of the system is as follows: the filtered groundwater from the inlet well is pumped into an underground reservoir and from there by a solar pump into the supply system, where it flows through the cooling panels and through a collector tube at a certain water temperature back into the reservoir, where the cycle starts again.
If the return water temperature exceeds a certain temperature, the heated water flows back into the drain shaft (by approx. 1-2 degrees). At the same time, fresh, cold water flows from the inlet well into the reservoir until the water level reaches the set value. The pump then switches off and the process can start again.

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