Low Earth Depth GeoThermal Heating

[MidnightWizard]

Stumbled across this looking for something else
Apparently better than a number of other technologies

Citrus in the Snow

GreenHouse in the Snow

Here is video to illustrate

Christopher Brandsdal in Norway ( four part series )

There are a few SA companies involved in this field as a bit of Googling will show.
Looks very promising to me