This may be more of a Skunk Works thread but if it's right then it's ancient civilization.
First electricity generation.
Should be easy to check this out if you live near a dolmen. You sing at the stone and it rewards you with electric current.
Now prehistoric ground source heat pumps.
Along the lip of an escarpment near here there are a series of stone chambers. It's thought they were originally roofed with huge slabs of stone, laid
like roof tiles, on top of the earth mounds covering the stone passages and side chambers. Dry and well insulated.
Ventilation and heating may have been carried out in the following manner.
Along the edge of the escarpment there are open fissures going deep into the rock. On cold days, due to the phenomena known as cave breathing, air
warmed by the latent solar energy trapped in the rock breathes out of the fissures in gentle gusts.
A shaft from the floor of a chamber down to the fissure beneath would direct warmed air into the chamber. A plug for the fissure outside would ensure
the warmth was not lost. Removing the plug from the fissure outside and plugging the hole in the chamber when air was being drawn back underground
would allow the temperature in the well insulated chamber to remain stable.
If you explore a few dozen yards south of this chamber en.wikipedia.org... along the lip of the escarpment you'll soon find
a fissure. On cold days you can feel the gentle gusts of warmed air.
Who would have thought our ancestors were so carbon conscious? Or maybe they just didn't want telltale wisps of smoke giving away their winter
hideouts.
Having experienced modern ground source heat pumps I suspect they were more efficient thousands of years ago. But that's another story.
Your welcome,
There are natural occurring sites like this
Mountains with micro quartzite providing the positive ions in a strong electromagnetic field along a geologic fault line, and
a bottomless cleft rock spring creating the negative attractor. Not sure what it does, but definite weirdness and UFOs ; )
If you like that here is the the Egyptian expert at a better dissertation. youtu.be...
a reply to: Kester