Heat by putting a metal rain collecting/heat collecting roof over the south
berm. Pipes circulating through the berm would have valves so that heated air could enter the top of the loops and exit the bottom but not reverse when the roof cools. Of
course you could reverse that if the climate or a storage space required cooling . A challenge
project for the
appropriate technology jamboree; make a
root cellar with a night radiating cooling roof on the north side.