Getting back to the rock piles...
There is a concept known as an air well that was researched for a while back in the day. Check out the wikipedia page
http://en.wikipedia.org/wiki/Air_well_(condenser) . There are also dew condensers that can create larger volumes of water thanks to an increased amount of surface area (this is also why wooded areas have more stable climates, the trees release moisture, buffering temps but also the leaves have a large cumulative surface area for dew).
In general, from what I have read, the air wells didn't produce "enough" for towns to make use of, but the concept (thermal mass / surface area / air flow /condensation) is still a powerful example of how elements within our designs can help to create beneficial microclimates.
I had mentioned on an earlier thread about the function of rocks as energy syphons and expanded that to a blog on my website:
http://pittsburghpermaculture.org/general-thoughts/ideas/rocks-in-the-garden -Troy
http://pittsburghpermaculture.org