Are ancient stone henges in fact solar/geothermal sterling engines?

sterling engines run off of the difference in temperature between two substances, liquid primarily. were the ancient henges used for this purpose, to irrigate water, grind grains etc? Ii have discovered that this is highly possible. some interesting facts in this regard:

1. here is the modern solar sterling engine. look familiar?: http://www.stirlingengine.co.uk/d.asp?product=KS90_SOL_KIT

2. stonehenge is made of alternating white and black granite pillars, which would absorb heat differently from the sun. in the summer the surface would be hotter, in the winter the ground...

3. three mounting points for 'posts' of some sort are found adjacent to stonehenge, which could hold a wheel of some sort.

4. a moat surrounds the henge, which could be used for altering temperature somehow

   
     I am no expert on any of this, i am reaching out to the community to help me understand this further. comments welcome!

                   *edited to get the link to work right

Although I do not live in the UK, over the years I've had the opportunity to visit a number of Britain's hinges. They vary considerably in size, construction, materials, layout. Stonehenge is just one of many, though it gets most of the publicity. Personally I don't see them being a sterling engine. Stonehenge especially is associated with numerous burial barrows. Other henges have adjacent structures more apt to be for religious/spiritual use than anything else. There are numerous other stone "works" all around the UK. I find them fascinating.

The temperature difference between the colored stones would not generate sufficient energy to do any work, in my opinion, especially not with stone and wooden machinery.  You might be able to get a paper pinwheel to spin due to the difference in temperature, but that's about it, I think.

Aside from well-established solar/lunar/seasonal correspondences in many henges, Stonehenge in particular went through many phases of construction in different materials before arriving at the configuration you describe as being similar to part of a stirling engine. I find it really hard to imagine that a certain stage of a millennia-established ceremonial center suddenly became used as a power generator, even ignoring the fact that it would not have been efficient enough to, as Tyler put it, power a paper pinwheel.