Its a bit disconcerting to see no ideas of implementing Larry Hall's Method of utilizing heat and Ammonia exchange cooling here.  I take it that for some reason or another it has been dismissed, but I dont see why.  I mean even Einstein put his name on such systems.

However, I dont want to misrepresent its name and so fourth.  So I dug this up to make sure its clear.
The origin of it was 1920's Crosley Icyball, and first patent on the Icy Ball was filed in 1927 by David Forbes Keith of Canada before Crosley Radio Corp applied an improved patent and sold it thus.  The Larry Hall I mention in the title and so fourth is because of a nice re-simplified instructional out there for people to mess about with it.  It is Really Simple, with safety considerations, and parts and plans.  Please search it out.  It is a mind opener with potentials.  Crosleyicyball.com has alot of info.

The Icy Ball, is basically applying heat to exchanging ammonia back and forth in a system to create deep cold.  You can easily research this and see potential for use within any sort of solar setup.  Now, you can use such units in various applications within a system with solar power, I just mention the solar evacuated tubes because of the high potential for heat with either water systems or even air ( I love the stirling engine with the piston being a solar evacuated tube.. wonderfully simple, but many possibilities.)

In any case.. as an idea thrown out that I didnt see here, I imagine you all can come up with wondrous designs including the ammonia system to make any number of cooling items involved with solar.  I mean.. theres potential with TEC's peltier, and with TEG's seebeck, back and forward cool to heat potentials, or simply one sided exchanges. 

I looked through the store here, and I failed to notice any TEG's or TEC's, and.. you know.. the newer Teg's with high heat up to 600f that state they are 18watt single units for 85 dollars obviously isnt cheap toying, but.. there are new improvements in these areas that should be noticed. 

Obviously the ammonia exchange isnt new, but.. for a simple system addition I hate to see it go unmentioned.

Cheers