[Greenbuilding] Evacuated tube collectors?

[Speireag Alden]

Hallo, all.

     The time has come to put in the first solar hot water collectors. 
These will eventually generate some amount of solar pre-heat 
year-round, with overcapacity through the summer, when excess will 
heat the ground around and under my earth-bermed house, AGS-style.

     The house is in west-central New Hampshire, so the system must be 
utterly resistant to cold temperatures, and it would be very nice if 
it could generate some amount of heat during December, when days are 
short and often cloudy.  So I'm interested in evacuated tube 
collectors.

     A bit of research turns up two types which seem promising:

     http://www.solarthermal.com/

     http://www.sssolar.com/

     Does anyone have any experience with these?

     Does anyone have other recommendations?

     I want to be pretty simple on controllers.  I'm thinking that 
I'll put one temperature gauge right where the pipe enters the 
ground, inside the insulation jacket, and another at the manifold for 
the solar collector.  Between them, I want to put a controller which 
will compare temperatures, and when the panel is warmer than the 
pipe, close the circuit on a solar-panel in-line pump hook-up.

     Although I like tinkering, I see no need to re-invent the wheel 
and I have plenty of other things to do, so I'm willing to look at 
off-the-shelf solutions for the control stuff, if someone can point 
me to them.

     Eventually, I will expand the system such that the hot water from 
the collector will be routed first to the house storage, and then 
when that is hot enough, to heat the interior of the house via the 
radiant floor, and when that is hot enough, to dump the heat into the 
ground around the house.  So there will need to be several sensors 
and switch valves.

     Can anyone guide me toward a good solution?

-Speireag.

-- 
Fill the molten glass.
Sit with singing summer frogs.
Think on Jack's wedding.