Here we have some info on Brendan and Kathleen's homemade 'coiled pipe' collector.
The first pic is of the collector panel. It is essentially a 'flat' type of collector using a coil of black plastic pipe instead of the more common arrangement of metal pipe clamped onto a metal back plate. The collector box has yet to be glazed. The next step is to install a temperature sensor in the panel, and then the panel will be glazed and insulation added to the back of the unit.
The collector will be situated facing southwards on an earth bank on a sloped site, so no need to climb ladders for roof mounting), or build A-frames which is normally required for a ground mounted system.
This collector is about 4' X 4', which is 1.48 sq metres. Peak heat output on a good summer's day would therefore expected to be 80% X 1000w X 1.48 = just under 1.2kw.
Once this one is installed and working, a second similar panel may be added.
A delightfully simple yet lovely solution.
The differential temperature controller being used is the very same one shown in the recent velleman thermostat hack thread, which itself is 'part home made'!
This pic shows the back of the collector, which has yet to be glazed.
This is a very similar design of panel to a project we collaborated on with Paul Morrice a few year's back
Brendan asked for details re how to make up a manual air bleed.
I recommended he install a 15mm tee (T) at the hot outlet of his panel, as well as at any other high points in the solar plumbing loop, with the T inverted so the long leg of the T supports an upright 3-4" (75-100mm) length of 15mm pipe, to the end of which is fitted a radiator bleed valve.
here's a picture of the plumbing components to be fitted to the long leg of the tee
(the other end of the 15mm pipe, not shown, would be inserted into the tee)
the short length of copper pipe provides a collection area ( or trap) for air which has come out of the solar fluid. A standard household radiator bleed key can then be used to bleed this air off.