On Sat, 21 Jun 2008 17:47:37 +0100 someone who may be MM
wrote this:-

Can
I feed the hot water (on thermo-syphon principle) into a black plastic
cold water tank as used in the loft?

You can. Whether this is advisable is another matter. One question
is what happens if the collector manages to make the water very hot,
perhaps creates steam. Even a small collector can do this if it is
only heating a small volume of water. Control of excessive
temperatures is an integral part of good solar design.

There are some thermal stores made out of plastic. A (very
expensive) range is at
http://www.consolar.co.uk/index.php?option=com_content&task=view&id=6&Itemid =15.
The difference is that the plastic vessel is designed for this use.

The other important factor in solar heating is insulation of the
cylinder/store to maintain temperature. As a minimum double
thickness sprayed on foam is desirable, triple insulation is better.
If I was making a small system for a few basins then I would
consider having a special cylinder made by McDonald Engineers
http://www.mcdonald-engineers.com/products/cylinders.htm or one of
their competitors.

For a home made collector plenty of designs are available and I
would study several before deciding on a design.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54