On 10 Mar 2006 09:48:43 -0800 someone who may be
wrote this:-

The system at http://www.imaginationsolar.com/system.htm has a
number of advantages. One of these is that it does not use mains
electricity, which can exterminate 20% of the savings gained by
using solar hot water heating [1]. The control system is very
simple, if the sun is shining it pumps water into the panel and
starts warming up the cylinder. If the sun is not shining, or there
is snow on the PV panel, then the pump is not running and the panel
is drained of water.

Imho this is more the hype than the reality. The one advantage of a
solar panel pump supply is simplicity, but thats all. The electricity
created by the solar panel is the opposite of a worthwhile investment
for 99% of end users. The control system is a bit crude, and will
result in the system actively cooling your HW some of the time instead
of heating it. In short it isnt worth it, unless you're just not
skilled to do anything better.

All people are not alike. Some want something simple. There are many
reasons for this approach. Lack of skill is just one reason, another
reason is less to go wrong. If people want that sort of thing then I
see no reason to denigrate them. The Solartwin system has not got
any lights or things like that, though they do supply a digital
thermometer, it just works away in the background and lets people
get on with more important things. The Imagination system has a few
lights.

At the other end of the spectrum is something controlled by say
http://www.resol.de/en/Produkte/Sola...larregler.html the
Resol BS Pro. This may wring every last bit of heat out of the
panel. Whether it is worth having or is just a boy's toy is
debatable. I say each to their own.


--
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