wrote:


First solar hw collector efficiency depends on water temp, the colder
the water being heated the more energy is harvested. So the idea is to
put them in the coolest part of the system where the output will be
useful. That means either heating the bottom of the hot tank /
heatbank, or running ufh, or using a solar preheat tank.

That's what I suggested... a Solar pre-heat tank.

2nd windmill heating HW is using high price energy (electricity) to do
the job of low cost energy (oil & gas). This step alone divides your
payback by about 3.

I know this, but, as I wouldn't be able to get a big enough mill (6KW)
on the space available (or planning) I can't realistically export
surplus energy to the grid, so when energy is being produced during
times of minimum power consumption (all hours outside 07:00 to 09:00 and
17:00 to 23:00) so about 16 hours of the day, I thought it better to
initially use electricity to "top-up" heat-bank (Water pre-heater)before
switching to ring main feed.

Of course, if I get a few PC's and servers running then I doubt I would
over produce anything anyway.

3rdly, solar dhw just doesnt compare to solar space heating. Space
heating is much cheaper, more efficient, yields far more energy
payback, and costs in the region of a tenth the price to install. If
you want good payback, solar space heating is the way.

But our South facing wall has a big window across it which I'd prefer to
keep!

And... the sun is a bit arse about face when it comes to space heating
requirements.

:¬)


--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://Water-Rower.co.uk - Worlds best prices on the Worlds best Rower.