Doctor Drivel wrote:
""Pet @ www.gymratz.co.uk ;¬)"" wrote in message
. uk...
I was contemplating a project for a long time in the future, and stumbled
upon an idea...

Our boiler MAN (ecohometec) can use pre-heated water to reduce/eliminate
required heat boiler input into DHW. Logical use of this is a Solar heated
water bank thing before the boiler. That's the easy bit.
Next idea was on Wind power. Our home is in an ideal location to catch the
SWesterly winds blowing up the Bristol channel see S.W. picture he
http://www.gymratz.co.uk/pete/sunset1.jpg

So, assuming I could get planning to erect a 2.5KW turbine, the ideal
scenario would be have the turbine feeding an immersion heater in the heat
bank (something like the following:
http://www.eco-hometec.co.uk/solar_cylinders2.html
So Solar by summer and wind by winter, but with the magical bit happening
when heatbank/store is satisfied....

Electricity being switched by tank thermostat and divered into ring main
as per usual method.

Can anyone see a possible flaw in my plan?
Currently we wouldn't be go the solar route as we only have East/West
sloping roof but that can be sorted with a future flat roof replacement
over the garage.

As it is, it's a "hmmmmm....." plan with much smaller things to be sorted
first, I thought I needed to get some thought on the idea before I waste
more time on theoretical pipe runs and Mast locations etc.
:¬)

Your Eco-Hometec (rebadged German MAN) is a combi version (DHW and instant
CH in one box) I assume. Roland seemed to be showing a heat bank - a
thermal store using a plate heat exchanger and pump for DHW take off for the
cylinder. Look at this web site for an explanation. http://www.heatweb.com

The Eco-Hometec cylinder is a normal unvented cylinder with a solar coil. It
needs to be fitted by an approved installer and cost around £60 to £100 per
year for an annual service. Any gain via solar or wind is negated by the
service charge, so a no. no.

Try a vented heat bank (variant of a thermal store using a DHW plate heat
exchanger) heated directly by the boiler (no heating coil in the cylinder).
Heat the cylinder via the CH section of the boiler. The wind turbine can
heat an electric immersion heater in the cylinder. Any solar can be via a
solar coil, or even directly into the cylinder using an auto drain down
system. This way any energy gained by wind or solar may be used for CH or
DHW, not just DHW. The CH circuit can be taken off the heat bank cylinder
using a Grundfoss Alpha auto variable speed pump.

The cold mains pipe goes through the DHW plate heat exchanger.

Now you have a redundant DHW instant section on the combi boiler. This can
be used for backup if the DHW pump fails on the heat bank, by inserting some
valves in the DHW cold mains supply by isolating the combi or the heat bank.

This is the best approach for you.

You could make better use of the DHW part of the combi by feeding the
mains input to the boiler with the output from the plate heat
exchanger. The combi will boost the hot water temperature if the
thermal store is empty or not hot enough.