I'd like to chat offline with someone who has installed a solar
array system that feeds your load AND backfeeds to the grid
And/or, I'm looking for a pointer to forums [formi??] centered
Weve been off grid for some 39 yrs.
used diesels for power generation, on demand systems by Lister, called
the startamatic set up.
5 yrs ago found 3 tons of nicad alkaline( sodium hydroxide ) batteries.
so then invested in an 3kw "outback" US system of charger/inverter.
Been in use for 6 months and has proved very efficient.
Next step is to use one of our 6/1 diesels running on straight
vegetable oil as a dc generator to eliminate the use of fossil fuel.
Will need to make a suitable alternator aka windmill permanent magnet type.
as for solar, this could be a possibility but due to the poor UK
weatherm sunshine is not reliable enough for us.
also the cost of connecting to our uk grid is prohibitive, due to the
Google for outback there the best right now for what you want.
I though UK sunshine was measure in inches per hour...!!!
I built a couple of the MEN style conventional wind turbines a few years
ago. They work OK but I'm thinking of building a couple vertical vane
units to eliminate many problems that you have with conventional wind
turbines. No need for a wind vane or directional control. Should be able
to put the actual generator at the base and use a simple shaft up to the
vanes. MUCH easier service that way.
With all the Amish around here now I might even have a market for them!
Most of them use an automatic diesel system for the milk house to
provide vacuum and cooling and air power.
Re Vertical axis wind turbine,
My son ,( now 26) researched, designed and built for his senior school
CDT final year project some 10 yrs ago a 10ft tall vertical axis 3 blade
darius windurbine for just this purpose.
The intersting bit was the blade making. If you like I can write up what
we did.We still have all the. bits somewhere in a shed. we used an all
metal construction for them.very strong and simple.
however the advantages of this type of wind turbine are outweighed by
its poorer efficiency than the horizontal axis type.To get the same
power output they need to be twice as big.
Ie there only 50% as efficient as the other type.Sorry to say.
whatever anyone else may say.
In 15mph wind tests it spun well , tho it was out of balance due to
We also had a neibour who built a horizontal axis turbine some 20ft dia.
using 4 3ft dia cones. this was effectively a drag machine with the
torque output being the difference between the drag of the down wind
going cups and the upwind . going ones.
Never heard how he got on. Been dismantled some time.
Can find out again if you would like to know.
in Dorset UK.
Your request doesn't seem to be an "off grid" request, but here's my reply.
a.s.photovoltaic is one newsgroup that deals with things solar-PV. You
have to put up with some guys who like to beat eachother up, but if you
persist, you can learn some things.
I have two friends within 50 miles of me who have put up 3Kw and 7Kw pv
They are both grid tied. One cost about $40,000 and the other cost
about $70,000. Rebates pay about 1/2 of that back in Wisconsin.
They both supply their local load and do grid tie, but if the power
goes away, neither of them generate for local use.
You have to spend more money to get that feature, I am told.
Also, neither one of them went with batteries. We have a pretty
reliable grid here.
David Lesher wrote:
On Sat, 27 Mar 2010 05:39:48 -0700 (PDT), the infamous Jim Wilkins
scrawled the following:
I'm interested in this stuff, too, and found the same lack of in-depth
info on AEH depressing. The breadth and depth of info found here is
wonderful. Great group.
"Not always right, but never uncertain." --Heinlein
systems sold here in the
PNW. I called them wanting a system that feeds back into the grid if
there's an excess *and* also provide us power if the grid goes down.
No can do, she said.
If your friends systems are capable of this, I'd really appreciate the
contact info of that company.
The problems I see of feeding back into the grid are multiple. Matching
frequency precisely. If there is a down line in the grid, and the power is
turned off for repairs, does the lineman die because your grid came online
and fed power backwards? Or your controller burns up, because the grid
looks like a direct short when no power in to the grid.
All true. But grid-tie systems are out there, in use.
The question is: what's available in dual mode systems:
a) Grid-tie, feeding power back IFF there is utility power.
b) Power failure mode: supplying the house from solar and battery when the
utility goes down.
All things that need to be considered and engineered in. The
frequency matching is easy, doesn't even take fancy computer
controls. One way to isolate the home side from the line is to use
the line frquency as the determining factor. It has to match that
anyway. Absence causes a mechanical trip and isolates the home side.
Require a manual reset AND line voltage presence to link again.
Presumably, if line voltage is there, there's no lineman handling
wires to toast somewhere.
What this sort of thing requires is a battery set, cells somewhere
between aquarium and swimming pool size. And all the maintenance and
proper venting that requires. Nothing like a hydogen explosion to
ruin your evening. Your charging device(s) would charge the
batteries, as and when possible, and a whopping big sine-wave inverter
would provide the AC, with synchronization provided by the line.
Battery cost is usually the killer here, they start going downhill as
soon as they're wet, 5-10 years would probably be a good lifetime.
Wonder if Edison cells would have a market these days? Railroads used
them in a lot of high-reliabiity, low-maintenance roles.
Yes it is, there's a growing industry relating to that in Europe too.
Germany is setting up solar systems on homes and buildings just for
this purpose, mini power generation systems feeding the grid for
distribution to where it's needed. That technology is here.
Exactly. If anyone knows a company that can provide both features,
I'd sure appreciate their contact info.
The way I figure this is that it would be a shame to have an excess of
solar generated power go to waste. I plan to over build this system
in order to ensure we'll always have as much as we'll need.