On Tue, 10 Sep 2002, Brendan Kirby wrote:
> Round trip efficiency for pumped storage is about 80%.
Really? I did not know that.
I've been harboring delusions of building a PV / Wind power system for
quite some time. The one nagging factor with the way that I want to do it
is that I don't want to waste any generating capacity. If they batteries
are full, find another way to store the energy. Pumped storage, I must
say, has "nifty factor" written all over it. The problems, however, are
numerous.
One is that you can only count on a pump to push water so far uphill. Two
is that you're probably going to have to start with a submersible
(well) pump and go from there adding pumps as necessary to insure
operation. Then you've still got to deal with the turbine, or generation
side.
The way I thought about implementing this just a few moments ago would be
to have two (covered) pools or tanks, one about 45 - 100 feet up a hill
and the other at the bottom. You use a submersible well pump (should be
good for at least 100 - 200 feet of head) to pull the water out of pool #1
and send it uphill to pool #2. Then when capacity starts dropping of and
the SOC comes down a bit, you switch the valves over (obviously will have
to be electric high-pressure valves) and dump the water through a turbine
and generator. This should provide a little bit of a "hump" in the middle
of the night so that the batteries don't go so low in the morning.
Of course, this ignores the fact that if you are 100% PV already, you
probably have more than enough PV capacity and battery capacity to do the
job. I'm just looking at storing wind power for later use. And on that
note, I just realized that an old windmill is the perfect solution -- less
conversion loss, and it pumps water to begin with!
--
Kris Kirby, KE4AHR <[EMAIL PROTECTED]> TGIFreeBSD IM: 'KrisBSD'
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