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re: on the market for backwards lamp dimmers
29 oct 2000
dlehmicke wrote:
>>1 kva trace sun tie inverters for $1700... i'm still convinced that
>>something like this can be made with about $25-50 worth of parts...
>maybe $75. the 1.5 kva and 2.5 kva models include 6-circuit combiners
what do you mean by a 6-circuit combiner? a big wire nut? :-)
>and nec mandatory dc gfci for roof-mounted pv. plus, all four have
>nec-required ac and dc disconnects, as well as contactors which open
>upon loss of grid signal, as well as hard-or-software which disconnects
>the inverters if line frequency falls out of the 58-62 hz window (might
>be 59.5 to 60.5 these days), or ac voltage falls out of the 106 to 132
>v window (all ieee/ul stuff).
doesn't sound expensive. why contactors vs semiconductors?
>ironically, when these things happen, they happen on the grid side.
i'm not sure what you mean by that. it seems to me these are all tests
for grid power failure. the inexpensive backwards lamp dimmers i have in
mind would have dc vs ac on the "inverter side." no sinewave synthesis
or standalone capability. no "inverter side sinewave."
>i agree, it's kind of funny to watch the utilities put up roadblocks
>to small scale distributed pv, the energy from which they can buy for
>retail (except in ca, where ab 918, effective 1/1/01, formalizes the
>rules under which tou and px customers can receive those rates for
>their pv kwh) when they're paying up to 10 times retail elsewhere for
>summer peaking power.
our peco utility near phila now pays 22 cents/kwh for tiny amounts of
pv (vs cogen) power delivered at peak times... (i think that was a puc
concession to "environmentalists" in exchange for being able to charge
ratepayers for $6.3 billion in stranded costs, eg the limerick nuke.)
>the funniest roadblock is the limit, in pg&e's territory at least, of
>0.1% penetration based on service area peak demand. that's about 15 mw
>(~4000 houses) in the pg&e service territory.
could that be related to thd or grid stability? sounds low...
this might be a new form of the lineman-frying scare story...
>btw, nick, please tell us your secret of avoiding the close inspection
>of your thermal doo-dads by the energy balance police.
we doan need no steeenkeeng energy balance police :-) but seriously,
it seems to me that free-market economics would keep this in line...
>no posts asking for the energy payback of r20 insulation, for example,
>or remmid-pmals, or plastic tubing, or the other stuff. do people
>just fear you?
solar house heating seems to provoke very large yawns these days...
what's a remmid-pmal? i kinda like the idea of uv poly plastic film
greenhouse duct for collecting hot water in parabolic concentrating
reflective solar trough cabanas and attics. only 2% of our us oil
becomes plastic. isn't that better than burning it?
>...i have seen the future, and the future is powerlight.
what's a powerlight?
nick
ps: i'm thinking about a new solar structure based on free-range plastic
55 gallon drums and leaves that should have a quick energy payback...
one company 5 miles from my house empties 4 plastic 55 gallon drumfuls
of honey-almond shampoo into small bottles every day. then they cut up
the drums and put them out for the trash people.
and fall is here, and people are sweeping leaves off lawns and putting
them in plastic bags for a special leaf collection at 75 cents per bag.
(pa law bans leaves from landfills, and many locales ban burning.)
so, i'm sitting in church the other day wondering how to make some sort
of inexpensive solar-heated shrine out of this stuff, something like
the wooden barrel structure in d. c. baird's boy scout shelter book...
say it's completely passive, and uses few other materials. some other
constraints: (1) making it 70 f indoors on an average 30 f january day,
when 1,000 btu/ft^2 falls on a south wall, (2) making the day-night
temperature swing 10 f max, and (3) making the indoor temp 60 f after 5
30 f cloudy days in a row. (we might do this by making the time constant
rc = -120/ln((60-30)/(70-30)) = 417 hours minimum, so after 5 days,
60 >= 30+(70-30)exp(-120/rc)).
it might be 20'x32' od, 14'x26' id, with 3'x9' tall walls made from lots
of 55 gallon plastic drums stacked 3-high, surrounded by plastic bags full
of leaves, with plants growing all over the outside to protect the bags
from the sun and make it look like a burial mound, except from the south,
where it looks like early cristo...
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