Posted by box.11 on April 29, 2006, 1:55 pm
I live in Columbus OH. Originally from sunny Boulder, CO. I have a
great job here and OH is not so bad as folk in Boulder believe. The sun
actually does shine here, yesterday, ALL DAY, it was beautiful.
Consulting the US insolation map, however, one would question if the
investment were wise, central OH having ~56% the W / day compared to
I understand at least, one's break-even point is further offset by cost
of additional panels to reach some kW target.
I'd like your opinions, as I'm now getting quotes for domestic solar,
and it ain't cheap.
Should I just spend the money elsewhere?
Please don't recommend I move back to Boulder. The cost of living here
Posted by nicksanspam on April 29, 2006, 2:43 pm
NREL says December is the worst-case month for solar heating, when
470 Btu/ft^2 falls on the ground and 650 falls on a south wall on
an average 31.9 F day with a 39.2 daily max.
Solar heat is much cheaper than solar electricity, per peak watt...
Sure. You need space heat. Buy a square foot of twinwall polycarbonate
glazing (about $5 per 4'x12' sheet) and gather 0.8x650 = 520 Btu/ft^2
of solar heat and lose about 6h(100-36)1ft^2xU0.58 = 192 for a net gain
of 328, ie 96 Wh, on an average December day.
In full sun, 0.8x250 = 200 Btu/h-ft^2 passes through the glazing and
(100-36)U0.58 = 37 leaves, for a net gain of 163, ie 48 watts, at
$.77/48 = 4 cents per peak watt.
Posted by SQLit on April 29, 2006, 5:00 pm
Recently there was a program done on PBS. There was a tour of sorts through
our local solar research site Tempe AZ. The men talking were saying PV
panels are ~12-20% effecient. Naturally the higher the efficency the
higher the cost.
Those numbers and the fact that my largest load is my A/C [~30 amps] stops
me dead in the tracks for PV. Given PV generates at or near 12v dc. The
equipment and the cost does not make sense for me.
I have and would have again a solar hot water heater. If I were heating
water with electricity.
Your area freezes so that might not be such a good plan with the way we do
solar down here.
Check with your local utility. Ask if what they are doing with the sun. Ask
to visit the sites, ( more than one hopefully). Drive around and talk to
people that have a set up.
I do have a solar panel in my truck. I have a pretty big load in the summer
time with all my tools, computer and the refrigerator. I still occasionally
have to get a jump at the end of the day because of the drain.
Insulation is still the best bang for the buck. IMO
Posted by Derek Broughton on May 1, 2006, 12:20 pm
??? PV doesn't generate "at or near 12V DC". Individual wafers generate a
fraction of that, then they're mounted in series to get to multiples of
12V. There's at least one person on this group generating hundreds of
volts DC. Still, it probably _doesn't_ make economic sense.
Heating water with gas or oil is just as good a reason to go to solar hot
It's fine with the way we do solar up here, though :-)
Posted by JoeSP on April 29, 2006, 6:54 pm
Solar power is very rarely a paying proposition when you have access to grid
power. Selling to the grid can help, but it doesn't put you in the black.
Valid reasons, in my opinion for using solar power are:
1) Green power (feeling good about doing your bit)
2) Saving power (cutting down the utility bill)
3) Standby power (having power when the grid goes down)
4) Geek power (like me, doing it as a hobby)