PV system sizing and cost calculations
Steve Spence
http://wedconx.green-trust.org/2003/pvsizing/ ), I have put together a
spreadsheet that helps you calculate the costs and output of a Photovoltaic
Power System. Follow these four steps to determine your loan payments,
output, and costs.
http://webconx.green-trust.org/2003/pvsizing/pvcalc.htm
--
Steve Spence
www.green-trust.org
Steve Spence
Steve Spence
and http://webconx.green-trust.org/2003/pvsizing/pvcalc.htm
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Steve Spence
www.green-trust.org
"Steve Spence" <ssp...@green-trust.org> wrote in message
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Steve Spence
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Steve Spence
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"Steve Spence" <ssp...@green-trust.org> wrote in message
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Steve Spence
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Grant Beuchel
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William P.N. Smith
> http://webconx.green-trust.org/2003/pvsizing/
> http://webconx.green-trust.org/2003/pvsizing/pvcalc.htm
Good stuff Steve, thanks! Does the SunFrost still enjoy a 4:1
efficiency over a 'normal' fridge or freezer? Some of the discussion
here of late has hinted that their efficiency ratio has evaporated due
to the new crop of Energy Star appliances...
Thanks!
--
William Smith wp...@compusmiths.com N1...@amsat.org
ComputerSmiths Consulting, Inc. www.compusmiths.com
Anthony Matonak
> Good stuff Steve, thanks! Does the SunFrost still enjoy a 4:1
> efficiency over a 'normal' fridge or freezer? Some of the discussion
> here of late has hinted that their efficiency ratio has evaporated due
> to the new crop of Energy Star appliances...
Compared to the Energy Star fridges the SunFrost does about 2:1
efficiency. I.e. An energy Star fridge might take 1.6 kWh/day
while a comparable SunFrost might take .8 kWh/day.
Anthony
George Ghio
"Steve Spence" <ssp...@green-trust.org> wrote:
> In complement to our PV sizing tutorial (
> http://wedconx.green-trust.org/2003/pvsizing/ ), I have put together a
> spreadsheet that helps you calculate the costs and output of a Photovoltaic
> Power System. Follow these four steps to determine your loan payments,
> output, and costs.
> http://webconx.green-trust.org/2003/pvsizing/pvcalc.htm
Well Steve they say that imitation is the sincerest form of flattery.
But I have got to say you have made quite a mess of my spreadsheet.
1) When will you learn that the best way to do an Energy Audit is on a
daily basis, weekly is a joke as you only have to divide by 7 (row 46).
Also all items in the energy audit should be listed separately including
all lights. The reason for this is that when you set up a system you can
fine tune your load item by item.
2) Row 16, Daily Watt hours divided by inverter efficiency expressed as
.9 for 90 percent or .8 for 80 percent etc. will give you the inverter
correction. Sure beats the hell out of your 83.4 percent guess.
3) Row 22, Daily AC Watt hours (corrected for inverter loss) divided by
system voltage i.e. 12, 24 ,48, will give you the daily Amp hours used
by the AC side of the system.
4) Row 27, Another time waster. Daily loads, listed separately for fine
tuning of the DC
load.
5) Rows 34, 37, 43, DC weekly Amp hours. Bugger that for a lark.
6) Row 46, Divide by 7. Point to George It all comes back to your daily
load.
Battery Sizing
7) See, Daily load in Amp hours. And after only 51 rows in the
spreadsheet. Of course the SS you cobbled this mess from only requires
31 rows to be finished.
8) After another 24 rows you get the battery Amp hours needed (adjusted
for temp) with the added embarrassment of getting the wrong answer.
9) After another 15 rows you find out that yes you really do need two 6
volt batteries. And after only 59 rows past the point that the original
SS has answered it all right down to the last panel
10) Row 92, The Array sizing. Long time coming.
11) Row 94, There is no AVERAGE here, if you did your energy audit
correctly you Know what you use. Leave average systems with average
performance for Nick. Strive for exultance.
12) Row 97, See item 2 above.
13) Row 100, If you size your system according to summer sun light it
will start to fail around mid fall and will require lots of generator
time for the next six months or so. Never use Average sun hours. If you
donšt know what PEAK SUN HOURS are learn now and check the NASA surface
meteorology web site to find out the peak sun hours for your location.
Also missing is the panel angle.
Sorry Steve but your attempt to rewrite my spreadsheet is but a pale
imitation of the real article. I am glad you found it worth the effort
but you should have just used it as is. I would not have minded in the
least.
George L Ghio
Solar Power Consultant
Spreadsheet by request at <gh...@netconnect.com.au>
George Ghio
"Steve Spence" <ssp...@green-trust.org> wrote:
> In complement to our PV sizing tutorial (
> http://wedconx.green-trust.org/2003/pvsizing/ ), I have put together a
> spreadsheet that helps you calculate the costs and output of a Photovoltaic
> Power System. Follow these four steps to determine your loan payments,
> output, and costs.
> http://webconx.green-trust.org/2003/pvsizing/pvcalc.htm
Well Steve they say that imitation is the sincerest form of flattery.
Nick Pine
"Solar Power Consultant" George Ghio <gh...@netconnect.com.au> wrote:
>...Strive for exultance.
Good idea, but probably not the one you intended :-)
Nick
wmbjk
"George Ghio" <gh...@netconnect.com.au> wrote in message
news:ghio-BDC465.2...@news.chariot.net.au...
>Leave average systems with average
> performance for Nick. Strive for exultance.
Yup. If superiance, triumphcy, and grandiloquessness are already taken,
then exultance is always a good fourth choice to strive for. Just don't
expect any more than about 40 amps per day from it.
Wayne ;-)
"Striving? We don't need no stinkin' striving." (overheard at the
computerless off-gridders' annual picnic)
George Ghio
I design working solar power systems and often neglect spell check.
If you need energy and want to get it from solar which advice do you
want?
George L Ghio
In article <bh8d7u$2...@acadia.ee.vill.edu>,
George Ghio
I design working solar power systems and often neglect spell check.
If you need energy and want to get it from solar which advice do you
want?
George L Ghio
In article <bh8d7u$2...@acadia.ee.vill.edu>,
ni...@acadia.ee.vill.edu (Nick Pine) wrote:
Nick Pine
>If you need energy and want to get it from solar which advice do you want?
Look for the man with the 200 amp resistor :-)
Nick
George Ghio
reasons known only by the manufacturer is also rated at 150 Amps as
opposed to the 36,000 Watts which would be indicated by the marked
voltage.
George L Ghio
In article <bhahos$2...@acadia.ee.vill.edu>,
BooBoo
Maybe that Rheostat is measured in Amp-Ohms
daestrom
> Wrong again Nick. The item in question is a 150 ohm rheostat. Which for
> reasons known only by the manufacturer is also rated at 150 Amps as
> opposed to the 36,000 Watts which would be indicated by the marked
> voltage.
>
It's been my experience, that *large* rheostats are often rated in Amps
instead of Watts. This is because the heat dissipating capability is a
function of how much rheostat is in the circuit. And that heat disspating
ability just happens to be nearly linear with the wiper position, much like
the resistance often is.
For example, each inch around the rheostat may be able to dissipate 100
Watts. If that same inch has a resistance of 1 ohm, then that section can
carry 10 amps safely. Move the slider so 7 inches of the rheostat is in the
circuit, and it can dissipate 700 Watts. If it is linear resistance, then
that 7 inches has 7 ohms resistance and the maximum current is still 10
amps.
Of course, the actual current depends on the voltage supply and the rest of
the circuitry.
daestrom