Posted by old dirtbeard on May 28, 2007, 3:25 pm
Hi all,
Just a performance report back on my recent installation of a 6KW PV system
consisting of:
30 - Kyocera KC200GT (200 watt) panels
1 - SMA Sunny boy 6000U inverter
It is a roof mount with a south-east exposure and has been operating since
mid-March in suburban Los Angeles, CA. So far it is exceeding my
expectations.
We are producing about 11KW/day more than we are consuming (averaging about
34KW/day production, and have seen 40KW production on clear days). We have
not needed to use the AC and I also will need to increase the pool pump run
times as it gets warmer, so the surplus may shrink.
Today I was particularly impressed by observing it actually outputting over
6KW (6,015 watts) around noon today (it is 68 degrees F today, and I can
see that cool clear days produce more power than hot days as the panel
efficiency clearly seems to drop somewhat with ambient temperatures over
about 70 degrees).
Even with an inverter efficiency rating of >95%, I am surprised to see it
actually exceed 6KW output, and today is cloudy. So far I am very happy with
the system and would recommend the components/configuration.
best,
doug
Posted by Roderick on May 28, 2007, 11:20 pm
Impressive.
If you have a picture of your setup, or even produce a web page on it,
I'd love to see it.
What is the orientation of your array, by the way? If it's pointed
well, I would not be surprised if you see 50 kWh days next spring when
it gets cooler!
Posted by dold on May 29, 2007, 1:55 am
> What is the orientation of your array, by the way? If it's pointed
> well, I would not be surprised if you see 50 kWh days next spring when
> it gets cooler!
My best days are in July, where I see 29kWh from a 3.8kWp CEC rated
system. Recently, I have had 14 hour run times, starting up about 10
minutes before sunrise, and ending 20 minutes after sundown. 425 hours
of runtime last July, 776kWh for the month. That's also where I see the
biggest financial benefit, offsetting some of the high-cost high-tiered
usage of air conditioning.
I've seen 4100 watts, presumably from scattered clouds and the cloud edge
effect, but I often run 3900+ on clear days in the spring.
My panels are at 214 aziumth, 26 elevation.
--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
http://cdold.home.mchsi.com/Solar-generation.htm $1643 avoided in 2006.
Posted by old dirtbeard on May 30, 2007, 11:24 pm
> Impressive.
> If you have a picture of your setup, or even produce a web page on it,
> I'd love to see it.
> What is the orientation of your array, by the way? If it's pointed
> well, I would not be surprised if you see 50 kWh days next spring when
> it gets cooler!
Hi Roderick,
Great questions, and I thought I knew the answers, but I could not locate
the documentation, so I queried the installer.
I know the azimuth is not ideal, but it is an existing house and I had to
work with the roofline I had. It takes about 525 sq. ft. for a 6KW panel,
so I ended up with a southeast face (once I hear back from the installer I
will post the azimuth and elevation). It really cranks from 9:00 a.m.until
about 2:00 p.m., but then falls off gradually until dusk. I also will shoot
and post a picture.
We were using 800KW - 1.5 MW of electricity each month (at the Southern
California Edison rates, you start paying about $.40+ per KW once you get to
200% over baseline, and baseline is about 10 KW/day, so much of our
electricity was purchased at $.40 KW).
I replaced all the incandescent bulbs with CF, put timers on things, etc.
and probably have reduced the draw from about 30KW/day to around 22KW/day,
but we have Koi pond pumps running 24 hrs./day, 1.5 HP pool pump running,
AC, etc. No matter what I did, we would be burning a good deal of wattage.
I feel very good about the "turnaround" from burning 30KW+/day to running an
11KW/day surplus. Since the March 9th install, we have generated over 2.5
million watts.
I would be interested in an electric car to capture the surplus we are
generating, and to get off the $3.35/gal. gasoline that we are paying here
in LA. The $100K Tesla probably is not an option, though. :)
best,
doug
Posted by dold on May 31, 2007, 1:24 am
> so I ended up with a southeast face (once I hear back from the installer
> I will post the azimuth and elevation). It really cranks from 9:00
> a.m.until about 2:00 p.m., but then falls off gradually until dusk. I
Depending on your rate schedule, that might not be a bad thing. Are you on
a time-of-use plan? I am south-west, which is good for the noon-6pm peak
plan that I am on. The newer multi-rate plan might do well to see some
earlier production. My system runs from 20 minutes before official sunup
to 30 minutes after sundown. It produces about 70 watts at startup, and
gets down to 30 watts before it quits.
And... you get the azimuth that you get. You plop it down on an existing
roof. Your installer probably only took a quick glance at a compass
to see what the orientation was, and maybe only cared about it in order
to do a good proposal, including expected generation. You can probably
make a pretty good guess by looking at Google Earth for your location and
using a protractor to note the angle.
You can also get pretty close by noting what time of day shadows fall
directly along one wall, and looking up that time on a sun calculator.
http://www.gcstudio.com/suncalc.html
> I replaced all the incandescent bulbs with CF, put timers on things, etc.
> and probably have reduced the draw from about 30KW/day to around 22KW/day,
I did the same thing, in between the original sales pitch and the contract
signing, and found that I had reduced my load enough that the installed
system was downsized from the original to match my new draw.
> I would be interested in an electric car to capture the surplus we are
> generating, and to get off the $3.35/gal. gasoline that we are paying here
> in LA. The $100K Tesla probably is not an option, though. :)
In PG&E territory, an electric car requires a different rate plan.
--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
http://cdold.home.mchsi.com/Solar-generation.htm $1643 avoided in 2006.
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> well, I would not be surprised if you see 50 kWh days next spring when
> it gets cooler!