Real Power for 5kw System

Re: Real Power for 5kw System

I like to compare against the PV Watts program. Using 5kW and defaults for everything else (assuming facing south at 33.5 degree tilt):

"Station Identification"
"City:","Phoenix"
"State:","Arizona"
"Lat (deg N):", 33.43
"Long (deg W):", 112.02
"Elev (m): ", 339
"PV System Specifications"
"DC Rating:"," 5.0 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 3.8 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 33.5"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:"," 8.5 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 5.09, 564, 47.94
2, 6.06, 608, 51.68
3, 6.61, 708, 60.18
4, 7.54, 766, 65.11
5, 7.53, 773, 65.70
6, 7.28, 699, 59.41
7, 7.13, 711, 60.44
8, 7.17, 720, 61.20
9, 7.15, 696, 59.16
10, 6.75, 707, 60.09
11, 5.59, 587, 49.90
12, 4.88, 547, 46.49
"Year", 6.57, 8085, 687.23

For December/January (this is a ~20 year average)--call it 555 kWHrs per month or:

555kWhrs per month / 30 days per month = 18.5 kWhrs per day

You can look at the hourly data output and see what each "average" day would output (load in spread sheet for total per day/week/etc. comparisons).

From the same site, they also have nice PDF files of the data... And you can visually see how much variation per day over 20 years there is.

For January, over the years, the long term monthly average power varies between ~4.0 and ~6.3 Hours per day of sun with an average of ~5.2 hours of sun...

So, it looks like weather wise, you can easily see +/- 20% variation from year to year results in power output.

Looks like a good start.

With solar--your mileage may vary.

-Bill

PS: From the hourly data--just a quick look shows that you should see an average maximum in early January of ~3,600 watts average for an hour...