Fixed Vs angled Panels

pogonip
pogonip Registered Users Posts: 14 ✭
in Grid Tie and Grid Interactive Systems #1
I am installing a grid tie system on the side of a south facing building. There will be 22 230 watt panels. I live in Alaska at latitude 65. Snow is an issue from mid October to mid April so during that time they would be fix vertical to the side of the building. On June 21 the sun maximum height is just under 50 degrees. Using a fixed mount is much easier than designing one that can be adjusted twice per year. So I am wondering if it is worth doing.

My questions are:

How much more production the panels will produce if I change the tilt angle twice per year?

What would be the best angle to place the panels on April 15 and return to vertical on Oct 15?

I have tried to figure this out but not getting to far. I also would probably trust my answer.
Thanks for the help.
· Share on Twitter

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Fixed Vs angled Panels

    At these upper latitudes the difference can be significant. Have a look at Mac's Labs calculator:

    http://www.macslab.com/optsolar.html

    Then you'll want to try some simulations with PVWatts:


    http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/

    (I hope that's the right link.)

    Maybe go for the "year-'round" angle compromise.
    · Share on Twitter
  • pogonip
    pogonip Registered Users Posts: 14 ✭
    #3
    Re: Fixed Vs angled Panels

    Coot thanks for the info.

    One question on the PV watt calculation. On array tilt is 0 degree tilt horizontal and 90 vertical?

    Dan
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #4
    Re: Fixed Vs angled Panels

    Yes.

    PV Watts Parameters

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #5
    Re: Fixed Vs angled Panels

    You won't lose much in winter as you will only get about 2 hours of insolation. (very little of anything for Nov, Dec, Jan.) Summer will be more significant (25% loss).

    Look at the five tilt positions here:
    http://rredc.nrel.gov/solar/pubs/redbook/

    (0 deg being laying parallel to ground, 90 deg being panel perpendicular to ground)
    · Share on Twitter
  • pogonip
    pogonip Registered Users Posts: 14 ✭
    #6
    Re: Fixed Vs angled Panels

    Thanks eveyone for the help. I figured out about 24% improvement by tilting the panels to 50 degrees from horizonal from April 1 to October 1. RCinFLA says 25% so that makes me think I am pretty close. Will figure out how to get that done.

    Dan
    · Share on Twitter
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Fixed Vs angled Panels

    Personally I think the permitting process is a bit broken by the downturn in housing. Inspectors and plan reviewers both know that rejections create repeats and job security.
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
    Re: Fixed Vs angled Panels
    solar_dave wrote: »
    Personally I think the permitting process is a bit broken by the downturn in housing. Inspectors and plan reviewers both know that rejections create repeats and job security.

    Did you mean to post this here? :confused: Doesn't seem to fit with the topic.
    · Share on Twitter

Categories