Seeking suggestions for panel placement on 30 panel array photos included!

Frankie_Bones
Frankie_Bones Registered Users Posts: 5
Hello, I am going to put up a 30 panel array on our house but I have yet to finalize the placement of the panels. I have a portion of south facing roof that can hold 18 panels however it starts shading in the afternoon from the roof line of the 2nd story. I also have west and east facing roof that can accommodate 25-30 panels per side. What configuration would be most efficient?
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Here is what the south facing roof looks like at about 4pm in july. It has similar shading at about 1:30 pm in January.

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This is the East facing roof at about 4pm in July. It looks the same at 1:30 in January.

So would it be best to split the panels between east/west or do south/west or south/east?

Thanks!

Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Seeking suggestions for panel placement on 30 panel array photos included!

    Is this a GT system? Is there a TOU agreement ? or is it a battery backed system for outages or?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Frankie_Bones
    Frankie_Bones Registered Users Posts: 5
    Re: Seeking suggestions for panel placement on 30 panel array photos included!

    grid tie with m215 micros and 250 canadian solar mono panels that im buying outright
  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    Re: Seeking suggestions for panel placement on 30 panel array photos included!

    I will point out just a couple of general things to consider. You can use PV Watts to figure out your best solution. Will need the "True azimuth" readings for each of your roof sections. Would try and stay clear of the shaded section as much as possible.
    having a clay tile roof requires someone familiar with them to install a solar system with the necessary stand offs and flashing to get it to where it doesn't leak.
    will need to check with local building department/fire department to see if they require panel clearance along ridge and ends of roof for access in case of fire. Normally require about 3 ft along ridge and ends, may be able to get waiver based on other access or local codes.

    Just something to think about.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • KozmoK
    KozmoK Solar Expert Posts: 42
    Re: Seeking suggestions for panel placement on 30 panel array photos included!

    Frankie,

    Are you installing it yourself?

    EDIT: I see you are by your previous post! Keep us updated on the progress!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Seeking suggestions for panel placement on 30 panel array photos included!

    Excluding the shading, you can use PV Watts or Solarelectricityhandbook to calculate each face of the array (i.e., E,S&W) and see what combination gives you the most energy--When you need it.

    Shading is a whole different issue... PV Watts will give you an hour by hour report--And if you know you have shadows after (for example) 2pm, you can zero otu the array or zero out a couple of panels (depending on how shadows fall and/or the MPPT voltage range of the controller, etc.).

    If this is a grid tied system with Time of Use metering (like mine)--I get about 3x the credit for the "summer" 6 months from noon-6pm. So, optimizing my summer afternoons are the best for me (even if winter orientation is not as great... Even if I "lose" 1/2 winter performance, I would just do better with 3x summer afternoon credits).

    If you are looking to go off grid, then you need to look at summer and winter collection--Perhaps you need more winter energy to keep from having to run the genset too much.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset