Help on suggested panel angle/direction

[MikeN]

So... interested in building ground mounts along our back fence line (would be up at fence height or higher), but the back of our house faces East. Have very limited space back there, and the house blocks the mid/late afternoon sun back there as well. We have limitations on location, exposure, etc due to HOA as well

My idea is to do a covered deck along the fence line and mount the panels as the "roof" or top of that covering. Issue is how best to mount the panels and at what angle? From my research, we should be at between 28-32 degrees but facing south. (75013 zip code).

To look the best, panels would be facing west (toward the house), but probably not ideal for energy. Other option would be to stager and face south (sideways if you will) -- but have to be careful that the panels don't block each other. General ideas attached --- Thoughts?

 

[45North]

Latitude of Dallas is about 33 deg so south-facing with 33 deg of tilt will work year-round.
Tilt 'em up to 15 deg steeper in winter when the sun is lower if you want more then and 15 deg less tilt in summer if you want more then when the sun is more overhead.
Also, panels are pretty cheap these days so you could face some more east to get more power in the morning and face some west for the afternoon.

 

[Madcodger]

Just Google PVWatts from the NREL and play around with the calculator to your hearts's content. Change azimuth, tilt, panel size, whatever. Your tax dollars at work.

 

[Steve777]

The details of your site can make quite a difference. Shadows from trees, buildings, etc. What you are doing with the power, do you want to maximize winter gain, summer gain, both?

It might be worthwhile looking closely at your site, see if there is shading, and fit that in with when you want to maximize your power gain.

 

[MikeN]

Just Google PVWatts from the NREL and play around with the calculator to your hearts's content. Change azimuth, tilt, panel size, whatever. Your tax dollars at work.

Thanks.... went and played with that, and it gave me some surprising info.

Estimates for example:

Facing south, at 27-29 degree tilt was 7927 kWh/yr (about best angle for facing south based on that site)
Facing east or west, best angle was 0 degree tilt, with 7078 kWh/yr estimate (lower number with tilt facing either east or west)

So roughly a 12% improvement facing south at those angles. Not as much as I would have assumed

 

[Madcodger]

I generally assume about a 15% reduction for west-facing panels so 12% sounds about right. Play around with the tilt a bit as well, and think about the time of year when you most want to offset energy costs (possibly summer, in Texas, due to AC). I'm in Maine with off grid systems, so for us it's all about winter production. Whatever you're trying to optimize for, PVWatts is a great resource.

 

[Mkgough]

You can do one of those single axis trackers so it adjusts the angle based on sun location…. There is a post about the guys DIY setup…pretty kewl. I use trackers to solve this issue as it is WAY more efficient