North facing array | what i can i get?

fca1

Hi my soth roof is full no more PV
So i'm thinking on installing an additional array on the north side..
My house as you can see have roof with 2 sides on facing south 30ºwest and the other facing north .
in the picture
Green =current array of 22 panels, i'm thinking on installing additional 10panels on the orange part but i can't find a tool that allow me to simulate what i would get out of that array.

both sides of the roof have 27º inclination...
Any using north facing panels ?? what are the results vs south ?

thanks

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solar_dave

Re: North facing array | what i can i get?

I don't know how accurate it is but PVwatts will accept a 0.0 degree azimuth. (north)
http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/

From your picture you are actually off 0 degrees somewhat, maybe 35 degrees? That means you get some easterly sun as well.

You can also rack them to be tilted more towards the south.

Cariboocoot

Re: North facing array | what i can i get?

How close are you to the Equator? Flat paneling is a lot less of a problem down there.
Up here you could expect a huge drop off depending on the time of year.

fca1

Re: North facing array | what i can i get?

far from the equaador north red spot i know i will loose but if i get 50% its better than zero...
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waynefromnscanada

Re: North facing array | what i can i get?

You could hope for many days when the sky is filled with bright clouds, but mostly I fear it would be like digging for water in the desert.

solarix

Re: North facing array | what i can i get?

Mounting on a 27deg north facing roof is akin to mounting them upside down. What you could do is tilt them way up to face south - it will look terrible from the back but either that or face them at the moon.
You can multiply your PV watts by the cosine of the panel's incident angle to figure your orientation loss. A 45deg angle will be a 29% loss, a 60 deg angle - 50% loss, and a 90deg angle will be virtually 100% loss.

zoneblue

Re: North facing array | what i can i get?

Yes and no. For Direct Normal irradience, yup, so sun, no amps. But that will depend on your local weather system. If your difuse irradiance is in the higher end, then for semi cloudy, cloudy, hazy, foggy, rainy weather, the direction matters significantly less. However it has to be said that optimising for these (typically low insolation) conditions, your ROI is going to suffer big time. For which you will need mega healthy FITs.

inetdog

Re: North facing array | what i can i get?

solarix wrote: »

Mounting on a 27deg north facing roof is akin to mounting them upside down. What you could do is tilt them way up to face south - it will look terrible from the back but either that or face them at the moon.

Well, at least the north facing roof has no effect on the output of the panels at night. So half or more of the time they will work just as well as south facing.

animatt

Re: North facing array | what i can i get?

You could mount narrow panels in landscape orientation. Make the mount further down roof taller. You could get away with mounts 1' tall and panels neither facing north or south. Obviously the wider the panel mounts would need to be taller to get panels flat. But could expirement with pvwatts to see if it is worth it. You would go this way you would want space between roof of panels on you roof. This way panels higher up would not shadow lower panels.

There still is visual issues with this but not nearly as much as huge mounts.

Animatt