I am in the process of building an off grid home. My main panels will be mounted on a south facing roof. I am wanting to know opinions on mounting a few bi-facial panels on a ground mount situated vertical and aligned north south. Looking to add morning and afternoon output. Do you think this would be of any benefit?
Vertical mounted bi-facial panel question
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MichaelK
Solar Wizard
I'm having a bit of trouble here trying to comprehend what you are saying? Are you saying they will be straight up and down, with one faced towards the East, and the backside towards the West?
I myself and utilizing ground-mounts, which can both rotate for azimuth, and tilt for declination. I'm finding that I can reach ~50% power right at 8AM by rotating Eastward, though not due East because of shading. Same facing West around 4PM.
If you want to orient panels to face East and West, I think you'll get a substantial amount of power right at sunrise and sunset, but little power the rest of the day. Just how important is that for you? I've placed another dual-row array facing due West on the West side of my cabin. That helps handle the air-conditioner late in the afternoon on hot summer days. I think that more or less accomplishes what your goal here is.
If you are going to put in a ground mount or two, I'd suggest copying my dual-row design, which can hold as many as 6 grid-tie panels, for 1500-1800W of power. They can then be positioned to produce maximal power for whatever part of the day you want.
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My home will be located about 25 miles east of Flagstaff AZ. During monsoon season it seems to be clear skies early in the morning and later in the afternoon. That time of year is worse than the shorter days in the winter, as the sky is much clearer then. Most neighbors claim they have to run their generators a couple hours a day, but rarely in the winter. Just thinking about about getting a little quicker charging, and it is sometimes hot and A/C is needed.
eXodus
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I'm not sure what you mean with aligned north south- do you mean "FACING" East West? So the broad side to East and West?
That would be a good way to capture sun in the mornings and evenings- not much during mid day - but adds a lot on the twilight hours.
I'm planning something similar - Main array on the house - pretty flat for maximum summer gains during mid day for A/C. Then some Vertical Solar Fences for capturing winter light.
Vertical Bi-Facial Solar Panels, Solar Fencing (not portray)
Hello, On the topic of using space more efficient: I found these article: https://cleantechnica.com/2022/07/25/new-research-says-vertical-solar-panels-have-improved-performance/ https://www.pv-magazine.com/2021/12/13/frances-first-vertical-bifacial-solar-power-plant/ I just did a few rough...
diysolarforum.com
shadowmaker
Solar Addict
Of course it is. Just get panels with >90% bifacial factor to harvest more afternoon sun than I do (mine are only ~75% bifacial). Also make sure there are no shadows coming from installation as they kill afternoon production.
There's a link to my thread in my sig, if you want to read more about my vertical/bifacial setup.
hwy17
Anti-Solar Enthusiast
Bifacial panels aren't 1:1, the backside generates a lot less than the front.
You would be better off putting two strings in a chevron SE and SW. And better off than that probably just building a south facing array and more battery to soak up the mid day peak.
You would be better off putting two strings in a chevron SE and SW. And better off than that probably just building a south facing array and more battery to soak up the mid day peak.
redalertdt
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You're designing it wrong...I mounted east-west for offgrid, but now I realize that it would be best to just optimize for max solar production for the worst time of year for your area. For me that means steep slant for winter. You'll need batteries so your design has to be to fill up the batteries everyday. The east-west design stuff etc. is useful if you have certain time of use pricing on the grid that you are trying to offset.
Design for the cheapest max production (vertical mount could be cheaper...) during your worst week of the year.
Design for the cheapest max production (vertical mount could be cheaper...) during your worst week of the year.
shadowmaker
Solar Addict
Not a lot less, but usually 75-95% compared to front side. Bifaciality factor can be found (at least should be found) in the spec sheet of a bifacial panel.
hwy17
Anti-Solar Enthusiast
So I would've thought that factor is more like the front side accounts for 75-95% of the generation, not that the back side is capable of 75-95% of the generation of the front
Here is my free advice: For one faced panels mount your panels tilting about 28 degrees backwards and facing about 5 degrees West of due South. I think for your location you will do best year round this way.
Then I found this from osti.gov:
"What is the best orientation for a bifacial solar panel?
We find that ground-mounted, vertical, east-west-facing bifacial modules will outperform their south-north-facing, optimally tilted counterparts by up to 15% below the latitude of 30o, for an albedo of 0.5."
Then I found this from osti.gov:
"What is the best orientation for a bifacial solar panel?
We find that ground-mounted, vertical, east-west-facing bifacial modules will outperform their south-north-facing, optimally tilted counterparts by up to 15% below the latitude of 30o, for an albedo of 0.5."
shadowmaker
Solar Addict
No. Bifacial factor is back production divided by front production under the same irradiation.
hwy17
Anti-Solar Enthusiast
Color me surprised then.
Here is an article with numbers. I haven't read through it but it looks like there is potential.
THE NEXT2SUN SOLAR FENCE CONCEPT
THE NEXT2SUN SOLAR FENCE CONCEPT
eXodus
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"Whether the module surface is facing north-south (annual electricity yield 900-1050 kWh/kWp) or east-west (annual electricity yield 1000-1290 kWh/kWp), electricity is also produced on the side not directly in sunlight."
that is promising. Those are numbers for Germany - for comparison you get 1200 kWh on a perfectly mounted roof array angling the sun.
When east-west Bi-facial are proving similar yields - that would amazing. With Panel prices rapid decreasing - it's just matter of time that all vertical Bi-facial systems would be cost competitive - no matter the direction.
There are trillions of miles of fence line in the world, it would take up ZERO additional space to power everything solar. Not taking up farmland, no stupid roof top permitting. Very interesting.
crossy
Solar Addict
Northern Europe seems to think it's a smart idea.
www.pveurope.eu
First large-scale vertical agri-PV installation in Austria
In Gabersdorf, Austria, Next2Sun has commissioned the first vertical Agri-PV plant in the country. The plant will be scientifically monitored over a
To bad there isn't enough silver.
Brucey
Solar Wizard
I think rule of thumb is around 15-20% additional output from the back side in ideal conditions?
Canadian Solar launches 700 W bifacial TOPCon solar modules
Canadian Solar is offering six versions of its 132-cell TOPBiHiKu7 solar modules, with power outputs ranging from 675 W to 700 W and efficiencies ranging from 21.7% to 22.5%. They have an efficiency range of 26.1% to 27.0%, with a bifacial gain of 20%.
www.pv-magazine.com
shadowmaker
Solar Addict
Kind of true, but with fresh snow I seem get ~40% additional. It really depends on the albedo of the surroundings. Even we up here don't get snow all year around, so manufacturers can't (at least they shouldn't) claim +40% addition production with bifacials. I would kill to get even +25% all year around, but still get my summers snow free...I think rule of thumb is around 15-20% additional output from the back side in ideal conditions?
Canadian Solar launches 700 W bifacial TOPCon solar modules
Canadian Solar is offering six versions of its 132-cell TOPBiHiKu7 solar modules, with power outputs ranging from 675 W to 700 W and efficiencies ranging from 21.7% to 22.5%. They have an efficiency range of 26.1% to 27.0%, with a bifacial gain of 20%.
eXodus
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When you have a vertical mounted Bifacial - East West - the "backside" changes depending on the time of the day.
When vertical mounting you take advantage of both sides. "additional" doesn't matter - because one side gets the sun in the first half of the day and the other side in the second half of the day.
Bifacial Solar Panels Give Increased Power Output Potential - Knowledge - DS New Energy
Bifacial Solar Panels Give Increased Power Output Potential
www.dsneg.com
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