Solar panels - portrait vs landscape orientation

roadweary

Hi,

I'm looking into designs for solar. The more I read / speak with 'experts' the more confused I become. Gemini has been useful, but also gets confused and has to be challenged!

Anyhow…

It seems that without shading this doesn't matter. Your choice might be down to which orientation allows you to get the number of panels you need in place if you are tight for space.

In my case, I want to install on my north facing roof also. I know it's probably at least half as efficient but the cost/value numbers add up.

However, opposite that roof on the other side of the road are tall trees. I'm assuming they'll throw a roughly horizontal line onto my roof although I accept that may not be 100% accurate.

I've looked at Aiko panels and their shadow optimisation, but I see this suggesting it's hugely exaggerated in real world conditions.

I believe most modern panels, including Aiko, have 3 vertical zones (looking at the panel in portrait) and then split those cells half way down.

My brain tells me that in portrait, a horizontal shadow touching the bottom of the panel would block all 3 long zones, but we have that split half way up….so it's blocking 3 out of 6 areas.

In landscape, that same horizontal shadow would only block one long zone, so 2 out of the 6 areas.

I don't know if this is correct,but short of individual optimisers, is there any wisdom as to which orientation would be better for what I think is mainly horizontal shading?

And any views on the Aiko claims from real word experience?

Thanks,

QrizB

I'm assuming they'll throw a roughly horizontal line onto my roof although I accept that may not be 100% accurate.

Theere are two group of trees behind my house. One of them sweeps across my panels horizontally, as the sun moves across the sky behind them.

You might want to check exactly how your shadows move.

It's nearly the summer solstice so now is when your nortg aspect will see most sunshine. A good time to get up early (sunrise here is about 0500 at present) and/or stay up late (sunset at 2100) and see exactly what happens?

Jemma01

I had about 3-4 months to assess my house shadows, and found that for me, vertical was the best choice, also helped me determine the stringing of the tesla battery and which panels were better grouped together.

I would suggest you do the same. I went out almost every day (once) and took out pictures sometimes very early morning, sometimes afternoon, sometimes near sunset. I was mainly concerned with winter sun, as summer sun I knew there's hardly any shadows.

Newbie_John

I don't really think orientation in general has much impact here.

It's just important to put them where there isn't much shadow - and if that means 1 vertical and 1 horizontal - let it be that way 😅

So go and have a look today where the shadow lands on your roof and how it travels.

roadweary

https://forums.moneysavingexpert.com/discussion/comment/82017320#Comment_82017320

The roof is comparatively small….6.1 x 4.6m, and it's being filled entirely with panels. That said, I do think panels in landscape cope better with a rising horizontal shadow….

Dave_Fowler

https://forums.moneysavingexpert.com/discussion/comment/82017385#Comment_82017385

Absolutely. When there is snow on the panels, and the snow melts and begins to slide off, the landscape panels begin to generate as soon as the top section of the panel is clear. The portrate panels hardly generate anything until they are clear.

roadweary

My wife has just rolled her eyes and told me that the north roof doesn't get shaded till late evening….I'm really bad at anything directional….anyhow, I'll take a look this evening. Sod's Law, it's quite overcast here today…

Jemma01

https://forums.moneysavingexpert.com/discussion/comment/82017548#Comment_82017548

do you get any direct sunlight there? I wouldn't put anything north facing

Heedtheadvice

https://forums.moneysavingexpert.com/discussion/comment/82017592#Comment_82017592

roadweary has already had advice regarding North roof panels, pros and cons, and has estimated it to be worthwhile in their case.

Regarding the orientation Q, your wife could be keeping you right! -:))

roadweary

https://forums.moneysavingexpert.com/discussion/comment/82017592#Comment_82017592

yup - we can get quite a few hours of direct sunshine and the cost benefit works in our case.

Newbie_John

https://forums.moneysavingexpert.com/discussion/comment/82017592#Comment_82017592

North facing roof has a huge benefit for self-consumption, provides more electricity in early hours and evening hours. Right now not good for selling but who knows what happens in future - I'd imagine it going towards Agile Export directions with higher rates around these times.