North Facing Install?

[ktech]

Inverter won't even fire up? That's like saying a west roof won't fire up until after mid day. My 4kw west roof starts at 5am in the morning this time of year, a north roof will also do similar. I would suggest undersizing the inverter is a consideration to maximise the generation.

 

[Seek-a-Geek]

Thanks for the reply ktech.

Please excuse my ignorance on this application. If the system is on a north facing roof at a 30 degree angle will it not be in constant shade from the apex of the roof? Also would it work in winter when then sun is at it's lowest?

 

[BruceB]

If you do the sums for the summer sun you will find that it is about 30 degrees away from the vertical in the Bristol area as an example. So the north facing roof will be in direct sun then. Put some numbers into sunny design and you might be surprised what a north roof will generate. 20 degrees slope will be better than 30 degrees, but even with 30 degrees I suspect you will get between 50% and 60% of south facing annual generation.

 

[Seek-a-Geek]

That's brilliant. I'll knock up the system in Sunny design and see what it comes out with.

Thanks for all your help guys.

 

[BruceB]

Just typed some numbers in myself for 30 degrees slope:
Plymouth c. 61%
Swansea c. 59%
Not recommended, but needs must.

 

[infinity]

I installed 4KW yesterday using solar world and Solaredge, its on a 45 deg pitch and 10 deg off north- north west. Figures still stack up using SAP!

 

[Ian-LS]

I'm not sure how you made a 45 degree north west facing roof figures stack up. I did a site survey a month ago and the customer was on about a north west facing roof with 45 degree tilt and I advised the roof was not suitable. 52-56% of a south facing system 35 degrees and no shading so unless the customers bills are really high then I'm not sure how the figures stack up to be honest.

 

[infinity]

Well they don't have gas for a start.
If you work it out using SAP, the investment is still a lot higher than having it in the bank.
Therefore that makes the figures stack up.

 

[whinmoor]

Well they don't have gas for a start.
If you work it out using SAP, the investment is still a lot higher than having it in the bank.
Therefore that makes the figures stack up.

Makes sense to me. An installation on shallower pitch of 30 degrees facing north should pay for itself within 10 years. If they are heavy consumers of electricity such as off the gas-grid, the annual benefit is considerable and much better value than saving in an ISA at sub 3%.

 

[Worcester]

Remember the 'smaller' the system the more of it's output you will use. Without an immersun type device all domestic South facing 4kWp systems will almost certainly struggle to get up to 40% consumption of generated due to the mismatch of generation / consumption.

 

[infinity]

Exactly, well I have solar edge on the system so I can update with actual figures of how it's performing

 

[darrentowill]

As long as all within MCS then its fine, you can get a good yield from North Facing but no were near as good as South, this is all presented in the MCS with application.
I would be happy to install as give correct advise and information payback etc, if the customer can see the facts and is happy then all is good.