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Re: Solar Panel Angles

PostPosted: Tue Dec 06, 2011 4:08 pm
by paul_celia
Hi Tracker

Drunk again :P

there are six on each string mate

Yours Paul

Re: Solar Panel Angles

PostPosted: Tue Dec 06, 2011 5:38 pm
by bashworth
For grid connected systems there is no need to go for the angle of 38 degrees. That is the the best angle for battery systems.

For grid connected system you will get similar efficiency over a full year even if the panels are as flat as 23 degrees. This is because the flatter angle is better for the summer months when there is more sun although it loses efficiency in the winter.

Even at 15 degrees you are probably only loosing 2-3 percent efficiency on total energy generated over the full year. It would probably be cheaper to get another couple of panels rather than change the angle.

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 5:57 am
by Tracker
bashworth wrote:That is the the best angle for battery systems.

That's an interesting comment, and I wonder why there is ANY difference.? ;)
I would interpret "Best for Battery" to mean maximum "Power", so if 38Deg gives an Island system most power, would that not be the same for Grid-Connect..?
but - having said that, I just fed 15 and 38 into PVWATTS and the yearly change is 1.5% - That's all !
(If I got the figures right)
In winter, you might get 20% more from the 38deg, and this reflects the real need to ADJUST the angle, a few times a year, if you want absolute MAXIMUM.
BUT - to achieve a 1.5% total yearly advantage by fixing at 38%, would likely be unprofitable.
Plus, the system would stand-out more on the house..
http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/International/inputv1_intl.cgi
Have a play with the calculator and see what differences it makes, and then see if the improvements actually warrants the changes..
..
.

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 7:53 am
by Gordon-Loomberah
bashworth wrote:For grid connected systems there is no need to go for the angle of 38 degrees. That is the the best angle for battery systems.


Actually, the best angle for batteries, ie off-grid, and also the best angle for grid-connected, is pointing right at the sun with a good tracking system! If you have to compromise with fixed panels, then you probably want maximum overall for grid-connected, which tends to be with flatter than your latitude tilted panels, but more steeply tilted for off-grid, to maximise winter production. Days are shorter and there tends to be more cloud for much of southern Australia in winter, so you generally need all the power you can get.

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 8:10 am
by Tracker
Gordon-Loomberah wrote:the best angle for grid-connected, is pointing right at the sun with a good tracking system!

The problem in this case is that the system seems to be installed on a suburban roof, and as such, they would not have the room to turn the house to track the sun.. ;) :lol:
Gordon-Loomberah wrote:but more steeply tilted for off-grid, to maximise winter production.

The irony is that the lower production (proportionally) in summer would be at a time when it is likely needed most.. :|
Bottom line - it's all a compromise... Ironically, there is not that great a difference Summer/Winter, because in winter, it's cooler and so there is greater output for the lower solar input.. In summer, it's hotter and power is reduced accordingly..
Gordon-Loomberah wrote:Days are shorter and there tends to be more cloud for much of southern Australia in winter,

Don't you mean in SUMMER under Climate-Change :lol:
..
.

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 8:53 am
by Gordon-Loomberah
Tracker wrote:...
Gordon-Loomberah wrote:Days are shorter and there tends to be more cloud for much of southern Australia in winter,

Don't you mean in SUMMER under Climate-Change :lol:


There seems to be more cloud than usual this summer, and last summer, but that is as expected under La Nina influence... but the days are definitely longer! :lol:

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 9:09 am
by Tracker
Gordon-Loomberah wrote:but that is as expected under La Nina influence...


Nina Who... Who's that... :?:
I only know about Climate-Change and CO2...
Surely, Your not trying to say that something else affects the weather... :geek:
The Rangar will not be pleased to hear what you say.. :(
..
.
PS - NOTHING beats a full Solar-Tracker, but who has the spacial capacity to install one!
and don't forget the real problem - THE WIFE :evil:
..

Re: Solar Panel Angles

PostPosted: Wed Dec 07, 2011 11:10 am
by bashworth
Gordon-Loomberah wrote:
bashworth wrote:For grid connected systems there is no need to go for the angle of 38 degrees. That is the the best angle for battery systems.


The point I was trying to make was 38degrees gives the best over the whole year efficiency with best winter generating potential Which is important if solar is your only source of electricity.

15 degrees flatter gives the best overall efficiency with best summer generating potential and is good for grid systems where winter generation is non critical.