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Solar PV Panels
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hope this is more accurate:
I just did some calculations regarding my fairly steep roof, 49 degrees, and how the Sun's height in the sky will affect depending on time of year.
Dec 21 - 14.5 degrees off perpendicular
Mar 7 - perpendicular (optimum)
Jun 21 - 24.5 degrees off perpendicular
could anyone point me to where i could get the information off how much % performance you lose from solar panels by relative angle to the sun.
ie perpendicular then 100% performance
20% off perpendicular then X% performance.
thanks
from my extensive scientific research (google search)
the optimum roof pitch for my latitude (51 degrees North,Essex) is 42 degrees for best all year round performance.
solar panel loss (in relation to roof angle to sun) at 15 degrees off optimum is 3%?
cannot find panel losses due to different angles during the year
I wonder if anyone knows a website that can tell you overall % performance for a roof angle, at a certain latitude (in relation to roof angle and optimum roof angle at that latitude)
hope that makes sense :P
For a quick view of the effect of orientation try www.greenshopsolar.co.uk/content/view/52/46. The diagram takes a bit of understanding.
Personally I'm surprised how slowly the output falls off as you depart from the optimum orientation.0 -
For a quick view of the effect of orientation try www.greenshopsolar.co.uk/content/view/52/46. The diagram takes a bit of understanding.
Personally I'm surprised how slowly the output falls off as you depart from the optimum orientation.
yeah, i was surprised too. correction, i was talking about tilt not orientation.
i found some research in California that stated that at 15% off optimum tilt, there was only a 3% loss in performance.
the PVGIS calculator bears out that it is a small loss too.
happy days :j0 -
Hi
However, you will find that winter generation is reduced by a larger factor ... our array is around 50 degrees off South and therefore the direct sunlight hours are severely reduced in the winter (if there is actually any direct sunlight), however, the summer generation is impacted far less, it's just that peak generation happens later, which isn't bad because it's more likely to be generating at a significant level when we use the most power.
HTH
Z"We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle0 -
Hi
However, you will find that winter generation is reduced by a larger factor ... our array is around 50 degrees off South and therefore the direct sunlight hours are severely reduced in the winter (if there is actually any direct sunlight), however, the summer generation is impacted far less, it's just that peak generation happens later, which isn't bad because it's more likely to be generating at a significant level when we use the most power.
HTH
Z
True, my system at -70deg or ESE has a Dec / June split of 50 / 400
Checking up on Don (sorry mate) his system is 30% better than mine (size 10%, orientation and location 20%).
He gets an annual 30% more than me (according to PVGIS) but split much better. He gets +10% June, and +200% December, much more useable spread. But still not jealous (son of a ...)
M.Mart. Cardiff. 8.72 kWp PV systems (2.12 SSW 4.6 ESE & 2.0 WNW). 20kWh battery storage. Two A2A units for cleaner heating. Two BEV's for cleaner driving.
For general PV advice please see the PV FAQ thread on the Green & Ethical Board.0 -
Martyn1981 wrote: »True, my system at -70deg or ESE has a Dec / June split of 50 / 400
Checking up on Don (sorry mate) his system is 30% better than mine (size 10%, orientation and location 20%).
He gets an annual 30% more than me (according to PVGIS) but split much better. He gets +10% June, and +200% December, much more useable spread. But still not jealous (son of a ...)
M.
and there was me thinking my roof angle was a handicap at first:D:D
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being updated0
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Darren0 -
darrenharvey wrote: »Hello all
My name is Darren Harvey...Are you for real? - Glass Half Empty??
:coffee:0
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