is the optimum year round angle what you really think it is?

Jamie.sanders

Solar Enthusiast
Joined
Dec 1, 2019
Messages
152
stay with me, I'm just throwing out my thoughts but.
I was playing with the solar calculator looking at the best angle for year round, my results were:

Summer, 70 degrees
Winter, 40 degrees
best year round angle 55 degrees.

I understand 55 is half way between 70 and 40, I get that, splitting the difference to work as well as possible during both seasons, basically
robbing the same amount of performance from both winter and summer. (both are 15 degrees from the perfect angle) but...

if you factor in that in the summer here in Arkansas the number of hours of full sunlight available to generate electricity is 5.29 in the summer
and 3.88 in the winter, so in the summer you have 1.4 more hours of good sun. so...
wound it not be better to angle the panels more toward the winter angle to get optimum sun in the winter since you get more hours
of sun in the summer which would help compensate for not as good of an angle? or am I missing something?
I understand 55 degrees basically robs a bit of performance equally from the winter and summer angles, but would it
be better to rob more from summer since you get more sun hours in the summer? so angle the panels something like 50 degrees?
 

acdoctor

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Oct 5, 2020
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212
Location
Central Arkansas
I am in Arkansas as well. I agree with your line of thinking but, it would also depend on what season you need more kw’s. If you burn wood say and need lots of a/c. I have a homemade single axis ground mount with 6.1 kw on it. I have them at 15 deg from horizontal in mid summer. Currently 60 deg from horizontal. I keep them with in 10 deg of ideal. It takes me about 5 or 10 minutes to adjust them. I have played with it and I can’t see any appreciable difference with in 10 deg.
 

wattmatters

Photon Sorcerer
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Apr 16, 2021
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1,056
You angle panels based on what production is more important to you. For maximal annual production it will generally be a tilt close to your latitude. If you want superb Summer performance then lie them flatter, if Winter is key to you then have them steeper. It all depends on what's most important to you - overall output or when the power is produced.

Then you need to work out azimuth and whether maximal peak production from a south facing array is more important than evening out production across the day with split azimuth facing east and west, or whether morning or afternoon production is more important. In some locations weather patterns might often see morning fogs or afternoon storms and so sometimes greater overall output is attained by an azimuth a little away from south (or north if you are in stern hemisphere).

For roof top array you kind of just put panels on the roof and the decision is made for you.
 

svetz

Works in theory! Practice? That's something else
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Sep 20, 2019
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Key Largo
It also depends on your usage and net-metering agreement. For example, if the net-metering agreement isn't great and you use most of your power in summer, it might be better to optimize for summer.

I suggest using SAM. It'll include the other important factor: your typical weather. For example, I technically get the greatest amount of solar energy during summer. But it's also when it's the stormiest so it's not realized. SAM lets you play with the tilt and see the annual or monthly energy totals.
 

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
781
Without knowing you peak usage time, hard to tell. For me in Florida - it's summer - so 85 degree :p (almost flat)

We need 3x in the summer what we need in the winter. (A/C)
I understand 55 degrees basically robs a bit of performance equally from the winter and summer angles, but would it
be better to rob more from summer since you get more sun hours in the summer? so angle the panels something like 50 degrees?

how much space do you got? I have panels are different angles and different orientations.

So you basically build 3 panel arrays (half circle) - one south-east facing, one south one south-west. This allows maximum sun catching for the money. Not space efficient - but cost effective. The morning and afternoon arrays are steeper then noon array.
 

retrodog

Solar Enthusiast
Joined
Mar 15, 2021
Messages
47
Also depends on what your system is used for (grid vs. off grid). I have a house in the Houston TX area and one in NE OK. I'm doing off grid backup systems for both. So here's the point... the primary season for power outages in Houston is the summer, during tropical storm season, while the primary issue in NE OK is the winter time... during snow and ice storms. So in situations where you have season-specific needs, that can also be taken into account. I'll probably set up the panels in OK to favor the winter angle.
 
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