Please help me understand my production rate vs my system size.....???? Confused...

[SunEagle]

Good one, I had to re-read it a couple of times. We have a font for that if you'd like to use it next time. I think it's "Comic Sans MS" and it looks like this:

In Japan's larger cities, rooftop solar panels are stacked vertically to save space.

When I am being sarcastic I use that Comic Sans MS font in my comment followed by a blue smile face like this.

That way I hope people will know I am joking and not being serious.

[sdold]

Came back to write this....now i don't have to. lol
I was joking of course....sorry, missed the obligatory emoji at the end....

Good one, I had to re-read it a couple of times. We have a font for that if you'd like to use it next time. I think it's "Comic Sans MS" and it looks like this:

In Japan's larger cities, rooftop solar panels are stacked vertically to save space.

[sharpd1]

Quit thinking and please do not vote. Proof public education has failed.

How can you be so sure covering the panels completely wouldn't work in maximizing energy production?

[Sunking]

How about a thick tarp or a roof type structure on top of the solar panels to be used to provide full shade during sunny days? The structure and/or tarp can be removed at night to allow for maximum energy production.

just a thought.

Quit thinking and please do not vote. Proof public education has failed.

[sharpd1]

"I am serious and don't call me Shirley".

Came back to write this....now i don't have to. lol
I was joking of course....sorry, missed the obligatory emoji at the end....

[Mike90250]

How about a thick tarp or a roof type structure on top of the solar panels to be used to provide full shade during sunny days? The structure and/or tarp can be removed at night to allow for maximum energy production.

just a thought.

That would work for keeping the panels cool. But they won't produce any power in the shade. No mythbusters test needed

[Kingram]

"I am serious and don't call me Shirley".

LOL ,

https://www.youtube.com/watch?v=KM2K7sV-K74

[azdave]

"Surely you can't be serious!"

"I am serious and don't call me Shirley".

[Kingram]

For extremely hot climates, like Arizona, has anyone come up with an air cooling system for PV's? Even a simple fan system to increase air flow around panels might be beneficial.

Wind , we get quite a bit of wind and usually have a breeze most of the time.

[Kendalf]

How about a thick tarp or a roof type structure on top of the solar panels to be used to provide full shade during sunny days? The structure and/or tarp can be removed at night to allow for maximum energy production.

"Surely you can't be serious!"

[sharpd1]

For extremely hot climates, like Arizona, has anyone come up with an air cooling system for PV's? Even a simple fan system to increase air flow around panels might be beneficial.

How about a thick tarp or a roof type structure on top of the solar panels to be used to provide full shade during sunny days? The structure and/or tarp can be removed at night to allow for maximum energy production.

just a thought.

[J.P.M.]

For extremely hot climates, like Arizona, has anyone come up with an air cooling system for PV's? Even a simple fan system to increase air flow around panels might be beneficial.

Not anything that's practical and workable much less cost effective. For many reasons, fans will be effectively useless and in workable.

Be VERY aware of scams and ignore the crackpot crap on idiot's bible Screw-Tube.

[discodanman45]

Somewhat technical bottom line is mostly yes. Array temp. is influenced mostly by three things, two of them easy to understand: The two easy ones are "Plane of Array" (P.O.A) irradiance and wind vector. More irradiance increases array temp. like a black object sitting in the sun gets hot. More wind decreases array temp. by increasing convective heat transfer sort of like cooling a piece of hot food by blowing on it. That convective (wind) heat transfer rate is mostly dependent on the wind velocity and (here's were the air temp. comes in) the difference between the air temp. and the array temp.

For extremely hot climates, like Arizona, has anyone come up with an air cooling system for PV's? Even a simple fan system to increase air flow around panels might be beneficial.

[J.P.M.]

Does the production rate decrease slightly when the air temperatures are higher?
Reason i ask is that we have had sunny days in the 50s where my 'current production' rate is stuck on 8.0 on my App for close to 1 or two hours......and then a few days ago, had a fully sunny day where the same rate was going between 7.4 and 7.8....never saw it go past that. temperature was around 85

There didn't seem to be any clouds whatsoever during the hot sunny day i mentioned above...so it made me think about the other factor that seemed to be different: temp.

Somewhat technical bottom line is mostly yes. Array temp. is influenced mostly by three things, two of them easy to understand: The two easy ones are "Plane of Array" (P.O.A) irradiance and wind vector. More irradiance increases array temp. like a black object sitting in the sun gets hot. More wind decreases array temp. by increasing convective heat transfer sort of like cooling a piece of hot food by blowing on it. That convective (wind) heat transfer rate is mostly dependent on the wind velocity and (here's were the air temp. comes in) the difference between the air temp. and the array temp.

That third method of heat transfer I mention is thermal radiation. Everything radiates thermal energy similar to what you feel when you sit in front of a campfire. An operating solar array in the sun will radiate thermal energy to its surroundings - and the sky - that are cooler than the array in a relatively complicated fashion. Depending on the array's and surroundings' temps., an array operating at, say, 50 deg.C. while the surroundings (and note, not the necessarily the air temp.) are at, say, 20 deg. C., may lose about 30 % of all the solar energy rejected (that is, the 80-85 % of the incident solar that is not turned into electricity) by thermal radiation to the surroundings.

Practical bottom line:

Your array's efficiency (output) will decrease approx. 0.5% for every 1 deg. C. increase in array temp. as measured from a S.T.C. temp. of 25 C. Finding/estimating an array temp. is complicated by influencing effects that interact with one another. Under clear skies and moderate wind (whatever that means - maybe 2-3 m/sec or so), my array's average measured temp. runs roughly between 24 and 28 deg. C. above the ambient air temp. on my roof which runs about 3-5 C above the amb. air temp. closer to the ground. Yours and others' arrays probably have a somewhat similar temp. behavior and profile.

[discodanman45]

Does the production rate decrease slightly when the air temperatures are higher?

Yup, there should be a coefficient that tells you by how much. Panels are rated at 25 degrees Celsius and can have a coefficient of -0.5%/degree Celsius. That mean if it is 35 degrees Celsius you will see a 5% decrease in efficiency. If it is 15 degrees Celsius you see a 5% increase in efficiency. BTW, on a sunny day the temperature of the panels will be well above the air temperature.