Air Cooled Panels

[svetz]

We've talked about water cooled panels, but this video indicates the economics for air-cooling panels is favorable.

Unfortunately, it's not exhaustive at all angles letting it run 24x7 - so it's not clear how economical it was. The bit about increasing the longevity of the panels was interesting too, need to investigate that more. Adding the heat spreads seems like a good idea.

I've always wondered if a passive arrangement to funnel breeze wouldn't be good and low-cost, but hurricane-force winds funneled under there would be scary.
Possibly a clever flap system that closes?

 

[meetyg]

My problem with his test is that he didn't compare to a bare panel, without the fan construction.
I would suppose that natural air convection, without being obstructed by the rear sheet metal he put there, might give better results than he got when he tested with the fans off.

In short, his test is incomplete and somewhat biased.
For example, in his test, he got a 10w loss because if heat buildup, and needed only around 3w to power the fans. So basically he gained 7w.
But what would the gain be if the the rear if the panel would not be obstructed?
I would think less...

Also, you need power for the fans, so that would means maybe another small solar panel.

 

[Solar Guppy]

Duplicate topic and same video already covered here

 

[timselectric]

The only worthwhile thing I got from the video was that it could increase the lifespan of the panels.
The production gains aren't enough to warrant adding moving parts that will eventually increase maintenance.
In my personal opinion.

 

[Solar Guppy]

The only worthwhile thing I got from the video was that it could increase the lifespan of the panels.

I haven't read / seen any peer review research that shaving 10-20C off a panel operating temperature would have any effect on useful lifetime or degradation of performance over time. If this was the case then manufacture warranties would not allow roof based installations and only be good for ground mount.

 

[timselectric]

I haven't read / seen any peer review research that shaving 10-20C off a panel operating temperature would have any effect on useful lifetime or degradation of performance over time. If this was the case then manufacture warranties would not allow roof based installations and only be good for ground mount.

A solar panel is just a circuit board.
The biggest enemy of electronics is always heat.
So to me, reducing heat to increase lifespan seems pretty basic.

 

[Solar Guppy]

A solar panel is just a circuit board.

No, its a thin slab of processed sand ( silicon dioxide -> silicon ) which has to get to ~2000C to melt and start processing it. The difference of 70C or 90C isn't going to do anything to the material.

 

[timselectric]

Ok

 

[Hedges]

How long do rooftop residential solar panels last?

Multiple factors affect the productive lifespan of a residential solar panel. In the first part of this series, we look at the solar panels themselves.

pv-magazine-usa.com

"In its annual Module Score Card study, PVEL analyzed 36 operational solar projects in India, and found significant impacts from heat degradation. The average annual degradation of the projects landed at 1.47%, but arrays located in colder, mountainous regions degraded at nearly half that rate, at 0.7%."

 

[BradCagle]

I've watched this one. My thoughts:

The gains are not worth the extra cost, and trouble.

The potential increase in PV lifespan? I'd be more concern about the lifespan of the cooling system. Heat, humidity, all the elements are brutal on electric motors, and whatever other mechanical systems need to be in place for this to work.

 

[400bird]

I've watched this one. My thoughts:

The gains are not worth the extra cost, and trouble.

The potential increase in PV lifespan? I'd be more concern about the lifespan of the cooling system. Heat, humidity, all the elements are brutal on electric motors, and whatever other mechanical systems need to be in place for this to work.

Good point, how many replacement fans do you have to purchase over the years that need to be offset by the 7 watt production boost?

What about the excess heat held in by this metal when the cooling fan fails? I'll bet the panel gets significantly hotter than a not modified version.

Also, it's a not insignificant amount of labor to add the heat sink and rear shroud.

 

[Solar Guppy]

Thank you for the link!

I downloaded the report and have attached for convivence

Didn't see anything about the India study.

One would have to have identical panels from the same production lot, racking, maintenance like cleaning , with high precision logging of dozen of parameters at warm vs cold locations. Trying to measure something is the 1% range in environmental conditions would be very challenging.

As can be seen from the report, not all manufactures and even lot to lot would be the same. An even in the report mechanical stress is a keep contributor which would be opposite for mountain vs low land locations than heat.

What is most interesting is not the heat, but whom you purchase from, larger variances than the discussion about heat effects.

My thought is they are using net production of large solar plants for comparisons and debris / pollution build up would lower the yields more at lower altitudes, even with periodic cleaning. Being higher also has higher irradiance and would negatively effect the cells over time ( and should have reversed what the study suggests ), so without all the details its hard to understand how the conclusions were made.