Solar Panel Heat

[Jim Burrow]

I don't see a thread on Solar panel heat so will has my question.

I've started testing my Solar panels output with respect to their temperature as measured with a temperature handheld gun.
Today, for example, the outside temperature in the sun is 70 F degrees, but the panels which are parallel to the ground are measuring 105 f degrees.

My question is, how hot can the solar panels get before it becomes a concern due to heat on the panels and it's performance.

Here in my part of California, the summer temperatures for a few days reach over 112 degrees F. and average 95 degrees. F. all summer.

Is their a heat point on the panels that I will need to dis-engage the panels from my 2424lv controller/inverter?

 

[Forbisher]

There is a good sized ground solar array in Furnace Creek, Death Valley.
130° F with 120° most of the summer.

 

[Q-Dog]

Output goes down as panels get hot. That is what they do. Some panels perform better than others as they heat up. If the reduced output is a problem, you can invest in higher quality panels that handle heat better and don't lose as much output as they heat up. But, it is possible the longer summer days (when it is hot) are enough to make up for the reduced output. Or just add more panels.

Otherwise, what can you do about it, shut them down when they get hot? What is better ... reduced output or no output?

 

[Jim Burrow]

Output goes down as panels get hot. That is what they do. Some panels perform better than others as they heat up. If the reduced output is a problem, you can invest in higher quality panels that handle heat better and don't lose as much output as they heat up. But, it is possible the longer summer days (when it is hot) are enough to make up for the reduced output. Or just add more panels.

Otherwise, what can you do about it, shut them down when they get hot? What is better ... reduced output or no output?

Good point. I have good panels. With tons of homes now around my town with Solar panels on their roughs, I'm sure heat will not be an issue. I have good quality panels.

But it is always nice to get the opinions of all you guys that have lots of real-life experience and not some report out of a lab under controlled conditions.

Thanks for your feedback.

 

[fafrd]

Good point. I have good panels. With tons of homes now around my town with Solar panels on their roughs, I'm sure heat will not be an issue. I have good quality panels.

But it is always nice to get the opinions of all you guys that have lots of real-life experience and not some report out of a lab under controlled conditions.

Thanks for your feedback.

If you are worried about your panels overheating, you could always consider water-cooling: https://www.google.com/amp/s/www.wi...-canals-with-solar-panels-is-a-power-move/amp

 

[Jim Burrow]

There is a good sized ground solar array in Furnace Creek, Death Valley.
130° F with 120° most of the summer.

If they can handle Death Valley temps, then I have no concerns with respect to my area heat in summer. Plus there is tons of home in my area with Solar and they seem not to be a problem.

 

[Jim Burrow]

If you are worried about your panels overheating, you could always consider water-cooling: https://www.google.com/amp/s/www.wi...-canals-with-solar-panels-is-a-power-move/amp

No, I was just curious what others with experience in the group observed with their systems. With Solar cells being a very, very dark blue, it is no surprise that they would be much hotter than the surrounding temperatures of other objects in direct sunlight.

 

[fafrd]

No, I was just curious what others with experience in the group observed with their systems. With Solar cells being a very, very dark blue, it is no surprise that they would be much hotter than the surrounding temperatures of other objects in direct sunlight.

I wasn’t being serious, but if you did not read the article I linked to, it’s worth checking out.

Cover canals with solar panels. Generates more than sufficient energy to power all pumps used in California’s water-distribution system, dramatically reduces water lost to evaporation, and water cooling of the panels translates to exceptionally high efficiency..,

Win, win, win doesn’t come around very often .

 

[Bud Martin]

I don't see a thread on Solar panel heat so will has my question.

I've started testing my Solar panels output with respect to their temperature as measured with a temperature handheld gun.
Today, for example, the outside temperature in the sun is 70 F degrees, but the panels which are parallel to the ground are measuring 105 f degrees.

My question is, how hot can the solar panels get before it becomes a concern due to heat on the panels and it's performance.

Here in my part of California, the summer temperatures for a few days reach over 112 degrees F. and average 95 degrees. F. all summer.

Is their a heat point on the panels that I will need to dis-engage the panels from my 2424lv controller/inverter?

I just measured mine, the front side of the cell is 99F, the backside of the cell is 105F, Current from panel is 6A, Panel Voltage is 36.30VDC, outside temp is 69F. I am in north bay. I do get more power on cooler day as shown in my other thread.

 

[Jim Burrow]

I wasn’t being serious, but if you did not read the article I linked to, it’s worth checking out.

Cover canals with solar panels. Generates more than sufficient energy to power all pumps used in California’s water-distribution system, dramatically reduces water lost to evaporation, and water cooling of the panels translates to exceptionally high efficiency..,

Win, win, win doesn’t come around very often .

wow! very interesting. As a retired engineer, that makes total sense. I'm glad I asked the question. I'm learning a lot from you guys.

 

[fafrd]

wow! very interesting. As a retired engineer, that makes total sense. I'm glad I asked the question. I'm learning a lot from you guys.

If you’d posted two days ago, I’d have nothing to contribute.

That article literally hit the web yesterday...

 

[dandenson]

In some sloped roof-mount products one of the design decisions is a specific gap from roof to back of panel based on the size of the panels/array to get maximum convection to help shed a few degrees. I've seen this in some freestanding racks as well, having a sheet of material mounted 8-10" behind the panels to encourage a convective flow.

I can't find it on google right now for some reason, but there is a ground array in Spain or Portugal where they have a netting attached below the panels to create a large shaded area (think camo netting) so the panels would be pulling cooler air up from that shaded area through a duct on the back to get a couple percent improvement. It was a university experiment if I recall, if I could just find it.

I don't think any of these efforts are to cool the panels to prevent damage though. Shaving a few degrees off the top on the hottest days can increase efficiency by a measurable amount and I think all of this came about when panels far more expensive. Now, one extra panel on the string and you've likely spend less money and got more power.

 

[Short_Shot]

Fire hazard? No.

Minor burns? Absolutely.

If your solar panels are hot enough to start anything on fire in the sun you've got way bigger problems than their energy output.

 

[Jim Burrow]

I have a temperature handheld gun and when the outside air temperature is 90 degrees, here in my part of California, the side of the house that is in the sun is over 155 degrees (the side of the house is almost white in color). The brick walkway is very much hotter.

Now your solar panels are a very dark blue, Think of how hot they may be in the summer. With respect to panel performance, the hotter they are the voltage will drop linear and the current will increase exponentially. So in the summer months, when it is hot outside, don't expect your panels to perform to their maximum. - At least that is my experience!

 

[Doug Wall]

"My question is, how hot can the solar panels get before it becomes a concern due to heat on the panels and it's performance."

You could always air condition them, or pull a rolling shade over them. ?
Seriously, they have decades of history without significant problems, and they are designed for that.
As far as decrease in power from heat, our system outputs about 17% less Watts (5kW- 6kW)on a hot summer day, compared to a cold winter day. We're in upstate NY. The interesting this is that we can actually put out more kWh/day on a cold, short winter day than on a hot, long summer day. In the winter, our panels get sun from almost the minute that the sun comes up, until almost the minute the sun goes down (almost horizon to horizon). In the summer, it has to get up a ways before it starts to hit the south facing roof.

 

[curiouscarbon]

Researchers in shanghai and malaysia are literally piping copper to solar panels to pump the sun heat out of the panel using water source heat pump and make hot water for domestic use.

By cooling the panel a couple dozen degrees, electric power yield increases as much as 10%.

The heat is low grade but usable. Removing it from the panel will definitely increase yield. Whether it’s worth it is highly dependent on conditions.