Clean Solar Panel Surface by Cooling it so much that condensation forms?

Can a photovoltaic panel mounted at an angle be cleaned by cooling it down to form condensation?

  • Yes

    Votes: 0 0.0%
  • No

    Votes: 1 33.3%
  • It depends

    Votes: 1 33.3%
  • What????

    Votes: 1 33.3%

  • Total voters
    3

curiouscarbon

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Has anyone done this or want to talk about doing this?

Run water/glycol through tube on backside of solar panel, use heat pump to cool down solar panel so much that humidity from local air condenses onto the solar panel, if mounted at an angle, it drips off, taking dirt with it. It would even increase PV yield due to temperature coefficient curve.

Don't get me wrong, I don't think it's the best way to clean a photovoltaic panel on a roof.

But has anyone done it?
 

Short_Shot

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I doubt anyone has done it because the condensing water, even if it runs off, wouldn't have sufficient scrubbing action to do anything. I suspect you'll find the "taking dirt with it" part doesn't occur.

It would likely just make the problem worse as dust settles in the water similar to how it gets there in the first place.

But I'm not against changing my opinion of it if someone shows it working.

Not to mention the high energy cost.

You'd have far better luck just putting sprinklers up there. Especially if it's not very humid out to begin with. I think that HAS been done before with limited results.

Better still, build or buy a hose fed window cleaner brush/squeegee like this:

Screenshot_20210810-102006_Amazon Shopping.jpg

There are cheaper options of course.
 

curiouscarbon

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If I am understanding you correctly, you're saying I hypothetically should collect the condensation that drips off, gently filter it, and then feed it to a sqeueegee spray robot over the panels to clean? :)

The reason for even considering cooling the panels in the first place is twofold: heat water for domestic use, and increase yield.
 

Short_Shot

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Hard to increase yield if you're spending that energy (and money) on cooling the panels sub-ambient. Even if it's periodic cycling of that system, you could just buy another panel or a bit more battery.

If you're doing it full time during solar hours for more output, surely the energy cost will exceed the increase and the condensation itself might interfere? At some point you gotta figure you can just toss a panel or three in the yard, no?


I'm rather interested in the idea of using the panels to preheat water, but that's another thread.
 

curiouscarbon

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I think it might sound very odd to cool that component, but I assure you I'm not a kook looking to chill PV panels for the thrill of the inanity of it all :)

Just openly brainstorming about possible utility associated with PVTHP. PhotoVoltaicThermalHeatPump.

PhotoVoltaicThermalHeatPump is good enough for the folks in Singapore and Shanghai to do some research paper publishing:

Numerical Study of Integrated Solar PhotovoltaicThermal Module with a Refrigeration System for Air-Conditioning and Hot Water Production under the Tropical Climate Conditions of Singapore
Thermal systems of buildings in the tropics are highly energy intensive. In this study, a novel integrated solar photovoltaic–thermal–refrigeration (PVTR) system used to produce hot water and air-conditioning in the tropical climate conditions of Singapore was analyzed.
The results show that attractive electrical and thermal perfor- mance can be achieved with a maximum annual cooling COP of 9.8 and a heating COP of 11.3. The PV e±ciency and power saving were 14% and 53%, respectively. The annual cooling, heating and PV energy produced were 9.7, 15.6 and 1.6 MWh, respectively. The ̄nancial payback period of the system was 3.2 years and greenhouse gas (GHG) emission reduction annually was 12.6 tons of CO2 equivalents (tCO2e).

Heating COP of 11.3 sounds good to me!

Didn't see any mention about self-cleaning in the paper, though 😅

It's commonly known that air source heat pumps can become inefficient in cold conditions. Augmenting that heat with heat from the back of photovoltaic panels makes sense to me when I think about it for a bit.. the PV yield increases during hot water generation.

If you want to talk about the reason for this silly post about low efficacy panel cleaning technique, come on over to this thread and please feel free to check it out! https://diysolarforum.com/threads/heat-pumps-harmonizing-heating-and-cooling-needs.26688/
 

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Boondock Saint

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Just, no.

Apply a ceramic coating when you fist buy the panels and dirt, bird poop will be easy to hose off.

If you use Rain-X get the regular yellow small squirt bottle, NOT the spray pump action bottle. They're different.


.
 

Short_Shot

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I understand why you would cool the panels.

Temperature coefficient is a thing.

However the energy consumption will be greater than the yield if you attempt to cool below ambient. Using water to absorb some of the heat is one thing, active cooling is something else.
 

curiouscarbon

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I think you might still be missing the part that cooling the panel is a side effect of a potentially useful activity of e.g. heating water.

I strongly discourage anyone from actively cooling PV panels without having a use for the heat. Absolutely don't do it for the sole purpose of cleaning the panels.

At the beginning or end of the day, humidity often spikes, and intentionally causing condensation to form to get a half hour rinse makes perfect sense to me. :)

Many people use systems that are disparate so this discussion would be very confusing and sound misguided even.
 

curiouscarbon

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1628611958793.png
1628611985575.png


I think cleaning the panels is clearly a wash (hehe), but if you're saying the math on solar source heat pump doesn't work then I'm confused.

This company is explicitly claiming 10% increase in direct PV yield and an additional 350% increase in thermal yield. I believe them. Things that sit in the sun get hot...
 

Short_Shot

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Oh I get that application.

If you are using the heat then that's different than just cooling the panel. However what I can't tell from that website is if the cooling effect is sub-ambient. If it is, then cool (heh)

If not, well, that may or may not be viable. Based on the diagram I suspect it does not cool the panels low enough to cause condensation.
 

Q-Dog

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I have some ground mounted panels and here in perpetually humid Louisiana they are covered in condensation every morning until the sun come out from behind the trees and hits them. If anything the condensation makes the dust stick a little better. When they are still wet is the best time to rinse them off.
 

Boondock Saint

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I suspect it does not cool the panels low enough to cause condensation.
Ya I can't wrap my head around the efficiency required to do that in daytime heat.

As far as dew and water and dirt and dust, it's a self perpetuating problem. The moisture makes dirt stick, the more the dirt sticks the more the water doesn't run off in order to rinse off, so more dirt sticks.

Either apply something to make the surface more hyrophobic or keep it completely dry.

Even with ceramic coatings, the above water/dirt cycle still applies, just somewhat less.

.
 

curiouscarbon

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Trying to induce condensation on something so dark during solar moon seems does seem like a total fools errand.

I notice dew on my panels in the morning and sometimes evening.

If I’m ever in the position of producing hot water by heating water with a heat pump that sources heat from the panels, I’d be sure to program it to cool down extra at dusk to experiment.

Don’t worry everyone, I’ll upload the csv of data if I try 😇

Thank you all for your very on point and wise warning and advice!
 

RCinFLA

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Just be careful of temp shock.

One way electronic components are given an accelerated life test is how many cycles of liquid to liquid temp shocks it can take before failure.
 

time2roll

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I would sooner add a spray system and a squeegee for cleaning panels. Not that I recommend it.
 
Last edited:

anadiner

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Aug 10, 2021
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Has anyone done this or want to talk about doing this?

Run water/glycol through tube on backside of solar panel, use heat pump to cool down solar panel so much that humidity from local air condenses onto the solar panel, if mounted at an angle, it drips off, taking dirt with it. It would even increase PV yield due to temperature coefficient curve.

Don't get me wrong, I don't think it's the best way to clean a photovoltaic panel on a roof.

But has anyone done it?
Havent.

This post got my attention with word condensation. Its not a bad idea. I just happen to live where ur shoes get wet until pushing 10am. Condensation here does more damage than good.

Guess it would all depend on humidity level where u r. Im saying high humidity theres no drip. That crap sticks. Then here comes pollen, dust...
 

wholybee

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Feb 11, 2021
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Hosing off my panels doesn't clean them without my also wiping them with something. How is is expected that condensation alone will?
 
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