Water cooled solar panels.

[Boatyarddog]

Originally Posted by mikk60

Some People on here are very rude and condescending! Do you just come on here to insult others??

Absolutely, you are correct.
SOME ARE VERY RUDE HERE.
AND you should report such behavior if you find it.

Use the red exclamation point, at the lower left.
Mention what posts.
And what you found condescending.

Forums are for learning not debasement.
BYD

[Mauruuru]

There are Gigawatts worth of solar panels installed on black roofs and in deserts that are not cooled by anything but ambient air flow across and around the panels themselves and they have a service life of 40 years......why would you imagine you need to cool them with water?

[Rumrace]

Calm down and forgive them.
It’s their therapy time to vent or establish self worth., or in rare occasions Smartest Person in the Room Syndrome which existed long before interweeb dweebs.

When your dead you don’t know you’re dead. It’s hard on other people.
It’s the same when you’re stupid.

[Rumrace]

Well as silly as it seems to cool a few panels on a boat, solar farms are affecting temperatures 700 miles away apparently.
The are a huge heat well changing weather so yes next panel self cooling is a great idea to develop.
Sovonics United Solar Systems out of Troy Michigan had the best rated panels at the space station. Also know as a brand Unisolar stated performs in space should not be confused with earths temperatures.
The cold space apparently is the place for performance

[Rumrace]

Maybe the water trapping gel used in cooling hats and a method to trap the humidity and recharge the gel. Just water evaporating and some sort of trap to gather the moisture.

[StuM]

Originally Posted by Rumrace

The cold space apparently is the place for performance

Um, depends on what you mean by cold

Space itself has no temperature. In thermodynamic terms, temperature is a function of heat energy in a given amount of matter, and space by definition has no mass so it's neither hot nor cold.
(The oft quoted 2.7K "temperature" is the Cosmic Microwave Background Radiation temperature - remnant of a very early stage of the Universe)

Solar panels in space when exposed to the sun and absorbing solar radiation have problems getting rid of heat and operate at higher termperatures than they do on earth. The only way they can lose heat in the absence of an atmosphere is through radiation - none of the air's convection and conduction that aid cooling on earth.

[Uncle Bob]

Originally Posted by mikk60

Some People on here are very rude and condescending! Do you just come on here to insult others??

Hi, at whom are you directing your somewhat pointed barb?

[GordMay]

Originally Posted by StuM

Um, depends on what you mean by cold

1. Space itself has no temperature. In thermodynamic terms, temperature is a function of heat energy in a given amount of matter, and space by definition has no mass so it's neither hot nor cold.
(The oft quoted 2.7K "temperature" is the Cosmic Microwave Background Radiation temperature - remnant of a very early stage of the Universe)

2. Solar panels in space when exposed to the sun and absorbing solar radiation have problems getting rid of heat and operate at higher termperatures than they do on earth. The only way they can lose heat in the absence of an atmosphere is through radiation - none of the air's convection and conduction that aid cooling on earth.

Indeed. Thank you!
1. Temperature is the product of heat.
2. The sun-facing side of the International Space Station [ISS], for example, can reach scalding hot temperatures of about 121oC (250oF), while thermometers on the dark side can plunge to a biting -157oC (-250oF).
Heat transfer doesn’t occur the same way in space, as on Earth, since two of the three methods of heat transfer [conduction and convection] cannot occur, without matter/mass [mostly absent], leaving only radiation.
On Earth, most heat transfer is by conduction.

[Rumrace]

I suppose the higher output is from the lack of atmosphere.
Space is not the void of emptiness your suggesting but yes convection certainly near zero.

[blueskymessenge]

Let me say we have an interesting crew on board this thread. Accepting and ignoring some of the more ridiculous responses, LoL, is pretty normal for such a motley group, e.g. when I put my sailboat up in space, I’ll definitely put in a thermal loop with a liquid capable of dealing with both the hot and cold sides of my ship. I suppose talking about how R/V coolant won’t cut it… but until that day, I’ll stick to more practical facts and info. So mikk60, yea, I agree, but moving on…

I agree with Seabeau about mounting panels on dual wall polycarbonate. Yesterday I visited a Lowes hardware store to look at the 6mm and 8mm panels they had in stock. RV folks have been doing this for a number of years with great success. Particularly when the RV is in motion air flows under the panel as well as above with forced convection. However, on a sailboat, particularly at anchor airflow needs to be a bit more aggressive. Convection isn’t going to happen much with either the 6 or 8mm, so I opted for 10mm which is sold at ePlastics.com and ePlastusa.com, among others. I talked with the staff at ePlastics about walking on the poly panel, they indicated that the 10mm, if fully supported underneath, like laying on a near flat deck, would work without crushing. They suggested no jumping. The 10mm has some reasonable air passage way which should allow better cooling of the backside of the panel. I will update the forum in a week or two when the stuff has arrived and I’ve tried it.

So, who can tell me which adhesive has the most thermal conductivity? LoL (back to the space discussion). Obviously “gluing” the solar panel to the polycarbonate actually will have some impact on that conduction of heat which then will be aided by the convection of air through the honeycomb. Thin epoxy with full surface contact might tear the backing material with heat/cool cycle expansion and contraction. Silicon based caulk give a fair amount of flex for the latter but sucks in regards to adherence. Any suggestions on this part? Seabeau, what did you use on those semi-flex? In my case I am using fully flexible panels, so there is no thick backing nor walk-on coating on the surface.
These panels are sandwiched: ETFE film : EVA film : HE Solar Cells : EVA film : TPT Backsheet . I am intending to give up some of their flex to get them cooler. Frankly the flex in my mind is only there to be able to get them onto a non-flat surface, as flexing them will obviously destroy them in the long run.

I also agree with the comments that converting the honeycomb channels to hold seawater, or freshwater for those cold shower mates, is a bit of a hassle, adds weight, complexity and well, a whole bunch of hassle for a few more watts. While I am sure the net benefit is positive (wattage of pump vs. wattage returned) it just seems to much maintenance and annoyance. I appreciate the tube snake backing that CustomMarineProducts makes, but what a hassle it would be hosing it to the engine room etc. and worse, yes, once the water was hot in the loop, there is no more cooling for the panel. If you pick 10mm dual wall polycarbonate, pick the ones with the hollow center. There are other varieties which put cross-members inside the 10mm channel which will make them to small for convection to occur freely.

However, that said, for you cold shower folks, you can convert these dual wall polycarbonate panels for water with a Dremel tool, wire stripper, or a needle nose wire cutter, and two strips of polycarbonate and some poly-glue. At the ends of each of the panels where the channels open, cut back the last 10-15mm on every other channel and alternate the other end. Put one strip over the end of the panel (10mm wide) over the surface are where you cut, - they make a 10mm strip for adjoining panels together which could be used for the end strips. see attached pic. The panel then becomes a single snake channel flow for circulating water, if that is what is desired. Attaching nipples at each end or other hot water hose attachments with JB Weld poly glue (an epoxy actually) and you’ve got your cooling coil. That was the original concept for cooling the panels with seawater. It just seems that unless the panels are fixed and all that hosing and connections are solid, it is a nightmare waiting to happen, winter needs winterization and draining...

I’ll post again once I’ve tried the air-cooled version of this all.

[JC Reefer]

Water heating and solar cooling seem to quickly become opposing goals. As a heater, I see insulation being used to trap the heat created behind the panel.

Or am I missing something. Or Is it an ineffective heat sink without the insulation?

[b_ohare]

Indirectly related (pun intended): New concentrator could help solar panels capture more sunlight – without tracking it

[StuM]

Originally Posted by Rumrace

I suppose the higher output is from the lack of atmosphere.
Space is not the void of emptiness your suggesting but yes convection certainly near zero.

At the recognised top of the atmosphere(TOA), it's near enough to empty with around 3-10 protons and electrons per cubic centimeter.
It's worth noting that they have an average temperature of 150,000°K but they are so sparse that there is very little heat energy there.

As you note, higher output would be because of the higher insolation from that lack of atmospheric filtering.
Total Solar Insolation(TSI) at the surface is about 1000 W/m²
TSI at TOA is about 1380 W/m²
So ignoring all other factors, you would get 38% more output from the same panels in space.

[Rumrace]

That’s really interesting Blue. Whole new set of problems on an RV I imagine. The polycarb sheet I don’t quite understand.
The hats you can buy which absorb water and cool by evaporation have a gel inside.
If the panel had a slight tilt the evaporating water could be collected maybe condensed and recovered. Some else mentioned an emergency water maker which absorb water and traps the salt. How how about dual duty desalinate and cooler.
I think for my purpose a heat sink in poly aluminum would be my pict. ESUN and a couple other plastic manufactures make it. It’s an petg plastic with 20 aluminum content. The air running between my canvas and panels would work great on a heat sink.

[FlyingScot]

I gave this a lot of thought as we are currently using solar generated energy to heat water the old fashioned way in one of our two water heaters using the inverter. This is obviously not very efficient but works very well.
Our conclusion was to rip out our LG NeonR 4 x 360wp to install 5 x LG Neon Bifacials 435wp.

Haven't installed them yet, but I hope this will this will keep it clean and simple.

I think the idea of cooling the panels will increase output enough to justify the pumping losses and then you get free warm/hot water as a byproduct.