Surprising Power Gains By Cooling Solar Panels
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- čas přidán 24. 08. 2023
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A comment came in on a past video stating they were able to get 10% gains in power output just by cooling their panels with a sprinkler. This got my wheels turning and I wanted to test this out for myself to see what kind of gains I could achieve running 2 panels side-by-side one with cooling and the other with no cooling. Overall the findings were interesting and hot panels definitely have some power loss compared to cool panels.
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I prevent my panels from getting too hot by keeping them in the shade.
Genius! 😂
😂😂
Even better if you keep them indoors
lmfao 🤣 nice one
Good luck with the power gain.
Saves $4, almost $5 on electric bill. Water bill goes up $6. Celebrates with a $7 beer.
Water supplier have to spent 5x the energy saved to supply water ;) Entropy always grows.
Dont forget cost of building a rig to get all your panels watered. Most people have 10-20 on a home setup. Single or small panel setup youre better off just wiping and cleaning by hand every month or so.
@@anekinoo7 its not about cleaning, its about cooling. cooler panels produce more power. you would need a water loop, idk why yall think you need to run fresh city water over the panels.
Ugh... beat me to it! Probably more like "Save $5 on electric bill, Water bill goes up $20." Max this out by hooking up window units to your solar panels 🤣 Point is they are supposed to be passive. What's next, "we can increase wind turbine output by running unused 747 engines in front of them". Some people....
Dude, this was a test on power generation.
In my country many there are people that uses automatic gardening waterer to only reduce temperature when the solar get at determined temperature. They uses water collected from rain.
The biggest advantage is the increase of longevity that you get for exposing your equipment to lesser temperatures
the company DualSun has a panel that can take in pool water to heat the pool while cooling the panels. If no pool, they can also be used to preheat water for your water heaters or go to any heat exchanger. It's a pretty cool system.
Was just about to mention them; currently planning to use some of those, and send the heat to a geothermal well that will provide heat for my house in the winter.
I always wondered if you could do some sort of micro-thermopile array setup on the back of a panel to generate useful power and cool the panel.
As soon as I saw the title I was thinking, combination solar thermal and pv is the ideal panel.
I hope the pun was intended.
What about all the bird and bat shit! Do they filter that out before you swim or shower in the run-off water?
I am so glad it is only 5% and we all not have to waste water to cool every single panel. Thanx for your work.
Being in a desert area I can't do the water idea but I did put a fan under one of my panels and got a better watt hour return than without the fan. Just moving air on the underside helped a lot!
If you ever get more panels in the future you might consider closed loop water cooling. I believe the panels need to be purpose built for it, but there's (almost) no water loss in closed loop systems and you can use the waste heat in the water to heat other things.
@@Mr_Soleomaybe putting it in a hot water tank that can then be used for heating at night
Dang... so essentially the cooling made it so you got more wattage per hour, more than enough to also power the fan? that's awesome if so. so basically the only cost was the fan. my next question would be how long until the fan is paid off?
a slightly hacky thing you could try is to stick old computer cpu cooling fins to the back of the pannel to move more of the heat from the pannel to the air
@@crestfallensunbro6001 so have a heatsink and a fan to cool it off, would definitely work
The problem is less the water, since you can simply capture it with a rainwater harvesting system and re-use it. The question is if you gain more power than you need to have a pump running all day. Maybe it helps if you just turn the pump on for about 20 seconds every minute, but that might drastically reduce the lifespan of the pump and might leave your panels covered in mineral residue left by the evaporating water.
There's actually a "starts per hour" rating for larger motors, but I wouldn't expect it to apply here. But if it becomes an issue then a soft start for the motor would be the way to go. And there are other ways to cool off the panels without running water over the glass on the panel (think water cooling found on PCs), such as a closed loop system that heats your water for home use by way of a heat exchanger.
Now would these modifications be worth doing? Single use water dripping across the top of the panels would be a horrible use of water, and probably (hopefully) illegal in most places.
A closed loop system that circulates captured coolant (antifreeze) and the dumps the heat into something that you want heated (hot water heater, pool, heating the house, etc), as a secondary use, or if you don't need the heat, sinking the heat into the soil would be far more efficient, and potentially reduce your energy costs in other areas of your home.
I don't think that I would do it for a meager 5% electrical gain. I would have so see a marked improvement in energy production as well as a cost savings in the secondary uses.
@@MrWaalkman I think the same way. Was also thinking of a liquid cooling loop like the one used for PC's. It could be applied to the back of the panels using heat transfer paste (like the one used on CPU's). But 5% is just not worth the time and money.
Another possible option on tilt roofs could be to capture wind from the line along the top of the roof and get it to blow under the panels. But It would only work when there is enough wind... and if there is too much wind it might get your panels airborne (if unlucky along with the roof)
The water is the less efficient way to address the problem. There are companies that are bonding heatsinks on the back of the PV cells and 'stealing' power from the cells to run wash-down fans controlled by a simple thermal diode. czcams.com/video/Mt9qLRN7JvA/video.html Tech Ingredients did a breakdown of it, and discussed using water briefly, but dismissed it mainly because a pump is a lot more power intensive to run, and the net effect is only about 5-7% where the heatsink and fan arrangement was 10-12% for a smaller power investment.
I'd give that a look because the discussion is a bit more in-depth.
Try putting a duct on the back of the panel that runs air up via convection through heat sink fins.
@@TheCablebill That's what @kmikl mentioned in the last comment before yours.
I would reclaim the water at the bottom, run it down into a geothermal system, in the ground, then when the water cools, it's pumped back up to start the cycle again. Many other uses for that hot water, hot water storage tank for baths, etc.
throw on a windmill battery charger for the pump and youve got free energy
The energy u need for that is higher than the profit gained from cooling.
@@lenardgor boy go on somewhere and study
People who act like a small pump uses significant amounts of energy probably yell at their kids for leaving LED bulbs on when nobody is home.
Thanks for making this excellent comparison. One cooling option is to use thermal conductive glue to attach aluminum heat sinks to the back of the panel. You could even hook up a separate solar powered fan to draw air over the heat sinks.
Yeah, that has some potential. Thanks for the idea. Increasing the shaded surface area with a little airflow would probably make a measurable difference. Sounds like I need to go shop for some aluminum 😁
@@everydaysolar The cost over gain would be enormous.
I think @TechIngredients did a aluminum cooler on the back with net positive output like that.
If you are gonna go all out like that I suggest you instead utilize the thermoelectric effect and also have the panel face under vacuum with water cooling via a pump and tubing on the thermocouple... or whatever those thermoelectric panels are called...
@@SkinnaMovTechingredients is the bomb!!
Thanks for doing the test. I think the 5% extra energy production seems low and probably will scale up to more if done over a home sized array of 2000+ watts. I've hosed down a solar arrays in the middle of the day and noticed upwards 10% power increase on just the watt output.
But, in addition to using up a lot of water, a big problem with is *hard water* stains on the panel's glass from using normal city tap water. Those minerals will get _baked in_ even harder with the intense daily UV and heating. Personal experience.
As someone else mentioned, this can only be practical with a heat sink system on the back of the panel:
(a) no hard water stains
(b) low to zero water waste as water is circulated
Requires a lot more materials like hosing, valve, heatsink, anti-bacterial additives, etc. If its going to give 10% energy gain then might as well spend 10% more on panels and spend less money and time. The ever falling prices of solar panels makes that the best alternative to get more energy output.
However...
I do like this idea of having a substantial behind-the-panel cooling system that would also save the heated water to a solar tank. That way, the house is getting much more energy efficiency from solar panels well beyond the ~21% efficiency of the latest generation solar panels.
Look up "2-in1 DualSun SPRING hybrid panel" that has all the heatsink and hosing built into each panel. The manufacturer claims it can give that 5% to 15% panel energy output efficiency improvement as well as heat the water to 70°C. This is a double benefit that's kind of a no-brainer if it can be made and installed economically. But it really shows what our sun is capable of when the correct set of technology is applied!
What if you use a heat pump system to move the energy from the heater water out on a pool water (basically a water-water heat pump) so then you send not just average temperature water to the solar panel but actually cooled down water like maybe at 10 degrees Celsius or lower. I think then you can gain even more than 15% in power production but it will be balanced out by the heat pump probably.
What if you don't put water on the photo cell itself so as not to distort the light wave landing onto the cells and reducing the power "creation" capacity? And cool the panel from the rear.
@@MR-backup you can expect somewhere between 10 and 15% improvement. Still not worth doing unless you also need the warm water for something like a pool.
@@alexandruilea915 Interesting idea. Can someone do the calculations please! 😁
@@MR-backup Hmm, got me thinking that maybe the solar panel can be manufactured with many thin channels embedded within backside plastic perhaps. It will just make the backside some 2mm thicker.
That allows water to run just under the solar cell substrate and provide a guide for the water without requiring the use of any heat sink.
These water channels would not be as efficient as an actual heatsink but would be a hell of a lot cheaper! Because these channels would not much more manufacturing materials -- just a small change to how the panel layers are sandwiched together at the factory.
Each panel will need some sort of inlet and outlet water ports. The smaller channel size will require a stronger pump but still should be net positive in terms of energy production. 🤔
I went in 2015-2017 to a energy convention and there was a company who had solar panels with hoses at the backside.
It had a couple of functions.
It was to cool the solar panel and to heat the water for your pool, shower.
Somehow I never saw it again as the idea sounded good.
You can watercool the panel by making the backside watertight and pump water through it, and use that water in your heat tank or swimming pool heating.
All in all, it's not worth the effort unless you really have a lot of difference between night and day, but the year itself is not changing that much. So if you do have cold nights, the heat is good for storage in a heat tank, and at night it keeps the temperature of the panels stable plus it lowers the amount of electricity needed to heat up cold water to 65+ celsius after it went through the heat tank. Be aware that you should either have cold water or hot water, but not in between due to legions disease that thrives between 20 and 60.
We have a buffer of 2000 liters that has it's temperature around 40 to 50 celsius during the entire summer but it's only for heat storage as the water that we actually use just flows through some copper pipes that are inside the buffer and the water simply absorbs the heat from the buffer without exchanging the water itself. Anyway, I don't think there are any bacteria in that water since during the winter that water sometimes reaches 85 degrees celsius when the heating is turned on.
to be clear, efficiency increases below STC. The flow meter was a nice addition. One additional test would be periodic water flow. Save water and allows the water to evaporate, cooling the panels. This will depend on humidity which varies by day and region. Also, if the heated water could be used for things like swimming pool heating or hot water preheating, it gets a bit more cost effective. Water also block longer wavelengths of light (so red more than blue), so cooling the back of the panels might be more effective.
This is informative. I wonder if an internal cooling solution may yield even better results. Not only because the actual cells would be cooled but your also avoid any potential loss of sunlight hitting the cells due to the reflection and refraction from the water cascading down the glass.
Might he something to consider for a future aide by side test.
There are panels that have cooling on the back side. Google DualSun Spring.
Maybe you should recommend dual use panels. They harvest the heat with watercooling loops on the back of the panels. So you 1. cool your panels down to get a better efficiency (more Wh) and 2. You can harvest the warm water from the system via heat exchanger.This way you have not wasted any water and get the dual purpose use out of the sun energy
Majority of the cooling is from water exaporating off the panel so this could probably be done with much less water at intervals. A supprisingly effectave way to cool your house when the ac cant keep up is to hose off your roof a few times throughout the day.
Sadly practicality trumps theory. Unless you have good quality distilled water, you'll have. Rapid scale buildup which will occlude panels rendering them useless.
Your swamp cooler approach can work if done on the back side
I’d say more cooling is from conduction (panel to water) than from evaporation in this test.
As a standalone fixture, the potential savings are probably offset by the water and power pumping it. However, if were done as a multifaceted system that is cleaning the panels (keeping pv efficiency ratio up), cooling the panel and also heating water for internal use, then the compounding effect could make it a more efficient and cost worthy approach. I think we'll see more cooling systems in future, as pv panels become more efficient and cost effective.
Off grid 20+ years and heat loss is an obvious factor you can mitigate. I don't recommend using water though and the way solar installers mitigate it is by adding additional panels to make up what is lost in high temperatures and on cloudy overcast days.
However, for DIY solar I recommend not putting your panels on a roof that is black or dark as that will increase heat loss even more and use a ground mount system over dirt or light colored rock. You can also increase air flow to the back side of the panels by removing obstructions and if possible set them so the natural wind patterns flows across the panels. Even a light breeze makes a difference.
A ground mount system with adjustable tilt and angle or a tracker is optimal.
I also recommend a ground mount system so you can wash the dust and bird crap off your panels and check and do any maintenance needs. My system gets washed off a few times a week.
My system is 1.4Kw ground mount with 600Ah LIFEPO4 batteries and Geneverse 200Ah and ALLPOWERS 200AH power station for extra capacity and that runs everything: water pump, lights, microwave, laptop, evap cooler, ebikes and recharges lots of tools and gadgets.
Have a capture system and directly put the reclaimed water back on the solar through a radiator in the shade with a fan and a pump you'd probably have to top it off cause of condensation and evaporation creating a loss you'll need to account for but could definitely work on super hot days
there's no way the extra 5% justifies the cost/waste of the water. Thanks for the video!
For sure
That depends on the climate. Somewhere that gets large amounts of rain could capture plenty of rain to do this and then use the water for other purposes like watering a garden. The water doesn't have to simply be wasted.
then use your brain, make pan that captures the water then cycle it back..
@@kahingaltv2023 it’s not worth it. But feel free to do it with your gigantic brain
@@kahingaltv2023Hi, think rain water harvesting, the panel becomes the means to capture the water. Using the tank water to cool the panel uses the rain water capture parts you already have. The big tank becomes the heat soak that gets liberated at night.
Take care all M.
Sundrum Solar has modules that attach to back of conventional solar panels and then use that heat generated for hot water needs, can be swimming pool, car wash, hotels or space heating.
Thanks for sharing. I’ve been looking for a way to warm my pool while simultaneously adding electricity. I’ll check them out.
If the water cooled panels are 10% more efficient, but cost 10% more it would be a wash. It may be cheaper to just add an extra panel or two.
@@thespencerowen I've never installed their product but I know they've done a number of projects and think it a very viable means to extract more energy from the sun while making PV panels more efficient due to the cooling provided by the system. If you're in an area that deals with snow it can also be used to melt snow covered panels.
when i was getting my degree in this field, i met a guy that installs flat fin tubing on the back of panels and the water was cooling the panels and was used to generate heat through thermo heat generators, and some went to domestic use.
the important thing to remember is to use as clean a water as you can if you are going to wet the panels to prevent degrading by mineral build up and water is a universal solvent and will destroy the frame over time
I remember reading years ago (early 2000's) that solar panels were more efficient in slightly overcast days, I have no idea if it was accurate or not, but this would kind of back up the theory that the panels work better at a cooler temp. Either way pretty interesting to me, thanks for making and posting this.
Basically sometimes a cloudy day will magnify the suns rays through the light moist cloud particles
Apparently the temperature coefficient changes with the age of the panel because I have some 14 yo panels with extensive spider cracks that have degraded by about 10-15% at STC, (basically when it's cool out), but when they really heat up in the summer the power output crashes. It was a simple test I did when they were very hot I took a hose and hosed down the panels. I saw over a 40% rise in amperage on my Amprobe. There could have been some SMALL variations in solar input but the sky was clear that day. It was an eye opener for me.
You'll want to use demineralized water for this, like distilled water or harvested rain water. City or well water will most likely leave mineral buildup
Nice video. I have 800w of ground mount Rich solar panels connected to an EcoFlow Pro and run the sprinkler in the heat of the day. I almost always get at least a 10% increase. It might be because I’m in Oklahoma and it’s 108 today 🤪. I checked my panels and even with water cooling they were 90+ degrees
Please stay inside. 108 is more than boiling point of water!!
i think he means 108F, America is in Fahrenheit not Celsius.
I have a small array in my yard with a 200ah lifepo4 battery. I use this for my pool equipment, outdoor lighting and power tool charging. You video made me start thinking of a way I could use my pool pump and reclaim the water to heat the pool.
Awesome test, with a large enough system it's worth running a chiller and recirculation of water. I got up to 16% gain. Love these tests 👍
16% PV KwH gain? That is absolutely impressive!! Care to share the specs? I'm very curious to hear what you got going!!!
i think the data is tainted due to the sprinkler tube being set up in a way that partially shaded the panel. i would say it needs to be rerun and setup in a way where each panel is equally shaded... 0% shaded.
i like the experiment though, curious to know what the real results would be
I not only have this set up for my 12.4K W backyard fence mounted system but I also have low pressure misters that clean my solar panel and pull my solar panels from 130° down to 88° increasing my total power production by 1200 W which is enough to run a small air conditioning unit.
I also have a smaller version of a whole home water softener for lime scale.
I really appreciated that you started with a control verification.
Water drops may also locally concentrate sunlight to a very small area, etching the silicon of the panel.
If the mini power meters are not calibrated, you may need to swap their positions to convince both read the same manner.
I did a project on this effect in my heat and mass transfer class, the math behind it is very interesting but it's only a viable option at certain temperatures, I primarily studied the effects of wind on the efficiency
Yeah! I've noticed this in my van one day after it rained. Also, it's counterintuitive but my panel covers a ventilation vent in the van, and running the fan produces more power despite the fan load than not.
One great use case for this is for an off grid tiny shack house with a single slope roof where nearly the entire roof is solar to block the sun. The water would keep the roof and shack cooler. In my case during those direct sun hours I'm running a 12v pump to filter rain water used for bathing, washing, cleaning and irrigation so might as well run it over the roof achieve this affect, which i think will also disinfect and heat the water.
Be careful with systems that only create warm but not hot water.
The risk is that you might accidentally grow Legionella bacteria in the system, which can be pretty nasty if incorporated with vapor of a warm shower.
This video gives me the idea of using patio misters to cool my 6 100w panels. Misting systems are very cheap and use little water, interesting. Thanks for the idea!
Such an interesting way to increase your power generation
I'd say some improvements are from cooling and some of the improvements are from light magnification from water droplets. Cool test tho. I'd say cooling the back side of the panel would give you a better knowledge of cooling alone without magnifying light on the front side
I don't think there's any appreciable magnification here - you'd need light that'd miss the panels to hit the panels instead, and there's almost none in this setup. There should even be a detriment from additional reflections away from the panel, since the albedo of the panels seems to have gotten brighter in the video.
@@AySz88 If anything the water is probably diffusing/scattering the light waves away from the panel
Very interesting test. It doesn’t seem though like it would be worth it long-term. The cost of running the water just doesn’t seem like it would outweigh the benefit of 5%. Now if you had a closed loop system where you had a way to naturally cool down the water (without some kind of conditioner running), and all you had to do was run a small pump, it might be worth it.
Again, very cool test. Thanks for sharing it!
I wonder about how to circulate the water to make it a closed loop. You could do a geothermal style loop and dump the heat into the ground.
Off grid 20+ years and heat loss is an obvious factor you can mitigate. I don't recommend using water though and the way solar installers mitigate it is by adding additional panels to make up what is lost in high temperatures and on cloudy overcast days.
However, for DIY solar I recommend not putting your panels on a roof that is black or dark as that will increase heat loss even more and use a ground mount system over dirt or light colored rock. You can also increase air flow to the back side of the panels by removing obstructions and if possible set them so the natural wind patterns flows across the panels. Even a light breeze makes a difference.
A ground mount system with adjustable tilt and angle or a solar tracker is optimal.
I also recommend a ground mount system so you can wash the dust and bird crap off your panels and check and do any maintenance needs. My system gets washed off a few times a week.
My system is 1.4Kw ground mount with 600Ah LIFEPO4 batteries and Geneverse 200Ah and ALLPOWERS 200AH power station for extra capacity and that runs everything: water pump, lights, microwave, laptop, evap cooler, ebikes and recharges lots of tools and gadgets.
We can place finned heatsinks behind the panels and wet these heatsinks regularly with micro sprays. In this way, semi-passive cooling can be achieved by evaporation on the increased surface of the heatsinks with fins. If we ignore the heatsink cost, I think this will be the most viable solution that provides the highest efficiency... I love your videos, keep it up. Thanks.
You could collect rain water, filter with a sand/charcoal. And use a small solar water pump to cycle the water… might do this for my solar shed 😁
That's actually less of an improvement than I expected, but now that I think of it, cooling the outside of the glass isn't going to cool the solar cells by much due to glass being a pretty good insulator. Also, one risks cracking the glass. Generally speaking it isn't worth trying to cool the panels due to the extra complication. Easier to just add additional panel(s).
You do a really nice job on these videos. Thanks for all the hard work you put in making your videos. Keep up the great work.
59 degrees F is about 15 C. You forgot to subtract 32 before 5/9! Love the everyday home stuff!
It looked like the PVC was casting a thin shadow across the top of the panel. that will cause a big drop in efficiency. Ideally you would only need to use as much water as necessary to evaporate on the panel and not run off.
I've certainly noticed this. My array produces more power on cool sunny days than on hot sunny days. My highest production days are actually during the winter! Of course it helps a lot that it only snows for a few minutes per decade in San Diego. This is why you should never mount solar panels with their backs against something solid, unless it's a good heat exchanger. They need the air flow to cool the backs. I think spraying the backs might work better than spraying the glass because they are in better thermal contact with the silicon layers.
People have been playing around with this idea since the 1980s! It is 100% impractical, but it does work! 😂 not a single commercial application of this idea has ever been implemented successfully. There is a warehouse north of Los Angeles that is stacked with gently used solar panels and you can pick up a 300 W module for about $40.
This has been on the table for decades.... Powerlabs, Engineering with Rosie, ..... have done this. The major point is cost efficiency. No use cooling the panels if the cooling costs more than the additional power from the grid would. I have seen water and air cooled panels (backside cooled) that use the extracted heat for heating purposes, but all those systems don't work well if you can't dump the heat somewhere. Running water over the front might even redude the light input into the cell.
Great video! You can also filter the water and pump it back through a heat exchanger. While not ideal, and it is more complex, there are ways to do this without using the water once and throwing it out.
Doesnt make sense. The pump would consume more than the 20 W / hr per Panel.
@@Chris-yy7qc what are you optimizing for? Energy or water consumption?
A ram pump can operate with 2-3 feet of head pressure. One might be able to build a self refilling system that requires no electricity. Or a pump that runs only to refill a reservoir intermittently, and use water height to drive the flow.
Complex? Way to complex. Benefits? Not enough IMHO. But potentially still a net positive effect for the effort.
Add a dedicated panel for the intermittent pump and you’re good. No battery, should stop running when the sun goes down anyway.
Thank you for all your efforts Scott, this video represents pretty much what YT *should be* about in my mind 🙂👍 A temp diff of almost 50% for a 5% gain in yield sounds pretty sobering to be honest. Even if this would vary up to 10%, will be it worth the extra investment for the required material, electricity (water pump) and the water itself, which will become a more valuable resource in the coming decades? BTW - have you observed a significant efficiency gain during winter then?
Ok, I have been thinking about this for a while so I cannot wait to watch this
omg thank you for showing both Celsius and Fahrenheit scales. much appreciated effort
I love it when videos do this cause sometimes the content seems like it caters just one global area.
"Combined heat and power" is so often an explicit benefit (steam from power plants at large scale, cars at small scale) that I'm surprised there aren't more systems doing it! I know water and electricity don't "mix" and it would be more complexity, but I would have thought all the puzzle pieces are already here given existing products like water-cooled CPU coolers. Must be missing something still.... 🤔
"My current power bill" . . . I see what you did there ;-)
Thank you for the testing..really appreciate it.. I think refraction help to improve the efficiency. This is how ETFE panel works.
I live in Alaska and have a place with a small solar system. The panels are mounted so in the winter the snow reflects some of the sun on them. I have seen them put out 30% more than advertised when it is close to zero F and the sun it bright on a late March day.
I love your videos.
I’ve been researching a solar heater for my pool. It may be possible to combine the tubes from a solar header with panels to make a cooling system.
Actually a negative power loss if you (should) distill your water to prevent lime buildup on your panels.
As a boater on a liveaboard boat, sailing from point A to point B.... floating "flexible" panels on the water not only provides all the "free" real-estate needed for a 4KW system, it cools the panels and makes them more efficient. When not in use, it is rolled up on a spool (like your garden hose) and stowed there for later use....
Had a friend that did copper panel backing with water lines running through it to pull heat from the the solar panel back in 07 as a some form of Master thesis, find myself looking for that final document now. To compare Results. He used his to heat the hot water/warm the house come winter. Wish I had the money to do something like that with my house, but that would be fresh constructions I am pretty sure for my design.
Try a much slower drip rate.
BTW it's really common in FL to have hybrid panels that channel pool water through the inside of a solar panel to both cool the panel and heat the pool.
Enhancement would be to swap the watering system to the other panel to nullify any panel performance discrepancies.
Such a cool experiment! Can't to wait to see what else you've got planned!
"cool" ;-) I see what you did there ;-)
I have an old panel that is made with a bunch of ~12cm silicon wafers affixed to a white surface. The white area is obviously not completely wasted space if it serves to cool the wafers. Keeping the wafers round also reduces silicon waste too.
I have to wonder if there is a increase in power from the magnifying effects of the water and if having a mister would be more effective to increase power that way or creating a steady completely covering flow over the face of the panel would be more effective. Likely a full front of panel covering with water would be best as it would even out any magnification and provide the best cooling.
I had similar questions and if magnification doesn't help, maybe the mister should be on the back side of the panel so as to not disturb the sun's rays?
I wonder what would happen if you just attached black radiator fins to the back of the panel? Passive systems are always the best if you can.
POSSIBLE FOLLOW UP TEST:
Consider a follow up test, to determine the quantity of power required, to run a pump to pump the water from a bucket, then use a rain gutter at bottom to direct the water back into the source bucket.
Then subtract the power required from the power gained to get a net gain or loss from water cooling.
thx
Also note: using recycled water may increase the temperature of the source water over time, so may need to measure temp of water over time, and increase size of bucket to give water time to dissipate the heat before it is reused to cool the panel.
Good test. You know many people have wanted to try this.
I've also seen a ton of improvement when I have cloud lensing. Usually about an extra 10% improvement.
Yes but it's generally infrequent and brief meaning the energy (not power) gain is minimal.
Use rain water, or distilled or reverse-osmosis (without a mineralization filter). Mineral build up on the panel won't be happy for solar efficiency. My water has enough minerals that it will turn splashed surfaces white in a few days. (e.g. around an outdoor water feature)
Or perhaps use micro misters onto the back side of the panel so that any deposits don't affect the solar efficiency - just reduce the cooling. It would also mean far lower water usage.
Thanks for the review of the concept. IMO, I guess another upside would be removing the dust build-up. Being from the SW-US, the other issues are: 1) Wasting water (I guess if you want to get complex, you could recirc it, but the more complex, the more things to break/maintain), 2) hard-water crusting/build-up on the panels (can be hard to remove), 3) what is pumping the water and what is its energy draw of that pump compared to the increase in power production (assuming you're not just tapping city water)? 4) if you have multiple rows of panels/large system, the plumbing to ensure all panels are cooled is a bit difficult. Finally, what about a simple air circ fan? Is that enough to actually cool the panel/... Probably not.
What if the water recirculates?
100 gallons of water for 20 watts? Also good luck with that Cybertruck, you'll need it.
if you set a collection system under the pannel, and then cycle it again through a small radiator for cooling the water, i think it’s worth it
if you set a collection system under the pannel, and then cycle it again through a small radiator for cooling the water, i think it’s worth it
This is also why early in the morning you can have your charge controllers trip on over voltage if you string is close to the max on your charge controller.
extremely interesting love the enthusiasim on solar
This gave me an idea to put my garden in front and under one of my ground arrays. I water the garden anyway, so I could let water run off the panels. My only worry is the water being too hot for my garden. I will have to experiment.
Failed to include the cost of the water for the minimal gain. My water bill is routinely much higher than electric.
Yeah, this type of system pulling from city water would be a definite No Go. I think the most practical system are integrated circulation systems for heating pool water. So you save money on heating the water and also cool down the panels.
The cost for the electricity on the pump will instantly wipe out any gains. What a daft idea….
better filter those calcium.
there is already a similar solution by using some hygroscopic foam at the backside of the panels. This foam is taking up the moisture during the cool nights and releasing it during the hot day. By this evaporation a cooling efect of the panels is obtained.
Love the video! I was thinking of using radiant PEX on the back side of the panels with a closed loop evaporative cooler in the summer to cool the panels and my shop, then the same concept for winter to melt the snow, still a closed loop system but this time pulling the heat with copper heat exchange from the wood burning stove in my garage.. Im very curious of the 5% gain would be much higher without water flowing acrosse the panel surface, but cooling it from the back.
It would be ridiculous to do that. Buy another panel
Nice experiment! I have rain barrels and a solar roof, I wonder if I could run something like this on hot days when I have full barrels. Would be interesting to measure how much water evaporates.
I really wish there was some product that was solar panels+water (pre?)heating. Not surprising solar installers don't want to do plumbing but would be interesting if it worked out well. Bonus would be the circulating thermal fluid could help keep the cells clear of snow, too.
Thank you for this test. I can currently not use it, because it is to hard to acces my roof (2 stories) but i think this could be valid solution for everyone, that collects rainwater like i do. That would cost no water in that case and also makes installation easier, as the water only needs to be distributed but gets collected with the system that already collects rain water. As long, as the extra energy gained is more than what the pump needs, it should be usefull.
Nice video and info but I think you will find 59F is closer to 15C not 33C. I can see with a roof with water capture that the loss of water could be minimised outside of evaporation and that with enough hot days, solar on hand or a separate solar pump perhaps this still makes sense. Simplified with a sprinkler or misting system perhaps both cost and installation time could also be reduced.
Awesome video, but one caveat from this experiment might be the increase in "surface tension" since the water molecules are in sphere shape which increases the area of light exposure.
I can see a line of shade from the water line to the cooled panel. That's bound to affect the measuring.
If you drill the holes on the side of the pipe, you could place it further away and probably get better results.
I use a similar system to keep the pannels clean from bird droppings and dust. They should last longer that way. I use those small sprinklers, for about 10 minutes. It works really well.
This is what I was thinking, while the cooling might not be worth it running it periodically to clean the panels probably would be
one guy did a flat rear cover then cut long opening on the bottom and put 3 120mm fans on the top. this seems to work amazingly
would love to see this test by cooling the back plane. Such a closed loop system could (pre) heat water for your hot water system.
Is it the effect of cooling the table or just having water running over the panel. Could you try it with hot water or some how have the panel on a cool table.
Thank you, Scott!
This is interesting, I'd not heard about the heat losses so this is a good idea, if done right.
Now, I want to see how to install a solar water heater.
I'm ~43 miles north of Florida so I could really benefit from a solar water heater add-on.
I want to do my own install because the install is, reportedly the most expensive part.
The potential savings could be substantial, specially this far south.
So that's why I suggest a video on installing a solar water heater add-on.
Have a GREAT day, Neighbor!
I live in southern Mississippi and temps can be 110+ F for weeks. I wonder if cooling with atmospheric water would prolong the panel's life over time.
Having a loop that feeds from the gutter on my roof could catch the water and feed it into a "U" shaped system that would make a small pump work easier. Problem is the water would eventually reach a temp not very far from air temp, maybe a 10F drop from air temp cooled just by evaporation. I could use a float value to keep the system at a needed level.
One con would be the increased constant humidity might encourage mold or mildew growth. Another is the pump isn't going to last forever, and keeping debree out is an ongoing issue.
I was in between Phoenix and Tucson this summer driving past a huge solar farm. I can't imagine how much their losses are in that 115 deg sun. I also couldn't imagine trying to cool them either.
I suppose with that sort of sun it's easier to just add more panels.
I've run a large water reserve through those pool-heater panels to preserve low temps during peak loads, and a single panel running a refrigerant.
Great, that's why floating panels are great.
Could you please try the same experiment cooling down the bottom side?
Well the panels could be manufactured to just have a heatsink and water to run trough them. So you can connect like 10 of them and make a closed loop to a simple head dispenser with a fan.
Would that be worth it? Dont know maybe if you have 800w large panels?
I’m curious if a misting would cool it as well, use less water, less distortion on the light coming in? I think some way of capturing more winter sun would produce higher results. My winter production is between 1/3 and closer to 1/4 of my best months in April/May. We know cooler is better because April has 90 minutes or so less daylight than June, but production is the same or better, thanks
I would think maybe using the sub-ambient atmospheric window cooling panels might be a better option, you won't have the light scattering like you do with the water droplets
This shortened the life of my solar panels, I think it causes the glass to become more brittle. I’ve found rear heat syncs which you then cool a much better and safer solution.
You would also need to account for the water's absorption spectra vs. what wavelengths of light the panels use.
Hi, it might be useful in conjunction with an irrigation system on a farm to mitigate the water use. Also, is it possible to capture ‘cold’ similar to sand batteries that capture heat. To cool the water ahead of use?
You can have a combined system that incorporates a passive solar water heater in the solar panels system.
this is a great experiment, thanks for sharing. I've always wondered if better air flow under the panels would improve their performance in the same way. I love the way that panel skirts look (like Tesla uses), but also worried about heat. How about a small fan under the panels to help with some air movement? Might be a wash (and probably why it's not done).
what about aircooling? would running a fan be better? i wonder if the diffraction and reflection caused by the water is reducing the impact.
I only thoughts is the gains in efficiency come from just cooling down the panel or does the water flowing across the surface have a reflection or amplification effect on the light?