Surprising Power Gains By Cooling Solar Panels

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.

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!

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 no way the extra 5% justifies the cost/waste of the water. Thanks for the video!

100 gallons of water for 20 watts? Also good luck with that Cybertruck, you'll need it.

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.

Saves $4, almost $5 on electric bill. Water bill goes up $6. Celebrates with a $7 beer.

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!

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.

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.

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.

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.

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

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.

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.

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.

59 degrees F is about 15 C. You forgot to subtract 32 before 5/9! Love the everyday home stuff!

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.

If the mini power meters are not calibrated, you may need to swap their positions to convince both read the same manner.

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.