4 Different Methods for Cooling Solar PV Panels

This video looks at solutions for cooling a solar panel if and when it gets too hot. There are a variety of ways in which PV panel can be cooled. This includes using PCM or Phase Change Materials and also using water sprays. Gallium Arsenide panels can also be used in hot regions.
This video is part of an Online Course on Solar Energy which can be accessed from the following link:

[MrPeterDawes]

I like option 3 best with a way of harvesting the heat for heating water. A combined Solar thermal and PV panel, rather than just dumping the heat into the air.

[chrisw]

The average insolation (solar energy gain) in southern South Carolina/northern Georgia in August (where I live) is about 5 kWh/m^2 - much less than Texas, Arizona, or especially the Middle East. This converts to 18000 kJ/m^2. The latent heat of fusion of PlusIce is 140 kJ/kg. So you'd need 18000/140 = 128.8 _kilograms_ of PlusIce _Per Square Meter_ ! (over 280 lbs!).
PCM's are great for moderate heat collection over a large area - such as your example of helping cool a desert home during the day and keep it warmer at night. The heat load of trying to cool even one 2' x 4' solar panel (about 3/4 sq. meter) is way over the capacity of any solid/liquid PCM for any practical application. Pumped liquid/vapor PCM's are viable (think heat pipes) but way more expensive - essentially an air conditioner attached to your panels.
Please note that I do understand a smaller amount of a phase change material would keep the panel cool for a set amount of time, and allow higher panel output for that set time. After that, the panel and now liquid PCM would heat up as a unit, taking longer to reach max temperature due to the extra mass and slowing the decline in panel performance. But for any practical fraction of that ideal amount of PlusIce mentioned above, that time would be measured in minutes less than one hour! (Assuming 14 hrs of sun a day, 1 hour would average 1/14th of the solar insolation. 1/14th of 280 lbs is still 20 lbs per panel.) Fusion PCM's (solid/liquid) are NOT a practical way to handle that much heat.

[majharulislam]

Excellent explanation.
Option 3 could be a better choice. Heat can be rejected at underground pvc pipe coil. Only a small circulation pump needed.

In Option2, Water spray can create hard scale on the glass surface if use ground water, which contains lots of minerals to deposit. Here, demineralized (DM), Rain or surface water ( from pond, river) after filtration can be used to minimize the problems.

[pinarellolimoncello]

Thank you very much for your video, I have found exactly the answer I was looking for in your short, concise but precise video. I love people that know how to use the internet correctly, and that is what you have done here.

[dennisboyle]

Another solution would be to use solar attic fans! Building an open overhead structure for pool area in Florida incorporating 6 mono 350w panels with struts to vary angle with several solar fans with a timer(thermo or hour) for hot periods during summer. Panels will provide shade, fans run on the sun and will also cool guests under it, sounds like a plan to me:) Will try the fans downward and upward under the panels for best results

[johntexan]

How about creating convection and routing it to a vertical wind turbine that is contained within a shroud? This would probably increase the output efficiency by at least 33%, and I suspect more. During the winter, when you have more wind, you can remove the shroud to get more benefit.

[sunsource]

Nicely done presentation. Thank you. Would you be able to provide any information on the improvement in efficiency with a spray system? It seems to me that in Brisbane Australia, every day there is a thermal loss of 10-20% due to our temperature range. This is the low hanging fruit for improvement in efficiency. Analysis of 5 years' of data from my own 5 kW system shows that it is highly unlikely that cleaning the panels will make any difference. Aside from heat, the other efficiency killer is the year on year degradation of the photovoltaic cells, which the manufacturer has guaranteed not to exceed 10% in 12 years and 20% in 25 years.

[mb-faze]

The best way to cool panels is to keep them in the shade :) You might think I'm joking, but I'm not. Use selective spectrum mirrors to shine light onto panels which are positioned in shaded areas and angled pointing slightly down towards the ground. Then you can cool the panels from the back using a closed loop water spray or other method. This method has the added benefit of limiting the dust landing on the panels. Yes, you have to track the sun with the mirrors but this is far from impossible. And the mirrors can be cheap, made of reflecting tape stuck on lightweight backer material.

[johnrogers]

Recent work in Switzerland suggests that placing panels on a green or cool (light coloured) roof will increase the panels' efficiency by between one and four per cent.

[tembofly]

I cannot find plans for constructing a solar panel system using PCMs. Do you have links?

[oskarnowak]

Systems based in places like the Sahara desert would benefit from chemical heat absorbers, even a pc water cooler would be a good option, mainly because of the excess heat throughout the year, which lowers the efficiency significantly. In places near the equator, lowering the temperature of PV panels would increase yield, but would also allow us to create something similar to the Noor plant in Morocco, which would probably be way more efficient (sun to electricity + heat, rather than sun to heat then electricity). Producing electricity directly, and removing excess heat from the equation is way more efficient, compared to x times more materials used in converting salt to a molten state. In places with your 'standard' 4 seasons, radiator air cooling using Bernoulli's principle, would be cost effective, as a chemical absorber would be next to useless and expensive compared to a few fans attached to the back, so retrieving the heat would be unprofitable = $/Kwh. Just a thought, if someone has interesting books/articles on chemical absorbers and prices, that would be cool. Anyhow, in a few years time, most, if not all building foundations will be designed with heat storages, to reduce heating costs.

[paulneilson]

I was wondering why no one is making a solar panel that has a heat exchanger behind it. The efficiency gain is quite dramatic 25% loss is crazy.

[johnrogers]

Option 5: Mount panels on a Cool Roof, i.e. a roof that is painted a light colour. This will reflect some of the heat away from the panels and make them about 2% - 3% more efficient.

[erichawkins]

We will be looking to licence our solar thermal cooling exchanger from April 2019, which you can assemble in your own country to any brand of PV panels to create a PVT low cost high performance panel

I love the water spray solution. But i seems like to pay more for the water consumption. So. What will be the best choice?

[stephenbrickwood]

A cooling breeze from a fan might be useful.
Air moving under the panels.
3% loss means 3 new panels in every 100 panels, or 1 new panel in every 33 panels. Each year to maintain output and micro inverters.
But micro inverters can degrade aswell.

[padre]

Use water of a swimmingpool to cool panels and then heat the pool.

[gabakusa]

Just add a big heatsink in the back like a CPU

[bryantaybor]

You showed how to install the others except the last/4th way. So how to install PCM Packets or Plucise to these already installed panels on residential homes? Can a layer of Plusice or the liquid out of. PCM Packets be coated over the Panels resulting in no damage to the panels or what do you suggest?

[keithgray]

Why not collect the heat and covert to more energy?