Vicky_BR
Member
Hello,
I am experimenting with a small solar panel array, consisting of 22 panels in Sahara Desert. So, you can understand the effects of heat and dust on them!
I wanted to increase their efficiency by making them cool and dust free. Please consider the facts that water is scarce there, the ambient temperature is too high. The advantage I am getting is a very good sun light.
Any suggestions?
dbindoff
Member
I imagine it is cool overnight, so you may be able to rig up a phase change material behind the panels to act as a heat sink and keep them cooler for some time. This would be a passive process so no parasitic losses. I imagine an active cooling system will be difficult to justify. Another passive approach would be to try to augment airflow for cooling by creating a chimney effect?
Vicky_BR
Member
dbindoff: Yes, I was thinking to take an advantage of the coldness at night! But, was not sure how much I can retain (the cooling) when the sun shows-up. I wonder if I can do something to let them remain cool, as long as I can! Or maybe use that cooling to generate some mist to nurture a plant underneath.
Benny: They are tracking the sun. You mean moving the panels reduces the dust deposits?
I'd rather suggest to solar panel with suitably rated solar controller. All solar energy panel no matter the size should use a solar controller. Solar controller regulates the voltage that is been fed to the battery. Ensuring against over charge as well as over discharge that can occur during the night that will help it to cool down faster. I got a solar panel that has a suitable controller too.
Here is the link: http://www.mrpositive.co.nz/projecta-12v-5w-400ma-amorphous-solar-panel/
Benny
Member
No I don't think normal tracking will help keep the dust off - I was just wondering how flat they were as the flatter they are the more they will collect. Perhaps the tracking controller could be specially programmed to tip the panels up as vertically as possible overnight to help the dust fall off - maybe even upside down ?
I think there are some electrostatic methods of getting dust off surfaces, but this might need a conductive film over the glass which would reduce the incident radiation.
I like dbindoffs idea of a phase change material attached to the back. Can you do calculations involving thermal capacity, latent heat, etc ?
Perhaps you could get some benefit from active cooling just with a fan ? You'd have to look at the trade-off - how much power the fan uses vs how much extra you get from the panels as they run cooler. Do you have any data at present e.g. what is air temp and what is temp on back of panels ?
johnmath
Member
Benny said:
I think there are some electrostatic methods of getting dust off surfaces, but this might need a conductive film over the glass which would reduce the incident radiation.
Brilliant Benny. Electrostatic dust protection has been developed to keep the dust of PVs on Mars, which has must drier dust than desert dust on Earth.
http://www.technologyreview.com/news/420524/self-cleaning-solar-panels/
Baldrick
Member
Many manufactures already coat the glass with special dust resistant coatings, this is one of the reasons why they tell you not to use detergent for cleaning.
I was at first dubious about the claims but I'm now convinced.
So contact the manufacturers of the panels about how good they are.
