Will Cool Water Break Hot Solar Panels?

I can offer this anecdotal observation: without worrying about the concern you raise, I hosed off my new Andalay 175W panels (24 of them) during the heat of the day, in direct sunlight (~3 pm) to remove the ash from the recent fires here in Santa Barbara. Although steam appeared and the panel surfaces dried in moments, none broke. The Pac reading went from ~2.8kW to 3.1kW after rinsing. Come to think of it, I have done the same thing to the two 75W Siemens panels on my boat - without damage.

in research : i asked this question :

was told that periodic cleaning of the panels was essential for optimum operation.

got that from 3 or 4 manufactures here in Calif.

both from flexable and " rigid " panel makers..

don't own any , yet..

So all i can contribute is a rumor

my two cents

Ahua and Hogdmo,

Thanks for your replies. I agree with both of you. I guess I just needed some positive reinforcement. I'm still doing research on how best to water cool my 36 panels (6kw). I'm still leaning towards using the landscape type mini-sprayers.

Hogdmo: I hope you make out OK with those wildfires. I can kinda identify with the situation. I'm a retired firefighter from New Orleans.

Any further comments concerning the glass panels, water cooling systems, etc. will be much appreciated. From what I've read, cooling increases the panel efficiency as well as their life expectancy.

Thanks again,

Don

Just a thought, but, you might ask your insurance carrier what they do and don't cover.

Does the manufacturer warrant them against rain damage?

My non-expert opinion is that no solar panel manufacturer is going to sell an outdoor device that can't withstand the outdoors.

Water and hot glass generally don't mix BUT what is the purpose of mixing the two.

If you want to wash - water wash after 8pm and before 8am...

If you want to cool the unit for some reason use the finest spray nozzle you can afford and provide adequate pressure to MIST or fine spray (1mm droplet dia)...If the unit is very hot...fine spray will vaporize before it contacts the glass BUT cool the air layer over the glass...once it doesn't vaporize the glass will be cool enough to not have any problems and the droplets will then wash the surface...

YankeeFlasher

There shouldn't be an issue with slowly cooling the panels. They are made to withstand temperature extremes... just not rapid changes. I fine mist will slowly cool the panels, a bucket of ice-water will break them.

Hello Don in LA,

No problems with 'long posts'! Can I assume you are talking of direct sun/electronic solar panels?

Just a point here..........They are designed to withstand 'cold' rain, so I would think it would be OK to use a sprinkle system on them?

You may have said and I missed it, can you tell me what the name of the solar panels is please? I can then find more info'. Have you tried getting in touch with the manufacturers?

bb

Babybear,

Thanks for your reply and ideas. Yes, I am speaking of direct sun photo voltaic solar panels. The manufacturer is Solar World. I did check with another manufacturer some time back before my installer suggested going with Solar World. The original manufacturer told me on the telephone not to cool with water because the cold water could break the panels. In its brochure, Solar World writes that panels can be cleaned "with lots of water". No mention of time of day and temperature. Of course, I should have read the brochure first. I will call Solar World on Monday. If I do use water I will use as fine a spray as possible that can throw water 15 feet (3 panels high). I have read several reports that say, depending on temperature, the PV panel can loose 10% efficiency or more due to elevated temperatures. Thanks again. I welcome any more suggestions/comments.

FWI: My state, Louisiana, is paying for half of my PV system. And the federal government is paying another 30%. Both are through tax rebates/credits. I've read that some European countries also have some very good enticements.

Don

I am considering putting something like the aluminum heat radiators they use with pex tubing under floors and attach them to the back of solar panels.

The heat can be used for pre-heating domestic hot water, and if you have a relatively large tank (450 gal 'totes' are readily available in this area, roughly 4' cubes with large plastic vessle covered by an aluminum cage that is fork truckable) and use a small pump to pump water through the pex placed on the back of panels to cool them.

It doesn't fix the issue of cleaning the front surface, but can cool the panels and help increase productivity of some cells.

Is it enough to make a difference? I have no idea, but if you want to ALSO collect low quality hot water, it shounds reasonable to me.

That sounds like a good idea using the aluminum heat radiators. It's something I would consider if my panels weren't already installed. I guess I should have done more research before. One thing I did have the foresight to do was to pay to have a heat collector installed with my HVAC heat pump. It basically collects the heat generated by the running of the HVAC and pumps it to my water heater. It provides hot water as long as the HVAC is used. We get enough rain here to keep the panels clean most of the time. There are times when pine pollen will be a problem.

Don

Hello servant74,

I built a row of south facing ordinary radiators painted black, and encased in plexiglass.

With the whole thing heating a swimming pool. It was very successful. Everything was second-hand, and it really did work well. And it was in Europe about the same latitude as London. It was a tennis court sized pool outside.

bb

Presumably the panels will be constructed so as to minimise the effect of damage to things falling on them:

• leaves
• twigs
• rain droplets
• snow
• hailstones
• etc.

won't they?

Yea, I guess the key word is "minimize". I've read several different company's instructions and, basically, they say to not use water on hot panels. I still wonder if it is just a case of CYA. If anyone out there has had good or bad experiences with this please let me know. There was one reply by someone in California (Sorry, I don't remember your name) who said he hosed his panels off in the heat of the day with no problems.

Another option would be to cool the underside of the panels with evaporative cooling via a mist on the roof under the panels, not directly on the panels. Any ideas?

If they are designed for outdoor installation and use in that area, then the CYA factor sounds like it is pretty high. I agree, don't throw ice water on them, but if you would be comfortable putting your hand or foot in it, it is probably OK.

Hi, Really a long but a very informative post! Please provide more details on Solar Panel systems!