Does Anyone Recommend Solar Panel Cleaning When Installing?

[Worcester]

And I bet your window cleaner has to do three passes to actual cleam them including rinsing.

There are good reasons why commercial window cleaning companies moved over to using #pure# water without dissolved solids - typically in our location the tap water runs at 280 - 300 ppm of Total Dissolved Solids, whereas a #pure# water systems will reduce that down to less than 5 ppm easily, and most will get down to a TDS of 000 - TDS of 000 removes bird s**t without scrubbing, without detergents, hence when cleaning panels is quicker, safer (no ladders, don't have to get up close), and more cost effective.

All Spots and Streaks are the residue from the Total Dissolved Solids (Dirt and Minerals) in the water when using 'tap' water, you just don't get those with #pure# water - You get a cleaner panel with less work.

How does it work,and why don't you need detergents?
When all of the dissolved solids have been removed from the water, it readily takes up more, so it actually dissolves the dirt and streaks on the panels. - Think of it a bit like water held in air, dry the air and any water around will evaporate much more quickly.

So two reasons to not use normal water and soap:
1) You will leave residues behind, however well you rinse.
2) It's slower and more costly.

 

[Worcester]

Here's a pretty comprehensive explanation from an Australian company:

See the original article here: Understanding Pure Water

Understanding Pure Water

TDS : TDS stands for ‘Total Dissolved Solids’. As pure water evaporates spot-free, any mark left on the glass when the water dries, is caused by the solids that were ‘dissolved’ in that water. So .. the TDS measures the amount of solids in the water, or in practical terms, the size of the spot once the water dries.

UK SYSTEMS : Pure Water for window cleaning was ‘discovered’ by Ionics in the UK. There, the water ranges from TDS 200 - 500. The marks left by their tap water (similar to Perth) are intolerable both commercially or domestically. The Ionics Systems are made in the UK mostly for these water conditions. The reality is that Australian water is so much better, that their systems are over-engineered for our conditions. Starting at TDS 80, we only need to remove half the TDS to get a Spot-Free finish.

SPOT-FREE : The Human Eye cannot see the spot left by TDS 50. This is easily proved. So ... getting the result below 50 will deliver a Spot-Free finish. In Sydney and Melbourne, with Tap Water now at TDS 80 and below (thanks to De-Salination plants etc), the use of Pure Water is not even necessary on many sites. Many Australian Window Cleaners are using Tap Water and Reach-IT poles without even a Se-Ca-DI.

TDS ‘000’ : TDS 000 means all the minerals have been removed from the water. This leaves the water in a different configuration to any other water. At TDS 000, water becomes an aggressive cleaning agent - desperate for something to be dissolved in it ! You see .. water wants to be dirty ... to get an idea, stir a teaspoon of fine dirt into a cup of coffee, and you will see the power of water to take solids into solution. So ... this means that, even the Tap Water style window cleaners in Sydney and Melbourne can benefit from a Se-Ca-DI Pure Water System - there is always a time when you will need Pure Water.

WINDOW CLEANING EXPLAINED : Window Cleaning (regular) involves only 2 steps - Agitation, and Removal. Traditionally, we agititate with an Applicator - this ‘stirs’ (dissolves) the dirt (solids) into solution. Then we remove the dirty water with a squeegee, working from the top edge down. The detergent has little to do with the cleaning process (other than greasy finger prints) .. it is really in the water as a surfactant to enable the squeegee rubber to glide over the glass. Cleaning with Pure Water is exactly the same but with different tools. The brush bristles do the job of the applicator and ‘stir’ the dirt into solution, while the jets of the brush do the job of the squeegee, starting at the top, working the dirty water off the glass. Done properly, all the dirty water is ‘chased’ off the glass, leaving only spot-free water to dry. As with the squeegee, if you miss any of the dirty water, it will dry leaving the dissolved solids on the glass.

 

[Gavin A]

load of marketing tosh though isn't it.

how long would it take for someone who's washing their panels once or twice a year with tap water to get any noticeable build up from these dissolved solids?

280-300ppm is 0.03% dissolved solid, so of the residual water that's left on the panel after the bulk of it has run off, only 0.03% of that is actually this dissolved solid that everyone's concerned about, and this will then have a years worth of rain washing over it to dissolve into and wash away.

it's complete marketing rubbish for most situations as far as I can see, unless they're planning to wash the panels every week or something. Maybe you could just about make out some form of blemish on a window, but it's going to have negligible impact on panel output.

 

[Silly Sausage]

Interesting stuff.
Looked up water for Manchester and we're getting about 12ppm (Ca), 30ppm (CaCO3), very soft.
But we mostly get fresh Lake District water, non of that foul stuff down south that puts scum on your tea!

 

[Solar Steve]

load of marketing tosh though isn't it.

how long would it take for someone who's washing their panels once or twice a year with tap water to get any noticeable build up from these dissolved solids?

280-300ppm is 0.03% dissolved solid, so of the residual water that's left on the panel after the bulk of it has run off, only 0.03% of that is actually this dissolved solid that everyone's concerned about, and this will then have a years worth of rain washing over it to dissolve into and wash away.

it's complete marketing rubbish for most situations as far as I can see, unless they're planning to wash the panels every week or something. Maybe you could just about make out some form of blemish on a window, but it's going to have negligible impact on panel output.

Assuming you have solar panels, why not go out and try to clean them with tap water? You'll soon see why tap water is not recommended. The white streaks left behind create shading and act as a base for future dirt to stick to. Dirt attracts more dirt, so your panels will get dirtier faster than your next door neighbour who has their panels cleaned by us.

 

[jason121]

I cleaned my panels around 4 weeks ago and has made no difference to the output. They are on micro inverters Maybe they didn't need cleaning

 

[Worcester]

Hi Steve

Did I miss it? DO you have the two week results of the back to back clean vs dirty test you talked about?

Can we compare hour by hour?

I know that there is a benefit, to quantify would be ideal.

 

[Solar Steve]

Hi Steve

Did I miss it? DO you have the two week results of the back to back clean vs dirty test you talked about?

Can we compare hour by hour?

I know that there is a benefit, to quantify would be ideal.

I don't have any more results at the moment, no. We are too busy cleaning the panels at this time of year to be focussed on increases in output. It is generally something I try to pursue in winter when I have a bit more time for it. We have cleaned over 105,000 in less than 1 year, many of which are repeat customers, so someone out there recognises the benefits.

 

[Gavin A]

Assuming you have solar panels, why not go out and try to clean them with tap water? You'll soon see why tap water is not recommended. The white streaks left behind create shading and act as a base for future dirt to stick to. Dirt attracts more dirt, so your panels will get dirtier faster than your next door neighbour who has their panels cleaned by us.

I've got a set up on a low porch roof, so I may just do that. Cleaned them with a hose a few times when we first got them, actually I was investigating the impact of the temperature reduction on the panels at one stage so they had a fair amount of tap water sprayed on them, and I don't remember seeing anything from it. We have a window overlooking them as well, so I should have noticed.

I'm currently using them as a test for how well the self cleaning works though, as we get wood pigeons literally crapping on them from a great height (ie the eaves above), and it's fairly amazing how the stuff seems to get almost entirely washed off even after being baked on, with just a very thin layer of residue remaining.

They're approching their 4th birthday on an 8 degree slope with regular soiling from above, and no cleaning at all since early 2011, tap water cleaning prior to that, and had their best years performance last year.

 

[Worcester]

We had our velux roof lights (we've got 10 of them on our house !) cleaned with the 'pure' water system, back at the beginning of March, previously we had just washed then the normal way. - They are still spotless today even after all the weather we've had since then, in previous years we were already thinking about when to clean them.

So I can definitely say it is better than cleaning with ordinary water. - We won't be going back to using ordinary water again.

What the financial benefit is on increased output vs the cost of cleaning the panels is still up for debate.

 

[Gavin A]

What the financial benefit is on increased output vs the cost of cleaning the panels is still up for debate.

that's the point I'm making as well, not that I'm disputing that cleaning with distilled water is better, or that cleaning them every 6 months wouldn't result in some level of improvement, just what's the point at which the benefits justify the costs.

 

[dansk]

It would be nice if Solar Steve pointed some of his clients to this thread for them to provide real life input. Im not in this game anymore but i am curious about the benefits of washing them on a large scale.

 

[Silly Sausage]

It would be nice if Solar Steve pointed some of his clients to this thread for them to provide real life input. Im not in this game anymore but i am curious about the benefits of washing them on a large scale.

More chance of a politician telling the truth!
Annoys me, people who make claims about something and won't provide any evidence to back it up.