Mould on solar panels

[AHoy]

Hi everyone,

I have a solar hot water system and notcied today that there's a lot of mould on the solar panels. It's been a cold and wet winter in Melbourne so I guess it's built up over the past few months. I'm not too keen to get up on the slippery terracotta tiled roof to clean it, so was wondering if anyone knows whether the mould will be burnt off as the weather gets warmer or whether I will need to clean it otherwise it will affect the effeciency of the panel. Any advice appreciated.

Tony

[Brad]

Hi Tony
Got some moss on mine where the glass meets the frame, that will hose off easily or get burnt off with some decent sun. I would check that it is not leaking if you can get a Melbourne day without rain to check your down pipe for drips, ours gave out at 30 years old and was leaking into the rainwater tank.

[Andy_Mann]

@AHoy, if you're concerned about roof safety, then fit an eyebolt on the opposite wall to your solar panels, near the bottom (in the mortar would be fine). Attach one end of a long rope to the eye bolt, then hurl rest of it over the rooftop to the other side, & use a gadget like this:

http://www.ebay.com.au/itm/Mountaineering-Tree-Rock-Climbing-Rappelling-Rope-9-12mm-Grab-Protecta-Eq...

[Kermit]

I would think the heat in summer would be more than enough to burn it off. The roof is a dangerous place - leave it for the pros. 

[Andy_Mann]

At this time of year when the weather's getting milder, clean panels are a good thing. You're maximising their efficiency, when your own draw during the day is lessened, & you can trickle in some export credit to help offset your non-solar consumption.

[Isobel]

This page http://www.velocitysolar.com.au/blogs/how-to-clean-solar-panels-2/ says you should get a pro in. 

"... utensils may be needed that could cause issues with the panels if not used correctly.  Unfortunately moss and Lichen cause large amounts of shading to panels and can have a detrimental effect on the performance of the solar panels."

[Andy_Mann]

@Isobel I too have noticed that some solar companies do recommend pro cleaning only, but then, others don't.

I think if people are careful, & use some form of fall protection, then it's pretty straight forward & safe.

Here's a no-nonsense vid that shows how to do the clean, that part, I endorse, BUT wearing skateboard/tennis shoes as the only safety measure, is only appropriate for his particular (low profile, bitumenous shingle) roof. People need to take far more precautions on more typical rooves.

[Kermit]

On Whirlpool there's a long discussion about whether you should use any cleaning agent, and whether you should even use water from the tap, with some claiming that both can do damage to the panel. 

[Andy_Mann]

@Kermit, as with any topic, there're going to be extremes of opinion, & panel cleaning is no exception.

What's to follow, is just my thinking on the matter, & in no way a personal attack on anybody.

To me, solar panels are made to withstand harsh environments & need to be very tough, imagine the turmoil if there was a full on hailstorm, & everyone's panels got wrecked.

The precaution of washing them early morning, early evening to avoid thermal shock, makes a lot of sense. As a bonus, It there's less likelihood of smears being left on the glass.

I agree that cleaning agents need to be chosen with care, but a splash of dishwashing detergent in a bucket of water, won't do any damage & I can't see how it would. Rinsing it off after the clean is common sense, & using a squeegee to remove excess water will prevent smearing. To be doubling sure, wrap a slightly damp micro fibre cloth around the broom head & sweep the panels to remove micro-droplets (if there were any).

The only difference from washing a car windscreen, is that the panels are on the roof, which brings me to the point, who in their right mind would wash their car windscreen with an abrasive cleaner? There's a lot of hysteria out there, & scare mongering by professional panel cleaners, probably to put enough doubt in people's minds, to hire a pro.

[AHoy]

I ended up not doing anything in the winter. Wanted to see what would happen with some warmer weather. We've had a couple of hot days now and hopefully more to come so have my fingers crossed that the mould will burn off.