snow efficiency and my new PV panels

[jmp101]

I have just got my 2.1 kw PV panels installed by Sam Walters (Solar Sam) a Navitron fitter based in Somerset who did a faultless installation and was very neat.

As you can see from the picture attached - they are covered in snow! but still generating 33 watts! Sam has done a good job fitting the design around the solar hot water panels.

Talking about efficiency, a near neighbour has 3.0 kw system installed a few years ago. Although he has higher efficiency panels,  on the same day he generated 2.9 kwh and I generated 3.71 kwh (Nov - some cloud in afternoon). That's a big difference. I think the reason is:

a) The Navitron Polycrystaline Silicone panels work better in lower light than the higher efficiency silicon ones.
b) New panels are more efficient not only because of technology improvements - but also they are cleaner! So clean panels.

If you want to see more details about the house and eco features my blog site http://www.mysiphouse.com has details. I'll post about the panels soon, but there is a  Navitron Solar hotwater system, SIP panels plus other energy saving ideas (the best being an energy saving shower head that I think Navitron should sell as it saves as much as the solar tubes but cost £30 and took 5 minutes to fit).

Jonathan

[Billy]

I have been wondering about dirt on the panels for some time.  A friend has seagull problems on his south facing roof.  He declined having pv as it would have been virtually impossible to clean them without a large cherry picker owing to a conservatory being in the way.  Even without birds I find an awful lot of dust/soot/muck settles on my tubes and roof.  It would be interesting to compare the outputs of the same panels in a clean and dirty state.  I wonder how many are up on the roof desnowing or even if it is possible.

Billy

 

[StBarnabas]

A bit more snow in Northumberland




Only generating c 50W at present

[guydewdney]

Interesting - my mum is building a SIP house in somerset - I've emailed her your blog - if you don't mind - where are you, if she wants to visit? Shes near Brissol airport...

Guy

[jmp101]

Yes she will be welcome to visit. I have had a lot of people visit who are also interested in SIP houses.

Jonathan

[Justme]

the best being an energy saving shower head that I think Navitron should sell as it saves as much as the solar tubes but cost £30 and took 5 minutes to fit.

Jonathan

They are often being given away by various online sources. The last one was from http://www.waterwidget.co.uk/ & the offer is still on.

Whilst talking freebies there is also a remote controlled standby killer avaliable HERE

[skyewright]

Getting back to the original title of the topic...

Normally our panels don't suffer shade effects, but I think the snow is demonstrating them quiet dramatically!

I have one "string" of 8 panels and just below that another string of 9 panels.

The snow has slid off the bottom string and that has been generating fine when the sun has been out.

The top string is mainly clear, but there is a stubborn strip of snow sat along the bottom 20% of the panels (presumably held back by the slight discontinuity between the rows of panels).

The top string row is generating less than 10% as much as the bottom string.

I'm hoping that difference is just the "partial shade" effect, and not that the snow & frost has got to something...

[StBarnabas]

I'm hoping that difference is just the "partial shade" effect, and not that the snow & frost has got to something...

You'll be fine. My array goes totally to pot when there is even partial snow covering. Was only getting about 150W today when normally I would be getting at least 1.5kW

[EccentricAnomaly]

These amorphous panels were producing just under 50% (of their unshaded output in low sun) when about half shaded: http://www.navitron.org.uk/forum/index.php/topic,9397.0.html.

Will get them set up again soon if I can work out how to get a cable in without drilling holes in a rented house.

[mikey9]

How's this for a run of three days production from 3kWp!

0.01 kW/h
0.00 kW/h
0.00 kW/h (today)

The self cleaning effect of 4 inches of snow occurred about 2pm today - then it snowed some more - then got dark.......

[marshman]

Fortunately  I can get to clean my panels. Yesterday morning had a good covering of snow and was producing around 40W from a 3kWpk system. After sweeping off the snow I was getting around 250W in the same overcast conditions. Total output for the day was - wait for it - 0.7kWh. Today it was 1.0kWh - though it did snow again late morning and I couldn't be bothered to get the ladder out again!

Roger

[biff]

i have a long reach wiperblade type scraper which does not scratch the panels,a few wipes and the difference is immediate. however about 3pm the temp dropped and ice formed on the surface of the panels,so i had to leave it be.
       the quicker the snow is removed the quicker it goes onto full output.im not looking forward to this freeze, the last time we had a deep freeze,(12 below) the batteries refused to take or give the charge for 3 days, thankfully i found out from navitron that all would be well when the thaw arrived and so it was,everything returned to normal.
                             biff

[wookey]

Down here in sunny-but-cold cambridge we got 4.7kWh today, which is quite respectable for end november.

[Outtasight]

I did ok yesterday when the snow was melting and I could scrape it off with my telescopic window cleaner (made 385Wh in gloomy weather) but today it snowed relentlessly and was sub-zero the whole day and dark too.  I scraped the snow repeatedly off the panels I could get to easily (the garage roof was now out of bounds) and only managed a feeble 76Wh today.  Just about enough for watching the weather forecast on the news and charging my mobile phone!

Eccentric, I had loads of those plastic framed amorphous panels from Maplins.  They're pants.  I've sold all but two of them, as they often break.  I kept two (stupidly for some "sentimental" reason) and one broke the other week again.  I took it to bits and discovered why.  They've got bad terminal strips on the glass laminate that has a strong copper wire soldered on the patch.  Thermal expansion and contraction over time causes the copper track pad to be pulled by the wire (which is immobile as it's set in glue) and the the pad cracks and comes away from the glass.  The whole module then goes open circuit (you might see some leakage current: 22V at something close to zero mA output).  Get rid of them while they still work, is my advice (or keep them in a temperature controlled environment, preferably not exposed to direct sunlight ). 

The eight aluminium framed "12W" ones I have from the same "Topray" Chinese maker are all still working though.

[skyewright]

I'm hoping that difference is just the "partial shade" effect, and not that the snow & frost has got to something...

You'll be fine. My array goes totally to pot when there is even partial snow covering. Was only getting about 150W today when normally I would be getting at least 1.5kW

Both strings were fully clear today and behaving quite normally. Phew!