Many houses 'round ere are having solar panels fitted. Usually 5 panels on one roof surface. Just a few questions for interest sake...
What would be the expected "peak" output power be? (Sun shining onto new panels)?
Presumable (I could be wrong) the DC from the cells needs to be converted to AC for houshold main use by an inverter. How does the sync happen between the phase of the incoming mains and the inverter output?
Does the switch to solar power happen on a regular basis driven by the available power from the panels?
Do the solar panels need cleaning and if so how? Hose pipe won't spray that high :-)
Do the roof timbers have to be strengthened for the extra weight of the panels.
How are the panels actually fitted to the roof. Are tiles removed for fixing? Or are the drilled though?
Panels are actually rated by their peak output, and are typically in the range 100 to 260 Wp
The inverter is required to monitor the mains voltage and phase. Its control electronics takes care of it. There are mandatory requirements to be met by any installation connected to the incoming supply.
The panels will produce an output voltage whenever enough light falls on them. As soon as the output is sufficient, then the inverter turns on and produces ac output. This continuously varies.
Formal instructions say that they should be cleaned periodically. How necessary this is may depend upon the location and the nature of any contamination.
I guess that, as the number of installations increases, there will probably be firms appearing who will do this for a fee.
Not necessarily. However it would be prudent to get a written waiver from building control. I required my installer to take care of this.
OTOH a friend discovered his roof timbers had warped and were no longer properly supporting the roof weight. This required professional assistance and the addition of reinforcing steelwork.
Depends a little on the exact design of your roof. In my case the tiles were simply slid upwards to enable the stainless steel brackets to be secured to the roof timbers. The tiles are then returned to their original position. Mounting rails are fastened to these brackets, and the panels then bolt onto the mounting rails.
There is a great deal of information on the web, with photos, videos, output predictions and so forth.
And of course if taking up the special offers you are restricted to a certain number of panels and that is it, unlike, it appears Australia and France, the latter where every seemingly available bit of space on farms has solar panels on them. Brian
That is the incident radiation. Allowing for the efficiency of the typical panel the electricity out tends to be around 20% or lower if they get dirty (and much lower if some are partially shaded).
It is interesting that in winter the cold makes the conversion efficiency higher so that output in full sunshine is not so bad. One or two folk with solar PV arrays also provide data of the output eg.
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means in winter the sun doesn't get very high above the horizon or for very long so both ways you lose incident power.
Only by the amount of power they generate surely?
Perhaps you would care to enlighten us how you would drill a tile with a squirty foam gun? ;-)
Pictures of the actual installation instrumented above are at:
winter sun can be strong as any photographer knows who had to set a manual camera from a lightmeter. trouble is not for long and not very often either.
I am tempted to say that you wouldn't then get paid at all;-)
But no, I think you will find that in certain cases you get paid what they are estimated to have generated etc etc.
Thats all wrong. A house in our street has got one on a North East facing roof as any fuleno the earth is going to have a FIT and change its orientation;!...
Ta all. The GTI you mention is interesting. Senses phase to within 1 deg I see. Also a disconnect feature to protect line-repair men should there be a blackout - i.e to protect them from the inverter(s) output still being up. Being electrocuted by the Sun is a right bugger :-)
The inertors don't have a means on ensuring that their output doesn't get fed back up the supply. Two reasons you don't want to fry someone working on the line repairing the fault and the poor little few kilowatt invertor won't like trying to power all your neighbours...
Surely it's possible to design an inverter / switch / thingy that will allow AC into the house's mains but not back into the outside world in that case?
How significant is the power available from the PV during a power cut? We're talking about deriving an emergency supply so a couple of kWhr is all that's needed to keep some IT going, a few lights and run the central heating, storing more is unnecessary and of course some of it will be used in real time when the PV is generating.
What do we need? Laptop ~11W how long? 4hrs/day? Lights 60W for 12 hrs/day
Central Heating 300W 4hrs/day?
TV 150W for a couple of hours?
That's just under 2.5kWhrs not allowing for efficiency of conversion and probably a few thousand quid in deep discharge battery but only
200 quid for a couple of lorry batteries. Power matching from the DC bus would be a problem unless you had about 15 12V batteries in series. How much can you store in a 95Ahr battery before it drops into the danger zone of 11V??
How much can be guaranteed from a PV installation on a dull December day? It's
At powercut your desktop will crash and may damage the hard disk
- UPS solves that.
i think a car battery is 40 amp hours,
12 volt * 40 AH = 480 watt hours. Laptop and router = 60 watts? so thats theoreticallys 8 hours (but that could kill the car battery)! and a lightbulb?
I have a small solar panel charging a car battery, independently of the big Solar panels.
Should have maintained battery backup emergency lights anyhow. And a petrol generator? [g]
I've suffered some power cuts at work from lightning strike and my desktop hdd hasn't apparently suffered.
OK mine is a diesel and rated at 95Ah
but you have killed the battery, or significantly reduced its life, by then which is why I specified no discharge below 11V my guess is this means you have less than 50% rated capacity available.
Yup I forgot the router
In fact I can do an awful lot of computer work off my android and still get 3 hours between charges, via the car socket.
I can see a whole new get-out clause for Insurance companies in the future, you lost your roof in a storm Sir ... did you get a structural engineer calculate loading of those panels .... no .... next please.
I've got a 2.98kWp array on the roof. Installed about 10th December, it had generated 107kWh by 31st Jan, I seem to recall it peaking on a sunny day late in December at about 600W output. Have regularly seen 2.1kW peak output in recent weeks.
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