So now I have a solar PV system how do I make the most of it???

don0301

EricMears wrote: »

I'm afraid all that proves is that you didn't understand the point the first time round and still don't.

I am of course well aware of the 200mm overall limit having read the relevant planning advice before commissioning my own installation. But that doesn't mean you're allowed to increase the height of your panels by 200mm. I couldn't possibly estimate by how much you are entitled to move your panels without knowing the details of your panel thickness and type of brackets and made it quite clear that the 100mm was an approximation.

Actually, you weren't well aware of the limit

EricMears wrote: »

For absolute maximum performance, you need panels mounted on a steerable array where the thing points Eastward (or thereabouts) at dawn & slews round to Westward at dusk. Panel inclination also changes from steep at dawn to shallower at noon & back to steep at dusk and of course the inclination at noon would be around 75deg in Dec and 30deg in June (depending on exact latitude of course). One such array would be a 'permitted development' but the multiple ones you'd want for a full 4kwp would require planning permission.

It sounds an attractive idea to jack up the top of your roof mounted array in the winter and lower it in summer. However, the permitted development rules only apply to panels fitted a small distance (off the top of my head I think its 100mm) above the existing roof surface and anything else would require planning permission. Two other snags are that having panels at an angle to the roof surface would increase wind resistance so you'd very likely lose them in a winter gale and if you tried to minimise that effect by tilting panels individually they'd probably shade each other.

I'm sorry it inconveniences you that i stated the actual distance, for anyone actually wanted to learn something true.

Where on earth did i say anything about increasing my panels by a height of 200mm???

EricMears

don0301 wrote: »

...various gibberish....

The subject of this thread is "So now I have a solar PV system how do I make the most of it???" This harping on about a few mms of panel clearance has nothing whatsoever to do with that.

I think the rest of the group have made it pretty clear that they have no interest in your query and would prefer you to stop nit-picking over minor details.

don0301

EricMears wrote: »

The subject of this thread is "So now I have a solar PV system how do I make the most of it???" This harping on about a few mms of panel clearance has nothing whatsover to do with that.

I think the rest of the group have made it pretty clear that they have no interest in your query and would prefer you to stop nit-picking over minor details.

I'm sorry my fact disagreed with your minor details....

I'm sure the rest of the group (other than Doc N and Larkim app) want to know facts.....

The_Green_Hornet

I have come across this company's web site which is claiming that they can redirect excess solar power generation to your immersion heater to heat up your hot water.

http://www.engensa.com/solar24/

I will leave it up to the reader to decide whether it is fact or fiction.

John_Pierpoint

Technically it is doable, if an inverter can track the mains, then presumably another gizmo can track the spare exported electricity. I would guess it "dims" the immersion by messing about with getting the amps and volts out of phase?

However it will be just another bit of kit to go wrong, with the added risk that it might unsettle the inverter?

Is it worth it to save a possible £1a week, when a more simple method of counting flashes and putting juice into a 1kW immersion might say save 75p a week. Don't forget clever metering is coming and the cost of heating a tank of water might well fall in the middle of the night.

I think it is just a method of attracting more interest to the web site - the post 3rd March price for 3 - 4 kWp system appears now to be in the £7 - 8k range.

I also noticed the number of punters who now have largely redundant solar thermal panels on their roof, as I clicked through their gallery of installations.

John_Pierpoint

Kernel_Sanders wrote: »

When this happens to my array (we get wood pigeons mainly) I intend using a soft bristle such as a car cleaning brush, dipped in a solution of hot water with copious amounts of washing-up liquid.
Any comments, anybody?

I think that is what I will do too, but there is an opinion in teh car wash business that says washing up liquid contains traces of salt??? So one should use special car wash liquid ?

sly_dog_jonah

The_Green_Hornet wrote: »

I have come across this company's web site which is claiming that they can redirect excess solar power generation to your immersion heater to heat up your hot water.

http://www.engensa.com/solar24/

I will leave it up to the reader to decide whether it is fact or fiction.

Unfortunately most companies peddling these claims shout very loudly about the benefits (usually over-stated) but aren't at all open about the costs and limitations of such a system. Some go to the expense of a Royal Mail 'To the occupier' advertising campaign, let don't update their website with any information about their product. See this thread for one such example. However in this instance the site's FAQs do give some insight into how the device works. It appears to be use multiple current taps to measure consumption and export, but as has been discussed at some length on this thread the ability to measure export depends on how the household and PV wiring is physically arranged. By regulating the voltage delivered to the immersion, the device allows existing 3kW immersions to be used at less than full power. This is quite different to switching devices where the immersion is either on of off.

The Engensa website claims that the typical export is 50% of generation, whereas most users on here will point out that import savings are typically only 25%. Unless your overall consumption has dramatically changed since getting PV installed, that therefore means that on average you'll be exporting 75% of your generation (since you're only using 25%). A water cylinder only has a finite capacity to store energy (due to thermostats which keep the water under a maximum safe temperature) therefore no such system can completely eliminate export.

One of the few products whose price is fairly transparent is the EMMA device which at an installed cost of well in excess of £1k is unlikely to be a sensible investment for a domestic installations.

Rudge Renewables also have a much cheaper but more basic device (~£300) which can be used to automatically turn an immersion on and off depending on the current PV output (using a threshold defined by the homeowner). But even that device has it's limitations which I've discussed previously in this thread. I emailed them to ask how easy it would be to address some of the limations several weeks ago, but no response yet (they must have been busy in the run up to the March 3rd deadline).

Over the weekend I finally tracked down the 'Ignore User' function on the forum and it's had a dramatic effect on the signal-to-noise ratio on this thread (and others). Might I suggest you follow these steps:

1. Click on a Username>View Public Profile.
2. Then under their username you'll see Users list>Add to Ignore List.

This will then collapse all posts by that user, but not quotes from that user. Hopefully the more people that choose to ignore such user(s), the fewer quotes we'll see. If you want to, you can expand their posts easily by clicking View Post, if only to confirm they are still worth ignoring.

Fabulous clear day in cider country this morning, our SSE panels were kicking out over 1kW by 0715 and now 2.2kW at 0830. They've already generated 2kWh. At this rate I think this could be a new record day (we've not had a clear start to the day in weeks).

Edit: In their Press Release (Dated 3rd March), they say the system is available 'from £250' http://www.engensa.com/blog/solar-power-news/engensa-launches-solar24/

EricMears

sly_dog_jonah wrote: »

Unfortunately most companies peddling these claims shout very loudly about the benefits (usually over-stated) but aren't at all open about the costs and limitations of such a system.

.........

Unless your overall consumption has dramatically changed since getting PV installed . . .

...............

Over the weekend I finally tracked down the 'Ignore User' function on the forum and it's had a dramatic effect on the signal-to-noise ratio on this thread (and others). Might I suggest you follow these steps:

1. Click on a Username>View Public Profile.
2. Then under their username you'll see Users list>Add to Ignore List.

This will then collapse all posts by that user, but not quotes from that user. Hopefully the more people that choose to ignore such user(s), the fewer quotes we'll see. If you want to, you can expand their posts easily by clicking View Post, if only to confirm they are still worth ignoring.

Fabulous clear day in cider country this morning, our SSE panels were kicking out over 1kW by 0715 and now 2.2kW at 0830. They've already generated 2kWh. At this rate I think this could be a new record day (we've not had a clear start to the day in weeks).

I think it's a pretty safe working rule that when a vendor doesn't make his prices clear there's always a reason for that and more often than not it's because you can do better elsewhere.

Works with market stalls, secondhand cars and a host of other things.


I hope my usage pattern will have changed since panels were installed. Small things like running a 500w kettle for 12 mins rather than a 3 kw kettle for 2m (which means that water for my cup of coffee costs nothing even when I'm only generating 1kw) should help as will doing washing at midday on a sunny day rather than 2am on E7

I'm only generating 1.5kw yet (true S facing, shallow pitch) but that should accelerate over next hour or two and will of course keep generating something till dusk.

The_Green_Hornet

sly_dog_jonah wrote: »

Over the weekend I finally tracked down the 'Ignore User' function on the forum and it's had a dramatic effect on the signal-to-noise ratio on this thread (and others). Might I suggest you follow these steps:

1. Click on a Username>View Public Profile.
2. Then under their username you'll see Users list>Add to Ignore List.

This will then collapse all posts by that user, but not quotes from that user. Hopefully the more people that choose to ignore such user(s), the fewer quotes we'll see. If you want to, you can expand their posts easily by clicking View Post, if only to confirm they are still worth ignoring.

Brilliant! I no longer have to read the comments of one particular annoying poster who regularly regurgitates his [STRIKE]anti-Solar PV[/STRIKE] anti-FIT rhetoric day in day out.

sly_dog_jonah

EricMears wrote: »

I think it's a pretty safe working rule that when a vendor doesn't make his prices clear there's always a reason for that and more often than not it's because you can do better elsewhere.

Works with market stalls, secondhand cars and a host of other things.

Yes all valid points, but I do understand why some companies will want to keep pricing info off their website as this will encourage cowboys/competitors to undercut slightly, yet the service from the company may differ dramatically. I may give them a call though to find out whether they will disclose the price without requiring a 'sales consultation'.

EDIT: found their pricing info 'From £250' http://www.engensa.com/blog/solar-power-news/engensa-launches-solar24/ I've updated my previous posting as well. At that price it's quite competitive with the Rudge Renewables device.

I hope my usage pattern will have changed since panels were installed. Small things like running a 500w kettle for 12 mins rather than a 3 kw kettle for 2m (which means that water for my cup of coffee costs nothing even when I'm only generating 1kw) should help as will doing washing at midday on a sunny day rather than 2am on E7

I'm only generating 1.5kw yet (true S facing, shallow pitch) but that should accelerate over next hour or two and will of course keep generating something till dusk.

Indeed, in which case your import savings will be higher than average. However your overall consumption of kWh in the kettle example above is the same, you're just skewing it in favour of using generated instead of imported power. Replacing appliances/bulbs/etc with more efficient versions or reducing usage will deliver consumption savings which will again improve your import:export ratio (as more of your electricity consumption will be covered by the panel's output, even on a poor day).

Of course if a household reduces consumption at the same time as getting a PV system, it makes it harder to estimate import:export ratio unless you can either accurately measure export or consumption in the home. That's because your import will have reduced due to both generation and consumption reduction.

We just broke through 3kW (3.7kWp system SSE facing at 45deg pitch) before 10AM. I may try to measure at what time the sun is perpendicular to the panels today. Of course this time will shift forward an hour later this month when the clocks move forward. It will be interesting to see where the peak output lies in relation to this, as the output will presumably increase as the sun continues to rise in the sky before midday, but also attenuate as the sun moves westward in relation to the panels.

Edit:
For our orientation (-36deg azimuth, or 144deg from magnetic north) and Lat/Long the sun was perpendicular to the panels around 10:15am this morning. (After 10am, but before 10:20am). The generation output has continued to rise since then as the sun gets higher in the sky. It's now outputting 3.6kW as of 11.15AM, and briefly exceeded 3.7kW when the sun just came back out from behind the sun (before dropping slightly as the panel temp increased I suspect). We just broke though 9kWh for the day so far, looking good for a new record (our previous pre-midday best was 9.6kWh).

I've double checked against this calculator and the azimuth angle was almost spot on at -35.85deg at 10:15AM today. Also useful to know our Solar Time here is 27mins behind GMT, so the sun will be due south at 12:27pm today. (as a side-note, this solar time doesn't stay offset to GMT by the same amount throughout the year)

As of today, the sun will be at an angle of elevation of just under 33deg in the sky at our Solar Noon. Since our panels are at 45deg inclination this is still sub-optimal. It looks like we'll hit 45deg elevation at Solar Noon on 5th April, and the sun will peak at 62deg elevation on the summer solstice. The sun will be perpendicular to the panels at 10:55AM (about 40mins later than now) on summer solstice, at an elevation of about 58deg. By contrast on the winter solstice the sun was only at 15deg at Solar Noon.

Apologies for going off on a number crunching tangent, but think you'll each enjoy having a play with that site too. I got Lat/Long from Google Maps: centre it on your house, then use the 'link' icon to extract the Lat/Long. Remember negative longitude is West of Greenwich, positive is East.