Could I use mirrors to improve Winter output in United Kingdom?

[SunEagle]

I cannot upload pictures that were uploaded more than once in past
years. I doubt the software has reduced the acceptable size. Bruce Roe

I guess it is time for our Admin to talk to the IT department and see why photos are hard to upload.

[bcroe]

I believe the forum software limits the size of the picture that can be attached. I have had to resize a picture in the past and I am afraid you will also need to find a way to get the picture small enough to be accepted.

I cannot upload pictures that were uploaded more than once in past
years. I doubt the software has reduced the acceptable size. Bruce Roe

[GodfreysGhost]

Hi J.P.M., I will be using two 4.8Kwhr Pylontech batteries in the beginning, and then add more as I need them.
I will be using MC4s, I said that I personally wouldn't be connecting one MC4 connector to another, all electrical work will be being done by my electrician, who is MCS certified. https://mcscertified.com/
He knows all about the electrical side of things and will be ensuring everything is compliant with any codes required in the U.K.

I'm not worried about getting the most power possible from the solar panels I've bought, because I know that to do that, I would have to spend more on an adjustable mounting system, and even then, it's impossible to get anything like the maximum possible output, because to do that each panel would have to have an automated tracker to follow the sun, and because each panel would be moving, each panel would have to be situated a certain distance from every other panel, in order not to cause shading, which would be worse in the Winter, and therefore I accept that any solar system is going to be a compromise. My current compromise is to get the largest Kw system I can fit into a small side part of my garden, for the lowest price. I didn't say that I believed all the loads on my system were downwards, I am very aware of lateral wind forces, and the upright poles I finally get will be more than strong enough - scaffold poles don't bend easily, otherwise scaffolding would be collapsing all over the planet, and I may go up to the size of scaffold poles for the uprights and horizontal poles.
Are you aware that plenty of solar farms use only ground screws? (Obviously much bigger than the ones I'm using.) https://www.youtube.com/watch?v=V5nezYeRZik
You have to bear in mind that the panels are going to run parallel to a five feet high hedge, and will be about five feet away from it (I am leaving just enough space for me to get through the gap and cut the hedge and the grass in the gap).
What sort of problems do you think could happen? It's no good telling me that I'm headed for problems without giving me a clue about what they are. I can't see an engineer coming up with a better solution than I've already suggested.
sdold - I can't see why those Short Tees are going to come apart because of wind forces on the panels, they are only going to be one panel high, 2.17m tall panel, with the top about 2.4m off the ground, with a five feet hedge right alongside it - and my back garden isn't on its own, there are about twenty more gardens either side, all with hedges, fences, buildings, etc.

Here are today's tests from my first panel, to give you an idea of how much it produces:
Canadian Solar 595w panel:
8th July 2022. Using an inclinometer, 2pm, full sun:
All angles from the horizontal:
90 degrees: 367w
80 degrees: 436w
70 degrees: 468w
60 degrees: 602w
50 degrees: 560w
40 degrees: 639w
30 degrees: 645w
20 degrees: 607w
0 degrees: 472w

So while the angle from the horizontal makes a difference, on a sunny day the panel is performing brilliantly. Since the panels aren't going to be tracking the sun, obviously for most of the day they will not be perpendicular to the sun, and not giving out the maximum amount, but panels are so cheap now that it's better to buy more panels and mount them as cheaply as possible, than spend even more money on adjustable mounts with fewer panels - which isn't going to magically produce the amount of electricity I need in the Winter, without sufficient number of panels.

I don't think it's rocket science to set up a perfectly good solar system - just lying the panel flat on the ground is giving me 472w per panel - times by 22 panels if I chose to just lay them on the ground. Just putting the panels straight up at 90 degrees from the ground still gives me 367w, and in the Winter that angle would be close to the optimum of 76 degrees in December. If we were talking about a 90% reduction in output for any of these angles, then I would agree that it would be vital to get somebody to design it all for me, but it isn't difficult - I know where the sun goes every day in relation to my garden, I wouldn't set the panels diagonally across my garden even if that would mean optimum output, because it would take up the entire garden, but as it happens I luckily don't have to do that, I am just making a long row going up the very side of the garden.

Having tested the panel multiple times in different weather, and seen exactly how much it pushes out at all sorts of angles, I know it's going to give out the most power possible doing exactly what I've planned already. If I found that it was giving out more power angled in a different direction, then I would consider that design, but luckily it doesn't.

I have no worries whatsoever about it all. The wind forces are not going to destroy the short tees, nor the U-bolts, nor the panels, unless it's a cyclone - which we don't get in the U.K. I'll get back to you in a few months' time when I've finally got my batteries and inverter(s), and set up the panels, and you'll see how much power is coming out of them. Just multiply the above figures by 22 for the best outputs on a sunny day - I'll probably be mounting the panels at 70 degrees from the horizontal, as I'm not expecting miracles in December. I am also probably going to put some more panels on my roof next year, to increase the potential Winter output even more.

[J.P.M.]

Hi J.P.M., we do have electrical codes, but I am hiring an electrician to do all of the wiring (literally everything electrical is going to be done by him, I'm not even going to be connecting one MC4 connector to another, I know how much power could be coming from these panels and I'm not going anywhere near that sort of thing), there isn't any review or approval process in the U.K. for off grid systems.
I came up with the 76 degree tilt from this website: Solar Angle Calculator | Solar Panel Angle Calculator (solarelectricityhandbook.com)
My garden slopes down from East to West, so I am aligning the panels straight up the slope, parallel to the hedge that forms the boundary between my and my neighbour's property to the left, I think it's maybe five degrees East of due South.
I haven't used any modelling tools, I just bought as many panels as would fit in the garden, in order to maximise the output in the Winter. I haven't read the Dummies book yet, or D&B, I will try to get onto that tomorrow.
My project goals are to get around 30 Kw/hrs per day out of the panels for at least eight months of the year.
Do you think my Option 2 won't work? I think it will be overengineered by a large factor, ground screws are designed to take much more than 30kg of weight, and this design can be removed from the garden without leaving a trace.

Well, that's the first I've heard about this being an off grid system. How do you plan to store the 30 kWh/day (average ?) energy harvest, if at all ?

As for not using MC4's, what type of connections does your design call for ?

I'm surprised there are no design requirements for off grid systems in the U.K. but, be that as it may, there are most certainly recommended good practice criteria that apply to electrical and mechanical systems. I was (at one time) quite familiar with most U.K. design codes as they apply to industrial, process and power generation equipment and found them similar to codes in the U.S. and other industrialized nations in terms of purpose and particulars for many applications. For your own safety, I'd respectfully suggest you double check for any required code compliance relief simply by virtue of being an off grid application and get the responses in writing from appropriate authority.

If you plan to maximize annual specific output from an array (in kWh/year per installed STC kW) - and I'm not suggesting you should - only that it's common to start with that goal and then size/design the system to produce the design goal output - look at something called PVWatts. It's an easy to learn and pretty good (with good inputs, GIGO applies here) residential PV modeling program. You'll read about it in the Dummies book.

Other geographical and site specific design constraints, mandates and preferences often result in less than optimal orientations, but a good model will show close to the long term optimum and also allow a designer to estimate penalties or considerations in the deviation from optimums.

In buying equipment before you educate yourself you did the "ready, fire, aim" method of design. That usually results in a less than optimum result in terms of both a less cost effective design and also a less fit for purpose design. I'd suggest you not spend any (more) money on equipment until you get more educated.

To your question: I don't know if either or any of your options will be suitable simply because I don't know enough about your site specific parameters or the approval parameters you're working under - and I'm pretty sure you don't either, starting with the design wind conditions and also soil conditions as well as a bunch of other stuff. To that end there's usually good design and then there's code compliant design. A good designer must meet both and know the difference between the two. Contrary to what those who do little else besides bitch about codes may think, the two are not incompatible.

By the way, disabuse yourself of the idea that the applied loads applied loads your design will see are all downward from weight as you seem think.
Again I don't know your site's specifics but I wouldn't be surprised if you'll have more to design for from wind uplift or lateral wind forces and resulting moments on anchors from high tilt angles than from dead loads on foundations from panels that apply small forces because panels weigh relatively little.

Then too, all that is before any consideration for what varying/unsteady wind loads will do to anchors that are only set in soil and will be less secure in their holes for the applied varying loads and resulting stresses. Posts are usually set in concrete for reasons other than that concrete is heavy (It's also pretty rigid at least in compression).

If all this makes me seem like a prick, so be it. Not everyone who tells you stuff you might not like or what you might not want to hear is trying to do you harm. Perhaps just the opposite. I just saw some of my past in your tale and took an interest.

FWIW, I'm trying to help you see that you are not in a position to do what you think you can do. I wish you the best, but in my opinion, you're in over your head and headed for problems you are not aware can befall you. Tell me to bugger off and I'll stop posting to your stuff.

Take what you want of the above. Scrap the rest.

[sdold]

I think it will be overengineered by a large factor, ground screws are designed to take much more than 30kg of weight, and this design can be removed from the garden without leaving a trace.

I wouldn't be concerned as much with the weight on them as with how much wind loads will try to pull them out, and pull everything else apart, like those Tees with the setscrews holding them to the pipes.

[GodfreysGhost]

Hi J.P.M., we do have electrical codes, but I am hiring an electrician to do all of the wiring (literally everything electrical is going to be done by him, I'm not even going to be connecting one MC4 connector to another, I know how much power could be coming from these panels and I'm not going anywhere near that sort of thing), there isn't any review or approval process in the U.K. for off grid systems.
I came up with the 76 degree tilt from this website: Solar Angle Calculator | Solar Panel Angle Calculator (solarelectricityhandbook.com)
My garden slopes down from East to West, so I am aligning the panels straight up the slope, parallel to the hedge that forms the boundary between my and my neighbour's property to the left, I think it's maybe five degrees East of due South.
I haven't used any modelling tools, I just bought as many panels as would fit in the garden, in order to maximise the output in the Winter. I haven't read the Dummies book yet, or D&B, I will try to get onto that tomorrow.
My project goals are to get around 30 Kw/hrs per day out of the panels for at least eight months of the year.
Do you think my Option 2 won't work? I think it will be overengineered by a large factor, ground screws are designed to take much more than 30kg of weight, and this design can be removed from the garden without leaving a trace.

[J.P.M.]

Ghost:

1.) Do you have any local, regional or national building or electrical codes, or any review/approval processes to conform to?

2.) How did you come up with the 76 degree tilt ? Or for that matter a 180 degree azimuth ?

3.) Rereading the last paragraph of your initial post to this thread: Large solar facilities orient arrays for lots of reasons. Maximizing output is a big one, but not the only reason. There are most likely lots of considerations that you may not be aware of. Your situation and design goals may not align with theirs.

4.) What modeling tools have you used to do the preliminary sizing and design for your project ?

5.) Have you read the Dummies book yet ? Browsed chaps. 2 & 3 of D & B yet ?

6.) Maybe I missed them, but have you set any project goals yet ? When you're done, what do you want to have accomplished ?

Do what you want, but that video from Engineer 775 is a good example of the unvetted and IMO often dangerous stuff that floats around utube, and a lot of the reason why I call utube "The New Idiot's Bible". A lot of uninformed people don't see the bad to dangerous (non)designs often lurking in a lot of the junk found there. Licensed engineers carry liability insurance for a reason.

If you think I'm ragging on you - you're right. Get some design help. Nothing personal but IMO, you're headed for trouble if you don't.

Take what you want of the above. Scrap the rest.

[GodfreysGhost]

Hi SunEagle, in the U.K. we just have 'Planning Permission' and I have already submitted my plan using Option 2 - the only thing the planning people are interested in is the height and area the panels take up on the ground, not the mounting method per se, so it's all okay. I like Option 2 because it will make mounting the panels (which are huge - 2172mm x 1303mm) much easier, I can just lift one up onto two ground screws with the help of a friend, and lean it against the horizontal tube at the top, and then I can take my time when fitting the U-bolts and metal brackets. The ground screws allow me to easily keep the bottom of the panels away from the grass underneath.

This is the 'short tee' I will be using to join the horizontal tubes to the vertical ones:


It takes up the least space possible horizontally, which is important because I can't put a U-bolt around a longer tee, unless I buy larger U-bolts. It all depends on where the short tees occur along the row of panels.

[SunEagle]

I am probably going to go for Option 2. Bear in mind that I am setting up my panels for the best output during the Winter, as I have 13Kw of panels, and don't need that much output during the Summer months, so the angle of the panels will be 76 degrees from the horizontal (although I may adjust this to a lower angle, as I think that no matter what I do (apart from buy even more panels) I am not going to get a very good output in December in the U.K., going by other people's experiences on various Youtube videos.) But the vast majority of the weight of the panel is going to be on the ground screw, and the ground screw can probably take 500kg, and the panel only weighs 31kg, so it will be well within its limits.
I think this design (Option 2) is the simplest way possible of setting up a ground mount, the only cutting work I will have to do is cutting the uprights of the ground screws.


upload pic

Certainly option 2 uses less hardware and may work.

I bow to Bruce who seems to be the guru of ground mount systems. Again any installation needs to meet your local safety codes.

[GodfreysGhost]

I am probably going to go for Option 2. Bear in mind that I am setting up my panels for the best output during the Winter, as I have 13Kw of panels, and don't need that much output during the Summer months, so the angle of the panels will be 76 degrees from the horizontal (although I may adjust this to a lower angle, as I think that no matter what I do (apart from buy even more panels) I am not going to get a very good output in December in the U.K., going by other people's experiences on various Youtube videos.) But the vast majority of the weight of the panel is going to be on the ground screw, and the ground screw can probably take 500kg, and the panel only weighs 31kg, so it will be well within its limits.
I think this design (Option 2) is the simplest way possible of setting up a ground mount, the only cutting work I will have to do is cutting the uprights of the ground screws.



upload pic

[GodfreysGhost]

Hi SunEagle, I've tried again to upload a picture to your server, this time using Microsoft Edge, now I get the message '500 Internal Server Error' with a 56kB PNG picture, which is 594 x 1105 pixels. When I try to use a tiny image, a GIF that's 2kB, 125 x 81 pixels, I get the message "Upload failed due to failure writing temporary file.".

This is a link to IMGBB.com, hopefully these will work:

[SunEagle]

SunEagle, I was very worried there for a minute, I had no idea what I had done wrong!
I have been thinking long and hard about whether I need to be able to adjust the angle of the panels, and I think that for the moment, I will build a static ground mount. I have made a couple of diagrams that show what I am thinking of: I am going to use a ground screw to take the main weight of the panel, as the angle will be quite steep, to take advantage of the Winter sun more than the Summer sun, because I have 13Kw of panels and won't need the full output in the Summer. I will cut off one of the upright sides of the ground screw (the ones I am using come with a 'U' shaped top, which you can put a beam of wood, etc. into, and then put screws through the top part of the ground screw, into the wood, etc.) and behind this I will have a galvanised steel tube, which I will hammer into the ground, and about 2.4m-2.6m of it will be above ground. Then I will have a horizontal tube attached to the top of this vertical tube, onto which the top of the solar panel will lean. I can then lift up the solar panel's base so that it rests on two ground screws side by side, the same distance apart as the width of one solar panel, with two panels' edges sitting on each ground screw, and then I will use U-bolts on the horizontal bar to hold a flat metal plate on the top of the frames of the solar panels, and that's it. I will use diagonal poles every five or fix panels, from the top of the vertical pole down to the bottom of the next one, to stabilise the structure more.
I have tried to upload my diagram, which is in .PNG format, but the forum software keeps insisting that I provide a source URL for it, even though I'm using the 'Upload' tab. I browse to my image, then I press 'Upload it to the server', then when I press Okay it says "Image source URL is missing." Do any of you know what I'm doing wrong? I've had no problem uploading images on other forums.

I believe the forum software limits the size of the picture that can be attached. I have had to resize a picture in the past and I am afraid you will also need to find a way to get the picture small enough to be accepted.

[GodfreysGhost]

SunEagle, I was very worried there for a minute, I had no idea what I had done wrong!
I have been thinking long and hard about whether I need to be able to adjust the angle of the panels, and I think that for the moment, I will build a static ground mount. I have made a couple of diagrams that show what I am thinking of: I am going to use a ground screw to take the main weight of the panel, as the angle will be quite steep, to take advantage of the Winter sun more than the Summer sun, because I have 13Kw of panels and won't need the full output in the Summer. I will cut off one of the upright sides of the ground screw (the ones I am using come with a 'U' shaped top, which you can put a beam of wood, etc. into, and then put screws through the top part of the ground screw, into the wood, etc.) and behind this I will have a galvanised steel tube, which I will hammer into the ground, and about 2.4m-2.6m of it will be above ground. Then I will have a horizontal tube attached to the top of this vertical tube, onto which the top of the solar panel will lean. I can then lift up the solar panel's base so that it rests on two ground screws side by side, the same distance apart as the width of one solar panel, with two panels' edges sitting on each ground screw, and then I will use U-bolts on the horizontal bar to hold a flat metal plate on the top of the frames of the solar panels, and that's it. I will use diagonal poles every five or fix panels, from the top of the vertical pole down to the bottom of the next one, to stabilise the structure more.
I have tried to upload my diagram, which is in .PNG format, but the forum software keeps insisting that I provide a source URL for it, even though I'm using the 'Upload' tab. I browse to my image, then I press 'Upload it to the server', then when I press Okay it says "Image source URL is missing." Do any of you know what I'm doing wrong? I've had no problem uploading images on other forums.

[bcroe]

Pre engineered parts can work. I question if the variable tilt would be
working after a few years in the weather. Steel bolts here rust up pretty
fast, removal means breaking them. The pivot points on just a bolt is
not a great idea. The parts may get more attached than you want. Will
those screws keep working for long? The tilt range is limited before
you must unbolt the screw and remount it. That might be more
important if you go for a vertical, snow resistant mount.

Another plan here is 6061 aluminum held together with 18-8 stainless
hardware. Not cheap, but it has done well and still can be serviced
without damage after 9 years. 6 tilt bearings on tilting array are regular
machine shaft greased ball bearings. Multiple hole braces must be
unbolted to change, but for strength they are at a much larger radius
from the pivot. With a balanced array little force is needed for the tilt
change. Bruce Roe

[SunEagle]

SunEagle:

Wrong poster/thread maybe ?

See thread started by eric@psmnv.

Thank you,
J.P.M.

You are correct. I posted on the wrong thread.