MCS Guide to the installation of Photovoltaic systems (shading analysis)

[Moffy Red]

Hi all

Topic -- MCS Guide to the installation of Photovoltaic systems (shading analysis)

Just getting to grips with the code, Has anyone got the shade analysis tool sorted, I'm struggling to find some good app's for Androids tablets or a camera that dose not cost more than the earth.

Any ideas gratefully received

 

[SolarCity]

The new shading analysis is pathetic. I've surveryed a few jobs using this method and I've yet to visit a job where it's a feasible option. Is anyone else having a bit of a game with it?

It takes far too long, looks far too amateurish and is nowhere near as good as 3D modelling.

 

[Ian-LS]

Its basic at best which good companies should be looking at better methods. Any modelling software has got to be better than this method as long as the model and shading sources are accurate as shading can be analysed for every hour and every day of the year whereas the DTI shading method at best just gives a snapshot of annual shading.

 

[Worcester]

I've created a film version of the shading diagram to fit the Solar Shading Meter : Solar Shading / PV Horizon Meter

Works OK, and can give a photocopy of the results to the client. Need an upstairs window close to the array for it to be of any use whatsoever... And there's still the challenge of what if the array doesn't face south......

 

[Ian-LS]

I've created a film version of the shading diagram to fit the Solar Shading Meter : Solar Shading / PV Horizon Meter

Works OK, and can give a photocopy of the results to the client. Need an upstairs window close to the array for it to be of any use whatsoever... And there's still the challenge of what if the array doesn't face south......

or the shading source is actually a chimney on the roof. Or numerous other flaws to this shading method. I for one will not be using its simplistic calculations preferring to use more accurate method such as modelling etc combined with average outputs expected for each month for any given angle and orientation.

 

[Matt_M]

I think the new MCS guide states that a shading analysis must be provided in each and every quotation - is it going to be feasible to use 3D modelling on every quotation completed?

 

[Ian-LS]

Seeing as the method was not consulted upon and we have a more accurate method of assessing shading then if we have to include it then we will but would resent having to be forced to use a method with don't agree with and weren't consulted upon.

and yes modelling can and is done on every quotation we provide.

 

[Gavin A]

I think the new MCS guide states that a shading analysis must be provided in each and every quotation - is it going to be feasible to use 3D modelling on every quotation completed?

we already do that as standard.

 

[SolarCity]

Checking shading from a window is an utterly laughable solution to this problem. What about the shading which affects certain parts of the roof and not the area we happen to be surveying from? What if there is no window?

I measure objects with my Leica D8 and accurately model the system with PV Sol Expert - Why, then, should I be conscripted into using a flawed method just because other firms do? Why shouldn't I point out to the customer that my method is better than the 'paper at the window' nonsense?

 

[SolarCity]

Likewise, we do 3D modelling as standard. I've yet to see an alternative method which is anywhere near accurate enough.

 

[Berneray]

I've been learning how to use SketchUp 3D Modeling with Geo Location via google earth. Its a brilliant and free tool....but to do accurately does take a lot of time....and you need accurate measurements.

And on side but related issue......Will products such as SolarEdge and Micro Inverters now become more popular and if so how would we account for them in calculations...

 

[Berneray]

And what about shading from clouds.....Impossible to avoid shading altogether when the sun goes behind a cloud and you can see the shadows move across the roof...

 

[SolarCity]

And what about shading from clouds.....Impossible to avoid shading altogether when the sun goes behind a cloud and you can see the shadows move across the roof...

Yeah, and what if the Martians arrive and park their spaceship right above your array?

 

[finchy]

I'm a expert on sketch-up and have been using it before we started solar pv however my question is, it still takes time to build then all the other paperwork. Is there margin in pv to do it, when you compete with bob the builder/double glazer working off a ladder !

 

[zeljuga]

Quote
(I've created a film version of the shading diagram to fit the Solar Shading Meter : Solar Shading / PV Horizon Meter

Works OK, and can give a photocopy of the results to the client. Need an upstairs window close to the array for it to be of any use whatsoever... And there's still the challenge of what if the array doesn't face south......)

Most likely Submarine type Periscope fitted with PV Horizon Meter on the top.

 

[SolarRoofSols]

I've been testing it out on a couple of projects and would appreciate a sense check by someone on a calculation for an aerial.

4kWp
Location 11
pitch - 40 d
Azu - 40 d
Angle above horizon 45 d
Aerial Sited at 20 d west of South

= 4 (kWp) x 849 (Kk) x 0.69 (SF) = 2343kWh

Is this right??

 

[Ian-LS]

:thinking:.....there is no way a tv aerial would cause 31 % shading losses. Is the tv aerial coming into 31 of the boxes for the shading horizon? If so then if using this method (which I for one am not) then I'd suspect that shading losses would be moe like 10% probably a bit less.

Another reason why the shading analysis is at best a draft version for an undergraduate degree thesis, maybe even A level project maybe even GCSE project.

 

[SRE]

PVsol for my Sharp NU180E & SMA 400tl reckon I should be getting 2800ish kwh/pa using SAP 2012 for NW England. Strange that with a phone line running diagonally across the whole of the array I've had 7685kwh in 29 months, the first ones of which were Nov, Dec & Jan .........

 

[Gavin A]

I've been testing it out on a couple of projects and would appreciate a sense check by someone on a calculation for an aerial.

4kWp
Location 11
pitch - 40 d
Azu - 40 d
Angle above horizon 45 d
Aerial Sited at 20 d west of South

= 4 (kWp) x 849 (Kk) x 0.69 (SF) = 2343kWh

Is this right??

have you worked this out as if the aerial is a solid object?

Obviously it's wrong in reality, I'm just checking how you've worked it out using the new / already badly outdated methodology to see if it really is that bad or not.

 

[SolarRoofSols]

How have I worked it out...?

The aerial is about 1 ft from the bottom of the array and the top of the aerial is at a 45 degrees from the bottom of the array.

I have plotted a line from the bottom of the chart to the 45 degrees line and then drawn a circle to see which areas the path of shading will hit - 31 squares in total through out the course of the day.

:willy_nilly: