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mmacleod

Best roof material choice for PV? (And any other tips for new construction)

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I'm busy building a new house, and intend to install PV on it.

The bulk of the roof is flat concrete, however I've had the architect spec a portion at the front as wooden trusses with kliplock instead, its main purpose is for PV and it also saves me a bit on the concrete and balustrade expenses so serves a double duty.

I've done some calculations and I should be able to fit roughly 16-18 large panels in landscape mode, or 14-16 in portrait.
This is around the 5000 watt mark so should be all I need, though I could always put another smaller string elsewhere on the house with perhaps a different facing, in the unlikely event I ever need more and CoCT rules change such that I'm allowed more...

Anyway my main question is (given I'm still busy with the foundations and there is still time to change this) if there is anything I should do (slightly) differently.

The main thing I want to ask is the roof material. The idea of putting up a roof that is just going to be covered entirely in panels bugs me a bit, it seems terribly inefficient so in an ideal world the panels would be the roof like I asked about here:

However I've resigned myself to the idea that this just isn't done yet, and so instead I'm left with the question of whats the best material to use? Is chromadek as specced here a good choice, or are there other materials that are better for this situation?
Should anything be done different/special with the trusses themselves?
Anything in general to consider that might make for a better/easier/cheaper install?
The house is on the mountainside in gordons bay so however its mounted it must be able to endure strong winds.

The tilt is 12 degrees (roughly NNW), there is not that much room to adjust this, but would it make a large difference? I guess I could try squeeze an extra few degrees if its really worth it.

Are there any other things that are worth considering for a new house with PV in mind? e.g. I'm considering doing my lighting differently:

If you were building a new house right now and planning to put PV on it are there any special things worth thinking about at the design phase?



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10 hours ago, mmacleod said:

Are there any other things that are worth considering for a new house with PV in mind? e.g. I'm considering doing my lighting differently:

@mmacleod, something I would suggest considering is the location of the DB and the sizing (most electricians install the smallest cheapest DB). If you install solar in my opinion it would be ideal having that extra space in the DB for things like sonoff switches to make automation easier. Also the location of batteries and inverter and all gear like wifi, cctv hard drive’s home entertainment systems that might be installed, having a dedicated area or room that can easily be kept cool and secure can make things much cheaper and neater. Also it might be worth considering solar tracking as an future option than the mounting area for such a structure could be planned ahead. These are things I would consider with my next build or home purchase.

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11 hours ago, mmacleod said:

If you were building a new house right now and planning to put PV on it are there any special things worth thinking about at the design phase?

I have recently build a new house. To simplify a PV installation I found the following issues important in addition to what @Gerrie said:

1.  Plenty of conduits to run the PV electrical cables (AC and DC must be in separate conduits)

2.  Separate DB board for AC and DC

3.  Electrician to wire the house based on an agreed to and signed off house wiring plan (with special emphasis on what is on the essential and non essential circuits and home automation requirements)

4.  As many individual circuits/circuit breakers as financially possible (will facilitate flexibility what can be moved/changed later on from essential to non essential circuits or vice      versa

5.  Electrician to label all cables 

6.  High electricity consuming appliances (Geysers, Heat Pumps, Pool pumps, Aircons etc.) to be remote controlled  

7.  Conduits for ethernet network/Alarm system/CCTV cameras etc. throughout the house.

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6 minutes ago, Fuenkli said:

1.  Plenty of conduits to run the PV electrical cables (AC and DC must be in separate conduits)

Ahh yes, I did already have the architect specify double conduit to everywhere, and conduit from roof/ceiling to garage.

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15 hours ago, mmacleod said:

If you were building a new house right now and planning to put PV on it are there any special things worth thinking about at the design phase?

another point I realize now in hindsight I should have done is to get a 3 phase grid supply

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On 2020/02/23 at 12:37 PM, Fuenkli said:

another point I realize now in hindsight I should have done is to get a 3 phase grid supply

What benefit would this have brought?

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1 hour ago, mmacleod said:

What benefit would this have brought?

 you can legally connect more inverter output power to the grid. I am on a 60A single phase grid supply and restricted to only 3.5kVa. This is just about sufficient for my small household. But the moment "feed in" becomes financially viable (I hope soon 🙂) much bigger systems will be required. It will then pay to completely cover your roof space with panels. In my case I could install about 15kWp of solar generation. 

Edited by Fuenkli

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