Another PV Photovoltaics Installation goes active.

[clockmanFRA]

Another PV Photovoltaics installation at ‘Le Vivray’ goes active.

In France, Normandy, I have put this post here as i trust it shows how we achieve AC coupling.

This installation is on the New Garage south side of the roof.   It is a 3.6kW installation with the latest 10off 360 watts 120 cell Monocrystalline panels. The Monocrystalline panels are good at producing electricity in the gloomiest of light conditions, they do not need direct sunlight.

I have separated the panels into 2 strings of 5 panels, and each with its own 1.7kW GTI, Grid tied Inverter. These 2 GTI’s were second hand from EBAY in the UK, £40 each, from a comercial installer who had updated some of his customers PV.

Under UK regulations and most other counties, Old equipment on a PV GTI that is connected to the Countries Main Electricity Grid is not allowed. So, for us these machines are a bargain and we re-use  them as is.

Our ‘OzInverter’ creates our Mini Grid 236vac electricity supply, these GTI’s take the DC voltage created by the PV panels and uses the Electricity Grid they are connected to and the 50HZ Frequency, (for USA there is a 60HZ and 120vac version), to then backfeed a few Ac volts back into the Grid, and for us they backfeed to the ‘OzInverter’.

 The Ozinverter is a H bridge design so the AC voltage can charge backwards and charge the 48vdc batteries.   This whole process is called …. AC COUPLING.  The neat trick is that these Slave GTI’s and yes they are slaves, they need our MINI GRID, can then supply direct to appliances around ‘Le Vivray’  so DC battery charging and extra cabling is not required, and a bonus is the batteries are not constantly be asked to supply the Mini Grid.  So a better life and less wear and tear on the batteries.

We now have 5off GTI’S connected into our Mini Grid and supplying up to 11kW of electricity.

Cost of the panels was £1200. about $1500.

[noneyabussiness]

Always a good read Bryan and as always sooooo neat... kudos

[clockmanFRA]

Thanks NB.

Just finished the install information for my Web site page....... here .... http://www.bryanhorology.com/pv-photovoltaics-installations.php

After 20 years of this stuff, i am just trying to get everything together for another publication.

I am on my own here, and due to Covid curfews and transport bans, etc,  I had to do this up on the roof as just me.

[SparWeb]

Look at all that silicon!
With your DIY skill, and all those bargains I think you'll have a payback time in the matter of months, not years.

[clockmanFRA]

Eye Eye, SparWeb.

Silicon, It just sits there and generates.

All done now, stuck all the required stickers and info on the correct bits.   As i get older my memory filing system needs updates, haha.

[DanG]

whoa - covering up faux** slate with crystal!, ain't that fit for royalty!

Is the roofing shingle polymer, composite or metal?

 ** Edit: bryanhorology link speaks of real slate, as pictured it is such uniform natural slate that it looks fake, so the PV paneling is really crystal weathergard for that royal slate : )

[clockmanFRA]

My Dear DanG,

They are French made fibre slate.

ie,  reconstituted slate, Mashed up bits of slate mixed with cement and fibre and pressed moulded. Nice to work with. About $0.75 each 240mm x 400mm.

Natural Slate around here is either from Spain or from China at a cost about $1 each.  Quality is not always great.

Yours, His Maj.

[MattM]

They are French made fibre slate.

ie,  reconstituted slate, Mashed up bits of slate mixed with cement and fibre and pressed moulded. Nice to work with. About $0.75 each 240mm x 400mm.

They look good.  Do they work the same with your pick hammer?  Does the fiber make them walkable?

[clockmanFRA]

MattM,

Yes pick holes, and cut, although i prefer jig holing with a jig and diamond drill press multiple slates, so holes are always perfect.

And cutting them yes you can use traditional methods, which I do on the roof, but again i use a diamond tile cutter when doing half tiles etc.

No, Never walk on normal tiles, and i never walk on these tiles.  Its always the fact that your shoe puts a lot of weight and stress on one spot.

Mind you this last lot of my re-constituted slate tiles l use, i really had to look hard around a 80 mile radius to get some, and then found some on a pallet on a top rack in a builders Merchants. When i asked them, blank faces all-round, head man had to come down into the yard shed with me, "Oh yes not showing on our stock records from when the shed was put up, yes we will do a deal". 

Will start looking for some more soon as i have another outside WC, 'Thunderbox' building roof to do, but this only needs about 400.

Never a dull moment. 

[MattM]

I can imagine they still way around 5kg per square meter (roughly 110 pounds per roof square) even reconstituted.

[clockmanFRA]

These reconstituted slate tiles weigh slightly less than a Spanish or Chinese slate tile, as they can guarantee overall thickness.

They come as a bundled stack of 20off and that is just about carrierable in one arm. A few years back i would carry about 40 at a time.

From the delivery pallet I unstack bundles and drill the copper holes with my hole gauge set up on the bench on the ground, then carry 20off at a time, stack about 100 in my winch basket and up to the roof.

The only draw back is that in winter they have a habit of Freezing together if stacked overnight on the scaffolding.

But they do cut real good and constantly consistent.

And just for MattM, some European tile laying, this is the old traditional way.   Other Forum members, please look away NOW.

 Today in France they use stainless steel hooks that go around the lath and hook under the tile. I wont use that method because sadly I am old school taught, I have used it on my own Dwellings but just as a decorative, but i still have copper clouts.

 Today Most Housing inspectors, House Agents etc,  do not know the traditional method and besides in Hurricane wind conditions i have seen modern French roofs stripped of their tiles with the hook only method.   Several Old French Paris roofers have looked in and said they are compelled to use the modern hook method by their companies because its cheaper, but they would rather do it properly.  Here in France, modern so called trained roofers have never seen a clout ripper.

[MattM]

Nobody will accuse you of cutting corners.

[clockmanFRA]

Matt,   please don't tell the Mrs, she reckons I am the slowest worker in Europe.

She says, "You Flipping Engineers"

I say, Do it once, Do it right, Get it right so it lasts for ever.

Sadly today Matt, that is not what the business World want to here any more.

[kitestrings]

I think I've got it (thanks for the link), so if the load isn't used on-site, the voltage rises, and the GTI's shut-down.  At first I was thinking, well, if you're pushing to the grid, you are net metering - that's what it is called here - but I think you are saying the voltage might push up slightly, but there are no kWh flow to the utility grid.  Is that correct?

The install is quite tidy, and I like the roof & flashing details.  Thanks for sharing.  ~ks

[Scruff]

..... those hazel bushes/trees are due for some severe pruning this winter, so no Sun shading those PV panels.

I gotta admire your resolve CM.
No messin'

Ah the rheorical is it green question? Landscaping with chainsaws to benefit solar input...I'm gonna say...yer...green..after a coupla years.
But sir that has power reliability written all over it.

[clockmanFRA]

Yes kitestrings, you have the basics.

Our Mini Grid that we create here, has absolutely no connection to the main utilities Grid.

The 'OzInverter' creates our MINI GRID for all our buildings etc, and its a Pure Sine Wave, for us its 50HZ, and a 236vac.

So The GTI is connected to our Mini Grid and its internal settings allow the power voltage its creating to push above the normal Mini Grid voltage. If you have normal appliances operating from the Mini Grid then they have first choice of the GTI created Power.

No appliances running or the GTI is creating more than you are using then the 'Ozinverter'  because it has a 'H Bridge' design, allows the AC voltage to flow backwards through the 'OzInverter' and create DC voltage at about 60VDC that then charges the batteries.    Somebody boils a kettle of water on the Mini Grid, then the GTI created AC power is diverted.

We have 11kW, 5off, GTI's working and connected into our Mini Grid, some of the GTI's internal settings i have altered so they shut down if there AC output voltage rises to high as the full 11kW is not required.

I have 3 other type of methods so the batteries do not get overcharged.

Three methods of controlling the back charging from GTI's is possible for 'AC Coupling'. 

A.   Use the Internal codes/settings in the GTI's to sequential shut down when a specified ac output voltage is reached. This works reasonably well with my system as some installations GTI,s are up to 400 meters away from the ‘OzInverter’ and batteries, and the batteries do push back slightly, but this depends on the cable voltage sag.   

B.   Use dc voltage comparators circuit to shut down the GTI ac side with a relay when the DC battery voltage rises above a charging rate voltage. But you will need to run a data cable to all your installations, and again allow for voltage sag. 

C.    Use PWM dc controllers that are connected directly to the 48vdc battery bank. These Diversion controllers, (Morningstar Tristar PWM at about 200 Euros each), will regulate the charging and any excess power when the batteries are full and will dump/divert to other permanently connected sources, ie, Air Heaters 2kW each or Hot water heaters, underfloor electric heating, etc, etc.

The above are a cost effective and very reliable system.

A is used most, and C is my guaranteed safety system. Where i do not have access to the GTI internals, then i use B. 

For a 19kW PV Array I prefer using 2off 1.7kW & 4off 2.5kW GTI's for 14kW, and using DC Charge controllers for the 5kW as these can gently finish charging that precious 48vdc battery bank.

NOTE,   I have not used a HF, High Frequency GTI, because second hand old heavy toroidal types are easily obtainable and very cheap, plus you get to use the GTI internal MPPT .   'Oztules' and others have experimented with HF types and do not find any real difficulties.

NOTE.  Its best to use GTI’s at a max output of 2.5kW as above this the GTI tends to surge on a long cable connection.

Its real simple when you really look at it.

And its cheap by using second hand GTI's. You don't need all those expensive MPPT DC charge controllers. You dont need all that thick DC cable. And very importantly your batteries are normally just on standby as the GTI's are running your MINI GRID.

I trust this helps?

[clockmanFRA]

Scruff,

Yes they are Hazel, and yes at Christmas we have lots of nice Hazelnuts.

Around this part of Normandy Hazel bushes are very, very common, but there life is about 20 years unless severely pruned, as they just fall over. So that chainsaw pruning, coppicing,  will not hurt them, and we have plenty more Hazelnut bushes.

I see the 'doug' has put some weight on?

[clockmanFRA]

kitestrings,

In an ideal world any excess power my Mini Grid is creating could be allowed to flow to the Countries Utility Main Grid and i would receive a credit from the Utility as its True Green created power.

However in France they are very keen on all there Nuclear Power stations and lip service is given to Green electricity. And a deliberate policy here is NO installation above 3kW is allowed to be connected into the Main Grid.  And then it needs to be done by all approved government companies and masses of paperwork etc etc and therefore its just not cost effective.

However, In France they actually have a LAW that states that i can make and produce as much as power as i wish as long as i do not sell it to anyone.  We have 10 buildings with a power supply that operate on our Mini Grid.

Spain and Germany have small co-operatives that produce Green electricity and have a credit scheme if you are not using all your own produced power.   They operate and sell and are also integrated into the Main Countries Utilities.

So we just do our own Mini Grid supply.

[MattM]

Matt,   please don't tell the Mrs, she reckons I am the slowest worker in Europe.

She says, "You Flipping Engineers"

I say, Do it once, Do it right, Get it right so it lasts for ever.

Sadly today Matt, that is not what the business World want to here any more.

Amen.