My New Project on the West Coast in Yzerfontein

[Mike]

hey guys,

thought i should share my new build with you all. i will add photo's as we go along.

To start with i have started with a 320m2 "green" home. We are now only on slab height but in two - three weeks we should be roof height. the cavities in the walls are getting polystyrene sheeting and eco insulation in the roofing.

I have had the roof trusses manufactured at 30 degrees and placed the house with the longest roof line of 24m facing North for my panels.

 

For solar power i have decided to go with a grid tied microcare 3kw inverter accompanied by their grid tied limiter and 11 x 285w panels in a series array,that should give me 495VOC and the limit on the inverter is 500V. in the event of a power failure i am going to put in a 3kw bi directional microcare inverter with 8 x batteries for critical loads.

 

For our water heating and cooking i will be installing a Atlas 28l/p/m turbofan gas geyser running off  2 x 48kg bottles that will supply the geyser and gas stove. Fridge and freezer are the new Bosch Solar line of A++ rated units.....they say no more than 100kw per year draw for both.

 

Alll the lighting will be 4w LED running from "the critical "circuit.

 

I am following the wind patterns here and so far every day / night there seems to be a wonderful amount coming in off the sea, so as alternative source, i intend using a 1 or 1.5kw wind turbine....but that i will attempt once the house is totally up and running.

 

okay pics to follow as we go along.....

 

PS .... i am always open to suggestions offers of help and guidance.

 

 

cheers

 

mike

[Wetkit]

Geeze Mike, that sounds great!

 

Question:

How you planning to run the grid tied and bi-directional invertors together off a single solar array?

Why only gas for water heating? No solar heater?

 

As you right at the sea, make sure you do not have issues with metals. Solar panles does have an alu frame, so mounting them on a diffrent metal could cause corosion where they fixed

[Mike]

morning Wetkit,

 

backup mode with grid tied limiter:  for this method of connection the gti always feeds all power available from the solar panels to the grid. if  / when the grid fails then the gti will shutdown and the bi-directional will power the load from the batteries.

when the grid comes back on line the gti will feed power back again and the bi directional will draw some extra power from the grid to recharge the batteries.

 

Gas = no complications and zero power requ for elements. trying to do the total green thing :-) the gas geyser gives me 28l per minute at 55 deg. i dont need more than that.

All framing is Aluminium

[leaves]

Geeze Mike, that sounds great!

 

Question:

How you planning to run the grid tied and bi-directional invertors together off a single solar array?

Why only gas for water heating? No solar heater?

 

As you right at the sea, make sure you do not have issues with metals. Solar panles does have an alu frame, so mounting them on a diffrent metal could cause corosion where they fixed

Hi Wetkit 

 

That is very interesting. I think many of us forget. The corrosion between dissimilar metals. It will be interesting to find a list of them, Really enjoyed learning this. Dankie

[___]

Hi all,

 

I'm a brand new member, registered this morning.

 

Just wanted to say, I wish I had the opportunity to start "fresh", but there's some things we have in common in our setup :-) I have also recently replaced the fridge and the freezer. The Fridge is a Bosch A++ unit (bought on special at Dion Wired). I cannot tell you what a pleasure this thing is... The freezer (this might be surprising) is a 210 liter Defy (eco range). It only has a 70W compressor and uses less than 1kwh a day. And it only cost R1999. I also put eco insulation in the roofs this year. But unfortunately my house faces West (mostly, slightly north), and the roof has ridiculously short faces on which you can barely fit anything. I could only fit a 150 liter solar geyser, so to have enough water we prefeed an electrical unit,  and I have my solar panels on the North-Eastern side, where they stop working at around 3:30pm in the afternoon :-(

 

Regarding corrosion between dissimilar metals, known as galvanic corrosion, the guys at my local supplier advised me to use this sticky rubbery roof insulation strips between the alluminium of the panel and whatever you are mounting it on. All you need is electrical issolation, because the corrosion is caused by electron movement from one metal to the other. I also have my panels on a home-made steel frame, so I use this method.

 

Initially I also wanted to go grid-tied, it's just so much more cost-efficient if you can skip the large battery bank, but because I was worried that we might have load shedding this winter (and face it, we came close a few times) I eventually went with a small off-grid system, I think it is called a grid fallback system. But I still have a long way to go with mine... at the moment it's no more than an overpriced UPS really.

[___]

Hi Wetkit 

 

That is very interesting. I think many of us forget. The corrosion between dissimilar metals. It will be interesting to find a list of them, Really enjoyed learning this. Dankie

 

Here's a good place to start. Basically, the more the difference in the galvanic index, the worse the corrosion. That is why galvanized steel is even worse when it comes to this sort of thing :-)

 

http://en.wikipedia.org/wiki/Galvanic_corrosion#Galvanic_series

[leaves]

Thank you, this is very interesting!

Wonder if a bit of copaslip can help

L

[Wetkit]

Mike, how many in the house served by that one gas geyser?

 

If I had to do my gas geyser over now, I would install the latest electronic ones, which will regulate the outlet water tempreature.

This way you do not have to constantly adjust the geyser to get the water right.

Reason for this is that you set your temp according to say running a bath at 28l/min.

Now you have a shower and only using 14l/min, so the water is nearly twice as hot

Then I would install a solar geyser, but without the electrical connection.

So basically the solar geyser would be a pre-heater for the gas geyser

 

Have you seen this AEC invertor as sold by PHD Powerhouse?

It is a combination of Grid-tied and Bi-directional, called Hybrid.

2 birds with one stone?

 

PowerHouse.pdf

[Wetkit]

Sorry, forgot another one about the gas, sorry.

When I did my gas install, I was also looking at doing 2 x 48kg.

I was then informed that you only allowed MAX 50kg of gas on your premisis at any one time, except if you are a supplier or commercial kitchen, ect.

Also, moving a full 48kg cylinder is NOT a job for me.

If you do go that way, make sure you have a local gas supplier that would come and fetch and deliver it again.

 

I am now using 2 x 24kg cylinder and that is heavy enough to kart around, but I only have to do that around every 4 to 6 months.

[leaves]

Fantastic. So when Grid fails it can draw from Battery?

I wonder if you can isolate just one circuit to run off the battery?

Like just lights and laptop?

L

[___]

Fantastic. So when Grid fails it can draw from Battery?

I wonder if you can isolate just one circuit to run off the battery?

Like just lights and laptop?

L

Your higher end Victron inverters (Multiplus >=3000VA) have a second output that is live only when the grid is live. I'm no expert on these matters, I don't know if pairing a victron with some other make of grid-tie is possible or whether it would mean the grid-tie inverter must be victron too.

 

In my house I have a pretty similar setup though, but with a smaller inverter (1600VA Victron Multiplus). I was lucky enough that the room I use as a home office and the entertainment area (simple 32 inch LED TV and a DSTV PVR) is on the same circuit, so issolating that one circuit was fairly easy. The idea is to use the programmable transfer switch in the multiplus to fail back to the grid if the batteries go too low or the load too high. I have no grid-tie setup though.

[Wetkit]

Leaves, isolating circuits for when running on battries or mains is very easy.

The difficult part is getting the wiring for each circuit sorted out.

Just use a contactor with the coil powerd from mains. When the mains goes off, the contactor falls out and there is no power going to that circuit.

Once mains is restored, contactor will come back on and circuit will be live again.

[Mike]

Mike, how many in the house served by that one gas geyser?

 

If I had to do my gas geyser over now, I would install the latest electronic ones, which will regulate the outlet water tempreature.

This way you do not have to constantly adjust the geyser to get the water right.

Reason for this is that you set your temp according to say running a bath at 28l/min.

Now you have a shower and only using 14l/min, so the water is nearly twice as hot

Then I would install a solar geyser, but without the electrical connection.

So basically the solar geyser would be a pre-heater for the gas geyser

 

Have you seen this AEC invertor as sold by PHD Powerhouse?

It is a combination of Grid-tied and Bi-directional, called Hybrid.

2 birds with one stone?

 

PowerHouse.pdf

wetkit, the geyser can serve multiple areas as it is the larger turbofan system used in a semi commercial environment. it has one remote unit to change settings with in the home. they say it will be no issue servicing 4 en suites and a kitchen with a scullery. I have always used 2 x 48kgs on a changeover regulator without issue. it has to service gas stove, gas geyser, gas braai and a gas pizza oven.....:-)

[Mike]

okay an update on Net metering....

 

Swartland Municipality allows for Net Metering, one has has to supply ones own meter box in the road for your smart meter at a cost of approx R1000 for the box and R1700 for the meter, R1800 deposit for Eskum for availability and then i am on tarrif code 11 which is energy in at a cost of R0.98 per kwh and export back to the grid  a refund of R0.68 per kwh. so now i must figure out how to set the grid tie limiter so they don't get more than i use at night so my bill can be jack zero.....

but i suppose this will be  a learning curve to iron things out. so far there are only 4 net metering clients out this side of the world.

[Wetkit]

Lucky you!

So far I know Mike, you can export more than you use, but they will not pay you the diffrence.

The question is if they reset you to ZERO every month, or can you build up credits in summer to cover the winter months?

[Mike]

nope, they will only credit equal to what your usage is from them, the rest they want for free......thats where the limiter must come in. i am not giving them back so they can sell it on to someone and they only benefit. as far as i am aware it is read once a month and remote reset via gprs

[Mike]

okay then, i had to remove my grid tie limiter and replace it with my own homemade combiner box comprising of 3 x 63a dual pole breakers to isolate the inverter and mains before the main DB.

Yesterday i officially switched on to the solar string.currently i am getting approx 1678w of power in from the panels but it should peak at 3125w later today. will post a few pics of what i am currently using...

 

so i now have a spare grid tie limiter if anyone has a need for one, make an offer

 

[Mike]

so by this evening with the GTI being online for 12 hours 30min i generated 19.7kwh of energy. The max Pac was 3255w, pvbus was 389w. Lets see what tomorrow brings.

[Wetkit]

Hi Mike,

 

Glad to hear all is working well.

So how much PV do you have installed?

What is the reason you removed the limiter? Can you now export again?

Guess the limiter will only work with Microcare invertors?

 

Where is the photo's man!!!

[Mike]

yesterday the panels peaked at  3325kwh and the pv gave just over 400vdc

i have a string of 11 x 275w panels up Wetkit. yep the Swartland municipality is kind of geared up and supports net metering. They were so helpful in assisting getting me my own streetbox , smart meter and connecting....

not sure on the limiter, but based on what it does it should run on any GTI with only the offset function then not being available. I am still not sure tho why anyone would use an offset. does one not want the GTI to be used to it's full capability?

[Mike]

it seems like i am getting around 20kwh per 12 hours...... does that sound right?

the mppt bus reports 385v, max watts on the panels have been 3325w which i think is approx 370 - 385v

[Wetkit]

Mike, I have 12 x 235W on the roof right now. I do not have a GTI, but running my pool pump and well point from it directly.

Doing around 15 to 18kwh per day, so yours sounds about right, but perhaps a touch on the low side?

[Clint]

Mike let us know how much you get back from the electricity supplier 

[Mike]

Hey Clint,

according to the tariff codes, i am on code 11, which is they charge me R0.98 per kwh supplied from Eskom to me and the refund me R0.68 per kwh for any surplus energy. i seem to be steady at 20kwh per day at the moment and i am using approx 13kw per day.

 

So based on the above i might have a surplus of 7kwh per day, but we shall see. I will post it as soon as i receive a bill

[Wetkit]

Mike, you will not be paid out that surplus at the end of the month.

Thing is if you would be able to use those "credits" during the winter months?

 

Still awaiting your picks