1kW solar grid interactive - update

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My Sharp/Fronius 1kW system has been pumping around 5kW/hr back into the system
on a daily basis since it started running on the 5th May. Perth is experiencing
an extended Autumn with sunny days in the mid 20's and no rain, so that is quite
good performance. It should do a lot better in full Summer. Our 2 person
household averages a consumption of around 7kW/hr per day and it is now down to
2kW/hr per day.

Today's West Australian reported on the state budget released yesterday and this
sort of news http://www.thewest.com.au/default.aspx?MenuID77%&ContentID14%1680
makes me feel a whole lot happier still.

In the budget it was also announced that WA would adopt a gross feed-in tariff
of up to $0.60 per kW/hr for renewable energy sources so currently I stand to
make a profit of about $2.60 per day. Of course, as the price of electricity
increases, the profit margin will drop - unless the FiT also increases (which I
doubt). I am now considering increasing my PV array by 4 x 175W panels to take
it to the maximum capacity for the existing inverter.

Re: 1kW solar grid interactive - update
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[snip]

Thanks for the update Ross.

Since I didn't have enough roof space facing north my system (similar 1kW in
Perth) produces only about 3.2 kWh/day right now, facing east on a 13deg pitch.

I wonder if there is a suitable tracking system on the market?

Tony

Re: 1kW solar grid interactive - update

:> My Sharp/Fronius 1kW system has been pumping around 5kW/hr back into the
system
:> on a daily basis since it started running on the 5th May. Perth is
experiencing
:[snip]
:
:Thanks for the update Ross.
:
:Since I didn't have enough roof space facing north my system (similar 1kW in
:Perth) produces only about 3.2 kWh/day right now, facing east on a 13deg pitch.
:
:I wonder if there is a suitable tracking system on the market?
:
:Tony


A few years back I investigated tracking systems for solar PV and found it not
to be economically viable for most residential properties. A tracking frame to
hold six Sharp 175W PV panels is quite large and expensive. It has to be
installed at ground level so you need a bit of space where it is not going to be
interefered with or damaged by other activities. Being outdoors this will
usually involve some underground cabling to connect the panels to the inverter
etc. This company has a DIY kit which would make it cheaper but you would need
to have some mechanical ability and tools. I don't like the fact that the
rotation beam only runs in plastic bushes instead of weatherproof bearings - but
it is cut down to a price.
http://www.renewablestore.com.au/catalog/index.php?main_page=product_info&products_id62%9

Re: 1kW solar grid interactive - update

:> My Sharp/Fronius 1kW system has been pumping around 5kW/hr back into the
system
:> on a daily basis since it started running on the 5th May. Perth is
experiencing
:[snip]
:
:Thanks for the update Ross.
:
:Since I didn't have enough roof space facing north my system (similar 1kW in
:Perth) produces only about 3.2 kWh/day right now, facing east on a 13deg pitch.
:
:I wonder if there is a suitable tracking system on the market?
:
:Tony


Another company has kits for various tracker frames where you don't have to
build it yourself.
http://pvcool.com.au/index.php?option=com_content&view=article&id53%&Itemid15%5

These are the instructions for installation .
http://pvcool.com.au/oldhstm/DownloadFiles/Tracker%20instruction%20STseries.pdf

Note that the tracking sensor requires DC 24 - 48V to operate so it seems these
are usually intended to be used when a storage battery is used. It should work
with a grid interactive without battery but you would need to use a mains
transformer coupled (or other) DC power supply to supply the tracker electronics
so that the panels would track back to face the east after sunset each day.

Re: 1kW solar grid interactive - update
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electronics
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Thanks Ross.

Having a rig on the ground is a last resort option, because of
shadowing, distance and space restrictions. I would rather have some
kind of roof mount thing.

I have an idea in my head that would involve 6 single hinged frames. God
knows what the shire would say though? :-)

Just wondering if anybody has seen a beast like this?

Tony

PS: my system started off with a "1500 for $1500" challenge by renewable
logic (http://www.renewablelogic.com.au /), an offshoot from cablelogic
electrical. With the dollar exchange rate going from close to 1:1 to $US
to 0.7 they faltered on the 1500 and, given the option of not system or
paying $2K75, I opted for paying $2750.
I wonder if they ended up doing 1500 systems after all?

Pictures: http://scarborofun.com/solar.html

Re: 1kW solar grid interactive - update

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http://pvcool.com.au/index.php?option=com_content&view=article&id53%&Itemid15%5
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http://pvcool.com.au/oldhstm/DownloadFiles/Tracker%20instruction%20STseries.pdf
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Before you start thinking about tracking systems, investigate the real
absorbtion ( current produced ) vs angle in both X and Y axes.  My
experience is that solar panels, at least monocrystalline ones, do not
follow the normal cosine law at all.  I found almost no change in output
over about +/- 40 deg on one axis, and rapid change on the other axis.
So by aligning the correct axis with the suns ( earths ! ) daily
movement, you get useful output almost all day.  Of course at high
latitudes you need even more angle swing than this, but it still helps.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Re: 1kW solar grid interactive - update
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An interesting aspect. I am afraid the observations with my panels show, if
there is a difference in reflection angle with axis, it is minor.

But I also think that having one axis tracked over the day and only manually
adjust the other one every month or so would be sufficient.

Tony

Re: 1kW solar grid interactive - update

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The daily change is the killer.  But dont forget that near the horizon
you get a lot less energy anyway, due to the atmospheric absorbtion.

The yearly one only changes the angle by +/- 22.5 degrees, so if the
panel does follow cosine law, your worst error is about cos(22.5) =
0.924, or only 8% drop.  By setting the angle a bit lower than optimum,
you can get slightly more output in winter, and a bit less in summer,
which is probably more even.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Re: 1kW solar grid interactive - update

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err, don't you mean the angle from the horizontal should be your latitude
PLUS 22.5% and orientated due north? (to peak winter output).


Re: 1kW solar grid interactive - update

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If you set the angle to peak winter output (latitude + 22.5), you will
get a 45 degree off axis angle in mid summer.  That will reduce your
summer output to cos(45) = 0.71 of peak ( assuming cosine law holds ).
But if you set say 20 degrees higher than that ( ie a few degrees lower
than latitude), you will get an off peak of cos(20) in winter, and
cos(45-20) in summer, which is a much better compromise.  Other values
are possible, depending on exactly what you think the winter/summer sun
ratio is, of course the cloud cover effects come into this too.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
We've slightly trimmed the long signature. Click to see the full one.
Re: 1kW solar grid interactive - update
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Thanks for the update.
I wish I was eligible for the gov rebate :-(
but I might be after it's revised in a few months :-)

PV systems have certainly gone from expensive oddity to mainstream
popularity very quickly, it seem like every man and his dog is installing
one, I feel left behind!

Dave.

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Re: 1kW solar grid interactive - update
On Fri, 15 May 2009 13:25:01 +1000, "David L. Jones"

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I wish I wasn't. :-(

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

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Not sure what you mean, Franc but I have done some digging around on
the issue of photovoltaics, rebates, CO2 reduction etc.  The feed in
tariff and the huge rebate are wonderful for those who can access it
and attractive financially.  However, in terms of climate change and
CO2 reduction, a solar hot water system is far more effective at
reducing CO2 emissions when replacing an electric water heater and
very close to replacing a high efficiency gas hot water system.  If
you want to do something for climate change, consider the solar hot
water system well ahead of the PV panel.  The rebate per tonne of CO2
reduction of a PV system is about 24 times that of a solar hot water
system not even considering the feed-in tariff (my calc for Canberra).

You can get info on comparative emission reductions here:
http://www.yourhome.gov.au/technical/index.html

see the section on energy use.

Think twice before going the PV route.

Glenn

Re: 1kW solar grid interactive - update
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He means he wishes his household income was over the $100K solar rebate
means test limit.
Under $100K and you can get the $8K solar rebate, with a few installers
saying they'll install it for that price (so it's supposedly free)
Over $100K and you get zip, so no incentive at all to install a solar
system.
It's just like the Rudd Money - you get all excited about getting it until
you realise you have to earn not a large amount of money in order to
qualify.

The means test is supposed to be gone at the end of June, hopefully a rebate
of some form stays so I can get my own system.

Dave.
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Re: 1kW solar grid interactive - update
If you dont mind me asking - what supplier / cost did you have for a
Sharp/Fronius system ?



Re: 1kW solar grid interactive - update

:If you dont mind me asking - what supplier / cost did you have for a
:Sharp/Fronius system ?
:

http://www.enviro-friendly.com/default.shtml

After rebates the out of pocket expense was $5,334. This does not include the
meter changeover fee charged by the local supply authority.

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The WA state government is giving Verve Energy $100 million dollars to
upgrade the 40 year old A and B units at Muja Power Station. Apparently
they predict a shortage of power in 2012 and 2013 so if they can keep
the units going it might get them through the summer. Those units have
been base load generators for pretty much their whole lives, pretty
impressive!

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Running the inverter at its design limit will reduce its reliability.

Sylvia.

Re: 1kW solar grid interactive - update

:> My Sharp/Fronius 1kW system has been pumping around 5kW/hr back into the
system
:> on a daily basis since it started running on the 5th May. Perth is
experiencing
:> an extended Autumn with sunny days in the mid 20's and no rain, so that is
quite
:> good performance. It should do a lot better in full Summer. Our 2 person
:> household averages a consumption of around 7kW/hr per day and it is now down
to
:> 2kW/hr per day.
:>
:> Today's West Australian reported on the state budget released yesterday and
this
:> sort of news
http://www.thewest.com.au/default.aspx?MenuID77%&ContentID14%1680
:> makes me feel a whole lot happier still.
:>
:> In the budget it was also announced that WA would adopt a gross feed-in
tariff
:> of up to $0.60 per kW/hr for renewable energy sources so currently I stand to
:> make a profit of about $2.60 per day. Of course, as the price of electricity
:> increases, the profit margin will drop - unless the FiT also increases (which
I
:> doubt). I am now considering increasing my PV array by 4 x 175W panels to
take
:> it to the maximum capacity for the existing inverter.
:
:Running the inverter at its design limit will reduce its reliability.
:
:Sylvia.


The latest model Fronius IG15 is nominally 1.5kW but rated for 2kW peak so I am
certain it will handle the extra 4 panels without any loss of efficiency.

Re: 1kW solar grid interactive - update
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I wasn't thinking about efficiency, but reliability. That is, how long
it will work, on average, before you have to get it repaired or replaced.

My guess would be that the peak is based on the thermal inertia of the
heat sinks, and the nominal based on the dissipation rate from the heat
sinks.

The higher the power you run it at, the hotter it will run. Hotter
typically means less reliable.

Sylvia.

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