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VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 02:29am 22 May 2010

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Hi Neil

I agree with that as a concept but it would mean that they would have to derate the panels and that isn't a good marketing tool so I don't think we will see it happen.

I think a good freestanding tracker in the middle of the vegie garden is the best compromise.

All the best

Bob

Foolin Around

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 03:39am 22 May 2010

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Hi Neil0mac,

No I won't be testing different panel positions.

I live in a location where there are a few hot days in summer, but a lot of the time, the wind comes from the southern ocean, and in summer, the max day temp is in the low 20's.

Gordon.

become more energy aware

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 05:15am 22 May 2010

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I think Bob is on the money with his comment of how panels are rated.

Panels are rated in respect to where the testing was done, so you can not expect it to suit any one location across the board.

As for cooling of panels to % of gain returned, i would surgest you do the full testing and report the results to all.

I have been involved with setup of solar systems and the logging of data in respect to tests done, and what you think, and what shows as actual fact, is often two very different things.

I would say monitor and log your panels preformance in relation to temperture and output for some time than do the alterations and again log the results to compare the actual data to see what the % of difference is.

Reading the odd peek and troughs dont really tell you a darn thing, its output verses time is where the interesting information is.

To kick the cat around is not telling you anything, but if you collect actual data it will tell you all you want to know.

I have seen the output curves of actual data verses conditions and think you should do the same to be better informed.

It would not be very hard to monitor, air temp, panel temp, and panel output to see exactly what you are on about here.

It would soon prove to you and everyone if there is worthwhile benefits in your theorys.

Concepts is a great thing, but proof of concept is the important part.

And no i dont live in Sibera.

Pete.

Sometimes it just works

KarlJ

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Joined: 19/05/2008
Location: Australia
Posts: 1178

Posted: 03:14pm 22 May 2010

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Neil there is always the PVCOOL panels that Valeri sells, I think he's in the 2.50/W range and then concentrators etc etc.

I think for non concentrated array the cooling is too much work but for a concentrator cooling must be on the list of must haves.

I still think Valeri's PVCOOL STS4 solar concentrator is a good piece of kit and with upscaling is the only way to get BIG bang for the 10KW panel limit for FIT 0.60.

If the tracking and concentrating is good for 50%+ more output then obviously it is going to pay real dividends.

Karl

Luck favours the well prepared

SSW_squall

Senior Member

Joined: 20/03/2010
Location: Australia
Posts: 111

Posted: 03:00pm 23 May 2010

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A couple of thoughts and observations:

We bought a breeze air avaporative A/C unit (Bloody awesome, easy on the power and made in SA) and on 40deg days the air temp coming out of the vent is a nice 26 deg, however by the time the air vents out of the windows it's above 30 degrees.
Even though a revese split system would have been much less hassle as we have a flat roof, with no roof space.
I've got the ducting for the evap coming in a floor level, which is quite unconventional. By opening the top lovered windows the cool air displaces the hot air from the floor upwards, a technique normally used for airconditioning large tall spaces. However it does actually work quite well.

Getting the air to actually cool the panel is the biggest problem, i don't think 32 or 40 deg is really the issue.
Ducting the air across the back of the panel could help have the desired effect:
In other words enclosing the the back of the panel with some polycarbonate sheeting or something and using some 12V 120mm fans to blow the air up towards a slot at the top of the angled panels.
Give a couple of these fans might use about 7 watts (powered of an additional solar panel) it would be interesting to see if this resulted in a net energy gain...
I would give it at least a 50% chance of working???

Black and white objects do make a difference in the sun, because we sell outdoor loudspeaker which come painted either black or white this gave me cause to do an experiment...
On one of those bloody hot day 41deg days i left the one of each out in the sun attached to the tin wall of our warehouse shed, as this would be a good worst case test.
The wall was sitting at about 65 deg (hot enough to poach an egg)
The black outdoor speaker: 56 deg
The white outdoor speaker: 47 deg
Almost 10 deg cooler!!

While on the subject of black:
As if buying a black car isn't bad enough, where every scrach and spec of dust shows up.
I can't believe ther are morons out there who think it's fashionable to have a JET BLACK corrugated iron roof on there house in Australia??
I struggle to think of anything more energy ignorant and stupid.
Aside form the extra thermal load imposed on the building, it's not going look very fashionable in 5-10 years time when the black has faded to a mottled grey-brown colour.
Still there nothing another $399 split system AC can't fix...

AB

Einstein: Everything should be made as simple as possible, but not one bit simpler

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