Solar tracking

[wpowokal]

Around 12 months ago I asked on this board about tracking solar panels,

I have now completed test tracking 4 panels on an old tracker,

with encouraging results.

The system is 24v, the maximum output from the 4 test panels when

in a fixed position was 5.5 amps (7.3 amps when tracked)

with a combined rated wattage of 130.

The remaining fixed panels have a combined wattage of 1060

with peak output of 33.6 amps on the test days.

The test was done on two consecutive days, slight variations in

figures on the test group are due to my not having adjusted

the array for some time.

Most articles on tracking solar panels report an increased output of 30%

for tracked panels. In my test I found this to be correct at peak sun

but the overall increase was in the order of 100%.

The extra power is picked up on the shoulder periods, the tracked

array went to 64% output at first sun while the fixed panels took 2.5 hour

to reach 60%. Likewise at the end of the day the tracked array was at 33%

just prior to sundown while the fixed was at 2% and was at 30%

some 1.5 hours earlier.

I looked at the results as a percentage of possible full output

and amp-hours achieved on the day from each installation.

While I have not designed and costed the hardware side of new trackers

this will definatly be a Autumn project for me.

Its summer here(south west Australia) and maybe I will not have such gains in winter

as the sun is lower in the sky all day and the fixed array will be focused

for greater periods. My low power period is autumn when we usually

have sun but no winds.

In the photo the columns are from left,

Time of day

Minuets in that period

Output amps of tracked array

Percentage of maximum possible output

Amp-hours

Fixed panels amps

Fixed panels percentage of possible output

Amp-hours

System volts

Amp-hours of tracked array if it was fixed using output percentage from other fixed arrays.  

[TomW]

Allan;

Nice writeup!

I find that I gain a LOT of additional power by tracking. Just like you, it is more obvious early and late.

Nice to see some data on it.

Thanks.

Cheers.

TomW

[ghurd]

I do not understand some of the figures.

A panel on a different mounting bracket increased the output from 5.5a to 7.3a?

A pv on a tracker is 300% better than fixed?

Just confused.

G-

[wpowokal]

Ghurd,

      All my fixed panels are on mounts which are unable to have their angle changed, ie no seasonal adjustmen possible.

By placing the test panels on the tracker I was able to achieve the best possible angle.

I guess it realy says my origional/existing mounts are a long way from satisfactory.

Allan

[BT Humble]

All my fixed panels are on mounts which are unable to have their angle changed, ie no seasonal adjustmen possible.

It's an impressive improvement with the tracker, no doubt about it.  I personally like the no-maintenance aspect of a solar panel, I think it's one of the most fantastic machines ever invented.  However, I do feel that any fixed installation needs at least an altitude adjustment for summer/winter positioning.  This makes a substantial difference to those "shoulder" periods you were talking about.  

Here's some pictures of the racks I made for my panels, mounted on a flat roof:

http://www.geocities.com/za2bb/solar/index.html

If you can't have an adjustable rack, then set it to the winter angle - you have more hours of daylight in the summer which makes up for the sub-optimal angle.

BTH

[pyrocasto]

Oh good, my tracker is almost done. I just have to make a mount for the extending part of the actuator. I tested it out tonight and everything looks good. I'm guessing I'm getting about 160 degrees or so of turn.

[Trivo]

Hi Allan

Im in perth and travel down south a bit would like to have a look if ok

Trivo

[wpowokal]

Hi Trivo,

         General directions, go to Wokalup stand in front of the pub look at the hills, that's us. go another 500m south turn left follow the gravel to the end.

For more info 'e' mail me at, my board name @ bigpond.com

Allan

[wpowokal]

Ok people lets be quite clear here my results are how I can improve my current situation.

I am convinced that there is conciderable power to be collected from

tracking, certinally above the quoted 30%. Also fine adjustment is critical,

 I am manually adjusting these panels so can monitor the fine adjustments.

From the way I currently have my panels mounted I can basically double my power.

I have a clear view from sun rise to sun set. Of course this is relative to

how the panels are mounted, others will have different situations.

No where in my origional reserch was there any explination of how much

extra power was available in the sholder periods, that is the crux of this test.

regards allan

[ghurd]

Now it makes sense to me!

That is the best usable data I have seen for trackers.  30% is what I usually see quoted too.  I figured it had to be higher.

Good work!

G-

[johnlm]

I like it, a man after my own approach.  Real honest to goodness data so that everyone can glean the info they want.  I say this as many posts have very vague info about testing results.  Good job.

Johnlm

[troy]

Although, in all fairness, you should compare you're tracker to an optimized fixed mount that you adjust quarterly.  If you have a crummy fixed mount, then it's easy to show big gains in total output.  The other criticism of trackers that is often heard is that they make the biggest difference in the summertime, not in the winter when you need it the most.

Having said all that, TRACKERS ARE WAAAAY COOL! There is no more compelling sight than a tracked array of PV's, with the possible exception of a wind turbine doint its thing.  One of the most fascinating things I ever saw was a short (~30 second) film using lapsed time photography of a tracked solar array with a 'mill in the background hunting the wind.  Really looked like they were alive.

Best,

troy

[ghurd]

I had a cool demo unit for a while.

About a foot tall, a 2w PV, and a control with 2 mini PVs aimed East / West from each other, with a little flat shade sticking out between them. No batteries.

The main PV ran the tracker motor, the 2 mini PVs decided where the sun was.

Artificial Intelligence???

I watched it do its thing more hours than I care to admit.

G-

[pyrocasto]

Yeah that's cool how it works. You use two solar cells(or leds, or whatnot)slightly angled away from each other. When the sun is shining more on one, it tells the circuit to turn the motor, until the power in both cells are the same.

It works the same way the RedRok tracker should.

I'm still waiting on one bracket, and my tracker can go on my roof. I'm so excited, and I'll be sure to create a time lapse movie of it.