SOLAR TRACKING SYSTEMS

Never mind that. I was still thinking of this as a little hobby thing and you're thinking of a big array.

OK I agree, It's a bit like "feel good" recycling. But I pay ~$1-200 a year (I'm not sure the exact number.) to buy all my electricity from the nearby wind mills. (I heard at one time that less than 1% of the nyseg customers signed up for this program... which again tells you something about "greenies".) To me wind power seems like a technology that mostly makes economic sense*, (I guess I won't know for sure till 20 years from now, are they still spinning?... and sure some are going to spin up and catch fire..) But you oppose wind power, (I think mostly because it falls on the wrong side of the silly dem./ rep. divide.)

George H.

• the farmers are getting ~-10k per year per windmill, and the windfarm projects pay taxes, which cuts everyone else's in the rather small rural towns. Kinda like oil in Alaska, but on a smaller scale.

OK I only looked at 2, (I'm at home w/limited download) but those don't look like tracking mounts, but wind damage to fixed installations.

We need an educated public that can make real science decisions, that seems impossible in the current political climate. (I'm trying to ignore politics and watch sports.)

George H.

On Thu, 22 Oct 2015 16:32:15 -0700 (PDT), George Herold Gave us:

Wind power and solar power are both TEMPORAL sources.

Oh look.... No sun. == NO POWER.

Oh look.... No wind. == NO POWER.

Power generation centers MUST have a ready-to-run 24/7/365 power generating capability at ALL times.

Renewable sources like wind and solar will NEVER be enough because folks turn their lights on at different times.

Cramer had the CEO of AEP on MAM today and he explained it quite well.

Coal fired generation is going to be around for a long time to come unless we embrace nuclear again (I am all for that actually) or get fusion reaction out of the "be ready in ten years" 20 times over slump it is in.

Why do you lump wind power with solar? to me these are two very different things.

George H.

I don't so much oppose wind power as I oppose subsidies. Well, chewing up birds is not nice.

I suspect that windmills will not be very reliable in the long term. The intermittent power output of wind and solar means they can't scale very well.

Fracking has removed any rational basis for most wind and solar power. Sure, if you're way out in the boonies, growing weed, off the grid, go solar if you want to. But pay for it yourself.

Uh, where does that money come from?

On Thu, 22 Oct 2015 16:50:38 -0700 (PDT), George Herold Gave us:

Funny that you would ask that just under the line where I stated that they are both temporal forms of renewable energy.

Are you always that thick?

Exactly, and an often overlooked aspect of home-brew trackers.

Do you know how the subsidies compare with big oil tax breaks? They stopped building wind here, so I think the subsidies have stopped.

I don't know yet about long term reliability, but intermittent power is certainly correct. I'm a think nuclear is the way to go, but I'm in the minority. I don't know about more or less CO2. In the short term, till we figure out if we want more or less CO2 I think we should limit it if we can.

And what about biomass fuels. I want to burn the trees in my woods. That seems very "green" to me. NYS thinks otherwise. Energy policy in the US seems silly to me. Oh, did I say I'm totally for fracking. That would help the local farmers around here too. In the short term natural gas is a total win! (How can this not be obvious to the rest of NYS?)

George H.

Like this? I think I mentioned one in this thread as a way for the panel to follow a groove in a template.

Yep, however there's a problem. Pantographs and similar kinematic contraptions trade range of motion for force. The tiny motor in the telescope drive might move a small distance and provide very limited force (torque). A pantograph that is expected to swing a 500 lb panel is going to need plenty of force (unless you want to balance the panels and float the pivot point on an air bearing). The telescope drive might be able to push the panels around on a frictionless bearing, but put a few birds on the upper edge of the panels, and everything would come to a grinding halt. The big astronomically expensive telescopes are very well balanced and are moved around with amazingly small motor drives. That can be done in a fairly well controlled environment, such as under a dome. Don't even think of it in the hostile environment of the great outdoors. More power than what can be provided by your department store telescope drive will surely be necessary.

No technical project ever succeeds unless it has a catchy acronym. Try again please.

Wattsun claims: "Get up to 40% more power from your PV system by using the

your power production compared to fixed racks or single-axis trackers." I've seen other claims that are usually around 30% increase in output. I have no idea where they get their numbers.

My own small scale experiments result in only about a 5% increase in output because I have a very narrow view of the sky due to surrounding tall trees, hills and buildings. Since the greatest advantage of a tracker is to catch the low angle light, which is blocked by these objects, I saw little benefit. To obtain a 40% increase, I suspect it was calculated based on large open areas, such as the US midwest or great plains. Methinks you're correct that trackers are of little or no economic benefit for most sites. The problem is that you can't easily install a big tracker on a rooftop, eliminating the huge number of rooftop grid tied systems as likely candidates. It only works with a ground mounted pole, where the surrounding clutter reduce the benefits.

Some detail on what a dual axis tracker looks like: The retail price is about $6,400 but there are cheaper models.

Saving money isn't cheap.

Trackers are usually ground mounted, where there's much less wind than on a rooftop. A few big sun farms have wind sensors that allow for automatic feathering (pointing straight up) to reduce wind loading. There are standards for solar array wind (and snow) loading. The roof mounted panels are covered under ASCE Standard 7-05 which has been incorporated into most building codes. However, it doesn't cover trackers (because trackers are usually not mounted on roof tops). There's probably something on the wind resistance of pole and ground mounted arrays, but Ubuntu 15.10 was just released and updating all my Linux boxes takes priority.

Even cheaper is to just add additional panels to make up the difference of tracking and not tracking. What do you lose with a fixed setup verses a tracking one? Maybe 30%. It might be cheaper to just buy 30% more solar array and forget about the complex tracking.

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On Thu, 22 Oct 2015 18:46:05 -0700, Jeff Liebermann Gave us:

I did not say to move the panel with the telescope motor. I said move a controller arm, which is sensed and followed by a PLC motor controller which is capable of moving the panel.

Did you miss that? The pantograph paradigm makes a larger drawing scaled and match to a follower tracing a smaller drawing.. I am not suggesting magnifying a force, I am suggesting creating a simple follower. Call it a smart hand turning a potentiometer attached to the actuator drive.

I did not need a primer on power in equals power out.

I suggested using a machine strong enough for the job, and making the telescope drive the hand of God which controls the machine.

So it isn't about kinematics at all as I am not suggesting using the scope motor to move the panel. The scope motor only moves the controller arm which controls the actuator which moves the panel.

On the mountain top systems used to run a remote radio site, the designers with a clue would put gaps between the ground mounted panels in order to reduce the wind loading. I've also seen rubber shock mounts in order to dampen vibrations. However, no trackers on mountain tops yet. The gaps seem to work as many of these arrays have survived 100+ mph winds.

Sigh. My view of product design is that one has 3 possible alternatives.

1. Educate the public so that they understand what they are buying. This has failed miserably because the production of fools and idiots greatly exceed the ability of society to educate the GUM (great unwashed masses). Most of the GUM resist education anyway and much prefer superstition, conjecture, and recycled opinions.
2. Build an idiot proof product. This has failed miserably because we are more adept at producing idiots than idiot proof products.
3. Build throw away products where the financial damage caused by inept design and inept users is minimal. This seems to be the current design strategy, which is unfortunately working quite well.

Watching sports seems like a good idea...

On Thu, 22 Oct 2015 19:19:42 -0700, Jeff Liebermann Gave us:

big snip

You could use a simple garage door opener, which is a reduction geared sprocket crawling on a tensioned length of chain.

On Thu, 22 Oct 2015 19:48:15 -0700, Jeff Liebermann Gave us:

Instead of doing an online "dist-upgrade", you should DL the danged iso and burn a disc or discs. Place them into the machine and it will ask you if you want to upgrade.

Then do the apt-get update&& upgrade thing.

I have found this method to be less bandwidth intensive and more hands free as well.

I even use daily isos from the up-n-coming releases that are not even out yet. I am a bit wily in that respect.

Wily Werewolf Ubuntu Studio (the best one IMO):

Yep. I was thinking of 8.5x11 inches. Gluing the laser printer printout to a cutting board would probably be good enough.

Incidentally, one of the first trackers I helped build (in about 1975) was based on two plywood cams. The horizontal azimuth cam was run by a clock motor. The vertical elevation cam was run manually by a hand crank. Motion was provided by a heavily greased cam follower bearing. It was intended as a demonstration and conceptual model, not a practical device. However, it ran a 1 meter parabolic dish, RF noise amp, and thermal paper tape data logger for about 3 years before it was knocked over by a lunatic teenager and his motorcycle.

Erector sets, Legos, and kinematics are fun.

Incidentally, it's my understanding that one can find quadrant phototransistor arrays, with perpendicular optical barriers between cells, that were once used for air to air missiles. They would lock onto the IR from the jet exhaust and follow it as the target attempted evasive maneuvers. Same with laser dot following missiles. Much of the optical sun tracking technology probably came from these systems (or was it the other way around): Such contrivances would make a tolerable optical sun tracker.

Sometimes great ideas don't scale well. In this case, the problem is that solar trackers are expected to be powered by a battery charged by the solar charging system. Usually, it's an auxiliary battery that's independent of the main battery pile so that any maintenance on the pile will not shut down the tracker (which then has to be oriented). The AC power necessary to run a garage door opener chain drive is non-trivial, and will probably run down the battery.

First, you offer an underpowered telescope drive. Now, you suggest an overkill chain drive. Perhaps offering something that matches the needs and capabilities of the system might be more useful? You might learn something from looking at commercial systems. Most use linear actuators for elevation, and worm gear drives for azimuth.