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Solar panel mounting and tracking. Answered

I have a new video about equatorial mount for solar panels.
If equatorial mount is turned slowly at the right constant speed, then the panels point at the sun all the time.
I also have a diagram about something to get that constant slow speed.

I have it done this way to avoid wind damage.
I think if you did it this way and had a sump pump to pump the water back up every morning the thing could be  automatic, cheap  and very accurate.



7 years ago

I looked at the rack-and-pinion part for a minute or so trying to figure out how it didn't just slowly increase the flow of water as it rotated, then I twigged that the whole assembly lowers as the drum rotates anticlockwise and a lightbulb went on over my head :)

I'd be interested to see how the valve arrangement works out if you build a working prototype- now I'm racking my brains to think of a way a small linear force can control a flow of water.  Perhaps the "kinked hose" type of improvised shutoff valve would work with the arrow closing the kink?

I have not made it. Really the nuts and bolts of experimentation has never been my strong point. I always do something shoddy.
There is a guy associated with the "mecatronics" (merging electronic controls with mecanical devices) course in University of Victoria who says that it would be perfect for the course. A student would design the electronic on off valve, clocking device, etc. BUT I have been caught off guard by optimistic professors before. Sometimes the students want something that is certain to work BEFORE they take it on.
A kinked hose would not work. Too much force needed. It is not much water. I successfully used the rubber tube for old style bicycle valves 20 years ago in a project. I do not think they make that soft thin rubber tube anymore (maybe 2 mm diameter) .
That was for regulation of air into a partial vacuum. Maybe there is an alternative that is similar and about 3 or 4 mm diameter? Maybe for medical machines. The typical clear plastic tubing that they sell in hardware stores, home brew stores, etc is too hard. Any ideas?

Your mention of bicycle valves raises a potential avenue- just remove a presta valve from an inner tube and use that? They seal well so the flow should completely stop when it's closed, and they open with a small linear force. The only problem is you press to open the valve rather than shut it, but that could be solved by reversing the direction of one of the components in the regulator system.

I tried one on my digital kitchen scales and it takes about 0.5 kg to open it fully!
I think the little rubber tube had a much larger internal diameter and it only took 0.2 kg or less to fully close it. (Probably less). I think a thin walled 3mm internal diameter rubber tube would be perfect.
Way back then, there were other bike valves on the market with internal rubber "pistons". The piston went up or down to open or close. This might be more comparable to the rubber tube but with less flow when fully open. But I do not know if these are still on the market.
If we can find the tubing, I am pretty sure it will work well. You only need about 2 inches of the tubing just under the wedge.

I have started an instructable about a half parabolic dish on equatorial mount. (For easy tracking) I have also started an experiment with making the dish. I post about it here because it ties in with this. I have taken a bicycle rim and used it as part of the dish frame. This will allow year round easy access to the food or stirling engine or whatever you put at the focus.
It is also ideal for something like the liquid piston idea to turn the dish to track the sun.
https://www.instructables.com/id/Dual-Parabolic-Dishes-on-Equatorial-mount-and-the/    It will be a while before my experiment is "clean" enough to include but for the moment, it has a facebook album link.
https://www.facebook.com/album.php?aid=278164&id=736625766&l=8b34cdb5e0  This will include additional photos and information  as I get closer to the goal.
I think it will help people make their own versions.  My back yard gets decent sun till the end of September but I might not get time off to get results and to  see how good the thing is.

Did you post this on I'bles a few days ago?  Yup, there it is.  Very nice; thanks!

It'd be great if you edited the topic source above to make the link active (highlight the link, use Ctrl-C to copy it to your paste buffer, then hit the "link" button -- globe and chain -- in the editor, and Ctrl-V paste into the box).

It sounds like you're designing this as a solar heater, rather than a PV system.  Very cool way to maximize efficiency!  How much power does the drive motor take?  Is there enough gain, if you do it PV, to run the motor directly off the panel output and still have net power for other uses?

It can be for either.  PV is much easier to set up on it than solar cooking or heating.
The amount of energy needed to run the mechanism is tiny.
Basically just the stepper motor (or whatever you use for the timing)  In the early morning, it needs to reset, and also in the early morning you could use a 12 volt sump pump or boat pump for about 2 minutes to pump the water back up to the top container. Probably as little as 10 gallons of water would work the beast.
I tried to put all the options in so that is why I try to explain the PV first  and then I spend time on various solar cooking options too.
My preferred solar cooking and heat collection method is the one in this short video.

Thank you!  This is really quite elegant; I'm glad you're willing to document it.