Tracking solar collector without electronics (2011) [video] | Hacker News Reader

Tracking solar collector without electronics (2011) [video]

youtube.com

54 pointsdmos6231 comments

Electronics are incredibly cheap and an electronic version would be smaller, lighter and more reliable.

I definitely appreciate the effort and am very interested in similar approaches, but for commercial use, electronics based systems are very cost effective, especially if engineered for a specific project and optimized.

This is meant for third-world countries where you need easily maintainable and accessible components. Plus, using electronics implies an infrastructure that we take for granted: it's more complicated in rural third-world.

You see that reflector, gears, evaporating liquid stuff in the solution, yeah that will not last 3 months in a rural area. For a rural area, this is a complex setup.

In 1 week, you would either have bird shit all over the control mechanism light reflector, probably have a bird build a nest in it, or perhaps have a flying piece of plastic tangle in the mechanism.

Electronics does not imply an infrastructure we take for granted. Just look at mobile phone usage in African countries. No one thought mobile phones are a bad idea because they don't have the infrastructure to repair them.

A motor controller with a motor attached is cheap, can be made to work for years, sealed off in a water proof and dust proof container, and still be configured with bluetooth.

And, the infrastructure problem you talk about, that will only be solved with consumers in the first place.

No one in Africa built a mobile repair business without the phones being their first.

Sorry, your perspective is negative and counter productive.

Look, you could be right. I don't really know what the supply dynamics are anywhere in the third world. The author does travel the third world for humanitarian purposes, so I'm making guesses based on that. This project, that was posted ~9 years ago, is the most complicated project he posted. His newer projects are mostly simpler and he did create electric wind and hydro turbines. So I'd guess electricity is a problem at least some places and electronics are accessible enough to consider these projects.

High-humidity areas will destroy any electronics. For example, you can literally watch mold grow on a wall in the Bali interior.

That's very clever, but wouldn't a simpler way to track the sun without electronics be to use a mechanical clock set to local solar time?

You'd have to rewind it and adjust the time slightly every few days, but then the mechanism in the video doesn't appear to have any way to return at the end of the day, so probably has to be reset daily anyway.

If you read the comments on the video he states he doesn’t have return mechanism set up yet but has some firm ideas on how to do it but just needs the time to do it.

That's a cool idea, though a mechanical clock could be hard to come by in certain places. Most of the things this guy makes are meant to be very cheap and accessible in the third world. I recommend his channel. A lot of fun low-tech stuff like DIY water filters in Uganda, a vertical wind turbine, a "Kiwi" DIY wind tunnel for that wind turbine (mounting it on a car and going for a drive).

You can make crude mechanical clockwork out of wood.

E.g. https://www.lisaboyer.com/Claytonsite/Claytonsite1.htm

These are obviously more elaborate than you'd need because they're artwork as well as functional clocks. (Some are just kinetic sculptures.)

Or you could just have a length of black hose in the sun without the solar collector at all. When the area of hose seen by the sun is the same area as the collector opening, the hose will be receiving the same amount of solar energy as the collector could provide.

That's interesting. In the 70's Steve Baer (Zomeworks) was doing this sort of thing using freon, which obviously became a chemical-non-grata. The zomeworks trackers didn't use gearing, just weight transfer between two freon canisters on either side of the solar receiver. It's nice that ethanol can be used in a similar way.

Probably water can be used in the same way, if the collector was larger.

Commercial application using wax cylinder: https://www.sulasindustries.com/media

Why wax? Is it unique in how it expands/contracts when heated/cooled?

Some info here: (About Paraffin Wax Technology)

https://www.sulasindustries.com/technology/

My guess is low/proven tech result in high reliability. Wax contract cycle return panel to face East for the next day

Wax has a very high expansion coefficient and is dirt cheap. Also, the force an expanding column of wax exerts is substantial compared to the size of the column of wax so you can use it to drive mechanical devices directly.

This principle has been used in a - now defunct - model of insulin pump.

Thanks for posting that. I like the creativity of the original post’s DIY solution, but I’m happy to see there is an engineered solution that is commercially available. That the solution is nearly identical to the DIY validates the OP’s design, but the commercial solution is both simpler and looks more reliable. Perhaps it relies on more machined components, but that should still be within the capabilities of a 3rd world machine shop.

I wonder how they deal with the clouds. Doesn't the system reset to the east and stay there till the next morning? How can it pick up after hour or two of clouds?

Nah, just another Rube Goldberg machine.

Deep parabolic mirror, hugely inefficient. Huge amount of materials to control the orientation.

If you split all the materials, you could have built two collectors facing different directions. You would not need much more space because a lot is already wasted. You would get better efficiency because for portion of the time both collectors would be operation.

I know it is nothing special, but I personally like simple designs that work dependably.

Nice to see this on here!

Also worth checking out the creator's $30 windturbine [1]

He also runs an active community on facebook around the designs [2]

[1] https://opensourcelowtech.org/wind_turbine.html [2] https://www.facebook.com/groups/windturbinemakers/

I think this is incredibly neat and when I see things like this often wonder what a person with such creativity could do if they had more free time and money.

I enjoyed his UN conference interview https://www.youtube.com/watch?v=bJGc5Jv6wr8 sounds like he spends part of his time doing workshops in the West and the other doing workshops in the global South, as he calls it.

I really enjoy his videos, however there was one where he created a packed bed filter and suggested it made the water safe. It certainly makes the water look cleaner but that is a long way from being safe to drink.

It made me think twice about his credentials.

If you expose water to sunlight UV, it will sterilize.

Absolutely, if the sun is able to penetrate (the container is UV transparent i.e. plastic bottles) and there aren't large clumps in the water which protect the pathogens from exposure. Which would make a packed bed filter a reasonable pre-filter before bottling and leaving in the sun for a number of hours. However, that wasn't what he said in the video, which was that the water hadn't been tested but was probably safe to drink.

I once saw a very elegant solar tracking mechanism with no moving parts. The panel array was hinged to swivel freely. 2 solid tanks sat below the fore and aft edges, and were connected by a solid copper tube.

As the sun moved though the sky, if one tank got more light, a working fluid would move from one to the other moving the center of mass. This caused the panel to swing to bringing them back into equilibrium.

Can these mechanisms recover from cloudy periods?

I suspect one can do something like this with a bimetallic strip that bends when heated, which can move the collector. You'd also need another bimetallic strip in the shade so that the movement is based on the temperature differential, not the temperature value.

The same machine but in action (time lapse)

https://www.youtube.com/watch?v=Lva3bm3psyI

OR, instead of a parabola, use the same space and cost in materials to aim several solar panels in different directions?

Not really 'tracking' but neither is the OP I don't think. Relies of the parabola to correct for angle. But sacrifices available surface area.

Single axis tracking is typical.

Reply on news.ycombinator.com