A Better Solar Panel Through Buckets of Water, Rocks

By Bill Andrews | March 6, 2019 11:00 am
solar panel frame

The simple frame that allows a solar panel to track the sun and increase energy production. Buckets would hang from either side. (Credit: Beth Parks)

Rare is the tech story whose main development is decidedly low-tech – but not impossible. Rather than a fancy atomic clock or rat cyborgs, for instance, this tech story deals with buckets of rocks and water. Well, solar panels too, but that’s not the cool new part.

Today, at a meeting of the American Physical Society, Colgate University physicist Beth Parks described a new way to wring even more energy from a solar panel — a major development for people with no access to reliable power, such as those in developing countries or folks who live off-the-grid. Rather than install the panel in a stationary position, Parks helped come up with a rotating frame that allows the panel to follow the sun as it traverses the sky.

Buckets of Fun

Here’s where that high-tech equipment comes in. Rather than use motorized components, Parks’s solar panel rig moves thanks to the power of gravity, using a bucket of rocks and a bucket of water. The former, a stationary weight, hangs off the west side of the rig. Counterbalancing it, on the east side, is the water — but, this bucket has a leak in it.

When it’s heavier, in the morning, it outweighs the rocks, so the solar panel points east, toward the sun. In the evening, after leaking all day, the bucket is lighter than the rocks, so the panel points westward, toward the sun. And in between, Parks got the panel to roughly follow the sun from east to west by controlling the rate of leaking water (a phenomenon familiar to any calculus student).

It’s the kind of idea that’s so simple, it really works. Over 20 random days of testing, the bucket-powered solar cell collected 32 percent more energy than a stationary setup nearby. That’s nearly a third more energy, all thanks to a couple of buckets!

Solar Panel Power

Parks came up with the idea, and tested it, during a year in in Uganda, where she worked with students at the Mbarara University of Science and Technology. They were careful to make the frame itself simple enough for local welders anywhere in the world to create.

Parks also calculated that the total cost of her setup — including the panel itself, a charger and the rotating frame (buckets not included I guess) — was about 10 percent less than the equivalent for a standard rooftop setup. So not only does this new design capture more energy, it actually costs less to use it.

Parks hopes her design can help people who live without reliable access to electricity (as about 70 percent of Ugandans do), where just keeping a phone charged and the lights on can involve long treks and hazardous conditions. With any luck, households and small businesses the world over might now have cheaper access to more energy.

And, not insignificantly, it’s an energy-efficient means of exploiting clean, renewable solar power. So it turns out this rare kind of low-tech tech story is also that rare environmental story — the kind with a happy ending.

CATEGORIZED UNDER: Technology, top posts
MORE ABOUT: energy
  • Occasional-Cortex

    1/3 of global green house gas output is by underdeveloped countries. They need low tech solutions like this to put a dent in that.

  • Nom de Plume

    The first thing that came to mind was “Where are they going to get the water?” That’s not a trivial question in many parts of the world, and while you can save and reuse the water, that might not be a good idea for places with mosquitoes and waterborne nasties. A simple modification would be to replace water with sand, and would likely be more practical.

    Practicality leads to the second issue. Manual solutions work best on small scales. How well does this scale up? Yes, we’re talking about smallish panels, but how many would be needed for a given application? It’s not a bad idea, but might not be workable on a large enough scale to do any good. But this is where prototyping comes in.

    There might be a better application for this: solar cookers and furnaces. Solar cookers are promoted for places with little fuel to use for cooking, and tracking the sun makes them more efficient. Since these are small, and someone is tending the food anyway, it would likely be more practical to use.

    • KenEb

      Sand is an eloquent solution. On a small scale changing the sand out once a day is less problematic than tending a coal or wood stove.

      • okiejoe

        Yes, the sand could simply drain into another bucket which would be swapped for the empty one like turning an hourglass.
        The sand would have to be kept dry, of course.

  • A. Nonnie Mouse

    An actual practical and reasonable way to deal with energy production that does not produce CO2. Very impressive.


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