Solar Panels Go 3D
Solar cells on a house or building are basically flat panels arranged to face the sun. But recently a team of researchers at the Massachusetts Institute of Technology asked why it had to be that way. In the process, they found that cube- or tower-shaped solar cells might be a better design, especially in locations far north of the equator.
Using a computer algorithm, the researchers, led by Jeffrey Grossman, associate professor of power engineering, looked at a huge variety of configurations and tested them at different latitudes. Then they built three of those designs, putting the panels on the roof of an MIT building.
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They found that the designs produced 20 times more power than fixed flat panels that took up the same amount of space. The reason is actually simple: If you have a combination of vertical and horizontal panels, the former will pick up more energy in the mornings and evenings, when the sun's rays hit them more directly. A horizontal or angled panel will tend to get the biggest power outputs at noon.
The difference is most pronounced at high latitudes — say, northern Alaska or Tierra del Fuego. In those areas, the sun never gets very far above the horizon for a big part of the year.
Motorized solar panels can track the sun, of course, but those motors eat up the energy being harvested. Tower-like configurations don't have motors and don't need to track the sun. A towering shape also avoids some of the problem of shadowing, since the blocked panels are offset by those still exposed to the sun.
One drawback is the cost of the panel structures themselves. Initially it will likely be higher, as making a dimpled cube shape is more complicated than a flat panel. But it may be that a simple cube is nearly as good.
The team will be testing that aspect next, seeing which shapes or configurations work best. One idea is an accordion-shaped design that could fold up for shipping.
Credit: MIT / Allegra Boverman