Australasian Science: Australia's authority on science since 1938

3D Layering Puts Solar on Track

By Stephen Luntz

Solar panels structured like a chessboard, where the white squares are slightly raised compared with the black squares, could reduce the cost of tracking the sun, helping to spread energy generation more evenly throughout the day.

Heliotropic flowers long ago recognised that the best way to maximise warmth is to turn through the day to follow the sun. Solar panels that do the same thing can generate 30–40% more electricity, depending on latitude. Moreover, the increased power occurs at times when demand is high but solar supply would otherwise be low, exactly when it is needed most.

Unfortunately, solar panels tilted to catch the sun can also act like a sail in high winds, necessitating not only motors to drive their movement through the day but strong mounting to prevent them from being torn off. The costs are often greater than simply adding more stationary panels.

“The decision whether to use tracking on a megawatt system depends on wind conditions, the cost of land, the latitude and whether the land beneath is being used for something else like commercial grazing,” says Ross Edgar, a PhD student at the Australian National University’s College of Engineering and Computer Science. Nevertheless, most large solar plants do not track, and tracking is unsuited to residential systems.

But Edgar has a solution. By raising half the cells in a panel he creates vents that reduce the pressure of the wind. Testing in a wind tunnel confirmed that the double-layer orthogonal-offset panel (DLOOP) allows 20% more cells on the same tracking device or the capacity to face winds 10% stronger than solid panels could handle.

“I think it will also help with cooling,” Edgar says. This is important, as panels lose 0.4% efficiency for every degree centigrade above their ideal temperature, and this can become significant in hot conditions.

Edgar says that DLOOP would not be suitable for stationary use since “the higher level would shade parts of the lower level for parts of the day”.

Edgar says the idea is new, and he is now trying to interest manufacturers. He doubts the insertion of struts to support the raised cells will greatly increase the cost of manufacturing since “even classical flat panels have a 3D structure to hold them up”.

He says that if he cannot get existing manufacturers involved he may build layered panels and tracking systems himself.