Perhaps Archimedes Should Have Focused on Jaguars, Not Galleys

Solar concentrators are a hot weapon in the renewable energy arsenal. Except sometimes they really can be a weapon.
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Solar concentrators are a hot weapon in the renewable energy arsenal. Except sometimes they really can be a weapon.


Our resident solar energy guru John Perlin asked five years ago if Archimedes had solved our (pre-fracking) energy crisis. His question arose from the promise of a very basic technology—curved shiny surfaces, basically—that concentrates solar rays to boil oil or even salt to “fuel” steam-powered turbines. (And molten salt can also store its heat for weeks, which further debunks the canard that solar can only provide electricity on bright, sunny days.)

Like so many promising technologies, Perlin explained, solar concentration arose from the military. Drawing from a pre-DARPA lab, to be sure, Archimedes (allegedly) weaponzied nice, friendly renewable energy, using curved bronze mirrors to burn up an unfriendly Roman fleet during the Second Punic War. Here’s how a 12th-century translator depicted the climactic, if apocryphal, event:

When Marcellus withdrew them [his ships] a bow-shot, the old man [Archimedes] constructed a kind of hexagonal mirror, and at an interval proportionate to the size of the mirror he set similar small mirrors with four edges, moved by links and by a form of hinge, and made it the centre of the sun's beams—its noon-tide beam, whether in summer or in mid-winter. Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons.

It was an attractive (and sustainable) tale that drew many putative imitators, whether geometricians or generals. Still, modern attempts to replicate this feat have fallen flat, although back in 1747 George Louis LeClerc did fry a model ship in Paris.

But some architects working on London’s Canary Wharf have given a boost to the true believers, creating a giant concave reflector that can shoot a beam hot enough to melt a Jaguar. A 37-story building originally dubbed the Walkie-Talkie (and now the Walkie-Scorchie) focused enough solar energy to cause £1,000 of damage to the Jag, plus other vehicles that were parked at just the right spot—and a doormat to the Re Style barbers. As Ali Akay perceptively explained to the, ahem, Mirror, "Customers are not going to come in if there is a fire in the front of the door."

"Fundamentally it's reflection,” Chris Shepherd of the Institute of Physics told the BBC. “If a building creates enough of a curve with a series of flat windows, which act like mirrors, the reflections all converge at one point, focusing and concentrating the light.”

The building isn’t yet finished, giving builders a chance to remedy the situation—which they say depends on a rather precise position of the sun that will only recur a few weeks out of the year.

These aren’t the first buildings providing a hot time in the old town tonight. Frank Gehry’s curvy, stainless-steel clad Walt Disney Concert Hall heated up condos across the street on sunny afternoons, turning local residents’ hoped-for mid-day views into eye-melting glare. And the Walkie-Talkie’s own architect, Rafael Viñoly, was responsible for Vegas’ Vdara hotel, which parboiled some poolside guests. A personal injury attorney likened the noontime blast to a “death ray,” which might have warmed the heart of Archimedes had it instead occurred at, say Caesar’s Palace....

There is one building, though, that might want to embrace this old/new architectural feature: the Pentagon.