World’s Oldest Solar Device

http://cleantechnica.com/2014/06/05/worlds-oldest-solar-device/

World’s Oldest Solar Device
Originally published on Green Building Elements.
By John Perlin

Special thanks to author John Perlin for this contribution about what is believed to be the world’s oldest solar device – a solar ignitor, or yang-sui . The material comes from Perlin’s recently published book, Let It Shine: The 6000-Year Story of Solar Energy.

During the sixth century BCE, Confucius wrote about the common use of curved mirrors shaped from shiny metal to concentrate the rays of the sun for making fire. These became known as yang­­-suis ­­– translating to solar ignitors, or burning mirrors.



According to another early text, the Zhouli, which describes rituals dating far back into Chinese antiquity, “The Directors of the Sun Fire have the duty of transferring with burning mirrors the brilliant flames of the sun to torches for sacrifice.”

Although scholars found over the years many ancient texts discussing solar ignitors, the discovery of an extant yang sui eluded them for centuries. Quite recently came the Eureka moment. Digging up a tomb that dated to about three thousand years ago, a team of archaeologists found in the hand of a skeleton a bowl-shaped metal object. While the inner side could have passed for a wok, the exterior trough had a handle in its center. That’s what caught the eye of the two archaeologist in charge of the dig, Lu Demming and Zhai Keyong. They immediately brought the relic back to the local museum and ordered its specialists to make a mold from the original and then cast a copy in bronze.