A new solar garden in the underground passageway of Jonggak Station, central Seoul, Friday. The backup LED lights are turned on in cloudy weather or at night. / Yonhap
Urban projects tap into city's underground infrastructure
By Lee Suh-yoon
Mini-gardens have become synonymous with urban regeneration projects in Seoul. Some, like the new solar garden at Jonggak Station on Seoul Metro Line 1, are popping up underground.
The solar garden ― small but claimed to be the world's first solar-powered subterranean park ― opened in an underground passageway at Jonggak Station last Friday, placed right in front of the Jongno Book Store and a row of booths selling handcrafted goods made by young artists.
Mandarin trees and verdant bushes grow under natural sunlight, emitted from eight ceiling apertures connected to light-collecting dishes installed directly above at Jongno Tower Square on the ground. The ceiling is dotted with backup LED lights used at night or on cloudy days.
Light-collecting dishes above the solar garden at Jongno Tower Square. Yonhap
"There are limits to what you can grow in underground gardens that are only powered by LED lights. Usually it's just wide, leafy vegetables like lettuce," said O Se-dae, head of the engineering firm in charge of the solar garden project. The company, SunPortal, originally developed the technology to provide healthy doses of natural light to underground offices or dark homes with small windows.
SunPortal is also commissioned for New York's Lowline project, which plans to set up over 100 light-irrigation tubes to light a 1-acre park inside an abandoned trolley terminal in Manhattan. The idea for sunlit underground parks was first conceived by Lowline architect James Ramsey, who also took part in the initial blueprint for Jonggak Station's solar garden, according to the Seoul Metropolitan Government.
It isn't the first time that urban projects have tapped into idle spaces in the city's underground infrastructure. An evacuation bunker discovered in Yeouido in 2005 is being used as an art gallery, while a Japanese-built air-raid shelter next to Gyeonghee Palace and an abandoned Line 2 subway platform similarly hosted temporary public exhibits.
Yeouido SeMA Bunker art gallery / Yonhap
"Seoul has started to make good use of abandoned underground spaces," Seoul Mayor Park Won-soon said during the opening ceremony of the garden. "Creating a garden in this bare underground passageway brings culture to the people."
The garden's light source comes from reflectors closely tracking the sun's movement from Jongno Tower Square. The collected light is redirected underground via a tube of mirrors. Anodized aluminum panels on the ceiling scatter the light around the garden.
SunPortal hopes to improve the technology to the point where the tubes can pull in natural UV rays of 200 and 400 nanometer wavelengths ― a safe range that can sterilize surfaces and purify air inside closed spaces.
"We are also looking into the possibility of underground solar power generation," O said.
Improvement of such light-irrigation technology can unlock new potentials for urban farming. Currently, underground farms ― like the new smart farm at Sangdo Station on Line 7 ― rely entirely on artificial light.
"We'll see if we can harvest these fruits in February," O said, pointing out the citrus fruit trees.
"Smart farm" at Sangdo Station / Yonhap