Urban Urchin


It is well-known that cities are getting hotter and hotter every year. Because the trees and landscape have been replaced by concrete and hard surfaces, the temperature of urban areas are slowly escalating, making outdoor recreation during the summer unbearable. It is only natural for residents to seek comfort in air conditioned buildings to escape from the heat. But, given more artificially shaded areas, the option of spending time outdoors during the hottest times of year may be feasible, and, if done right, the culture of hiding indoors can be reversed.

Urban Urchin is a project that proposes a new outdoor culture for Holon and for Holon residents. Its large iconic shape is intended to raise awareness amongst the greater public to consider alternatives to spending more time indoors. Taking inspiration from local Mediterranean Sea organisms, the sea urchin (echinoid or sea hedgehog) is an animal that is familiar to all. It reacts to touch by moving its spiny tendrils. Urban Urchin also moves its articulated pieces, but, unlike the sea urchin, it reacts to the sun's rays. The 24' tall organism is made from a clear, inflatable structure, where the geometry is determined by the performance of the thermobimetal attached to its underbelly, relative to the moving sun over the course of a summer day. Curling when heated, the thermobimetal canopy is designed to perform differently depending on its location on the surface. Near outer edges, the thermobimetal tiles filters the sun to filter the amount of light that reaches the areas below; In the middle area, the tiles perform as solar reflectors to aim the sun towards the center of the structure; And, in the central area underneath the structure, the bimetal, sandwiched with an insulating material, acts as a valve to allow hot air to escape. The combination of these performances is smoothly pieced together to make a cohesive surface that hugs the belly of the urchin and provides a shimmering space below.

Upon entering the cavity below, the visitor can enjoy the spectacle of being inside a shiny, tessellated cave away from the sun while sitting on concrete pool benches. Added evaporative cooling (light breeze) is provided by the three fans located at the edge of the three pools of water. These fans are operated by the large turbine above, which spins as the hot air escapes through the solar chimney. No electricity is needed in this system. As long as the thermobimetal surface collects, reflects and controls the heat below, the movement of hot air out the top will keep the turbine moving and the fans spinning. The result is a breezy, shady area for a number of visitors below. The spatial experience will be incomparable to any other.

The project is designed to be reproducible and can be assembled and dissembled in a short amount of time. The inflatable structure and concrete benches will be manufactured locally, while the lasercutting of the thermobimetal pieces can be done either locally or abroad. While costs will determine the method of manufacturing, all portions of the project will be engineered according to local requirements.

Design Team: Doris Sung (principal), Justin Kang, Hannah Yi, Dylan Wood, DOSU Studio Architecture
Structural Engineers: Roel Shierbeek, ARUP Engineering
Sustainability Engineers: Russell Fortmeyer, ARUP Engineering
Fluid Dynamic Engineers: Alexej Goehring, ARUP Engineering
Graphic Designer: Michael Faber, DESIGNEST
Product Designer: Oded Lahav, DESIGNEST