OPEN unveils the design for Sun Tower

OPEN has revealed the design of its Sun Tower project under construction on the coast of Yantai, a booming city on the Yellow Sea coast. Recipient of the special Jeu d’Esprit award from the AR Future Project Awards 2021, the Sun Tower includes a semi-outdoor theatre on the ground, a winding exhibition space and a library. The building also has a unique semi-outdoor space at the top, called the ‘phenomena space’, designed for people to observe the magnificent natural phenomena throughout the year. The city wanted to create a landmark on the coast, its rapidly developing new district, one of the country’s first special economic zones and now an industrial powerhouse. OPEN’s response to the design brief was to move towards a more purposeful structure, something that would evoke the ancient rituals of nature worship, while providing much needed convivial facilities in the new urbanised district.

The form of the building is a large curvilinear structure; the structure is designed according to careful studies of sunlight and appears to be sliced by beams of light, revealing the spaces within to the majestic sea. The 50-metre high structure is located within a gently sloping square. The building is a composite shell structure, two layers of sloping white concrete shells are connected and supported by horizontal slabs and ramps. Facing the ocean, the concave inner shell of the Sun Tower acts as a sound collector, absorbing and amplifying the sounds of the sea. The smaller, inverted upper shell houses the light-filled library and ‘phenomena space’ with a breathtaking view of the ocean and sky above. An oculus in the centre of the ceiling of the phenomena space allows rainwater to enter and fill a small pool below in summer. In winter, the pool will be dry and used as a fireplace.

At the base of the tower, in the square also designed by OPEN, a shallow pool completes the circular form and features misting devices and gushing fountains. A specially designed water channel cuts through the square, which will be the straight line that the shadow of the Sun Tower will follow on equinox day. A series of elliptical rings are set into the paving pattern; the intersections between the rings and the water channel mark the footprint of the building’s shadow at specific times on equinox day. In one of the outer rings, a series of fountains have been designed to celebrate the 24 solar terms of the traditional Chinese calendar; on normal days they are synchronised with the high and low tides. The project will be opened to the public in 2024 and while it is open to the public, it will be featured in the forthcoming book Reinventing Cultural Architecture: A Radical Vision by OPEN published by Rizzoli in April 2022.

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