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No Shadow Towers: British Architects Fight Dark City Spaces

LONDON/UK, March 30, 2015 – Wouldn’t it be great if the space between tall office and residential towers was light and welcoming when you move in or out of the building instead of dark and dusky? A British team of architects has come up with a solution to tackle the dark side of skyscrapers, by creating a design which redirects the sun’s beam to the base of the buildings.

By Lasse Lommel

Dark cities and “Fryscrapers”

Like Daedalus and Icarus experienced the evil side of the sun, many inhabitants of London and Las Vegas have made similar, yet not fatal, experiences on the ground. Skyscrapers with a concave glass surface facing towards the south redirect the sunlight onto the spaces opposite their façade. In London, this has lead to a new nickname for the former “Walkie Talkie Tower” which is now called “Walkie-Scorchie” after its reflections melted and damaged cars parked on the other side of the road. Similarly, guests of the new Vdara Hotel in Las Vegas found themselves in pain and with severe burns after trying to use the hotel’s swimming pool – again located at the bottom of the south-facing curved glass façade.
On the north side of such buildings, on the other hand, long shadows take away the daylight from the surroundings which remain dark in the mornings and late afternoons. Recently, the long shadows have even led to angry residents and problems with planning permissions in London. The city faces a population boom and skyscrapers are considered a part of the solution to the ever growing numbers of Londoners. Currently, 236 towers have been approved or are pending approval, which the New London Architecture forum describes as a “veritable tsunami of towers” which will have a lasting effect on the city’s look and feel.

NBBJ's no shadow tower at work

The 'No Shadow Towers' seen from the top. The No-Shadow tower reflects the sun in a computer-optimized way to create an even distribution of light instead of a single focal point. This allows for more daylight for pedestrians and people in nearby buildings. | animation: NBBJ

No Shadow Tower: How it works

The international architectural firm NBBJ has now developed a way out of the darkness. Christian Coop, Designer at NBBJ, reports: “Our ‘No Shadow Tower’ aims to mitigate the problem of over-shadowing, by creating two high-rise buildings that work together to redirect sunlight and visibly reduce shadows at the most active place, the public realm at the base of the towers.”

Rendering of the 'No Shadow Towers' in London on the banks of the Thames

“We optimized this form by further parameters: even distribution of the reflected light, views on the Thames and a maximum of reflecting surface area” explains Coop. | photo: NBBJ

The model was developed with an algorithm which traces the incidence angle of the sun over the days of a whole year. It then creates the building form according to the results of the computation. The model tower studied by the London designers is located at 0°W on the Greenwich Meridian to emphasize the site’s relationship with the sun. However, its form can be adapted to any location on the globe.
The surface of the two towers is made up of many individual planes at different angles that reflect the sunlight one by one instead of all at the same time. This creates a more even distribution of light compared to flat surfaces which reflect light in only one space. The impact of the new design is magnificent as it reduces shade up to 50% on the ground, especially in the space between the towers. The shade on the North side, however, remains. Architects of NBBJ and the New London Architectural forum are optimistic the computer-aided design is a key element to lighter cities despite skyscrapers.

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Vertical reflections of the sun over the course of the day

The No Shadow towers and how they reflect the sunlight over the course of the day. | animation: NBBJ/The Building Specifier