LOISOS + UBBELOHDE : Architecture . Energy  
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london office tower solar convergence

Located in downtown London, this 34 storey, 670,000 sf office building contains southern and northern facades that are all glass and concave in shape. While the building was under construction, it was discovered that this curved southern facade was concentrating sunlight on nearby cars and buildings, causing damage.

Loisos + Ubbelohde was asked to characterize this solar convergence phenomenon and assist with mediation. This involved three main tasks: measurement of the intensity of the solar convergence, simulation to describe the extent of the issue, and simulation to study mitigation strategies. Loisos + Ubbelohde collected thermal and visual measurements on site using research-grade instrumentation and simulated the phenomenon using a robust, full-spectrum simulation engine. These first two steps were essential to ensure the accuracy of the simulated data.

Finally, Loisos + Ubbelohde worked with the design team to study a variety of mitigation strategies, including adding louvers to the exterior, adding a custom film, and making adjustments to the geometry of the facade. The final solution was a series of horizontal louvers that has been installed and has resolved the convergence issue.

Animation showing simulated compared to observed solar convergence.


Axonometric drawing of louvers installed on facade.

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View of south facade during convergence.

instrumentPyrheliometer being used onsite to measure reflected solar radiation.