KieranTimberlake’s green US Embassy

The environmental features of KieranTimberlake’s US Embassy scheme were key to their competition win. Has sustainable architecture come of age?  Today I will be interviewing James Timberlake and Stephen Kieran to find out.

Read more about the sustainable aspects of the scheme below. All four finalists are presented in today’s AJ.

In announcing the winning scheme, US Ambassador Louis Susman said: ‘We feel the design concept put forward by KieranTimberlake best meets the goal of creating a modern, welcoming, secure and energy efficient embassy for the 21st Century. It was also the most environmentally friendly of the four projects.’

Diagram of glazed envelope with ETFE scrim

In their competition submission, KieranTimberlake said:

‘The goal for this design … is to establish leading edge international standards for energy efficiency and environmental sustainability. Simply put, the project is to ‘lead by example.’ The [brief requires that the] design comply with a BREEAM Excellent rating, a LEED Gold rating and an EPC “A” carbon rating as required by the GLA and UK energy requirements. We think these environmental goals are too low for a project expected to be completed in 2017. By that point, new environmental standards will exceed the suggested ratings.

Our design team has achieved the following stretch goals above and beyond the already stringent requirements established for the new London Embassy:

Study of ETFE cushions with integrated PV on west, south, and east elevations

•    Carbon neutrality
•    Closed loop water system
•    Embodied energy and carbon tally
•    Development of methodology
•    Analysis of material energy intensity vs operational energy impact
•    Optimization of daylighting and occupant control of systems
•    Habitat Platinum (above the required Gold)
•    BREEAM Outstanding (above the required Excellent)

Through holistic integration and iteration efforts, we optimized the massing of the main structure while minimizing the external footprint on the site thereby maximising the amount of open space remaining for habitat and public amenity. The building was performatively oriented, taking sun cycles into consideration for heating and cooling, to maximise daylight and to relate these factors to the anticipated 2020 build-out of the surrounding properties. The pond assists the closed loop water system by storing rainwater harvested from the roofs and previous surfaces for irrigation and other purposes. It also is integrated with the evaporative cooling cycle. Each of the characteristics of the complex’s design is intended to serve three or more purposes addressing goals, lowering life cycle costs, improving – and not just maintaining  - the environment.

Leading by example in this case means achieving net carbon neutrality while creating a habitat  worthy of London’s finest historically significant parks, and incorporating substantial renewable energy sources. This project is expected to not only be efficient but beautiful in doing so.’

Environmental features of the scheme include:

  • building floor plan with optimal balance of daylight and views
  • maximum daylight to reduce need for electric lighting
  • envelope with light shelves, reflectors, and fiber optic collectors to bring light into building
  • mix of indirect and task lighting
  • occupancy sensors and photo-responsive control of lighting
  • underfloor air distribution
  • passive chilled beam and perimeter thin film radiatiors to meet peak needs
  • a biomass fueled combined heat and power system
  • a pond for heat ejection
  • HIT (Heterojunction with intrinsic thin-layer) PV panels on the roof
  • onsite wastewater treatment plant which collects grey water and waste water and treats it for reuse in flush fixtures
  • roof rainwater collection for cooling systems and irrigation
The building’s most dramatic visual feature will be its glazed envelope with an outer scrim of ETFE pillows with integrated thin-film PVs on the east, west and south elevations. The ETFE cushions will also reduce downdrafts and wind in the plaza and walkways at ground level.

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