One of the primary goals of Kieran Timberlake’s design is to demonstrate exceptional environmental leadership that is at or beyond the leading edge of practice when the building is completed.
The design team established the following goals above and beyond the already stringent requirements established by the Bureau of Overseas Buildings Operations for the New London Embassy:
- Carbon negative
- Self-sufficient water system
- Optimization of daylighting and occupant control of systems
- Habitat and public amenity creation
- Aiming for LEED Platinum (above the required Gold)
- Aiming for BREEAM Outstanding (above the required Excellent)
Energy and environmental design issues have been balanced with the overall project goals of openness, diplomacy, functionality, security and value. Employing technologies that use alternative energy sources and reduce peak energy demand and overall energy consumption represents a commitment to sustainable design.These strategies also provide enhanced occupant comfort which has been shown to contribute to better functionality and productivity by improving employee satisfaction.
The strategies included:
- Consistent with the Mayor of London‘s energy hierarchy, as outlined in The London Plan (via .gov.uk);
- Exceed the London Borough of Wandsworth local planning requirements;
- Consistent with the United Kingdom government’s announcement in the 2008 Budget that new non-domestic buildings should be zero carbon by 2019.
- The first step toward achieving carbon neutrality is to use energy reduction strategies and technologies to minimize consumption.
- After minimization of the building’s energy consumption, renewable energy technology is used to minimize the Embassy’s carbon footprint.
Minimizing Energy Consumption
- The electric lighting strategy for office spaces seeks to reduce lighting power densities by 45% below the ASHRAE 90.1 guidelines, while maintaining OBO requirements for lighting levels at task and viewing areas.
- The integration of indirect and task lighting and lighting of vertical surfaces opposite windows will deliver a balanced lighting environment.
- Dual-technology occupancy sensors will be used in conjunction with photo-responsive controls.
- The building will use energy efficient lighting such as LEDs to maximize energy performance, while maintaining a high level of architectural integration and glare reduction. Exterior and site lighting will minimize light pollution.
- Daylight is a key driver in the building design and will be utilized to minimize the need for electric lighting.
- The building dimensions afford the optimum distance to daylight and view.
- The façade has been designed to maximize natural daylighting with a high percentage of transparency.
Reduced Fan Power
- In order to reduce building energy consumption, the proposed systems will double the cross-sectional area of filters while maintaining all other air handling units and filter specification standards, reducing annual energy consumption and building carbon emissions.
Underfloor Distribution and Chilled Beam in Open Plan Office Spaces
- A highly efficient underfloor air distribution system will be used to provide cooling where required. Passive chilled beams and perimeter thin film radiators will provide additional peak cooling/heating without increasing overall air change rate.
High Performance Building Façade
- A high performance building façade uses multiple layer laminated glazing with an outer scrim of pressurized ETFE (ethylene tetrafluoroethylene) pillows on the east, west and south façades to screen excessive solar gain and glare while ensuring a uniform distribution of daylight to the building interior. The glazing is low-iron to promote transparency. The ETFE scrim provides a second air gap and enhanced resistance to thermal transfer.
- The ETFE scrim mitigates wind downdrafts improving the comfort of the landscaped plazas and walks below. The shape of the ETFE pillows makes the building visible to migratory birds to reduce the risk of bird-strikes. The material is self-cleaning and will reduce window cleaning expense.
Cooling for the building will be generated by absorption chillers that use waste heat from the Natural Gas fueled combined heating-power (CHP) system.
Renewable Energy Technologies
Photovoltaic (PV) panels will be used as an effective, low maintenance method to produce electricity on site:
- HIT (Heterojunction with intrinsic thin-layer) PV panels will be located on the roof of the Chancery building and access pavilions at optimum orientation.
Natural Gas Fueled Combined Heating-Power (CHP)
A biomass fueled Combined Heating-Power (CHP) system will serve the embassy and be linked into a district heating scheme providing heat to the surrounding community.
- The building will be connected to the utility grid, and will feed from and also back-feed electricity to the grid.
A number of innovative components work together to reduce potable water use and reduce the demand on the municipal wastewater system.
- A deep well aquifer is intended to provide on-site self-sufficiency in potable water.
- An on-site wastewater treatment plant collects both greywater (waste from flow fixtures) and wastewater (from flush fixtures) and treats it to a level that can be reused in flush fixtures.
- Roof rainwater collection and property storm water runoff will be used for irrigation and flushing.
- Property storm water management for larger storm events reduces discharge by up to 85% from existing conditions for large storm events.