The development of a new sustainable building planned as a showcase headquarters for the World Wildlife Fund. This project has been awarded BREEAM Bespoke ‘Outstanding’, the highest accreditation. WWF compiled a challenging brief that reflected the core sustainability and energy values that needed to be incorporated into the design and operation of the building.
The daylight and artificial lighting has been carefully conceived with the architect to provide a highly integrated lighting scheme that compliments the stunning architecture.
The curved timber ‘diagrid’ roof with embedded skylights maximizes natural light throughout the building. The artificial lighting scheme was designed to provide a highly integrated and understated scheme, to quietly enhance the form of the building rather than distract. There was a focus on using efficient luminaires and lamp sources along with extensive DALI controls to minimise energy usage and maximise the use of daylight. Not only beautiful, at 5.5W/m2, the installed lighting load was considerably lower than a conventional office of its time: this was a significant contributor to the 90.66% BREEAM pass mark.
A mixed mode ventilation strategy was designed for the whole building. This includes mechanical ventilation with heat recovery in winter and natural ventilation assisted by earth ducts for passive cooling in the summer. The mechanical ventilation strategy allows the thermal energy extracted from the exhaust air to be used to heat the supply air, thus dramatically minimising the need for additional heating in winter.
The earth ducts supply naturally cooled fresh air to the AHUs. The exhaust air is extracted at high level through wind cowls located above the roof. A displacement ventilation system supplies low velocity fresh air from low level and extract exhaust from high level within the building.
PVs incorporated into the scheme will offset approximately 46% CO2 emissions arising from fans, pumps and lighting. The estimated peak output is around 55kW.