In early 2008, Erick van Egeraat was invited by the Netherlands’ Chief Government Architect to prepare a study for a hypothetical sustainable office building.

The design of Erick van Egeraat combines the primary focus of the brief with additional factors that may be less quantifiably ‘green’, but do compose a serious impact on the sustainable character of a building. The result is a design with an impressive GreenCalc+ score of 350 that addresses integrated climatic concepts and durable installation principles as well as aspects like densification, compactness, flexibility and aesthetic and spatial qualities.

The concept consists of two triangle-shaped buildings of different height. Their very similar floor plans are designed to accommodate interchangeability of the programme from offices to housing. Both buildings are connected through a plinth that stretches over the first three floors and houses a mix of functions.

The atrium of the office building is used to naturally exhaust air that is supplied to the offices from the buildings’ perimeter. This cross ventilation is supported by a mechanical exhaust system to exercise greater control over airflow and temperature. Dynamic and static sun shading is integrated into the facade, whilst air intake is either preheated or cooled with concrete core cooling. Clad in white natural stone and ceramic, the façade utilises materials with thermal heat storage properties. Steel encased in concrete is used to construct the columns and cores.

Two approaches towards the aspects of renewable energy and installations were chosen. The first was to create the possibility for easy future upgrades or refurbishments. The second was to incorporate renewable energy sources where they can perform most efficiently. For instance, maximum solar gain and wind exposure were to be gained from the highest roof location, which determines the best location for photovoltaic cells and wind turbines. The lower building employs a green roof inclined towards the south for water collection and storm water run-off. The complex as a whole is about maximum integration and minimum interdependability and exemplifies Erick van Egeraat’s vision on green architecture.