While world leaders get together in Copenhagen for COP15, the United Nations Climate Change Conference, our friends from Various Architects share with us a very interesting project, that is also a statement addressing sustainability in office buildings. Skagen ØKOntor is currently the most sustainable office building currently planned in Norway. Developed together with engineers from Ramboll UK in Bristol and Pollen Architecture in Austin, TX, the project is also a showcase of concepts that can be applied elsewhere in the Nordic countries as you will see on the diagrams and project description below.
I´m very happy to see architects speaking through their projects, reacting to what is currently being debated these days and that has a lot to do with our profession. Various Architects and Ramboll believe that the ØKOntor project demonstrates that architects, engineers, and developers of new office buildings should push harder to develop highly energy efficient buildings with a zero net-carbon construction. We should not accept the minimum reductions required by law as standards, but should see them as a challenge to do better. Good luck to the COP15 representatives. Project description and images after the break:
The building’s wooden facade of individually operable insulated shutters is it’s most visible and dynamic feature. Floor height shutters can be opened during the day to allow in daylight and passive solar heat, or closed after sunset on cold days for added insulation. The shutters can transform the facade from 60% to 20% window area. The inside surface of the shutters are tiled with LED lights to produce artificial daylight during the dark winter months to help provide a well-lit and healthy working environment year round. The insulated shutters are calculated to provide an additional 15% savings on heating yearly.
The natural resources of the seafront site are all carefully utilized by the design. 4 Quiet Revolution wind turbines on the roof provide 24.000 kWhr of clean energy (10% of the building’s energy demand). The windy and often overcast weather on the norwegian west coast, combined with long dark winter nights made wind a more efficient alternative to solar panels in this case. The sun is controlled for solar shading and passive heat in the west facing atrium space, and through the many south facing windows. Sea water is used as an energy source for both heating and cooling via water cooled heat pumps and sea water free cooling. This, coupled with high efficiency air heat recovery, demand led controls, and high levels of thermal insulation have significantly reduced the thermal plant demand. Natural ventilation is possible for most of the year, with cooling through refrigeration only necessary when sea water temperatures are at their peak (no more than 4-8 weeks a year). Green roof surfaces collect and filter the area’s prodigious rainfall in rooftop water tanks for use in low-water fixtures and fittings, reducing the need to waste treated water.
Low embodied carbon materials were chosen where possible to reduce the project’s overall CO2 footprint. A structural system of cross-laminated timber (CLT) panel walls and floors was chosen for being locally sourced with a high level of carbon sequestration. CLT represents a significant reduction in embodied CO2 compared to a traditional concrete or steel frame. The building exterior and insulated shutters are clad in Kebony, a norwegian wood product that is sustainable, low-maintenance, and suitable for the exposed seaside climate. The newly implemented TEC2007 norwegian building directive requires the energy marking of all new buildings. From 2010 office buildings have a maximum allowable energy use of 165 kWh/m2/year (Energy grade C), a typical office building today uses around 270 kWh/m2/year. At 72 kWh/m2/yr the ØKOntor would achieve a Grade A energy rating, less than half the required maximum. Norway does not have a Passivehaus certification system yet, but the ØKOntor complies with the certification principals of heat recovery, excellent airtightness, summer solar shading, high levels of thermal insulation, using useful passive solar/equipment heat gains and a net energy use of less than 75kWh/m2/yr. *Energy estimates calculated by Ramboll using IES dynamic modeling software.