The office building Bengt Dahlgren in Gothenburg, Sweden was finished in 2009 and it has an area of 4,113 m². The building was designed and built with the aim to be energy efficient, cost efficient and have low maintenance. It has five storeys plus one technical floor, mostly filled with office spaces, and also conference rooms, apartment, cafeteria. The building has steel and concrete construction supplemented with insulation to secure very good thermal properties and the facade has 60% of glass (U-value = 0.85W/(m².K)).
The building was awarded by Green building certificate in 2008. The designed energy demand was calculated to be maximum of 75 kWh/(m².a) and the monitoring actually proves the real consumption between 75-79 kWh/(m².a) in first two years of operations of a building. The design target for indoor climate was category B (ISO 7730) with 90% satisfied people with cooling with air and heating with water (district heating source). The demand controlled ventilation system uses many sensors to control indoor climate: temperature, CO2 in conference rooms and VOC on each floor.
Article by Henrik Jönsson and Berth Olsson for Passivhus Norden 2013. In Swedish language. The heating energy is supplied from district heating, and it is provided with a system with heat recovery from chiller & outdoor air heat pumps. The heat is distributed via radiators. There is a special cooling equipment for server. The chilled air is distributed in offices with mechanical ventilation with heat recovery (demand controlled ventilation system). The building is equipped with motorized external blinds and also the building has its own solar power.
September 2015. The presentation is all about the idea behind the Bengt Dahlgren building and its design. In the presentation are also details about shading, ventilation system, building management system (BMS), and Green building certification. The building uses low temperature heating system and has two parallel air handling units with heat exchanger and rotary wheel. District heating is used when internal heat loads and the sun is not enough. Heating with radiators is sequentially controlled with supply air diffusers. Spill heat from cooling machine is used for hot water and radiators.
The cooling is supplied by air/water heat pump to DX coil in air handling unit (AHU). Heat pump is placed in exhaust air stream. There is separate cooling system for a server room. The shading of a building is secured by external shades controlled automatically to provide cool environment on sunny days and at nights the shades are shut to keep the warm in a building in cold nights.
September 2013. Max talks about design, operation and results from monitoring of a Bengt Dahlgren building. He shares is view on performance of this Green building certified building.
Images by Max Tillberg