Cooling demand and daylight in the new Tallinn Town Hall buildings the influence of facade design

The site of the new Tallinn Town Hall designed by the BIG architects is situated to the north of the medieval city center on the edge of the green ring close to the waterfront. The goal is to create a new urban typology that combines the human scale and intimate experience of the medieval townscape, with the public space and municipal symbolism of the modern extension. The New Town Hall will be an open and permeable public institution, extending both town center and the green ring all the way to the water's edge. The building will be created of a village of ten individual departments and two for common space and meeting rooms. Each department is accommodated in its own dedicated office building. A thirteenth building, the tower hosts the City Government, the City Council and the Council Hall on the top floor. The departments are grouped together to meet the programmatic requirements of adjacencies. The departments are consolidated in a village-like cluster, allowing them to perform as a single open office structure as well as ten independent departments. The departments are hinged on the corners and rotated to leave courtyards for daylight and views between them. The many generous openings also provide views to the public ground floor below as well as the sky above. The current paper gives an overview of the daylight modeling and facade design, describes passive architectural cooling strategies considered. Estonia is situated in latitude 59 degrees which means that the solar angle of incidence is rather low from late autumn to early spring. The maximum solar angle of incident is just 7 degrees in December 21st. Then at the other side the summer temperatures are of average 27 degrees C which makes the shading strategies essential. The building is currently in detail design phase and the construction work will presumably start in early 2014. The building has been already shortlisted for a World Architecture Festival Award in the Future Projects and Competition entries category. (C) 2012 The Authors. Published by Elsevier Ltd.