Project Description: 22-storey, 11-m wide office building with cross ventilation and a double-skin thermal flue on the west-facing façade. 

This 11-m wide office building allows for cross ventilation. The east façade consists of automatically and manually-operated triple-glazed windows with between-pane blinds. Louvered metal panels also occur on the east façade to admit fresh air independently from the windows. The west façade consists of a double-skin façade with interior double pane windows that are operated both manually and automatically and a sealed 10-mm exterior glazing layer. The interstitial space is 0.9 m wide. Wide, vertical, perforated aluminum louvers located in this interstitial space are also automatically deployed and manually adjustable. The louvers can be fully extended to shade the entire west façade. 

Outside air admitted from the east façade provides cross ventilation to the opposing west façade. The prevailing window direction is from the east. The west façade acts as a 20-storey high shaft inducing vertical airflow through stack effect and thermal buoyancy. Where partitioned offices occur, sound-baffled vents permit airflow across the building.  During the heating season, the air cavity between multi-layer façade acts as a thermal buffer when all operable windows are closed. Warm air is returned to the central plant via risers for heat recovery. Fresh air is supplied from the raised floor system. Radiant heating and cooling are provided. Thermal storage in the ceiling and floor was created using exposed concrete soffits and a cementitious voided screed system. Various building systems such as lighting and diffusers are either integrated into the soffit or into the voided screed.
	Typical floor plan of the office building, showing the existing tower on the left (gray) and the new 22-storey tower on the right (yellow)
	Sectional diagram showing wind- and stack-induced cross ventilation.

Reference 

-. 2000. "Urban green: headquarters building, Berlin, Germany." Architectural Review 208 (1246): 72-75. 

Clemmetsen, N., W. Muller, and C. Trott. 2000. "GSW Headquarters, Berlin." Arup Journal, February 2000, pp. 8-12. 

Hodder, S. 2001. "GSW Headquarters, Berlin." Architecture Today 116: 30-49. 

Russell, J. 2000. "GSW Headquarters." Architectural Record 188(6): 156-161.

Question/Information: eslee@lbl.gov