A Prototype for a Zero Carbon Emissions Office Building in St. Louis, MO.

Massing and Exterior Envelope

An early climate and context study analyzed local solar intensity, wind potential, temperature and humidity ranges and cycles, and the effects of the St. Louis latitude and building type on daylighting potential and shading options. With 150-180 cloudy days per year classifying St. Louis as an “overcast sky” zone, the team designed to an 18.5 percent window-to-floor area and 35.2 percent window-to-wall ratio to achieve a minimum 1.5 percent  daylight factor across a 60-foot-wide floor plate. 

The program organized most optimally into two four-story, 300-foot-long office bars oriented east-west and joined by two links that enclose a 60-foot-wide landscaped courtyard. The north and south facades optimize vision and daylight glazing with insulated opaque areas to leverage natural light while maintaining a high performance envelope. The east and west facades are essentially solid, blocking glare at low sun angles and adding to the average R-value of the building skin. 

Exterior walls of the office bars consist of R-40 rain screen construction with tile façades to the east and west. Vision and daylight panels are triple-glazed, double-low E with Argon fill set in wood frames to provide optimized and controlled daylight into the workspace, views to the exterior and maximal R-value. 

On southern facades, evacuated solar thermal tube panels provide both a unique aesthetic and a heat source for the building. The roof is sloped at 10 degrees south and incorporates solar PV and solar thermal panels over an R-30 insulated roof. The east and west facades of the links are faced with a vegetated wall to provide aesthetic continuity to the natural aspects of the courtyard, moderate the outdoor climate for tenants and even soak up a few additional carbon dioxide molecules (not included in the total analysis).


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