Visualizing Daylight

The Radiance lighting simulation program was used extensively throughout this project to produce data and images for the owner, lighting designer, and manufacturers at the pre-bid, post-bid shop drawing, and commissioning phases of this project. Radiance, developed by LBNL, produces photorealistic images and data given 3-D input of the building geometry and surrounding urban context as well as reflectance properties of the various surfaces. LBNL and Anyhere Software created a detailed three-story interior model of the Headquarter's tower and a building model of the entire Headquarters building placed within the urban context of Manhattan. Automated control of the shades and electric lighting system was simulated.

Radiance model of The Times Headquarters in its urban context.

Initially, simulations were performed to help the building owner visualize and understand the energy and visual comfort implications of automated shade design and control alternatives that were under consideration in the pre-bid phase. In the post-bid phase, Radiance studies were used to assist the selected manufacturers with the practical aspects of defining zones and sensor locations on shop drawings and selecting fabrics for various floors and façade orientations for engineering shop drawings that needed to be submitted to The Times in the first quarter of 2005. Data were also provided to help the manufacturers understand if their control systems would be reliable under the specific daylighting conditions within a complex urban environment. Images were produced to help both The Times and the manufacturers understand the dynamics of the daylight within the space over different days throughout the year and on different floors of the building.

Daylight illuminance distribution studies provided the lighting manufacturer with photosensor and work plane illuminance data which could be used to calibrate their photosensors' response to daylight (right). An image database was created to check the shade operations for each façade (left).

A shadow study was conducted to determine the pattern of shadows from urban obstructions on the exterior tower façades in elevation, the podium courtyard façades in elevation, and the podium skylight in plan view. These simulations were used to produce a schedule for when a shade control zone was entirely in shadow from urban obstructions and therefore not requiring direct sun control.

A web page was created that links to 23 QuickTime movies corresponding to 6 plan views and 17 perspectives of the New York Times tower building, with split views showing the 6th and 26th floors, simultaneously. These images provides one with an understanding of the lighting quality, direct sun control, window brightness, and illuminance distribution throughout the space resulting from daylight as managed by the automated shades. Click here to access these movies.

Propensity for exposure to the sun throughout the year by setting clear sky conditions at every hour. The spatial map shows the distribution in exposure across the façade and with height enabling the owner and manufacturer to determine whether to use dense or more open weave fabrics on different façades and floor levels.

These Radiance simulations and more are documented in the final reports, found in the Publications section.