High-Performance Building Design Presented By: Hend Mohamed Ibrahim By:Ross A. Leventhal May 2001

Digital design tools are essential in the latest efforts toward sustainability in architecture. Steven Winter, FAIA, founder and president of Steven Winter Associates, Inc., and his associate Michael J. Crosbie, Ph.D., RA, gave a presentation called "Lessons Learned from Commercial High-Performance Building Projects." Steven Winter Associates, IncSteven Winter Associates, Inc Digital Tools

What is Green? Winter began his presentation with a few ideas that help define "green" buildings, which do more than just conserve energy. To earn this status, green buildings must be economical (requiring less material and maintenance), comfortable, productive, healthy, and good for the city, the region, and the planet. Winter listed many ideas that help to create a high-performance building:

The whole team is part of process from the start. The whole building is one system. Energy, resources, and materials are used efficiently. The building has a positive effect on its occupants. The building has a positive interaction with its site and neighborhood. The building has a positive interaction with and effect on the natural environment. Economic decisions consider life-cycle costs. Materials and systems are durable, requiring less maintenance, but they are also recyclable.

Tools for High-Performance Analysis With Algor 3D modeling software, Steven Winter Associates measure heat flow through building components. These visualizations show how heat follows the path of least resistance, through conductive materials like aluminum window frames or concrete structural slabs. Analyses like this should inform more effective detailing of buildings. Algor modeling to visualize heat loss through a wall. The steel shelf angle at the edge of the slab is the main problem; the light blue indicates a potential condensation problem. Algor shows the temperature (in degrees Fahrenheit) inside a wall. Condensation might form under the wall, where the floor short-circuits the insulation, leading to a potential condensation problem.

Daylighting can greatly reduce electric lighting needs. The section diagram shows how step dimming allows us to turn off lights when enough daylight penetrates into a space. Deeper into the building, the amount of light needed from electric lighting increases. Progressive dimming provides adequate light levels with less electricity. A Lightscape-rendered space displayed qualitatively, yet accurately.

Lightscape Softwares With software such as Lightscape and Radiance, 3D computer models can be rendered with accurately simulated daylight and electric lighting. Light levels are quantified and graphically represented so that one can quickly assess deficiencies as well as areas in which lighting levels could be reduced. Lightscape Radiance Lightscape Radiance Precisely calculated, color- coded luminance levels in a Lightscape rendering.

Airflow Simulation When pursuing natural ventilation schemes, architects must understand airflow and temperature gradients. Steven Winter Associates use computational fluid dynamics modeling to simulate the process of air entering the building through openings and moving through the designed space. computational fluid dynamics modelingcomputational fluid dynamics modeling A Radiance rendering indicates glare at the windows without a lightshelf.

This tool can also be used to study HVAC functionality. With multiple section cuts color-coded by air temperature, it is possible to see if the air is mixing properly and if it is at the right temperature at the right place where it is needed for heating or cooling. These studies allow for system optimization, replacing traditional system oversizing. When a lightshelf is added, Radiance demonstrates reduced glare and light bounced deeper into the space

Conclusion This conference session reinforced the concept that good ideas need good design and data in order to be implemented. This level of study has not traditionally been part of the building design process but is essential to achieve integrated building solutions that perform at high levels of efficiency.