There are many options available to today's design teams for creating dynamic building envelopes. Controllable interior blinds and shades, exterior louvers, and remote-operable windows are just a few of the choices mentioned in an article in this month's Automated Buildings magazine by solar buildings expert Thanos Tzempelikos.

These dynamic features, linked with lighting and temperature control, could significantly reduce peak cooling load and energy consumption, while maintaining good indoor conditions for workers. How much reduction is possible? Evaluating the impact of a given choice -- especially those that are not widely installed -- can be challenging.

When no member of the design team considers the overall optimization of the indoor environment, the challenge is even greater. In the final stages, teams often opt for the safety of traditional passive designs. Tzempelikos writes:

"Nevertheless, the advantages of dynamic elements on the building envelope are obvious. For example, glare can be controlled efficiently if automated shading is used in perimeter zones. Roller shades move automatically so as to block direct sunlight and allow diffuse light into the room, thereby eliminating glare and creating a pleasant luminous environment; horizontal (venetian) blinds will re-direct natural daylight deep into the space and improve lighting uniformity even in open plan offices; automated operable windows will allow for natural ventilation in order to reduce overheating and bring fresh air in the building."

Most HVAC controls are concealed in walls and ceilings. Lighting control is different. Occupants could manually control light dimmers or roller shades to maximize daylight and minimize glare. They've done so for years, but not with the greatest efficiency. The complexity of central control adds overhead to the design process, but removes the inefficient and random control by people in a room.

The article discusses the qualities of shading -- the colors, translucency, and manual override options -- and the superiority of exterior over interior shading. Then the author discusses the integration of these features with building control systems.

The total system, comprised of sensors, lighting, HVAC, and a dynamic envelope, allows designers to install smaller chillers and operate lighting more efficiently. Teams need to plan that total system from the earliest design stages of a building, to make the right choices in the final stages.