Technology Reviews: Dynamic Curtain Wall Systems

This review addresses a technology area of interest for the future. Current systems falling into the category of dynamic envelopes are rare, of unknown cost effectiveness on a general basis, and probably most useful in climates harsher than in California. However, the concept of a dynamic envelope holds great promise for building optimization and perhaps even for a zero energy building perimeter. Future building technology developments are likely to include systems in this category, potentially leading to cost effect integrated systems that include the building skin as well as internal building systems. This technology section discusses rationale behind development of a dynamic building skin and presents the few existing examples in this category.

Building envelope design to date has addrcssed the combination of various materials and components to produce a building skin that will act primarily as a static banier to the extremities of the climate outside the envelope. This is in contrast to the dynamic behavior of an analogous system, our own skin. In the human body, the interface between internal and external environments is dynamically controlled through the complex interactions between the internal loads of the body, the thermal resistance of the clothing, and the conditions of the external environment such as air temperature, mean radiant temperature, air velocity and vapor pressure. Human beings have several means at their disposal to modify their comfort conditions, either through conscious thermo-regulatory control (e.g., removing clothing layers or changing locations) and/or through involuntary responses (e.g. sweat secretion or vasoconstriction). Our ability to dynamically use a variety of regulatory tools enables us to survive through a wide range of adverse conditions.