The technology to support adaptive building systems is both available and dependable. Adaptive façades are poised to capitalize on technology transfer from other disciplines, which can allow the building industry to mass produce sustainable building parts and bring down the cost of these systems to attractive levels.

The technology to support adaptive building systems is both available and dependable. Adaptive façades are poised to capitalize on technology transfer from other disciplines, which can allow the building industry to mass produce sustainable building parts and bring down the cost of these systems to attractive levels.

“When one talks about adaptation, one talks about accepting the reality of these impacts and putting in place technological and policy measures by which we’re able to manage the problem. That’s absolutely essential.”

— Nobel Prize winner Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change

For most architects and engineers, the idea of optimizing a building’s design in relation to its location is so ingrained as to be a reflex. Still, most building professionals have a difficult time making the conceptual and practical leap to the notion of performance-based or “adaptive” buildings. We call these adaptive buildings because they can adapt their shape and function in real time to environmental changes. This field remains far less developed than other areas of practice, but the logic of adaptive performance — which is time-based, responsive, and dynamic — is compelling. Buildings that continuously attune their configurations in accordance with changing environmental conditions use less energy, offer more occupant comfort, and feature better overall space efficiency than static buildings.

Buildings represent the single largest contributor to carbon output in the United States. It is clear to colleagues in our industry that buildings and their associated energy use pose a major challenge for cities and urban environments now and in the future. Recent carbon inventories for major American cities indicate that 60 percent to 70 percent of carbon emissions in densely urban areas result from the construction, operation, and demolition (often, without recycling) of buildings and their associated infrastructure. Cities that aim to reduce carbon emissions are facing this seemingly insurmountable challenge. For instance, New York City’s PlanNYC calls for 30 percent carbon reductions by 2030 based on today’s emissions rates. Such ambitious targets require fundamental rethinking of the way we approach architecture.

The good news is that building operators, owners, and developers are increasingly concerned with reducing energy use and carbon emissions in order to achieve LEED (Leadership in Energy and Environmental Design) certification or simply to increase bottom-line performance. In our experience as engineers for projects in the United States and abroad, we have seen that city planners are attempting to decrease carbon footprints at the urban scale by organizing and mandating environmentally efficient building standards. Developers and elected officials alike are looking beyond attaining low energy use to net-zero energy and carbon-neutral strategies.

The desire to increase energy efficiency is not limited to the developed world. As the population of countries in some of the warmest parts of the globe continues to grow and as more sophisticated approaches to buildings are required to moderate those climates, the demand for more efficient and adaptive systems increases. Rising energy demands for Western-style, energy-intensive infrastructures on the part of developing countries may well be one of the defining problems of our century. Solutions are needed to curtail demands on the already strained infrastructures of the Middle East, India, China, and Southeast Asia.

And as climate change is undeniable, the time is ripe for a new breed of energy-saving products. Adaptive façades are one way to solve these complex problems. It is not only the environmental argument for sustainability that is driving their application to large-scale structures. Changes in the building and construction industries are making such systems less theoretical and more viable than they had been in the past.

Through experience and temperament, we are realists; however, we share the conviction that in the face of global climate change, the way buildings are designed and made must also change. We believe that performance-based strategies offer a critical contribution to the broad goal of reversing environmental damage

Given the fact that sustainable strategies such as energy-efficient and passive systems have been readily adopted by the building industry, adaptive strategies provide a third alternative. Even with newer passive and energy-efficient systems, most buildings do not use natural resources effectively, whereas adaptive buildings can change their form, building surfaces, and interior spaces in response to intelligent controls that monitor dynamic feedback from the environment. Solar and wind energy, daylight, water, and weather can be harnessed by buildings and reused efficiently provided they are modulated by technological inputs.

For this reason, adaptive systems combine the best of existing strategies: low energy use and control over building environments. For instance, a building’s energy requirements can be considerably lowered if its design can adapt to diurnal fluctuations in temperature. An adaptive system that is modulated to control the volume and direction of heat flow in response to external and internal conditions can enhance comfort and energy performance.

The development of adaptive forms and façades is both a technical, sustainable solution and an end product. It is true, however, that the creation and implementation of adaptive building strategies are not simple matters. Performance-based solutions require that we devise new methods to design and make buildings and that we place greater emphasis on multidisciplinary cooperation. Such solutions require that we take a series of incremental steps as an industry to create buildings that are more energy efficient, active, and optimized. And we need to take steps to develop these products quickly, as energy and carbon use are decreasing our potential to restore the environment.

From Vision to Reality

Although performance-based buildings have been around for decades, they have never entered the mainstream practice of design and construction. A common thread binds a progression of architectural developments over the past half-century that have been labeled kinetic, temporary, flexible or mobile. Over the years, various practitioners have presented performance-based prototypes as technological, social, and utopian solutions for the problems of their day. More philosophically, many people are attracted to buildings with moving parts because motion seems to herald change.

Early explorers of the adaptive architectural dimension include Buckminster Fuller, whose geodesic domes minimized cost, materials, and impact on the environment. They could even be transported by helicopter. Fuller proposed houses that traveled with their occupants, and he famously asked the great architects of the day if they knew what their buildings weighed. (Few did.) Likewise, Frei Otto’s tensile structures proffered a new system for lightweight, demountable buildings. He created a series of retractable fabric coverings controlled by cables, a type of roof system that remains in use today for buildings such as large-scale sporting venues.

Jean Nouvel introduced a new type of performance-based building in 1989 when he designed a kinetic curtain wall for the Institut du Monde Arabe that responded to the position of the sun. The building’s adaptive elements mediated between the external and internal environments, but they were layered within a static building form. In the 20 years since Nouvel’s building was commissioned, responsive shading systems (primarily passive systems) have gained increasing acceptance. A recent example is Renzo Piano’s New York Times headquarters building, for which ceramic rods were applied onto the exterior façade to create an energy-reducing sunscreen.

In recent years, Hoberman Associates has worked with firms such as Foster + Partners and Nikken Sekkei on alternative models for shading and covering systems. Before that, the firm first explored the application of performance-based systems for projects of civic and symbolic value, such as public art and theaters. It is not surprising that the entertainment industry would be the first to embrace these concepts since they are more capable than private developers of absorbing and distributing risk and therefore more willing to use innovative technologies within a framework that allows for greater experimentation of form.

As these projects indicate, leading architects, engineers, manufacturers, and product designers are starting to experiment with performance-based solutions that are economically responsible, easy to manufacture, and aesthetically beautiful. These novel solutions are the result of creative, interdisciplinary teams of designers, engineers, and builders from industries as disparate as show-ride manufacturing (for amusement parks) and aerospace.

Advancing the Cause

The logic for performance-based strategies is straightforward: Buildings that maintain optimized configurations relative to changing environmental conditions function more effectively. While the use of passive — that is to say, fixed — systems can respond to environmental changes within a limited range, they must always be supplemented by traditional fossil fuel-burning heating, ventilation, and air conditioning systems.

Several promising performance-based methods and materials are in various stages of development. So-called “smart materials” include electrochromic glass, which is controlled by electrical currents to vary the amount of light transmitted. Adaptive ventilation devices are often used in conjunction with double-glazed façades to direct air flows and exploit convective heat transfer for heating and cooling. These systems have become increasingly popular, aided by a dramatic decrease in the cost of the embedded computation necessary to run them and the development of sophisticated algorithms that can synthesize and interpret environmental data.

Currently, performance-based systems are most widely used for lighting control. Applied to the interior or exterior of buildings, motorized shades, blinds, and louvers can intelligently control light levels and solar gain. The energy benefits here are two-fold: They absorb or reject radiant energy, which reduces the use of heating and cooling systems, and they employ natural daylight to decrease the need for artificial lighting.

Despite these advances, performance-based technologies have barely lived up to their full potential. For example, the physical design of shading devices has remained largely unchanged for many decades; further improvement is necessary to improve performance significantly. Adaptive building responses to environmental parameters such as wind, precipitation, and conductive heat (as opposed to radiant heat) are all ripe for development.

Better performance-based systems are now possible, due in large part to recent advances in diverse computational tools that allow engineers to comprehend building environments. Using sophisticated energy and thermal modeling technologies, professionals can more effectively analyze energy use of buildings over time and provide more responsive energy conservation solutions than ever before. These technologies are opening up the development of a new generation of building envelopes.

Computational fluid dynamics modeling, which simulates fluid flow (including air), helps building professionals surmount the challenges associated with envelope design. When used properly, computational fluid dynamics can provide a detailed prediction of air flow patterns and transfer of heat energy through conduction, convection, and radiation. Data from such analyses aids in the development of façade systems by allowing engineers to understand how adaptable systems can influence envelope optimization.

The catalyst driving these new developments is the increased computing power and affordability of new computer systems that perform thermal and energy modeling. These tools help professionals gain insight into exchange of energy that occurs between the external environment and the internal spaces of a building over the course of a year. Using energy modeling and dynamic thermal models, designers can predict how, why, and when a building will consume energy. This dataset allows professionals to integrate active controls that harvest wind, sun, and water into a building’s façade.

Other computational tools include accurate lighting simulations, which have allowed engineering consulting firm Buro Happold to analyze how performance-based building envelopes can maximize the use of daylighting when combined with dimmable artificial lighting and photosensors. This is significant since artificial lighting can account for 30 percent to 40 percent of a building’s electrical use — the primary source of a building’s carbon emissions. Accurate daylight modeling can help engineers and lighting designers develop self-balancing lighting systems that automatically dim when natural daylight is available. With computer modeling, engineers can evaluate how façade systems can also play a more direct, effective, and active role in reducing energy and optimizing daylighting systems. It is conceivable that they can dramatically reduce or even eliminate the need for artificial lighting in future buildings during daytime hours.

Still, buildings are inherently complex systems, and many factors affect their total environmental performance. This complexity is further compounded by the decentralized nature of the construction industry, which is composed of an enormous number of small to mid-sized companies. Despite the technology that is available to us, the construction industry has been reluctant to change. Unlike technology-intensive industries in which even a few breakthroughs can have a significant impact, the building industry often makes parts as a series of one-offs, which means that technical advances are few and often slow to catch on.

Performance-based façades necessarily raise questions of reliability and maintenance, problems that can plague poorly operated infrastructures. On the positive side, computer-aided manufacturing and the globalization of manufacturing allow us to produce building components on an unprecedented scale and with a great deal of accuracy and reliability. For example, automobile drivers do not question the reliability of their automatic windows or even their cars’ airbags, which are much more complex. So why should an operable window or one with integrated shading be considered unreliable by the occupant of a building? The technology to support adaptive building systems is both available and dependable. Adaptive façades are also poised to capitalize on technology transfer from other disciplines, which can allow the building industry to mass produce sustainable building parts and bring down the cost of these systems to attractive levels.

The building industry is large and powerful enough to tackle these problems. We can certainly reap benefits from the cost models of other manufacturing processes. Robustness and integrity in the design and production of building products are essential. Yet the urgent need for energy reduction and greater manufacturing reliability are converging in ways that offer us clear solutions.

Next Steps

To reiterate the words of Rajendra Pachauri that open this article, we believe that adaptation is the absolutely essential means to manage the problem of climate change.

The principle of adaptation represents a paradigm shift in the building industry: an adjustment of our thinking that comes about as the result of new discoveries, inventions, or real-world experiences. If we readjust to this adaptive mindset, then the building industry is poised to enter a new era of innovation.

The Adaptive Building Initiative, which brings together designers and engineers to create adaptive systems for architectural projects, is our response to the need for next-generation adaptive systems for buildings. ABI will provide solutions for specific projects and perform longer-term technological investigations that are required to realize the potential of adaptivity for the building industry. It will perform research and development, create intellectual property, and enter into strategic partnerships to move this critical area forward. We hope ABI will act as a catalyst for new ways of thinking and that it will be able to instigate the kind of dynamic conversations about sustainability that are now taking place in our industry.

While the conditions of our present day are unprecedented, the approach and ethos of previous generations of designers and engineers are an inspiration to us, and hopefully to others as well, to begin to resolve the daunting challenges that face our society.

Chuck Hoberman is the founder and president of Hoberman Associates, a multidisciplinary practice headquartered in New York City. The firm’s work includes development of retractable façades, responsive shading and ventilation, and operable roofs and canopies. Hoberman, who won the Chrysler Award for Innovation and Design in 1997, holds a bachelor’s degree in sculpture from Cooper Union and a master’s degree in mechanical engineering from Columbia University.

Craig Schwitter is a partner in and the regional director of Buro Happold North America. In 2001, he was appointed the first Bedford Distinguished Chair of Architecture and Engineering in the architectural and civil engineering departments of Rensselaer Polytechnic Institute. Schwitter has a bachelor’s degree in structural engineering from John Hopkins University and a master’s degree in structural engineering from the Massachusetts Institute of Technology.