With all the hype regarding the use of automation in 21st century homes and the looming concerns regarding the global environment, understanding the smart materials from a product context entails us to move from micro to macro perspective. What can smart materials actually do in order for a designer to yield optimal results for a sustainable architecture?
Centering on the human occupation and use of spatial environment, smart environments respond to human's focal point of a quality "live, play and work" lifestyle. In a common design context, simple types of smart materials with property-changing and energy-exchanging attributes are combined with other materials to produce devices and components serving the complex functions. Consequently, components are upgraded into building systems that are shown visibly such as the management of the thermal, luminous and acoustic environments while other smart systems operate hidden in plain sight such as the dynamic structural control.
Analogous to an architect's intention, the domino-effect questions remain unanswered on the table: What are the building system design needs? What are the relevant material characteristics? Finally, what are the representative applicable smart materials?
Window and Facade Systems
Leading the pack and obviously embraced wholeheartedly by architects and engineers, window and facade systems dominate the use of smart material application. Energy transfers of facade system operate bi-directional simultaneously - heat conducts outside with interior radiation, and entering light must be in equilibrium to the exterior view. Low-emissivity, solar reflective and non-reflective thin films coat the glazing; automated louvers alongside energy management control systems operate to reject excess solar radiation; and double skin systems dampen the thermal swings, covering the building in glazing twice.
Much of the concerted effort to improve the efficiency of building energy process gears toward the light systems. The fundamental savings that come along from the use of smart lighting systems encourages users to install photovoltaics or light-emitting diodes (LEDs) which continually assess daylight levels using a reflectance light sensor and a photodiode. Automatically switches on when daylight level dims, and turns off when the sun illuminates brightly, LEDs unceasingly operate on an inverse relationship of illuminance measurements, resulting in a seamless blend of lighting 24/7.
Optimization of HVAC systems through temperature, humidity and CO2 sensing calls for the reduction of greenhouse gas emissions. A room thermostat works in the energy exchange with the bending of a bimetallic strip, of which two metals attributing different coefficients produce an output signal.
Most of these systems deal with the detection, monitoring and control actions of combined sensor-actuator systems. But as we go back to the micro scale aforementioned, inherent characteristic of a smart material can act alone as a sensor responding to a change by generating a perceivable output. One example worth noting is a thermochromic material yielding color response capabilities when sensing fluctuations in the environment's temperature. The possibilities from here are endless for smart materials.
As an architect or a designer, what smart materials have you used in your building specifications for optimal human-environment efficiency? I bet if smart materials can talk, they'd pull this one-liner, "Change is constant." So, what's yours?