CROMA

We worked with NY-based firm SOFTLab to illustrate conceptual scenarios of interactivity enabled by our OECDs.

Performance and (not versus) Experience

Façades play a key role both in the energy-efficiency and in the aesthetic qualities of a space. The modern architecture use of brise-soleil to cast shadows and protect the building’s interior from direct sunlight, exemplified in major works of architecture such as Le-Corbusier’s Citroen House or Renzo Piano’s New York Times Headquarters, shows how these light-controlling elements can also act as the defining features of a compelling architectural language. How can current advances in technology help us re-think the notion of brise-soleil, and of the window itself, through current technologies to create beautiful, energy-efficient, and responsive architectures?

The solution to this question lies outside the traditional disciplinary boundaries that separate Architecture, Science, Engineering and the Arts.

A basic premise of this work is that a programmable and responsive façade element can not only be aesthetically provocative and improve energy-efficiency of architecture, but also has the potential to alter the ways we relate to buildings and surfaces, opening exciting avenues for new kinds of interaction and experience, and requiring new skills and competencies in the fields of design, architecture, and engineering.

Electrochromism

Electrochromic devices change their optical properties in a reversible manner when voltage is applied and current flows through them. The material responsible for transmitting this charge needs to be sensitive to electrical charge variations. Electrochromic windows currently available rely on a thin layer of electrochromic material composed of the oxides of certain metals that change transparency by the reduction/oxidation induced by a voltage. Researchers have shown how such light-controlling devices can generate substantial energy-savings in a real-life application (Argun, 2004) by controlling responsively (by an individual) or globally (by environmental sensing) the amount of solar energy that enters the building. The novelty of our approach is twofold: first, instead of energy-expensive metal-oxides we use cheaper and easier to produce organic polymers, byproducts of oil, and extractable from waste, that have been recently shown to display electrochromic properties (Argun, 2004). Second, we are using sensing technologies to allow for direct, tactile interaction with the surface.

Some advantages of organic electrochromism over LCD devices

Some advantages of organic electrochromism over LCD include a) allows for transparency gradients: in contrast with conventional ECDs, in OECDs (organic electrochromic devices) transparency is a function of voltage. This means that the device can be designed such that depending on the pressure applied on the window the transparency can vary accordingly. Conventional ECDs, and LCDs have only ON/OFF states; b) OECDs do not require constant current for retaining their state. Voltage needs to be applied onlywhen switching. In contrast conventional ECDs and LCDs require to be constantly powered. It is important to note that despite the relatively low charge required by LCD devices, once scaled to a building’s size, the use of these devices can become energy expensive.

Schematic 3D Image of our organic electrochromic device (OECD) currently under development

This video shows the development of the first touch-sensitive organic electrochromic device (OECD). Thanks to the MIT Council for the Arts Grant for partially funding these prototypes.

Local control of an electrochromic facade affords new kinds of gestural control over architectural surfaces, revealing potential new experiences and design opportunities.

It is estimated that 50% of the heat that enters a building does so when there’s no one to look through the window. Can we make a smart facade that saves energy by regulating the amount of sunlight that enters through the window?

This proof of concept OECD changes transparency gradually when touched. It worked reliably during a test session in the lab. We are working towards obtaining a better contrast between the colored and the transparent states.

Recent advances in the development of organic electrochromic devices (OECDs) were shown last week in the last version of eCAADe (Education and Research in Computer Aided Architectural Design). Download paper here

This test in the lab shows the color change of a small piece of acetate treated with organic electrochromic materials in response to a charge. Can we use this technology to create a smart OECD (Organic Electrochromic Device) facade that improves the energy efficiency, as well as people’s experience, of a building?