Award: Toward Carbon Neutrality—High-Performance Biochromic Window

“Algae projects are tough to fall in love with because it’s not always pretty stuff. This system takes an aesthetic and functional approach to create an interesting and attractive solution.” —Juror June Grant

In the era of climate action, a façade that reduces energy consumption and actively sequesters carbon can hardly come sooner. A microalgae window system by the Integrated Design Research Lab at the University of North Carolina Charlotte checks both boxes while cultivating a renewable energy source and supporting occupant wellness through improved indoor air quality and reduced glare and solar heat gain. The patent-pending unitized façade system serves a dual purpose by integrating photobioreactors with vision-glazed panels. The adaptable X-shaped microalgae growing modules interlock to form a latticelike structure, which is then housed within metal framing complete with a transom and mullions. The modules are factory assembled for quality control and suitable for whole-building retrofits or small-scale interventions, such as adding the system to existing windows like blinds.

The closed-loop system does not require fresh water or fertilizer. Ambient air—which contains carbon dioxide—enters through openings at the base and, warmed by the sun, rises through the latticework. The microalgae grow faster with more sunlight, providing the most shading in the summer. The oxygen they produce is pumped into the HVAC system. Fresh microalgae are pumped into the top of the system, while the carbon-loaded algae sink and exit through a pipe at the base. The harvested algae are transferred to a dewatering facility and then converted into biofuel.

IDRL has tested six strains of microalgae with a range of useful bioproducts: Chlorella vulgaris, Chlorococcum, and Scenedesmus obliquus can all be used as biofuel; Haematococcus pluvialis can be used for bioactive compounds; Spirulina as food; and Pyrocystis fusiformis as a bioluminescent. These strains were also selected based on their hardiness and aesthetic, including color and bioluminescence.

IDRL’s innovation stands apart from existing microalgae façade products with its aesthetic and open pattern that still allows clear views out and daylight to penetrate the interior, reducing the building’s electric lighting load. “Due to its innate … photosynthesis performance responding to solar intensity, our microalgae window contributes to an energy-efficient and healthy built environment,” says IDRL director and EcoClosure founder Kyoung Hee Kim, AIA. She estimates that enclosing a building completely with the microalgae system could reduce its energy consumption by 20% to 30%.

Architecture, engineering, biology, and construction management students have contributed to the nine-year-old project, building full-scale mock-ups and testing structural integrity and watertightness.

IDRL is now in the process of developing an artificial intelligence–powered system to control microalgae tint and color, depending on user needs for visual and thermal responses, which will further distinguish this technology from its precedents.

^{Assembling the biochromic window}

Project Credits
Project: Biochromic Window
Location: School of Architecture, University of North Carolina at Charlotte
Client/Owner: U.S. National Science Foundation
Architect/Designer/Inventor: Kyoung Hee Kim, AIA (EcoClosure founder; UNC Charlotte associate professor of architecture; Integrated Design Research Lab director)
R+D Team: Garrett Herbst, AIA (EcoClosure, Little Diversified Architectural Consulting); Yau Shun Hui, James Hung (EcoClosure); Chengde Wu, Arturo Lujan, Matt Parrow, Ok-Kyun Im, Milad Rogha, Alexander Cabral, Robby Sachs (UNC Charlotte)
Cost: $200 per square foot

Materials and Sources
Prototyping: EcoClosure and UNC Charlotte

This article has been updated since first publication.

• R+D Award: Long Range Glass

  A team from the University of Michigan and Arcgeometer is shaping glass for broader acoustic and optic qualities.

  

• R+D Award: Tangential Timber

  A team from After Architecture and the University of Virginia School of Architecture proposes a construction application for non-linear wood through the development of a digital fabrication workflow.

  

• R+D Award: V-Soleil

  Architecture Research Office collaborated with Heintges Consulting Architects & Engineers to develop V-Soleil, a curtain-like terra-cotta brise soleil inspired by the organic forms.

  

• R+D Award: Tortuca

  A collaborative research team initiated and led by Masoud Akbarzadeh, the director of the Polyhedral Structures Laboratory and assistant professor of architecture at the Weitzman School of Design, created an ultra-thin hollow glass structure, which spans 10.5 feet.

  

• R+D Award: E-games-lab—eFargo

  A team from the University of Minnesota College of Design and North Dakota State University created an interactive game to help reduce carbon emissions and energy use to fight climate change.

  

• R+D Award: Kaleidoscope—Embodied Carbon Design Tool

  Payette created a simple and straightforward tool that allows designers to compare the embodied carbon across a range of façade and interior systems.