Design Evolution
Professor of Architecture Kyoung Hee Kim began developing microalgae-filled building façade systems years ago, prompted by an environmental science class in graduate school. Knowing algae’s ability to sequester carbon and improve air quality as well as potential uses as food or energy sources, she began to design window installations in which microalgae could grow.
The algae’s greens and blues provide shading from the sun, and a pump circulates air through the system, filtering out carbon dioxide and impurities and releasing fresh oxygen. Periodically, the algae can be harvested for other uses, such as biodiesel fuel.
Kim and a team of student researchers began prototyping in 2011. Over the years, the work has been funded by several different grants from the National Science Foundation and the American Institute of Architects. As she has learned from her successes and failures, the architectural design of Kim’s installation has changed dramatically, resulting in three distinct typologies. Currently, Kim has an installation at the Innovation Barn in uptown Charlotte, where she and her team have been testing its performance for six months and are continuing to make improvements.
“Design, make, operate, and validate. Those are the key steps that have been occurring throughout the different typologies,” Kim says. “I just have been very curious. What if I do this?”
Here, Kim explains the development of each design.
Design 1: The Interlocking or X Module Prototype
When I design a system, I often think about either a design motif that inspires me or symbolic meanings. So, as you may tell from the word “interlocking,” I was very interested in how to make humans and algae coexist in a space, and I thought creating an interlocking structure can communicate my design intent.
When I am thinking about design, I’m also thinking about functionalities. Throughout all the processes since 2011, one design criterion from the human perspective was view out – whether I have a place to view out and let the daylight in to the space.
And the second function from the microalgae perspective is that it has the right cultivating environments to grow. I need to have a good amount of solar exposure, and I need to also provide air into the system.
I’m thinking about symbiotic relationships. Humans produce biogenic carbon dioxide, and then algae can use that waste from humans for their nutrients. And in return, algae produce oxygen, and humans use oxygen for our benefit. I need to incorporate the inlet of the air, which will be bottom, because air rises. And then I’m going to put the outlet of oxygen from the top.
And then, for the cultivation of microalgae, I am bringing the young algae in from the top and incorporating the algae harvesting outlet at the bottom. So those are four outlets. And that hasn’t changed as different typologies evolved.
You also may notice it’s not a planar X. It’s a three-dimensional X. The angle is considered for solar angles. So, if I install in, let’s say, Seoul, Korea, you may want to bend more, because the sunlight is always very steep. So we could adapt to different locations.
“Interlocking” won a 2021 R+D Award from Architect Magazine.
The problem: Modules are good, to be adaptable to different sizes of window and different shapes. But because of these modular pieces, I needed to deal with leak potentials in those joints.
Design 2: Crownshyness
I was inspired by the crown shyness – the spacing in the canopy of trees. If you look up, you see that the crowns yield a little bit to each other. They create a gap to let the daylight in. There is a self protection through this, and also an altruistic behavior for other little vegetation.
With this design, I still need to provide a view out at human eye level, to create a transparent view out. So the top and bottom of the panel are thicker, for growing more microalgae, and the middle is much thinner and translucent, transparent, for the viewing experience.
The original intent was ultrasonic welding, which needs specialized equipment, a very high pitch frequency to weld two pieces into one.
I was using half-inch thick polycarbonate. Two sheets would become just one sheet, a one-inch sheet of polycarbonate. The intent was to find a manufacturer who could do ultrasonic welding for us, and we spoke to a few, but then their machines were very small.
So the button is a mechanical connection to hold two sheets together without bulging. But the original design intent was very clear: two sheets of polycarbonate glued to each other as one piece.
“Crownshyness” won the Bronze Award for Product Design in the 2025 Design Educates Awards.
The problem: This design had no leak, but it was not up to our true design intent as far as the view out goes. And in order to create the crown shyness texture, it requires thermal forming. We apply the heat and then let the heated polycarbonate sit on top of the mold. But that heating process, in fact, creates a stress to the textured panels, and eventually they become brittle.
“Those kinds of failure moments really make me pivot. That’s why we pivoted to the blade, the other typology.“
Design 3: Blades
Extrusion-wise, this design is much simpler. It doesn’t induce stress brittleness during the manufacturing process.
If one blade goes wrong, I can replace it. Versus the big panels: One panel becomes contaminated, I need to drain and refill the entire panel again. It’s such a big waste. So, in terms of the operation and maintenance, this has been the best so far.
The nice thing about the blade is that it is able to rotate, depending on what the algae needs. And then, in the meantime, between the blades, I can also create a totally clear view out, if I make the blades all 90 degrees perpendicular to window. If I need privacy, I can also close off, so no one can see from outside into the space.
“The algae are growing well. And they’re also performing air purification. It proved to be as we hypothesized.“
Of course, there are many areas that I am also working on. For example, I want to incorporate light. Light is not only good for pleasing people, but also I can use it to supplement lighting for growing algae. The way I did it here was just to sink the LED light, but that’s not good, because I cannot take it out. So, I want to incorporate light into the cap. The cap will have a pocket that does not leak, but will let the light shoot into the blade. So that is the thing that I’m working on.
The automatic nutrient dispenser is something I’m also working on. At the moment I go to the Innovation Barn every other week with two buckets to give nutrients for the algae. But I can automate the nutrient dose.
I’m also incorporating the automatic biomass sensor in the system and I’m looking into AI integration as well. If, for example, I want to grow a certain algae species – let’s say it is for biodiesel production – then I need to grow Nannochloropsis, which is different from Spirulina, which is used for food. I can incorporate AI to predict the best growing environment for that algae, depending on the dynamic environmental conditions.
So I am adding more functionality to the operation and maintenance. I’m using this Innovation Barn installation to fully modify and develop and refine the system. Then it will be ready for a commercial setting.
