This is Part 2 in a five-part multimedia feature examining Cornell's cutting-edge, interdisciplinary contributions to solar energy research as New York state works to achieve its goal of 70% renewable energy by 2030.
There is more to photovoltaic panels than the materials that comprise them: The design itself can also drive - or potentially diminish - the widespread adoption of solar technology.
Put bluntly: Most solar panels are not much to look at. And their flat, nonflexible composition means they can only be affixed to similarly flat structures. But what if photovoltaic panels were instead a hinged, lightweight fabric that was aesthetically attractive and could wrap around complex shapes, even contorting its form to better absorb sunlight?
Thus was born the idea for HelioSkin, an interdisciplinary project led by Jenny Sabin, the Arthur L. and Isabel B. Weisenberger Professor in Architecture in the College of Architecture, Art and Planning, in collaboration with Itai Cohen, professor of physics in the College of Arts and Sciences, and Adrienne Roeder, professor in the Section of Plant Biology in the School of Integrative Plant Science, in the College of Agriculture and Life Sciences and at the Weill Institute for Cell and Molecular Biology.
"What we're really passionate about is how the system could not only produce energy in a passive way, but create transformational environments in urban or urban-rural settings," Sabin said. "Sustainability is about performance and function, but equally, it's about beauty and getting people to get excited about it, so they want to participate. The grand goal is to inspire widespread adoption of solar for societal impact."
HelioSkin is a lightweight, stretchable architectural fabric that is aesthetically attractive and can wrap around complex shapes.
Sabin, the inaugural chair of the new multicollege Department of Design Tech, has made a career of collaborating with diverse disciplines and taking cues not just from architecture, but also engineering. And physics. And mathematics. And, perhaps most importantly, biology. All of her projects are united by the same question: How might buildings and their integrated material systems behave more like organisms, responding and adapting to their local environments?
"Nature is not efficient," Sabin said. "It's resilient, and biology is in it for the long game, over much longer time scales. Additionally, it has been demonstrated that plants that track the sun exhibit a photosynthetic advantage. And we think that's a pretty powerful way to think about sustainability and resiliency in architecture."
Sabin's design interests address a very real need. The primary convergent problem is that 40% of total greenhouse gas emissions in the United States comes from buildings, according to the International Energy Agency.
"By developing a new solar skin product that can scale, we aim to turn the needle by getting homeowners and businesses to adopt solar to reduce the 28% of CO2 that comes from the heating, lighting and cooling of buildings," Sabin said.
HelioSkin originated in a partnership between Sabin and Mariana Bertoni, an energy engineer at Arizona State University, who is also a member of the HelioSkin team. Together they combined computational design, digital fabrication and 3D printing to create customized filters and photovoltaic panel assemblies - what Sabin calls "nonstandard angularity" - that could simultaneously boost light absorption and architectural beauty. The key to that effort was looking at the mechanics of heliotropism - how sunflowers track sunlight.
For HelioSkin, that research foundation expanded to include Roeder's expertise in heliotropism and cellular morphogenesis - i.e., how plant cells grow to bend the plant toward the sun - and Cohen's specialization in using geometric methods such as origami and kirigami to improve the mechanical performance of metamaterials, increasing their flexibility while expending very little energy.
The flowering Arabidopsis plant is an ideal model for HelioSkin because, as "the fruit fly of the plant world" according to Roeder, it's easy to study at the cellular level. Those cells play a vital role in changing the curvature of the plant's stem as it angles toward the sunlight, with the Arabidopsis' hormones causing the cells on its sunless side to expand by 25%, bending the stem 90 degrees.
"We've already figured out how to translate our plant cells' tracking mechanism into Jenny's architectural software," Roeder said. "Now we have to start figuring out how to make that transition in HelioSkin."
