Construction of the LafargeHolcim Awards winning net-zero energy greenhouse at Wellesley College, USA was completed in 2019. Sustainable design is at the very core of the structure, form, and system – meeting sustainability metrics as a matter of course and then goes much further to achieve a virtuosity of integration. The Global Flora conservatory at the Margaret C Ferguson Greenhouses will open to the general public when renovation of the Science Center is completed, planned for early 2022. More than 1,000 varieties of plants are housed in the bio-friendly greenhouse – and are showing signs of handling the transition well.
The collection includes relocated plants from the old greenhouses including the iconic 150-year-old Durant camelia, as well as new specimens such as tree ferns that are taking advantage of the soaring 12-meter interior height that would be impossible using conventional construction methods. Global Flora opened for limited hours to members of the College community from September 2019.
Reimagining the Greenhouse
A typical greenhouse is an energy- and water-intensive building. But for this project, Boston-based Kennedy & Violich Architecture (KVA) led a project team that worked to reimagine the structure as a sustainable, net-zero energy building. Together with Wellesley College, they designed a greenhouse that is much more than simply a climate-controlled envelope. It houses a preeminent plant collection, supports an innovative public education curriculum that integrates sciences, humanities, and the arts, and enables studies of plant form adaptations.
“Global Flora will just floor people with diversity of form and texture and color. It’s a cathedral of sorts, a temple of biodiversity,” says Rob Nicholson, Botanical Collections Manager, Wellesley College Botanic Gardens.
“We are going for Living Building Challenge certification,” says Cathy Summa, Associate Provost and Director of the Science Center at Wellesley College. Global Flora must be open for a year to collect data to be eligible for the challenge, administered by the International Living Future Institute. It recognizes buildings that connect occupants to light, air, food, nature, and community; are self-sufficient and remain within the resource limits of their site; and create a positive impact on the human and natural systems that interact with them.
Beauty that’s more than skin deep
The secret is the structure’s ETFE cladding. A thick, translucent plastic, ethylene tetrafluoroethylene (ETFE) is lighter and more flexible than glass. Using it requires much less structural support, which allowed the architects to add more height and volume than the previous greenhouses had. “Nobody anywhere has built a greenhouse of this shape and material,” says Kristina Niovi Jones, Director of the Wellesley College Botanic Gardens. “There’s about half as much steel as there would have been if this were glass.”
The exterior consists of two-layer pillows of ETFE. Each pillow is connected to a compressed air system that blows air in or lets air out, constantly measuring the pressure in that pillow. As atmospheric pressure fluctuates, the pillows respond. The pillows also make a huge difference in insulating the building. Single-layer ETFE doesn’t insulate much, but the envelope of air between the layers is a great buffer for temperature differences. Last winter, the inner layer of ETFE barely felt cold. The strength of the material has also been proven, with the structure easily handling the New England snow load.
Consideration of the plants’ basic needs – water and light – was central to planning the design. The south-facing conservatory is replete with light. A computer-controlled interior shade system mitigates summer glare. Recycled rainwater from the roof of the structure and from the Science Center roof is captured in two massive underground cisterns. The water is then drawn up, filtered, and used for hand-watering the plants as needed. Data from sensors, as well as manual observation by staff, determine which plants need what, and when.
A biological research space of EPIC proportions
Global Flora is intrinsically a research facility. The Exploring Plants in Context (EPIC) platform uses sensors in the soil to continuously gather data about water content, pH, salinity, and more. The data will be available for analysis in interdisciplinary science courses. “We’re monitoring the water and how we water. We’re monitoring the air temperature, humidity, and so forth. We’re monitoring the nutrients in the soil. We’re monitoring everything we possibly can,” says Cathy Summa.
“The new structure provides a place where growing season lasts year-round, Kristina Niovi Jones says, making it ideal for teaching. “The opportunity to study plants, microbes, fish, predator-prey interactions, and things like that in a ‘bubble’ in New England is really cool. We’ll have a lot more ecology going on in here, studying the relationships between things. Because the plants are out of their pots and in the ground, they will be interacting underground, and we’re trying to visualize more about what’s happening underground with the sensors. We’re interested in things like how nutrients are moving through the system, how the water is moving. It’s still a museum of plants, a really amazing collection, but they’re also part of a community that we hope will interact with each other.”
Global LafargeHolcim Awards recognition
Global Flora was a finalist in the Global LafargeHolcim Awards competition in 2018. In recognition of this achievement, the project’s main authors Sheila Kennedy and Frano Violich of KVA were presented with a finalist’s certificate at the LafargeHolcim Forum 2019 held in Cairo. The project was praised by the Awards jury: Greenhouses stand for challenges posed to the profession of architecture to reduce the means needed for enclosure. The jury greatly valued this project for addressing this history with a reduction not just in material for enclosure; but also in the resources needed for ongoing use.
The project was named US Building of the Week in September 2020 by World Architects.
Credit: This project update was originally published in December 2019 but updated in September 2020 to include new images of the project and further details generously supplied by KVA Architects. Selected text in this article sourced from “The new global flora collection celebrates plant diversity” by Catherine O’Neill Grace, photography by Webb Chappell in Wellesley Magazine, Fall 2019.See more
Greenhouses have a very long history of providing microclimates for plants dating back to the Romans. Nevertheless, they can be completely rethought – as evidenced by the very ambitious project for a net zero greenhouse on a college campus.
In one of his works, the Roman writer on agriculture Lucius Iunius Moderatus Columella recommended covering plants with panes of glass in winter – essentially reducing the exposure to cold and harsh conditions using a greenhouse. From the 16th century, the princely houses of Europe boasted of their orangeries, and soon thereafter the advent of imported pineapple plants gave a boost to the development of greenhouses. The first greenhouse with underfloor heating was built in Amsterdam in 1682; supplemental radiator pipes heated the air. Industrialization ultimately enabled the construction of vast structures of glass and iron, some of which can still be admired today, such as at Kew Gardens in London. Greenhouses have great tradition.
Sheila Kennedy tends to question tradition and likes to develop new solutions to old challenges. Her education has prepared her well for this. She holds a Bachelor of History, Philosophy and Literature, studied architecture at the Beaux Arts Ecole National Supérieure in Paris, and holds a Master of Architecture from the Graduate School of Design at Harvard University. In 1990 she co-founded the practice Kennedy & Violich Architecture with Frano Violich. Sheila Kennedy has worked as a consultant to the United States Department of Energy, the National Academy of Sciences’ Government-Industry Partnerships, and the Vision 2020 National Technology Roadmap. In 2014 she and Frano Violich won a LafargeHolcim Acknowledgment Prize North America for one of their residential projects in Boston.
The new structure will replace the outdated and closed Ferguson Greenhouses on the Wellesley campus. The greenhouses were named after Margaret Clay Ferguson (1863-1951), a leading botanist of her time.
Ferguson was a student and later a lecturer at Wellesley College, a renowned women’s college. In 1929 she became the first female president of the Botanical Society of America, and she is recognized for her research on mushrooms, pines, and petunias. Realizing a project like Global Flora requires more than architectural expertise – it requires knowledge that architects typically don’t receive through their training. That’s why Kennedy & Violich worked with scientific specialists almost daily for four years: geologists, biologists, botanists, and the like. In this way, a broad pool of knowledge emerged – and this allowed the architects and the scientists to learn from each other.
Global Flora is scheduled to open in spring 2019 – not only for the scientific community, but also for the public. The greenhouse will provide a learning platform because it produces “knowledge in real time” about the condition of the soil and the air, about plant root growth, and about relative humidity – and not only for visitors on the premises but for anyone interested around the globe, thanks to the internet. Scientists around the world will surely welcome so much useful data provided by the bio-feedback sensor platform. It will allow biological processes to be tracked over long periods of time without requiring the constant presence of a researcher on site.See more
As one of the three main LafargeHolcim Awards winners for North America in 2017, “Global Flora” automatically qualified as a finalist in the Global LafargeHolcim Awards 2018. All 15 finalist project teams were asked to submit an updated and more comprehensive entry that was evaluated by a global jury in March 2018.
The results of the global phase of the 5th LafargeHolcim Awards competition were announced on March 28, 2018.
Kennedy & Violich Architecture in Boston designed a greenhouse that is much more than simply a climate-controlled envelope: It houses a preeminent plant collection, supports an innovative public education curriculum that integrates sciences, humanities, and the arts, and enables studies of plant form adaptations. The approach of using local materials and labor is particularly respectful of the environment. “Sustainable design is at the very core of the structure, form, and system. The project meets sustainability metrics as a matter of course and then goes much further to achieve a virtuosity of integration,” noted the jury.Read more »
This project is an expansion of the botanical collection at Wellesley College. It is conceived as an educational link between the institution and the community. This project reimagines the greenhouse – typically an energy- and water-intensive program – as a net zero energy building. Particular care is taken to source all materials for the projects locally and with low resource intensity both for construction and operations. The lightweight pillow cladding weighs just three percent of what the same area would out of typical insulated glass. The three biomes – dry, temperate, and humid – help support each other through passive air and heat exchange.
From Joseph Paxton onward, the greenhouse has been a compelling architectural type for everything from plants to exhibitions to radical housing. Greenhouses stand for challenges posed to the profession of architecture to reduce the means needed for enclosure. The jury greatly valued this project for addressing this history with a reduction not just in material for enclosure; but also in the resources needed for ongoing use. Sustainability is at the very core of the design in structure, form, and system. The project meets sustainability metrics as a matter of course and then goes much further to achieve a virtuosity of integration.See more
Global Flora’s sustainable design strategies strengthen the collective public realm
The sustainable use of living soils connects Global Flora plant specimens to local topography and ecosystems, enhancing Campus use as a public resource. An innovative Interactive Platform provides real time air, water, soil and energy status, expanding public access for on-site and online users. Instead of being bounded by a lot line, Global Flora creates a precinct of shared clean energy and water exchanges that remediate the natural landscape and improve land use, value and the sustainability of renovated and new Science buildings. Repurposed masonry, stone and wood from Campus and region-sourced ETFE cladding minimize embodied and operational energy. Global Flora meets living building net zero challenges with intelligent, passive design and humid air transfer between biomes.
Global Flora reinvents the “stand alone” conservatory typology with net zero performance
Global Flora achieves net zero and expands public programs with a new integration of site, buildings, biomes and sustainable passive systems. 1-hectare precinct site is net zero water, managing rainfall in cisterns and filtering waste water from the Science Center roof. With a 10K kwh solar grid, harvested water is reused for plants, toilets and maintenance, minimizing high energy municipal water treatments. Passive design, site orientation and material choices minimize energy use. Global Flora is heated by on-site geothermal wells, and 100 % passively cooled through natural ventilation, fans and water design. Each biome helps to support another’s needs through passive air & energy transfer: the design demonstrates ecological synergy and supports comparative study of adaptive plant biology.
Interdisciplinary innovations advance design, natural sustainability and public education
Global Flora advances practice with interdisciplinary collaboration and innovative integration of affordable, passive ecological principles and architectural design. Use of thermal mass with ETFE minimizes structure, enables air/heat exchanges and direct visual comparison of plant biomes. Public knowledge on sustainable natural specimens is disseminated globally with an open source interactive research and bio-feedback sensor platform. This monitors and enables on-site and online access of matter flows in Global Flora, and the display of ongoing research and data that reveal plant processes and growth over time. Linking immersive, physical experience of nature with digital technology, Global Flora’s design redefines public access to nature and transfers knowledge of its systems.See more
Net-zero greenhouse for Wellesley College, Wellesley, MA, USA - This project reimagines the greenhouse as a …
The sustainable design of Kennedy & Violich Architecture's greenhouse for Wellesley College delivers heating and cooling …
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