KELSEY EVANS/THE CAMPUS
Construction of the Carr Hall Garden greenhouse started over the summer months as part of an ongoing collaborative project with students and faculty.
According to Sustainability Coordinator Kelly Boulton, ’02, the construction of the greenhouse and an additional storage shed in the garden has been made possible by a Constellation New Energy Grant: E2 Energy to Education. When the garden was established in 2013, space was left with the intention of eventually building a greenhouse, Boulton said.
Boulton and Environmental Science Professors Ian Carbone and Eric Pallant applied for the grant last fall in the “zero waste” category.
“Letting the light come through to the plants and capturing what isn’t usable by the plants, that’s kind of a stretch of the definition of ‘zero waste,’ but I think it was pushing the boundaries of what they were asking for in the grant and is probably what got us the grant in the first place,” Boulton said.
Boulton said several elements will help contribute to the “zero waste” concept, including the structural design, panels, a pellet stove and a connection to the campus electrical grid.
“A lot of greenhouses would be all glass or all plastic,” Boulton said. “The reason this one is not is because it’s very insulated as well, so it tries to balance letting light in through the roof and through the windows, but also insulating to the point where you can grow through the winter without just cranking the heat constantly.”
Tangible plans for the greenhouse began with a spring 2015 junior seminar course led by Carbone.
“The design process was largely hammered out by students at Allegheny and then we went and found a commercial design that sort of fit the criteria that the students wanted,” Carbone said.
According to Carbone, those criteria included a south facing shed-style roof to maximize electricity production, a well-insulated compact framework and the pellet stove heat source. Carbone said the pellet stove will burn switchgrass pellets from Ernst Conservation Seeds in Meadville.
The panels on the roof are called luminescent solar concentrators — which have solar cells and a luminescent dye embedded into them, Carbone said.
“We’ve chosen that dye to absorb green light, and the great thing about that is that green light is not one of the light wavelengths that most plants depend on for photosynthesis,” Carbone said. “What we have is a plastic material that will basically absorb all the green light out of the light that’s coming from the sun, and a large fraction of that rattles around until it strikes a solar cell and is converted to electricity. So it primarily collects green light and allows all the important photosynthetic light to go down through to the plants underneath.”
Carbone said the electricity produced through the greenhouse must be converted in order to connect it to the electrical grid.
“To make that solar panel electricity usable by the grid and the rest of campus, we’ve put micro inverters on there,” he said. “So those micro inverters turn the solar panel signals to something that we can use in our building.”
Boulton has also been working with Information Technology Services to connect the greenhouse to a dashboard in Carr Hall.
“[The dashboard] will allow us to visualize and think about the greenhouse in terms of an energy budget, because ideally we only want to use as much energy in this greenhouse as we are producing,” Boulton said. “The idea is that students can then look at the production of energy and how we budget the use of the greenhouse based on that energy budget so that it’s carbon neutral.”
Carbone said Owen Ludwig, ’18, worked with Physical Plant to secure a construction contract. Ludwig said several local contractors bid on the project at the beginning of the summer, but Howe Contractors of Meadville was selected. Ludwig also built a new storage shed and a wash station for the back of the greenhouse.
“It was really fun and rewarding to partake in those construction projects because now I feel like I’ve left a very tangible imprint on this campus,” Ludwig said. “[The greenhouse] is a really cool educational piece about sustainable energy, about season extension, growing food during the winter in a place where you usually can’t grow food and even physics.”
Boulton said Sarah Nathan, ’18, spent the summer solidifying these educational aspects into materials and curriculum.
“I was working on education, kind of from every standpoint,” Nathan said. “At the very basic level, I created signage that will be going up on the greenhouse so anyone who is walking by can read about the technology and how it works.”
Nathan said she has connected with Crawford County Career and Technical Center’s horticulture program for those students to tour the greenhouse and learn about its technologies and has been writing curriculum for Meadville area schools at the middle and high school levels.
“I’ve been working on creating lesson plans that specifically go into the biology of switchgrass and how biofuels work and why it’s such a sustainable way of heating the greenhouse,” Nathan said. “Similarly with the luminescent concentrators, I’ve been writing lesson plans on the physics behind all of that and how solar panels work and why that technology works so well with a greenhouse.”
Boulton said materials have also been created for Meadville Cooperative Preschool students who usually visit the garden once a week.
“The garden has always been intended as an open space as long as you’re respectful, so anyone can come and sit at the tables and study and work, or hang out,” Boulton said. “People are welcome to come and look into the greenhouse.”
Boulton said the final elements of the greenhouse should be completed this semester.
“Everything of course did not go as planned — some of the solar panels arrived two weeks late, they got lost in shipment, three of them were broken so then we had to wait three more weeks to get replacements,” Boulton said. “It should all be done in the next month, but we’ll see if it goes smoothly.”