COURTESY/SAIT
David Silburn, research associate, and Andrew Hewson, chef instructor, at the School of Hospitality and Tourism, at SAIT pose in the bubble greenhouse.
Here we go again!
It’s coming around the corner, it really is, believe me. Spring is on its way. You know how I know? We’re talking about gardens and growing things again after a cold, white, wet winter.
Recently, SAIT unveiled its bubble greenhouse to Calgary. It’s quite the feat and insanely clever, with the growing season being so short here — we get random frosts and chilly nights out of the blue (AND I’ve been told it can SNOW in the middle of August! What?!) — this greenhouse project, headed by SAIT research instructor David Silburn, will not only allow the chefs in SAITs culinary program access to fresh produce all year round, but also become more familiar with where their food comes from.
“It’s pretty awesome actually,” says Silburn. “(Temperature control is) one of the biggest things that we’re doing, and main the reason we’re doing it is to teach the culinary students about food production, and how much better food can taste.”
COURTESY/SAIT
Plants in the bubble greenhouse have the luxury of being catered to, temperature-wise, with heated beds and misting lines for those veggies that like humidity, to ventilation controls for drying out the environment for those that flourish in low-moisture conditions.
So how does it all work?
SAIT students basically built one greenhouse inside of another, making sure it was airtight, and engineered a mechanism to pump a soap-water solution through a pipe at the top of the structure where air is added to create the bubbles between the two walls.
“The air nozzle, and the pressure of the air, and the amount of soap-to-water dictates how the foam is going to perform,” says Silburn. “The soap become a relatively dry, dense foam that works well as insulation.”
It takes 45 minutes to fill the greenhouse walls from scratch, and that lasts about three hours. Every three hours the timing cycle kicks in and tops up the soap bubbles for 15 minutes. The soap is then recycled through the entires greenhouse.
“Theoretically one could run the entire greenhouse on very little electricity and two bottles of soap … for the entire year,” Silburn says. “(But) we found over the last year of testing that it’s a good idea to dump it and start over again.”
The idea to run a greenhouse on biodiesel fuel and soap bubbles didn’t just come out of thin (bubble-free) air. In 2000, Silburn helped build Canada’s first foam-insulated greenhouse in Perth, Ont., for a friend and his wife who wanted to have produce grow all year round. Silburn says typical greenhouses on the market are opaque and don’t allow for plants to grow all year long, and the best they can do is extend the season by a few months.
Click here to see a report of soap bubble insulation technology from Silburn’s first project in Ontario.
“One thing that we wanted was an insulation that could be semitransparent, so that the light could come through and continue to allow the plants to grow. And then at the same time, provide a significant amount of insulation,” says Silburn.
“The goal is to conserve energy, to insulate well, and to allow the light to come through.”
Plans were drawn up for SAIT’s greenhouse in 2010 and spent a year going through the city for permitting. The structure was then built with the help of some internal grants and, of course, SAIT students. Silburn says it’s hard to pinpoint the cost of the project, since they had “a lot of passionate labourers” working long hours.
I asked Silburn what a project like this can cost, maybe I could build one for myself? It’s quite the undertaking.
“Building a cedar timber framed greenhouse vs. a standard greenhouse are pretty different things already, so it’s hard to talk about (the costs). The soap is certainly an add-on feature, the biodiesel system is an add-on feature,” explains Silburn.
“You can put a smaller (structure) inside a bigger one and fill the inside with foam, you can buy all the part off the shelf for probably less than $8,000-10,000.”
Okay, so not something I can currently do in my tiny balcony. But if you have a good-sized yard and the ambitions to grow your own food ALL the time, it’s certainly possible.
Stay tuned for more cool projects coming Calgary’s way with the help of SAIT and its hardworking students!