Our mobile education greenhouse: The Passive Solar Roller

Thanks to a Canada Healthy Communities Initiative grant, Cultivate Cochrane has brought an education greenhouse on wheels to the streets of Cochrane! Similar to the large community hub we’re planning, the “Passive Solar Roller” uses passive solar design to demonstrate a sustainable way to extend the growing season in our challenging climate. Built on a trailer, the greenhouse can travel to travel wherever we wish to showcase it and provide hands-on programming on food growing, nutrition, and resiliency.

We’re thrilled to have already offered regular family and youth programming through BGC Cochrane & Area, the Family Resource Network, plus several local schools. But you’re likely to see us at the farmers market, public events, and more youth and seniors’ venues in the future!

The Big Vision: a passive solar community greenhouse hub for Cochrane!

What is a Passive Solar Greenhouse?

Passive solar buildings are structures designed to meet their heating and cooling requirements simply through their interaction with the sun’s heat. The term “passive” is in contrast to “active” solar like photovoltaic or solar thermal systems which require conventional energy in their functioning. With passive solar, heat from the sun is collected, stored and distributed without any additional energy inputs - it’s all in the materials and design. This makes it cost-effective and highly sustainable. Key elements include proper building orientation, thermal mass, glazing ratios, optimal insulation, and calculated roof overhangs. 

A passive solar greenhouse is an ideal solution to season extension in a cold climate since it allows the sun’s heat to penetrate its south face while the rest of the building is well-insulated to retain that heat overnight and into the cooler months. Thermal mass integrated throughout the greenhouse absorbs the solar warmth, storing it for slow release once the sun goes down and reducing the risk of overheating during the day. Nighttime heat loss can be further reduced by drawing thermal blinds over the glazed south-facing wall. 

A strictly passive system can be complemented by an active “climate battery”, also called annualized geo solar (AGS). This system uses fans to pump excess heat from the greenhouse to the well-insulated ground beneath it to be drawn back out when the building drops below a threshold temperature. The power needed to move air in this way can be provided by photovoltaics or other renewable sources.

For anyone interested in designing and constructing their own passive solar greenhouse we highly recommend the Passive Solar Greenhouse Design Course over at smallfarmacademy.com

Our Community Greenhouse Hub Vision

Community Needs 

We live in a tumultuous era with many demands on our time, our wallets and on our psyche. Even though we are more connected than ever before through the internet and social media, loneliness is at an all-time high. People are longing for meaningful in-person and community connection. There is a great need for place-making hubs that act as central gathering places for socializing, learning, collaborating, sharing and experiencing. 

Along with the need for a community social hub, there is a keen interest in this community for access to fresh, local, quality food. Over the years, discussions with friends and neighbours reveal that more and more people are interested in growing their own produce and supplying their families with food they trust from known sources. Food security is a high priority for many people even as knowledge of how to grow, prepare and preserve our food is dwindling. Depending solely on imported items leaves many people feeling vulnerable to the whims of climate, politics and finances. But growing food in Cochrane is rife with the challenges of a difficult climate marked by a short season of hot days, cold nights, little rain and lots of wind.

In addition to the need for community connection and more local food resiliency, Cochranites are interested in alternative ways of living more sustainably with the environment; there is a pragmatic aspect to our western heritage culture that seeks local solutions to local challenges.

Community Solutions 

Cultivate Cochrane plans to help meet community needs in these areas through the building of a centrally-located passive solar greenhouse hub. Our greenhouse could be stand alone with meeting rooms, café, commercial kitchen and indoor and outdoor demonstration food gardens, or it could be incorporated within a larger community hub (like a new library, arts centre, innovation hub, or senior’s centre). Our wish is to provide a ‘green’ centre that honours our farming and ranching heritage while moving it into the 21st century of green urban land use, green building and use of smart technology. Taking inspiration from Cochrane’s town slogan, we wish to show the world “How the West is Now”.