Projects
YEAR-ROUND LIQUID FOAM INSULATED GREENHOUSE PROJECT
Common Ground is currently constructing a 20' x 40' LFI greenhouse at its demonstration garden in Pippy Park...the first of its kind in this province! The greenhouse will serve as a demonstration site for the promotion of this technology, and as a social enterprise that will grow and sell fresh produce to support our non-profit activities.
LFI greenhouses use soap bubbles as insulation in winter, and cooling shade in summer, enabling year round food production!
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LFI greenhouse technology has evolved over a period of 25 years, based on concepts developed by inventor Richard Nelson of SolaRoof, a Canadian company based in Montreal. The technology is held in the public domain by Creative Commons Public License. Operational field units have been built in communities around the world, including Perth, Ontario (the first in Canada), and Lindum, Norway.
An LFI greenhouse is essentially a greenhouse within a greenhouse, which uses soap foam injected between two layers of plastic as insulation during the winter, and as shade during the summer. Soap solution is blown through two centrally-mounted fans to produce foam. During winter months, the foam can create an R30 insulating cover for extending the season of many different greenhouse crops. Liquid can also be used for daytime cooling and for capture of thermal energy in a water tank heat sink for cool nights.
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LFI Advantages
Reduced carbon footprint
LFI greenhouses require less energy to operate than conventional greenhouses, which consume large amounts of fossil fuels for heating and cooling. In summer, conventional greenhouses deflect and waste excess solar gain rather than storing it for use when temperatures drop at night.
Reduced operational costs
Since LFI greenhouses require less energy to operate, they are also reported to be more cost effective than conventional greenhouses. Though initial construction costs for an LFI greenhouse are higher than those of conventional greenhouses ($20,000 to $40,000 for a 1,200 ft. square Homesol structure), energy use is much less.
A 2014 study conducted by the University of Vermont found that an LFI greenhouse system (for a 2200 sq. ft. structure) resulted in a 39% average reduction of gas for heating and $2983 lower heating costs than control. John Groh at University of Arizona measured R3 per inch in 1968, while AHRAE research by Shamim & McDonald in 1995 measured R1 per inch. In 1995, Bill Sturm built a 12,000 SF tomato greenhouse with a soap bubble insulated roof in Calgary, measuring 84% energy savings at -20 F. 2006 research in the Yukon by Ruth and Andy Lera in the Yukon also demonstrated the viability of this technology for northern climates. "Freezing (liquid phase change) enhances thermal performance, overheating is eliminated, and natural lighting is unaffected, ensuring optimal year-round plant growth."
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BIOCHAR RESEARCH AND TRAINING INITIATIVE
Biochar is a form of charcoal produced by baking organic matter, resulting in a porous, carbonaceous material which when added to soil, increases microbial activity, increase water retention and reduce the need for fertilizers. By boosting yields and reducing the need for agricultural inputs, biochar can have very positive economic impacts on farming operations. Additionally, farm waste material can be converted to a valuable product!
Biochar also has a number of significant environmental benefits. Reduced use of fertilizers contributes to long term soil health and reduces runoff into waterways. The production of biochar can also also generate bio-energy, reducing fossil fuel use. Generating biochar from waste reduces stress on existing landfills. And, adding biochar to soil reduces emissions of nitrous oxide and methane and sequesters carbon in soil. According to the International Biochar Initiative, sustainably produced biochar could store 2.2 gigatons of carbon annually by 2050.
From 2008-2012, Common Ground conducted a biochar field trial at its urban demonstration garden at the Gathering Place, and in 2013, organized free public workshops on biochar use and production for local farmers, gardeners, and government agricultural representatives.
For a wealth of information on biochar, visit the International Biochar Initiative website here.
St. John's Safer Soil promotes safe gardening and recreation in areas with elevated soil lead levels.
For more information on this project, click here!