How it Works

In cold weather, daytime solar energy enters greenhouses to light and heat crops. At dusk, Sunarc’s liquid foam is infused into the cavity formed by the two layers of polyethylene membrane covering double-poly greenhouses, conserving the daytime heat through the night. At day break, the remaining liquid from collapsed foam is drained back into the surfactant reservoirs and recycled to be used again the next day. Sensors ensure automatic production by regulating the operation of foam generators and sprinklers as conditions demand. Software is programmable to local needs and may be monitored and operated by remote computer control.

Sunarc’s On-Demand Insulation & Shade System maintains the thermal equilibrium in a structure by admitting, converting and retaining solar energy in a controlled environment. As a result, optimal temperature conditions during each 24-hour cycle can be maintained year-round, while heating fuel requirements are dramatically reduced.

Exponential escalation of energy prices is forcing cold-climate growers to abandon operation in winter or consider alternate sources of energy such as biomass and low-grade fuels like bunker oil. Heating cost increases of 100% or more in the last year are not unusual. The Sunarc On-Demand Insulation System enables greater than 50% savings on heating costs.*

Compared to Thermal Screens

Sunarc contracted a leading national research organization to measure the thermal resistance of its proprietary liquid foam. The results were insulating properties in excess of R-15 (equivalent to the exterior walls in a modern home in northern U.S. states and southern regions of Canada). This is a dramatic increase from the R-1 to R-2 ratings for current double-poly greenhouse structures. The result is 50% or more savings in heating costs.*

Energy savings of 25% to 30% can be anticipated when thermal screens or curtains are used in glass-covered greenhouses. Double polyethylene greenhouses already deliver an economy; adding a thermal curtain only improves the energy savings by 10% to 15%. As a result, thermal screens or curtains are not used in double poly-covered installations. As heavier thermal curtains can only be used at night, they are not useful for shading. Growers who install screens choose to compromise with a screen that isn’t as efficient for insulation; however, it can be used for both insulation and shading. When curtains are deployed, they significantly lessen natural convection in the greenhouse, which affects plant growth. This is a distinct advantage in favour of the Sunarc On-Demand Insulation System.

Disadvantages of using thermal screens

1. Thermal screens cause significant humidity control problems; humidity drips on the plants and mars them.
2. Thermal screens cause ventilation/air circulation problems; placing a horizontal thermal or shading ceiling several feet below the curve of the greenhouse roof reduces the functional ventilation and air circulation of the greenhouse design.
3. Thermal screens cause condensation problems. Thus when ventilation is introduced through an opened curtain, preserved heat is wasted.
4. Thermal screens restrict crop growth height.
5. Thermal screens are significantly more complicated to retrofit on a double-poly greenhouse. Crops hang from the part of the structure used for thermal screens the Sunarc System can be retrofitted over the crops without disturbing their production.

New Opportunities

1. Gain one or more additional turns of a crop results in incremental revenues.
2. Produce larger crops earlier – this will provide premium sales compared to competitors (including imports).
3. Enable growers/operators to time the delivery of any crop.
4. Produce and ship larger, stronger plants, generating increased revenue and profits.
5. Generate higher margins by producing vegetables from the late fall through winter when prices are highest.
6. Reduce imported produce, as northern region growers can now promise consistent deliveries 12 months of the year to their local market.
7. Produce more cut and potted flowers: These crops thrive in warm climates; many are not produced in northern greenhouses, because the heat required to grow the crop is not economical relative to market prices. By reducing heating costs, growers may begin to produce flowers to meet local demand and become more of a full service provider to their retail clients.
8. Enable growers to have complete control of their environment: The reduction in heat extremes diminishes the need for ventilation and facilitates better use of CO2 enrichment in all seasons.

How to Calculate your Cost/Savings

Calculating the savings on heating costs is simple. Simply divide your heating bills in half; the savings will be at least 50%.*

Several key elements go into calculating the payback of the Sunarc System.

1. What type of fuel is being used to heat the greenhouses?
   What is your current cost?
2. Do you cease operations for a limited period during cold weather?
   If you continued to operate 12 months of the year with 50% reduced heating costs, how much additional revenue/profit might be generated?
3. For vegetable growers: factor possible crop yield increases of 10%-20% as a result of the agronomic benefits that the Sunarc System delivers.
4. For vegetable growers: greater control of your micro-environment enables quality to be maintained or improved despite the scorching summer sun. Maintaining AAA quality = revenue and earnings expectations are met or possibly exceeded.

These are just some of the factors; Sunarc will assist growers to determine their payback period. Generally the payback is about 24 months; however, it is possible to achieve payback in as little as 12 months depending on grower-specific factors. Contact us and we will help you determine your payback period.

*Demonstrated greater than 50% energy savings over two winters at the Faculty of Agriculture and Food Sciences at University Laval in Quebec City. Field demonstration trials are currently under way, results may be different in the field.

Installations

Existing Installations

1. Université Laval, Faculty of Agriculture and Food Sciences – Tomatoes
2. Agriculture Canada's Greenhouse and Processing Crops Research Centre, Harrow, Ontario – Tomatoes, Cucumbers
3. Les Jardiniers du Chef, Site #1 – Herbs grown in Blainville, Quebec. Ground-to-ground greenhouse structure
4. Les Jardiniers du Chef, Site #2 – Herbs grown in Blainville, Quebec. Gutter-connected greenhouse structure
5. Sunarc's Research and Development Centre – St-Sauveur, Quebec
6. Sunarc's Product Development & Distribution Centre – Laval, Quebec
7. Cedarline Greenhouses – Bell Peppers grown in Dresden, Ontario
8. Pyramid Farms – Tomatoes grown in Leamington, Ontario