Frequently Asked Questions (FAQs)
Can the Sunarc System be installed on any type of double-poly greenhouse structure?
How much energy can I save using Sunarc’s On-Demand Insulation System?
What is the benefit to using the Sunarc System for shading versus traditional mechanical shading screens?
University Professor response
Greenhouse Consultant response
Research Scientist response
What is the payback period for the Sunarc System?
Do you offer different levels of shading?
Will the surfactant leave a film on the membrane and affect the amount of light transmitted into the greenhouse?
As a vegetable grower, what yield improvement might I anticipate?
As a vegetable grower how will the Sunarc System improve the quality of my crop?
As a flower, plant and perennial grower, what yield improvement can be achieved?
As a flower, plant and perennial grower, how will the Sunarc System improve the quality of my flora culture?
How much does it cost to operate the system?
What are the water requirements for the system?
What are the electrical requirements for the system?
Do you have a solution for glass greenhouses?
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Can the Sunarc System be installed on any type of double-poly greenhouse structure?
Yes, the Sunarc System can be installed on the most popular double-poly greenhouse structures. Greenhouses that use natural ventilation at the gutter, mid way roof vents or mechanical ventilation are easily adaptable.
How much energy can I save using Sunarc’s On-Demand Insulation System?
You will save more than 50% on your heating energy costs using Sunarc’s On-Demand Insulation System.*
What is the benefit to using the Sunarc System for shading versus traditional mechanical shading screens?
The benefit to using the Sunarc System for shading versus traditional mechanical shading screens is answered by three world-class experts.
University Professor response
“Traditional mechanical shade screen systems work in conjunction with forced air or natural ventilation to cool ambient air. Forced ventilation is not optimal to maintain a uniform climate in the greenhouse; it may introduce diseases and insects, which corrupt the growing process and hinder CO2 enrichment by removing valuable CO2 from the greenhouse. Traditional mechanical screen systems reduce the efficiency of natural ventilation. To avoid this situation, growers will not close the shading screen entirely, leading to a non-uniform climate condition that results in uneven growth in the greenhouse.
The combination of Sunarc’s On-Demand Shade System and natural ventilation substantially improves crop management by reducing temperature extremes, creating a uniform climate and favouring CO2 enrichment. Higher yield and improved quality result from such improved greenhouse conditions.”
Greenhouse Consultant response
“Traditional mechanical shade screen systems are placed inside the greenhouse structure creating a “warm pillow” between the shading system and the poly/glass when vents are closed. Sunarc’s On-Demand Shade System is the opposite; it is incorporated into the greenhouse structure. This, in combination with a far better thermal insulating factor than traditional shading systems, enables the grower to keep the vents closed or the mechanical ventilation system off for a longer time without increasing the temperature.
Keeping the vents closed and the mechanical ventilation systems off keeps pollen and pests out. Valuable added CO2 is at the same time kept in the greenhouse.
Overall Sunarc’s On-Demand Shade System reduces the pest and pollen pressure, lowers the energy costs and gives you a more beneficial use of added CO2 as well.”
Research Scientist response
“Commercial greenhouse growers rely mostly on natural ventilation to reduce greenhouse air temperature (cooling) and humidity (dehumidification). Natural ventilation uses less energy, in comparison to forced air ventilation.
Mechanical shade screen systems use natural ventilation to reduce excess solar radiation and greenhouse air temperature. However, the shade screen interferes with and blocks the air movement/exchange in the natural ventilation process, thereby reducing the cooling efficiency of natural ventilation. Sunarc’s On-Demand Shade System does not interfere with the natural ventilation process and is therefore more efficient in greenhouse cooling.
Carbon dioxide will be lost to the outside during the ventilation process regardless of the methods of ventilation, as long as its concentration in the greenhouse air is higher than the outside. The amount of CO2 lost to the outside will depend on the concentration difference inside and outside the greenhouse and the air exchange rates. With dynamic liquid foam shading, because of higher efficiency in cooling, the air exchange required is less, which allows a higher concentration of CO2 to be kept in the greenhouse.”
What is the payback period for the Sunarc System?
The payback period ranges from 12 to 30 months depending on variables such as cost of energy, latitude location of greenhouse range, the crop grown and other factors. The majority of growers will enjoy a payback of two years or less. Sunarc will assist you in determining your payback time.
Do you offer different levels of shading?
Yes. Sunarc offers different levels of shading. Currently the range is from 20% to 45%. This will be expanded and enhanced in the near future.
Will the surfactant leave a film on the membrane and affect the amount of light transmitted into the greenhouse?
No. The surfactant will not leave a film on the membrane and affect the amount of light transmitted into the greenhouse. Every foam cycle is followed by a rinse cycle leaving your membranes clean and clear.
As a vegetable grower, what yield improvement might I anticipate?
Sunarc is still collecting data on yield improvement for vegetable growers. However based on research data to date we anticipate 10%-15% in the winter and up to 40% in the summer.
As a vegetable grower how will the Sunarc System improve the quality of my crop?
Protecting the crop from excessive heat due to solar radiation when needed (on-demand) enables the grower to have greater control of the micro-environment. This protection means the photosynthetic process can continue for up to 15 hours per day producing healthy AAA quality on a consistent basis.
As a flower, plant and perennial grower, what yield improvement can be achieved?
For flower, plant and perennial growers who operate year round, the (most likely) improvements would be on the total time it takes to produce market-ready product.
As a flower, plant and perennial grower, how will the Sunarc System improve the quality of my flora culture?
The situation for flower, plant and perennial growers is similar to vegetable producers; however the increased yield is total flowers not extra pounds of vegetables. The growing methods are similar; flowers are picked off the plant, as are vegetables. Roses and other flowers need higher growing temperatures and light levels. If artificial light is used, it is possible to see increased leaf temperature and increased light in the greenhouse that could result in increased flower production (similar to vegetables).
How much does it cost to operate the system?
The annual cycle is separated into two distinct operating periods, summer and winter. In the summer, the Sunarc System uses a combination of sprinklers and foam during the day when solar radiation can damage crops; in the winter, foam is installed at night and the sprinklers operate during short periods for rinsing residual foam in the morning.
Shade
Assuming the shading operates 100 days per year (150 days during spring-summer-autumn less 50 cloudy days) following this program:
- 6 hours of sprinklers
- 3 hours of foam and sprinklers combined
Insulation
In colder weather, the on-demand insulation operates up to 180 days per year as follows:
- 3.75 hours of foam production during up to 14 night time hours in winter. These are average operating data and will vary due to solar cycle (time of year), geographic location (weather conditions) and culture type (greenhouse operating temperatures).
In Quebec the total costs are: $0.022 per square foot per year for electricity and $0.09 per square foot per year in surfactant and freeze inhibitor. Total operating cost is $0.11 per square foot per year.
In Ontario the total costs are: $0.048 per square foot per year for electricity and $0.09 per square foot per year in surfactant and freeze inhibitor. Total operating cost is $0.14 per square foot per year.
What are the water requirements for the system?
We need approximately 0.30L of water/sq.ft. Basic treated city water meets Sunarc's quality standards. It should be colourless without any visible content. Transparency should be 95% or better. Hardness should not exceed 130 ppm of calcium carbonate. PH can range from 5.0 to 9.0. Water used does not have to be potable but should have an aerobic count less than 2000/mL and total coli form count under 1000/mL.
What are the electrical requirements for the system?
Preferably, the Sunarc System uses 3-phase, 600V electrical motors.
Do you have a solution for glass greenhouses?
Not yet. We are working on it.
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