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Vertical ventilation at Freeman Herbs

"Canada: "Less disease pressure, and higher energy savings"

Vertical ventilation is also interesting for commercial vegetable growers who are looking for a way to prevent a dead climate, decrease disease pressure and lower energy costs. The method has proven itself in many ornamental production and cut flower greenhouses already, but a Canadian herb grower is now also achieving great results with the Nivolators.

The Nivolator is a greenhouse fan that is placed vertical instead of the traditional horizontal mounting. The Nivolator draws the air from the ground level as well as from above the fan, mixing the two air streams, preventing a dead climate in the greenhouse. It blows the air from the top in an angle of 45° back inside the crop to prevent draft. A big advantage of this is that the heated air from the top of the greenhouse is mixed and also blown back, so a lower heating pipe temperature is required beneath the crop. As well as this, the risks for diseases as botrytus and mold are decreasing as the airflow below in through the crop has a dehumidifying effect.

Canadian greenhouse supplier Global Horticultural Inc. installed the first Nivolator fans at Freeman Herbs in the fall of 2014. The motivation of the trial at this grower was technical; the crop was suffering from the high humidity, while it was also very hard to achieve an equal climate and crop growth.

Global Hort's Ray Houweling explained that after the installation, the grower did not only experience a better climate, but noticed cost savings as well "Besides the equal climate, he also noticed that he was saving on his energy costs as he was able to bring down the temperature of the heating pipes. As well as saving the heating costs, the fans itself are also very energy effective. One of the users said that he was saving 80-100 dollars per fan on his hydro costs compared to other fans on the market. The Nivolator fans are also eligible for energy rebates from natural gas suppliers as part of their mandate to reduce emissions."

As the Nivolator mixes the air from the top and bottom of the greenhouses in a slightly diagonal angle, a homogeneous distribution of temperature, humidity and CO2 is created. The warm dry air form the top of the greenhouse is blown gently in to the crop with a speed that does not exceed 0,5 m-s, so the crop does not suffer from stress. Over the past few years it has been widely used in cut flower cultivations as roses and gerbera's and in bedding plant and lettuce cultivation. "Recently we also started a trial with a cucumber grower", said Houweling. "Also for this the expectations are high, as the grower also experienced less mildew inside his crop."

If you would like to obtain more information about the Nivolator, please contact Ray Houweling at Global Hort, or visit them during Cultivate '15 in Columbus Ohio.

Global Hort
Ray Houweling
[email protected]
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