In case outside temperatures are lower than inside the greenhouse, while at the same time humidity levels are higher, opening the windows will not necessarily have the right effect. Even though real temperature levels might go down, humidity levels and therefore the amount of energy in the air, the so-called enthalpy level, might nevertheless increase. Put simply: very humid conditions combined with moderate temperatures might be less pleasant than conditions hotter but less humid. This goes for people and plants.
By means of smoke, the working of Nivolution combined with Nivolators is illustrated.
This short theoretical introduction is necessary to understand the workings of Nivolution, a dehumidifying system developed by Nivola. Nivolution blows cold, dry air from above the greenhouse screens down, thereby intermingling with the warmer, more humid air below. Thus the greenhouse is cooled and dehumidified in an energy-efficient manner.
Yesterday, Nivola, the company which developed the Nivolution and Nivolator, invited a few growers and technical installation companies working with Nivola for a short seminar presenting a test project at Dutch gerbera grower Kwekerij Antonia. Together with the grower Frans Mans, research specialist Peter van Weel (also known for his involvement with the Plant Empowerment project), lectured those present on establishing a healthy, homogeneous, lively greenhouse climate.
In essence a grower wants to maintain the most optimal growing conditions. In doing so, he needs to cope with ever-changing weather circumstances, while at the same time trying to be as cost-efficient as possible. A precarious balance, but to some extent knowledge of the ways energy is preserved can help. Energy loss, Van Weel explains, either blown out the window (literally), radiates through the glass, or is lost when (trying to) getting rid of humidity. The first two can be countered by closing windows and screens, the latter by taking control of evaporation.
Crops need to evaporate water, for if they don't, plants will be less resilient while also botrytis and mildew settle in more easily. Therefore perpetually guaranteeing conditions in which crops can evaporate water is crucial. Knowing both temperature and relative humidity, both inside and outside, should make a grower focus on absolute humidity levels. Absolute Humidity, Van Weel stressed, ought to be one of the most important parameters any grower should see to.
Nivolution is already operational at different cannabis growers in both Canada and Portugal. In The Netherlands, a handful of growers is putting it to the test. Grower Frans Mans is one of them, trailing the Nivolution in combination with the vertical vans called Nivolators. Results can be consulted on request, for now, it will suffice to say the grower himself is happy. He's hardly seen any botrytis and no mildew since, and also temperature differences within the greenhouse are greatly reduced. One thing to be improved concerns tuning it to all the other settings within the climate computer, an assignment no doubt the different producers have taken note of.
Peter van Weel. Photo: Nivola
More information about Nivolution - the machine can extract over 500 liters of water per hour per hectare and save up to 50% on energy costs - you can find here.