In-Depth Breakdown of the Past, Present and Future of Greenhouse Dehumidification with Eef Zwinkels
In a recent HortiDaily interview, DryGair Product Specialist at Royal Brinkman, Eef Zwinkels, discusses the importance of greenhouse dehumidification.
Zwinkels dives into present-day greenhouse humidity control techniques and challenges and provides insight into the future of the horticulture sector.
The following excerpts are taken from the interview HortiDaily interview.
Growers’ Struggles with Humidity and Humidity Control
“I see a lot of growers struggling with humidity. They can’t lower their RH (relative humidity) easily, so they heat their greenhouses and open the windows. That’s what everybody did. It’s also what we did in the past, with our tomatoes. The pipe temperature was holy. But that costs a lot of money.
So humidity was a problem, and diseases, such as botrytis, were widespread. Today, many growers realize that they can avoid that. Heating and venting were never an ideal solution. Today, with the DryGair units, growers have a steering wheel in their hands – you can reach any RH you want.”
Energy Saving Potential
“First and foremost, the system does an incredible job of saving energy, around 50%. That’s a huge impact. What I also hear from growers, is that they now dare to grow a few degrees colder. That also saves energy. In the past, they couldn’t lower the temperature, because they would reach the dew point.”
Higher Yields and Stronger Plants
“In terms of the cultivation itself, the first thing I heard from growers was that they can close the screen 100%. That alone creates a much more even climate in the greenhouse. So uniformity and activity are the greatest benefits I see for the plants.
The DryGair fans keep running, so the unit constantly circulates the air, creating an active climate. An active climate is better for the plant’s nutrient uptake, such as calcium, which is an immobile element, only available through the uptake created by transpiration. So we see much stronger crops.”
Returns and ROI Projections
“The only operational cost of DG units is electricity. So the benefits only need to be greater than the price of electricity. My program says you can earn back the price of DryGair in 2-5 years, depending on energy prices and the crop value. At the end of the day, there’s no need to make this investment blindly. It’s all calculated ahead of time, and our projections are quite accurate.”
Shift to LED Greenhouse Lighting
“I see a lot of growing potential for future DryGair installations. Greenhouses are becoming more closed, and more and more growers are changing to LED lighting. LEDs are interesting because they save money on electricity, but I want to warn that they’re different from traditional lighting.
LEDs are a colder light. They emit less heat radiation than the older SON-T lamps. As a result, you need to maintain a higher temperature in the greenhouse. This gives some ‘extra space’ for moisture, but also generates more plant activity. Without these adjustments, growers suffer from higher disease rates, such as botrytis.”
