Home/BLOG/Dutch Rose Grower Uses DryGair to Save Greenhouse Energy – Onder Glas Magazine

Dutch Rose Grower Uses DryGair to Save Greenhouse Energy

Van der Hulst Rozenkwekerijen have been growing greenhouse roses for many years, always striving for the highest energy efficiency. In the past year, due to rising energy prices, the entrepreneurial rose growers sought to further save on energy.

To do so, they’ve invested in DryGair dehumidifiers, leading to an additional 35% savings on gas. The integration of DryGair also led to better yields and opens the door for additional energy-saving technologies.

The full article was published in Dutch greenhouse magazine, Onder Glas.

Energy Efficient Rose Cultivation

“We have always focused on low energy consumption,” says Sjaak van der Hulst. “For example, we grow much more quietly than other rose companies and we introduce less tube heat into the greenhouse. As a result, we only get 200 roses per square meter, with colleagues that maybe 300.”

Saving 35% More Gas with DryGair

“Due to high energy prices, the family decided to accelerate their investment in DryGair units. “I was already looking into purchasing these dehumidification units last summer,” says Paul van der Hulst. “Especially because we grow a few cultivars with a high evaporation rate. That is why we had to stoke extra, but that in turn had negative effects on the quality. We could prevent this by better dehumidifying the greenhouse air, or so the idea was.”

However, further saving on energy is now the main reason for purchasing the dehumidification units. These should be running at the Paul van der Hulst location in mid-June and at the other two company locations in September.”

“In recent months, we have been lighting at half power. And there is a good chance that this will also be the case in the coming lighting season. But when you light less, you have less radiant heat and therefore less dehumidification. Over the past period, this forced us to regularly open a crack in the screen cloth and open the windows. However, that cost a lot of energy; after all, we had to bring more heat into the greenhouse. That was the reason for us, as the first rose grower in the Netherlands, to invest in the DryGair. These units extract moisture from the warm greenhouse air and heat is released during the condensation. This raises the greenhouse temperature by one to two degrees.”

Better Yields and Fast ROI

The entrepreneurs have high expectations of the dehumidification units: they think they can save about 35% on their gas consumption. A unit will be installed on every 3,500 m² that can dehumidify 20 cubic meters of air per hour. “That requires an investment of approximately nine euros per square meter. But with current gas prices, we should be able to recoup this within two to two and a half years. Also, because we have received both EHG and EIA subsidies on this investment,” says Sjaak van der Hulst.

The entrepreneurs hope not only to be able to save money, but also to achieve quality gains. Now the moisture percentage in the winter months is often around 90%, later this should be around 83%. “This will probably result in a firmer crop. We expect the greenhouse climate to be more even and the mildew pressure to go down, as the greenhouse air is drier. But we all have yet to experience that; as mentioned, we are the first rose company to work with this system.”

DryGair Opens the Door for More Savings

An additional advantage is that, according to the entrepreneurs, the dehumidification units make it easier to take further energy-saving measures. In the long term, for example, they may want to invest in a second screen and in LED lighting. Paul van der Hulst: “Initially LED was not really an option, because then you no longer have radiant heat and therefore keep too much moisture in the greenhouse. We tackle this problem with the dehumidification units. But we do it step by step. And of course, the further development of energy prices will determine whether additional investments are needed and when. But if the situation remains this way and the gas price does not fall below the euro per cubic meter, extra steps are inevitable.”
For more information on how DryGair is used to save greenhouse energy, feel free to contact us!

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