Revol Greens

A peek in the new 8 hectare leafy greens greenhouse

A peek in the new 8 hectare Revol Greens greenhouse in Texas
Revol Greens is in the process of expanding. The leafy greens grower, with greenhouses in California and Minnesota, has recently had an 8-hectare greenhouse built in Texas. In the future, the location could be expanded to 32 hectares. Quite a job for a greenhouses designer. Geerd van Geel is the project manager for DLVge, which takes care of the design of the entire greenhouse: construction, screening, water, energy, electricity, heating, and cooling. He's closely involved with the Texas project and offers us a sneak peek.

"The first phase is 8 hectares, but we've already planned the greenhouse in such a way that also, with 32 hectares, there will still be a logical building. Things like a central packing hall, offices, etcetera. It's quite a jigsaw puzzle, and you have to take into account things like the shape of the plot and utilities. The question is how to scale it up later."

Dealing with the climate
Once the contours of the jigsaw puzzle are in place, it comes down to the details: "Irrigation systems, and climate systems in particular – summers get very hot in Texas, so we had to look for a suitable installation."

Geerd's colleagues, Ronald-Jan Post and Ruud Brouwer, who specialize in energy, made a climate plan in 2020. "We came up with a climate system where the combined energy screens are closed in summer. There is then no exchange with the outside air but only climate control with cooling units inside the greenhouse. These cooling units control the temperature (cooling and heating) as well as the humidity. When outdoor conditions permit, the greenhouse can function as a traditional greenhouse. The conditions outside determine how the system is used."

Chillers and heat pumps
To make it as sustainable as possible, a combination was chosen of centrifugal chillers and heat pumps. "Part of the cooling needs, which are very high, were met through heat pumps. Wherever you're cooling, heat is released, which we use for dehumidification." And the heat pumps can also be used during cold nights in Texan winters.

Indoor farming
DLVge sees this way of growing with closed energy screens and indoor farming. But things could have been even more revolutionary. "We looked into the possibility of closing the greenhouse completely with sandwich panels, but that wasn't economically feasible. Construction would have been a bit more expensive, but energy use, in particular, would be a lot higher because you need to light constantly. The additional insulation isn't worth that extra investment."

The current greenhouse does have lighting, LED to be precise, but that's more to increase production. "That way, the grower can guarantee quality and production, even on days with less sunlight."

Putting it to the test
The ingenious climate system was devised in 2020, but the first 4 hectares of the new greenhouse have only been operational since 2023. "That's pretty exciting for us as well. When designing, we take into account 95% of the extreme weather conditions, but you can't plan for every eventuality, otherwise the installations would become so big they're no longer profitable."

Start-up of cultivation
"During the construction and commissioning of the greenhouse, we check the operation of the installations and support the customer during the start-up of cultivation. The moment I start cultivating, the customer will have to learn how to use the various installations", he adds.

Various weather scenarios but also the seasons will influence how the various climate installations can be used in the most optimal way. For example, at this time of year comes the heat peak of summer. "So when it gets warmer, you'll reach the maximum capacity of the installation. Then we have to help the grower understand what he can do with the installation and how to operate it. With those increased temperatures, you really have to consult with the grower but also with the installer, Dalsem, who are a great help as well. That makes it ultimately very rewarding – building a great project together with the customer."

hwww.hortidaily.com/article/9549877/a-peek-in-the-new-revol-greens-greenhouse/

Publication date: Thu 10 Aug 2023
Author: Annet Breure
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