Custers Ref Afb (5)

Condensation drying

  • Independent from the outside air
  • Drying onions twice as fast
  • Quality of onions is better preserved
  • 80% less energy costs
  • A substantially higher yield
  • Use of residual heat

What is condensation drying?

ENGIE Refrigeration has developed a new way of storing onions, bulbs and other agricultural products. With this solution, called condensation drying, you are no longer dependent on weather conditions. This results in better preservation of the quality of your onions and considerably lower (up to 80%) energy costs, or in other words, higher profits. For a long time, the agricultural sector depended on the outside air for drying and cooling crops. Climate changes cause a quality loss for arable farmers with the long-term storage of onions. Thanks to condensation drying, they will no longer suffer from this.

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Drying onions twice as fast, without being dependent on the outside air?

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How does condensation drying for onions and bulbs work?

With condensation drying, also known as cool drying, outside air and gas heaters are a thing of the past. The condensation dryer is a cooling and heating installation in one, which makes this technology unique. With this, we bring the air below the condensation point, so that a lot of moisture can be removed and the onions and bulbs dry. We use the heat that is released during the cooling process to keep the onions at the correct temperature. Also, the system is equipped with a heat pump to be able to heat batches of onions. The entire system is controlled by an in-house developed operating system, which can be operated and monitored both locally and remotely via a PC or smartphone.

‘Now we can dry our onions twice as fast, regardless of the outside air conditions’
- Roger Custers, owner
Custers' Farm
Read the case

Storing onions in the conventional way results in loss of quality and high costs

Onions must be dried as soon as they are harvested. It is common to do that with the outside air. However, the quality of the outside air rarely fully meets the requirements to guarantee the quality of the onions during the drying process. To solve this problem, the outside air is heated with gas heaters. This enables the air to absorb more moisture, but this costs a lot of gas. The additional disadvantage is that 1.6 kilograms of moisture are released per kilogram of propane gas burned. This moisture must also be removed again, with an additional 10% gas consumption. Storing onions in this conventional way therefore not only costs money but also impacts the quality of the onions.

ENGIE Refrigeration has now developed a condensation drying system which allows you to dry independently from the outside air conditions and with lower operating costs than with conventional systems. A method for storing onions with only benefits.

The results of condensation drying

Since the introduction of condensation drying, dozens of installations have been running. "Growers are very enthusiastic", says Marcel Bennink, Project Manager at ENGIE. “They have much more control over the product and can keep the product longer so that they can respond better to market conditions. The margins on the product are still good at the end of the season.” Read more about this in the cases.

Condensation drying & Potato storage

Mechanical cooling is an excellent method for storing potatoes. With this, you always ensure a stable temperature and humidity during storage, which benefits the quality of your product. The potato germinates slower and retains its size and weight.

Everything about Potato storage

Condensation drying & Mechanical storage

With mechanical storage, you can store products such as carrots, leeks, apples, pears, and soft fruit longer and better. The storage conditions are always optimal for your product because you no longer depend on the weather conditions. The quality is maintained and due to a longer storage time, you can respond better to price developments in the market.

Everything about Mechanical storage

Storing onions and bulbs: existing technology applied again

“It not new to store onions like this”, Marcel Bennink says. “We have been using this technology for years in cheese warehouses and climate chambers. The results in this industry have made us think and ultimately led to the development of an effective approach to preserving onions. Our rich experience in various industries helps us to innovate continuously. It inspires us to translate techniques that work well elsewhere and in other markets. The condensation drying technique for onions and bulbs is a good example of this.”

Multiple applications of condensation drying possible

ENGIE Refrigeration has developed and successfully applied a condensation drying system for potatoes. We are also investigating the possibilities for other products, such as cultivation boxes, Salicornia, and valerian. Are you curious whether condensing drying is also the solution for higher product quality of your products? Or would you like to know more about storing onions and bulbs with this innovative technique? Don’t hesitate to contact us.

Financing options

If you are interested in our solution but are currently unable to invest in sustainable technology, then ENGIE will help you. In addition to design and realization, ENGIE can also help you finance and operate it. This way, you will immediately benefit from lower energy costs and sustainable entrepreneurship. Explore the options.

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Gert Jan Knippenberg
Gert Jan Knippenberg
Agriculture | Storage | Climate chambers | Horticulture