Grain silo ventilation: a crucial factor for optimum preservation

Grain silo ventilation is essential to preserve crop quality, prevent mould and infestation, and avoid economic losses. It regulates temperature and humidity, limiting heating and condensation, which can compromise grain safety and preservation, making the grain unfit for consumption.

Why ventilate your silos?

Preserving grain quality:

Limits heating and condensation, preventing mould.

Securing harvests:

Reduces insect infestations.

Optimising costs:

Effective ventilation management can significantly reduce energy consumption.

The 3 ventilation levels recommended by Arvalis

Step ventilation is a technique commonly used to efficiently cool grain stored in silos. This method involves gradually lowering the temperature of the grains in successive stages, maintaining constant temperature levels for defined periods.

Advantages of step ventilation :

Progressive, even cooling: Step-by-step ventilation allows the grains to cool gradually and evenly, avoiding thermal shocks that could alter their quality.
Better humidity control: By gradually lowering the temperature, step-by-step ventilation encourages a gradual reduction in grain moisture, thereby limiting the risk of mould developing.
Energy savings: This technique optimises energy consumption by targeting cooling only when necessary.

Find out more about the three ventilation levels

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Optimising ventilation performance with digital technology

For storage organisations, ventilation is a key element in guaranteeing the quality of the products stored, but it is also the biggest energy consumer, representing a cost that can reach several tens of thousands of euros a year. In this context, climate change is exacerbating these challenges by reducing the optimum windows for effective ventilation.

The impact of global warming on grain storage in silos

Global warming is having a major impact on silo ventilation, resulting in :

A reduction in ventilation windows, with 7 % loss in summer and 12 % in winterIt's the same throughout the country.
Increased vulnerability for silos located in hot zones, such as the South West Franceand for large-capacity silos.

To meet these challenges, it is essential to adopt precise, automated control systems capable of optimising the available ventilation ranges, guaranteeing optimum grain preservation and reducing economic losses.

Replay of our conference: Anticipating the impacts of climate change

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The solution: automatic ventilation control

At Javelot, we have developed an automatic control mode to optimise ventilation performance. This automated mode identifies the ideal ventilation periods by taking into account real-time weather conditions and the temperature differential between the inside of the silo and the outside.

Ventilation is triggered automatically when the temperature of the outside air is between 8 and 20°C lower than the hottest point of the grain. This differential can be adjusted according to the equipment and heating in the ventilation shaft.

This approach ensures maximum efficiency, reduces energy consumption and optimises grain preservation, offering a sustainable and cost-effective solution for storage organisations.

*Hourly mode: manual activation based on weather forecasts, with fixed ventilation times.
**Automatic threshold mode: automatic activation when the outdoor temperature falls below a predefined threshold.
***Automatic difference mode (Javelot system): activated according to the difference between the warmest temperature of the grain and that of the outside air, with a target difference of 7 to 10°C for the first year and 8 to 20°C for the second.

Trials currently being carried out by Arvalis on the Boigneville experimental platform (91) confirm the effectiveness of Javelot automatic control by temperature difference, compared with the conventional thermostat and hourly control.

Initial tests show that the Javelot system consumes the fewest hours of ventilation to reach the target temperature of 12.5°C.

Over the 2023/2024 campaign, it will enable a significant reduction in operating hours: -65 % compared with the conventional thermostat and -52 % compared with hourly operation, while still achieving the target temperature on the same dates.

The study confirms that the Javelot system optimises grain cooling, reduces energy consumption and ensures more efficient and responsive control in the face of temperature variations.

Find out more about the Arvalis study

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