Knowing when it’s time to turn on the aeration fan

A free web-based program uses local weather data to make recommendations

aeration fan on a grainbin

If you turn on the aeration fan, are you adding or removing moisture from stored grain? A free web-based program called BINcast can help make the decision.

“Determining when to turn fans on and off for maximum efficiency, just by guessing, is problematic,” says Ian Nichols, business manager for Weather INnovations Consulting (WIN), developer of the system. “If started at the wrong time, under poor conditions, moisture is actually pushed back into the grain.”

Weather-related factors, he explains, are key when calculating whether aeration will remove or add moisture to stored grain. These include the temperature and relative humidity of the surrounding air, along with the moisture content of the stored grain.

This is where BINcast comes in. Developed by WIN, it provides a five-day, location-specific, hourly forecast of not only when fans should or shouldn’t run, but the most optimal time to run them, Nichols says.

You can try BINcast now online. Use the Google map to zoom in on your farm and click the exact bin location. Then select the type of grain in storage. BINcast calculates the equilibrium moisture content (EMC) for that grain. EMC is reached when the moisture of the grain will neither go up or down due to the combination of the air’s temperature and relative humidity.

Running fans when the EMC is higher than the grain’s moisture content pumps moisture into the grain. When the EMC is lower, running the fans will remove moisture from the grain.

When to turn on

Here’s an example. The corn in your bin is 20 per cent moisture and you want to bring it down to 15. BINcast forecasts the EMC at 25 per cent between 10 and 11 a.m., meaning running the fan at this time will add moisture. Between 1 and 4 a.m., however, the EMC is forecast to be 14 per cent and turning on the fan during this period will remove moisture from the grain.

“The decision of when to turn aeration on and off is up to each farmer,” Nichols says. “BINcast just provides information to assist in the decision-making.”

In the research and development of BINcast, WIN analyzed all the parameters for the inputs and how the model will adjust to each grain. There are other factors to consider when aerating grain, including its temperature after harvest. Grain should be cooled after being put in the bin.

Once a stored crop gets close to its safe storing moisture content, BINcast can be used to make aeration more efficient, Nichols says. Cooled corn can be safely stored quite awhile at 16 per cent. Say your corn is at 16 per cent moisture but you want to take it to 15.5 per cent.

“So you can wait for a day when the equilibrium moisture content drops to 13 or 14 per cent moisture and turn on the fan,” he says, “then you’re removing a lot of pounds of water per hour and that gives you your efficiency.”

Although aeration is cheaper than using a grain dryer, which burns natural gas or propane, aeration fans don’t run for free.

The current version of BINcast available online is a general-purpose advisory, requiring no specialized equipment or programming. Additional features and complexity are available for those producers with on-farm stored grain who are looking for more detail and accuracy.

An automated weather station can be installed nearby and linked to the system. BINcast can also be programmed to accept essential fan, bin and grain details, such as bin shape and diameter, grain depth, fan numbers and type, horsepower, and initial and desired moisture content. BINcast then provides a forecast and real-time readings. The system can be further augmented through the integration of internal bin sensors. Farmers can set up alarms or warnings to be emailed or texted to them about individual bins.

WIN, based in Chatham, Ontario, specializes in weather-based modelling, climate and environmental monitoring and online agronomic solutions for agriculture. It also offers SPRAYcast to determine the best time to avoid drift, and delivers late blight disease forecasts via, the Manitoba Potato Weather Network. It has also partnered with Glacier Media, owner of the Manitoba Co-operator and other farm publications, to operate the WeatherFarm network. Its western business manager is Morden-based Andrew Nadler, former agro-meteorologist with Manitoba Agriculture.

About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



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