IN-BIN DRYING DATA
BY DANIEL STEFNER • GLYCOL HEATER PHOTO COURTESY OF OLDS COLLEGE
Not every farm can justify investing in a grain dryer. Some farms are too small and others may not receive enough annual moisture to warrant the expense. While farms in both of these categories still need to dry grain, they may consider alternatives to full conventional setups.
Olds College Smart Farm staff have spent recent years trialling in-bin drying technologies. In-bin drying makes use of existing bins with aeration systems and supplemental air heaters. Such setups efficiently allow standard aeration bins
to remove upwards of five per cent moisture content.
When drying grain within a bin, just because you can fill it completely, doesn’t mean you should. The optimal extent to which a bin should be filled depends on its size and the configuration of its air delivery system, fan output and supplementary heating system. It is commonly suggested to ensure a minimum airflow rate of one cubic foot per minute per bushel. To calibrate this rate for yourself, use your manufacturer’s fan curve charts in combination with a fan plenum pressure measurement. Alternatively, pressure gauges can be purchased to account for fan curve and indicate airflows based on how full a bin is.
Working with Calgary-based startup Top Grade Ag, the Smart Farm has tested and validated its in-bin technology over the past three years. As part of the process, the Smart Farm provides feedback and suggestions for improvement. Together, the company’s sensors and online platform enable users to remotely monitor estimated moisture removal rates. This allows the farmer to make informed decisions as to when the grain is dry enough, as a bin average, to turn off the fans. Of the six moisture removal trials conducted in 2021, the final moisture content of the grain was measured at plus or minus 0.16 per cent of the number predicted by the platform. As a farmer, I consider this high degree of accuracy more than acceptable for on-farm use.
Note that while the entirety of a bin’s contents may be dry on average, it’s not recommended to simply shut the fan off and let it sit until the following May. The moisture content of the dried grain will not be uniform. The best practice is to pull the grain out, take a few moisture samples and verify it is dry. The process of moving the grain will blend it more uniformly and ensure it is safe for long-term storage.
With a bin decked out in Top Grade Ag tech, last season we dried down 4,400 bushels of tough canola in late September from 11.6 per cent to 8.3 per cent over five days at a cost of just under two cents per point per bushel.
The bin system setup made use of supplemental, indirect propane-fuelled heat. With it, ambient air can be warmed to between 30 and 35 C without the addition of moisture from exhaust that in-line heaters produce.
In-bin drying isn’t perfect for every farm, but where smaller quantities of tough grain is within four to five per cent of safe-to-store moisture content limits, it is a good fit.
As Smart Farm staff gear up for harvest, plans for continued in-bin drying research are underway. The objective is to collect data on total energy consumption, work with untried bin and fan combinations and compare metrics against conventional dryers.
Daniel Stefner is a smart agriculture project lead and farm liaison with the Olds College Centre for Innovation. For more information, visit oldscollege.ca/smartfarm.