Zephyrus: Grain Aeration Strategy Based on the Prediction of Temperature and Moisture Fronts

Grain aeration is an established low-cost and chemical-free technology for maintaining favorable storage conditions for the safe preservation of grain quality. Currently, the most efficient controllers are based on simulations of the aeration process. They frequently depend on complex programming codes, which limit their implementation for professionals who work in the postharvest sector, resulting in longer computing times. In this work, a new aeration control strategy, called Zephyrus, was proposed based on the prediction of speeds and changes of temperature and moisture fronts while air is passed through a grain bulk. The proposed controller was tested in a pilot study, resulting in a grain cooling of 11.4 °C with a moisture content variation of 0.6%, also maintaining an average temperature gradient of 2.6 °C throughout the grain bulk. Along the 6 months of study, the energy required for cooling 0.42 t of grain was 0.06 kWh t−1 °C−1 (0.30 kWh t−1). The proposed control strategy was also compared with two other controllers by using simulation procedures. Results showed that Zephyrus was more efficient to achieve grain cooling for 56% of the simulated scenarios. When considering the power consumption, Zephyrus required lower electrical energy per mass of cooled grain in 44.5% of the simulated scenarios. Zephyrus control strategy can be used with different aeration system designs, automatically adjusting its set points according to the geographic region and season.