Aeration of stored wheat in the Canadian Prairies
Metzger, John Frederick.
Airflow rates and fan control methods for aeration of stored wheat to maintain quality during storage were evaluated. A computer simulation model which predicts grain conditions in two-dimensions of a cylindrical granary, with no aeration, and with aeration, was developed. The model was verified by comparing predicted and experimental data obtained during the 1979-80 storage year, and was used to investigate various design parameters of aeration systems. Historical weather data for 15 or more harvest years from four Canadian Prairie locations ranging from Fort St. John, British Columbia, to Winnipeg, Manitoba were used. The effects of climate, initial moisture content, harvest date, and initial grain temperature on the condition of stored wheat were determined. The condition during storage of 15% initial moisture content wheat was predicted with no aeration, with aeration rates from 0.5 to 3.0 (L/s)/m3, and with four different fan control methods. All aeration airflow rates and fan control methods reduced the rate of grain deterioration. An airflow rate of 1.0 (L/s)/m3 was optimum for continuous aeration. The optimum fan control methods were humidistat control with settings between 50 and 70%, 6 h time-clock operation at night, and differential thermostat control with settings between -10 and -15oC. The choice of fan control method is independent of climatic variation within the range of climates studied.