Effective Aeration Management for Grain Storage: Key Considerations and Techniques
This lecture focuses on the essential aspects of aeration in grain storage, highlighting the importance of managing natural air movement to control moisture and temperature. Key management strategies include maintaining the bin's center temperature within 10 degrees Fahrenheit of the ambient temperature and ensuring air flow rates of 1 cfm per bushel for bins and 2 cfm for flat storage. It covers the implications of positive and negative pressure on aeration effectiveness, cautions regarding humidity controls, and the appropriate types and sizes of ducting needed for efficient air movement, emphasizing energy savings and grain protection.
Effective Aeration Management for Grain Storage: Key Considerations and Techniques
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Presentation Transcript
Lecture 16 Aeration
Aeration • Natural air movement issues - moisture, temp • Management Issues • keep center of bin within 10 degrees F of ambient temp • .1 cfm / bushel for bins • .2 cfm / bushel for flat storage • not any lower than 32 degrees F • not any higher than 60 degrees F • Table 5.1
Positive vs. Negative Pressure • pushing adds 2 degrees F • negative prevents condensation • uses solar heat from top of bin • bottom last to cool, difficult to determine when dry • positive requires smaller duct diameters
Air Flow rates • .1 cfm is adequate • if larger fan, then less time • 160 hrs @ .1 — 32 hrs @ .5 • caution - can overdry &/or add moisture
Caution w/Automatic controls • humidistat not enough • thermostat & humidistat required • best if computer controlled • saves energy • less likely to damage grain • record information (temp, etc.)
Duct types Used • plastic, steel • 6" - 36" • round & ½ round • plastic - perforations not as much • plastic - cheaper
Sizing • Assume level surface • Depends on: 1. Cross sectional Area 2. Surface area exposed to grain minimum cross sectional area = total volume (cfm) Allowable duct velocity (fpm)
Sizing • Total air volume depends on: • fan • bin • grain type Exit velocity for escaping air Min. total surface area = Total air volume (cfm) Maximum velocity of duct exit air (fpm)
