To Dry or Not to Dry? – Wisconsin Energy Efficiency and Renewable EnergyThe equilibrium moisture content EMC of a hygroscopic material surrounded at least partially by air is the moisture content at which the material is neither gaining nor losing moisture. The value of the EMC depends on the material and the relative humidity and temperature of the air with which it is in contact. The speed with which it is approached depends on the properties of the material, the surface-area-to-volume ratio of its shape, and the speed with which humidity is carried away or towards the material e. The moisture content of grains is an essential property in food storage. At a constant relative humidity of air, the EMC will drop by about 0. The following table shows the equilibriums for a number of grains data from . These values are only approximations since the exact values depend on the specific variety of a grain.
Grain Drying, Handling, and Storage Handbook
If late fall and winter are so damp that grain does not dry, spoilage will begin with the onset of warm weather in the spring. Corn should be down to A bushel of corn at Thus, the farmer would have delivered bushels x 0. Usually a 0. Many elevators use a shrink of 1. For this example:.
If drying is unavoidable, consider allowing crops to dry in the field as much as possible to reduce energy costs. Keep in mind, however, that there is a point where field losses will increase. One also has to account for the time needed to harvest grain based on the capacity of your equipment and the risk of weather damage or weather impeding harvest. Chapter 8 in the Corn Handbook on Corn Harvesting by Huitink discusses how to estimating field losses . The moisture content of the standing grain at harvest initiation will depend on weather conditions, the amount of grain to harvest and harvest and drying capacity.
As you plan new or renovated grain handling facilities, consider both your immediate needs and your long-term needs. Keep in mind that life expectancy is probably 5 to 10 years for fans and some types of conveyors, 10 to 20 years for dryers, and 15 to 30 years for storage bins. Cash incentives through the ActOnEnergy Custom Program can help make your grain drying project happen — which will lower energy bills and boost your bottom line. Cash incentives are also available for a variety of other energy efficiency projects for agribusinesses — including livestock waterers, circulation fans, and variable frequency drives. Visit ActOnEnergy. Not registered? Sign up to receive our email newsletter and access other members-only features.
Kenneth J. Hellevang, P.
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