Energy to Lower MC by 1% for one bushel of wheat

With this blog, we would like to know what it might cost to use supplemental electrical energy to remove one percent moisture content, MC, from one bushel of wheat.

Assumptions:

  1. All the energy goes into evaporation.
  2. wheat  60 lb/bu
  3. Cost of electrical energy  is 0.12/kW hr.
  4. Latent heat of evaporation,  energy to evaporate  2257 kJ/kg

One bushel is 60 lbs, so 1% MC would have a weight of  0.6 lbs or 0.2722 kg

2257/.2722 = 614.4 kJ to evaporate 1% MC from one bushel of wheat  and to put this into hours divide by 3600  =  0.17 kW hr.   and in terms of dollars,  0.17 x $ 0.12 = $ 0.02 to evaporate enough water out of a bushel of wheat to lower the MC by 1%.    That doesn’t sound like much but for 3500 bushels, it would cost $71.68, and to drop by 2% MC it would be $143.36.  It must also be remember that this is the ideal efficiency.  In the real world, we may have to double our cost again.

Could we use the free heat in the air to dry grain?  —  I think so; but it will take careful management and control of the aeration fans.

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