EQUILIBRIUM MOISTURE GRAIN DRYING WITH HEATER AND VARIABLE SPEED FAN

摘要

A grain drying system and process includes a controller that is electronicallycoupled to a variable speed fan and to a heater or a heat pump to supply airthrough aplenum and the grain. Also coupled to the controller are ambient temperatureandhumidity sensors, internal plenum temperature and a humidity sensor. Thecontrolleradjusts a fan speed in combination with operating the heater or heat pump todeliver atarget equilibrium moisture temperature, during a first period when theambient air isoutside the equilibrium moisture target. The controller operates the fan at aminimumspeed, during a second period when the ambient air is outside the equilibriummoisturetarget, and the controller is unable to obtain equilibrium moisture target airin the plenumin view of operational limits of the fan and the heater or heat pump.