EQUILIBRIUM MOISTURE GRAIN DRYING WITH HEATER AND VARIABLE SPEED FAN

摘要

A grain drying system and process includes a controller that is electronically coupled to a variable speed fan and to a heater or a heat pump to supply air through a plenum and the grain. Also coupled to the controller are ambient temperature and humidity sensors, internal plenum temperature and a humidity sensor. The controller adjusts a fan speed in combination with operating the heater or heat pump to deliver a target equilibrium moisture temperature, during a first period when the ambient air is outside the equilibrium moisture target. The controller operates the fan at a minimum speed, during a second period when the ambient air is outside the equilibrium moisture target, and the controller is unable to obtain equilibrium moisture target air in the plenum in view of operational limits of the fan and the heater or heat pump.

主权项

1. An equilibrium moisture grain drying system, comprising:
a grain drying controller electronically coupled to a variable speed fan and to one of a heater and a heat pump associated with an air plenum to supply air through the plenum and through grain in a grain bin; an ambient temperature sensor positioned outside the grain bin and electronically coupled to the grain drying controller; an internal plenum temperature sensor positioned within the plenum and electronically coupled to the grain drying controller; a humidity sensor positioned outside the grain bin or within the plenum and electronically coupled to the grain drying controller; wherein the grain drying controller includes instructions to adjust a fan speed of the variable speed fan in combination with operation of the one of the heater and heat pump to achieve internal plenum temperature sensor data from the internal plenum temperature sensor corresponding to a target equilibrium moisture temperature, during a first period when the sensor data from the ambient sensors indicates ambient air is outside the equilibrium moisture target; wherein the grain drying controller includes instructions to operate the variable speed fan at a predetermined minimum speed during a second period when the sensor data from the ambient sensors indicates ambient air is outside the equilibrium moisture target, and the grain drying controller is unable to obtain air in the plenum within the equilibrium moisture target in view of operational limits of the variable speed fan and the one of the heater and heat pump; wherein, when the variable speed fan passes air within the equilibrium moisture target through the plenum and through the grain, the equilibrium moisture grain drying system adjusts the moisture content of grain in the grain bin toward a desired target grain moisture content corresponding to the equilibrium moisture target.