There are four types: crossflow - air blows at a right angle across perforated columns of grain; concurrent flow - air and grain move in the same direction down the columns; counterflow - air blows up the columns opposite the grain; and mixed flow, which incorporates a combination of these air flows.
How many BTU is a grain dryer?
The energy required to evaporate a unit mass of moisture in a high- capacity grain dryer (i.e., the specific energy efficiency) ranges from 1500 BTU to 3000 BTU per pound of water (3.5 MJ to 7.0 MJ per kg of water), depending on the dryer design and the ambient conditions.