One of the most energy intense operations in arable farming in temperate countries is grain drying. Several studies have indicated that using higher drying air temperatures offers opportunities to save energy during grain drying, but although to a certain extent grain can tolerate drying at higher air temperatures, this may compromise the viability of the grain. The aim of this study was to examine the energy saving approaches achieved by using an elevated drying air temperature and by manipulating drying airflow in a scaled-down mixed-flow batch grain dryer. The drying airflow was reduced gradually as the drying process proceeded, and the drying air temperature was allowed to rise. The relative humidity of the exhaust air was used as a control factor to adjust the airflow. Energy savings were expected from the higher drying air temperature and, due to the reduced airflow, from the higher exhaust air humidity. The results showed energy savings of 5% for drying barley and 14% for drying oats. Increases in the evaporation rate of 5% and 17%, for barley and oats respectively. However, some degradation in grain viability was observed especially with oats. Further research is needed to find the correct control parameters and temperature limits for each cereal species.
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