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Abstract
Coffee beans are actually the seeds of coffee cherries that are inedible before roasting.
Coffee beans experience many chemical and physical changes during the roasting process to turn
green coffee beans into the dark brown beans seen in coffee shops across the world. The roaster
design outlined in the project is a hybrid of the two leading coffee roasting designs: drum and
fluid-bed. Drum roasters primarily transfer heat to the coffee beans by means of conduction
while fluid-bed roasters transfer heat by convection. The hybrid coffee roaster design
incorporates both heat transfer methods to create more uniform roast across the batch. The
hybrid design was modeled in SOLIDWORXS and then constructed to be used for small-scale
roasting and academic purposes at the University of Southern Indiana (USI). Although coffee
roasting is mainly seen in large-scale settings (industry), there are also applications for small scale
roasting of approximately 200g batch sizes. This hybrid roaster combines elements from
control theory and heat transfer theory to serve as a valid model to be expanded upon in the
Linear Control Systems (ECE 443) course at USI.