INSTANTANEOUS DRYER INDEXES FOR ENERGY PERFORMANCE ANALYSIS

A new definition for instantaneous energy and drying efficiencies whic h can be integrated over the drying time to yield the cumulative effic iencies was proposed. This definition was then applied to experimental data for fluidized bed drying of corn, potato cubes and alumina beads , which represent hygroscopic, partially hygroscopic and nonhygroscopi c materials with significant, moderate and negligible resistance to in ternal moisture flow, respectively. Further, the instantaneous drying and energy efficiencies were used to analyze literature data on batch and continuous drying in through-flow, crossflow and concurrent-flow c onfigurations. It was shown that instantaneous indices may help to imp rove the overall energy performance by indicating modifications to the dryer design and specifying optimum operating parameters.