Excel-Based Tool to Analyze the Energy Performance of Convective Dryers∗

Abstract

An algorithm to examine the energy performance of convective dryers was developed and transformed into an Excel-based calculation tool. Provided with the input data for a given industrial dryer, this tool allows the energy use to be quantified in terms of the specific energy consumption and energy efficiency. The energy use can then be compared with the corresponding values for an ideal adiabatic dryer to identify the potential for energy savings. The algorithm accounts for direct and indirect dryers as the single- and multistage units operated in closed or open cycles. In addition, the maximum energy efficiency can be determined for nonhygroscopic materials through the sorption isotherms. The tool permits the identification of the major sources of dryer inefficiency and allows energy savings to be calculated for several low- and medium-cost measures such as dryer insulation, partial recycling of exhaust air, feed preheating, and others. The tool is built as a modular system comprising the following main components: dryer identification, calculation of actual energy consumption, comparison with the theoretical energy consumption, identification of sources of energy inefficiency, and analysis of options to reduce energy consumption.