1 Fundamentals of Energy Analysis of Dryers

Drying is a highly energy-intensive process, accounting for 10–20%of total industrial energy use in most developed countries. The main reason for this is the need to supply the latent heat of evaporation to remove the water or other solvent. There are thus clear incentives to reduce energy use in drying: to conserve finite resources of fossil fuels, to reduce carbon footprint and combat climate change, and to improve process economics, but it is a challenging task facing real thermodynamic barriers. Effective analysis of current energy use is a vital first step in identifying opportunities for savings. An initial lower bound of dryer energy needs is provided by calculating the evaporation load for the amount of water to be removed (Section 1.3). This shows howmuch energy is inherently required and, by comparing with current measured energy usage, what opportunities exist to reduce energy consumption. These fall into three main categories;