Process monitoring for energy assessment of parts drying processes

Abstract

Rising surface quality requirements in the metal-working industry have been a leading cause in the steadily growing importance of parts cleaning and drying processes. Coupled with energy shortages and rising energy cost, this brings more attention to the significant energy demand and energy efficiency potentials of these processes. Focusing on parts drying, energy assessments are necessary for the detection of energy savings potential and allocation of energy efficiency measures as well as comparing the energy efficiency of different drying processes. Influencing factors, such as part geometry, as well as the achieved drying result, must be taken into consideration when characterizing the drying process to enable a suitable comparison in energy assessments. The authors propose a set of energy performance indicators (EnPI) for describing process performance and energy efficiency, such as time per part or energy consumption per removed moisture, for evaluating the corresponding energy consumption. In order to sufficiently determine indicators describing the drying task, an approach for quantitatively describing the parts’ geometrical complexity is presented due to its significant influence on the drying process. Furthermore, a thermography-based concept for monitoring the drying result is developed to compare process outcomes with varying process settings and energy consumption. The process monitoring concept is demonstrated using a throughput convective drying process, and the proposed EnPI are calculated for different process settings. The implementation, as well as the resulting indicators, are discussed and used to compare the energy efficiency of the considered process settings.