Towards time and energy optimization of the drying process via structural redesign of a tray batch dryer

• CFD-guided redesign improved airflow uniformity in an industrial tray batch dryer. • side-wall inclination and air straighteners enhanced drying efficiency. • drying time shortened by 39%, improving process repeatability and product quality. • energy consumption reduced by approximately 35% This study addresses time and energy optimization in the industrial drying of decorative concrete tiles motivated by quality defects caused by non-uniform drying, particularly surface discoloration of finished products, through structural redesign of a tray batch dryer. The baseline system exhibited non-uniform airflow, which extended cycle times and increased energy demand and led to non-uniform moisture removal across tray levels. A combined approach, computational fluid dynamics (CFD) with realizable k–ε turbulence modeling and in-situ measurements of air velocity, temperature, and relative humidity, was used to design and validate two modifications: (a) a 40 mm side-wall inclination and (b) air straighteners implemented as 700 mm panels with 30 mm slots, applied to a full-scale industrial dryer with lateral air supply. Simulations predicted, and measurements confirmed, a substantially more uniform velocity profile over the chamber height. Critically, peak velocities in the central region were shifted downward from 1.2 m/s to 0.8 m/s, while mid-zone over-acceleration was suppressed, yielding a flatter profile that supports consistent moisture removal across tray levels and improved drying uniformity of concrete products. Process-level effects were quantified on the production line: the average drying time decreased from 18.5 h to 11.5 h (about 39%), and batch energy use dropped from 250 kWh to 156–198 kWh. Given the near-linear growth of cumulative energy with cycle duration, these results correspond to an estimated 35% reduction in energy consumption. Extrapolation to multi-chamber operation indicates potential electricity-cost savings approaching €376 k over four years.