This study evaluates the potential of high-power near-infrared (NIR) laser technology for industrial drying of moist porous media through fundamental and experimental analysis using blanched potato slices as representative samples. A 4.5 kW monochromatic diode laser with a typical wavelength of 975 nm was used to assess incident energy distribution, penetration depth, drying kinetics, energy performance, product quality, and statistical significance of process parameters. Laser energy uniformity was confirmed over a 400 cm 2 irradiation area, with spatial variation below 9%. At an initial wet-basis moisture content of 75.35 ± 3.98%, the average penetration depth was 7.00 ± 0.16 mm under two power densities, P1 = 2.05 W/cm 2 and P2 = 3.35 W/cm 2 . Intermittent laser drying reduced moisture content to 7.92 ± 0.25% in all experiments. Higher power density, larger substrate openings, and thicker samples enhanced moisture removal, with peak drying rates ranging from 2.54 to 6.83 g/m 2 s. Energy analysis identified preferred laser-use windows for dryer retrofitting by applying a specific energy consumption threshold of 2.2 kWh/kg of moisture removed in the optical-to-thermal energy conversion during laser drying. These windows occurred after initial sensible heating, corresponding to moisture-content reductions of 13.45–42.10% and average SEC values of 1.53–1.91 kWh/kg. Product quality remained acceptable, with browning index below 37, shrinkage below 44%, and final water activity between 0.35 and 0.72. Two-way ANOVA with Tukey’s HSD showed that sample thickness and power density were the dominant factors affecting drying performance and quality, while substrate configuration had secondary but significant effects on drying time and selected quality attributes. This study demonstrates that monochromatic NIR laser technology can establish high-efficiency operating windows for retrofitting conventional dryers or developing new drying systems, enabling targeted energy input during periods of peak energy factor and low specific energy consumption. • Fundamentals of near-infrared (NIR) laser drying were established and validated. • NIR laser offered uniform energy deposition with high penetration depth in potatoes. • High drying rates achieved with optical-to-thermal energy use below 2.2 kWh/kg. • Product quality preserved (color, shrinkage, water activity). • ANOVA revealed significant effects of power density and sample thickness.
Harris et al. (Fri,) studied this question.