Comparison of the performance of a modified temperature-controlled microwave dryer to improve heat-mass transfer, increase energy efficiency and preserve quality characteristics of shad (Alosa fallax nilotica)

Abstract

In this study, shad (Alosa fallax nilotica) was dried in microwave (360, 720 W), developed heat controlled microwave (50, 70 °C), hybrid microwave (350 W + 50 °C, 350 W + 70 °C) dryers. Drying time, drying rate-rate, effective diffusion, color, hardness, energy consumption (SMER, SEC), exergy energy, energy efficiency, heat-mass transfer value of the drying processes were investigated. The shortest drying process was determined as 450 seconds at 720 W power, while the longest was 414minutes at 50 °C. Effective diffusion values calculated for microwave, temperature controlled microwave and hybrid drying processes are 1.32–9.43 × 10−8 m2/s, 2.43 × 10−8-2.41 × 10−7 m2/s and 8.52 × 10−7-2.76 × 10−6 m2/s, respectively. Has changed between It has been determined that the most suitable drying method in terms of total energy consumption and energy efficiency values is the drying process performed in a temperature-controlled microwave dryer. Exin and Exout values of the temperature-controlled microwave drying process were calculated to vary between 2.20 and 5.16 J/s and 1.82–4.68 J/s, respectively. Exin and Exout values of the hybrid drying process were calculated to vary between 1.94 and 4.84 J/s and 1.70–4.68 J/s, respectively. The heat transfer values calculated for the temperature-controlled drying process varied between 0.104 and 0.00269 W/m2K and the heat transfer values calculated for the hybrid drying process ranged between 0.100 and 0.00270 W/m2K. It was determined that the most suitable drying processes for color characteristics were 360 W and 350 W + 50 °C. For the hardness value, it was determined that the 350 W + 70 °C drying process was statistically more appropriate (P < 0.05).