Energy utilization and exergy indices: A comparative analysis of a convective (Electric/gas) dryer

This study investigates Energy utilization (EU) and Exergy indices of a convective dryer utilizing electric and gas heat sources at temperatures of 45 ℃ and 60 ℃, with a drying air velocity of 3m/s. Energy utilization result indicate that at 45 ℃, the minimum energy utilization (EU) for the electric heat source was 0.8862 kJ/s, while the gas heat source recorded a minimum of 1.1 kJ/s. At 60 ℃, the maximum EU values were 3.87 kJ/s for electric and 4.2 kJ/s for gas. A clear trend was observed, showing an increase in EU with rising temperature. Exergy efficiency comparison consistently showed superior performance of gas, with recorded efficiencies of 45.5% for electric at 45 ℃, 53.3% for gas, 62% for electric at 60 ℃, and 70.1% for gas. The study suggests optimization opportunities, noting higher potential for improvement with electric at both temperatures. The Exergy Sustainability Index indicated gas's better utilization of available exergy at 2.14 and 3.344 for 45 ℃ and 60 °C, respectively, compared to electric at 1.835 and 2.63 for 45 ℃ and 60 ℃, respectively. In conclusion, the study recommends gas heat source for superior efficiency in drying African mud Catfish.