Thermal performance and specific energy consumption of traditional tobacco curing barns in Tanzania

Abstract

Traditional tobacco curing barns remain the dominant technology in Tanzania due to their low construction cost and accessibility, particularly in major producing regions such as Tabora. However, their thermal inefficiency results in excessive firewood use and environmental degradation. This study presents a field-based performance evaluation of a traditional flue-curing barn at the Tobacco Research Institute of Tanzania. Environmental parameters and fuel consumption were monitored at 15-minute intervals throughout the yellowing, leaf drying, and stem drying stages. The curing process handled 429 kg of fresh tobacco using 1,016 kg of firewood, equivalent to 16,256 MJ of energy input. The specific energy consumption was 165.3 MJ/kg of dried tobacco, thermal efficiency was 5.99%, and moisture removal efficiency was 0.42 kg of water per kilogram of firewood. More than 90% of the supplied energy was lost through conduction and uncontrolled airflow, highlighting the structural inefficiencies of traditional barns. These findings provide localized benchmarks under actual operating conditions and demonstrate the urgent need for retrofitting measures to reduce fuel demand and promote sustainable curing practices in rural Tanzania.