Design and experimental evaluation of a renewable energy-assisted fermentation system with wind agitation and magnetic braking for thermal uniformity

Abstract

Small- and medium-scale fermentation processes often present problems of thermal stratification and energy dependence due to the use of agitators and thermal systems powered by conventional electricity. This article presents the design and pilot-scale experimental evaluation of a renewable energy-assisted fermentation system that integrates: (i) two thermal tanks (primary for heating and secondary for cooling), (ii) wind-powered agitation with electrical recovery via a generator/charger, and (iii) servomotor-controlled magnetic braking to stabilize mixing speed under wind variations. Performance metrics were established in terms of thermal uniformity (ΔT), agitation stability (RPM), energy balance (E_rec, E_cons), and overall efficiency (η). The results indicate that wind agitation reduces thermal stratification from ΔT=5.4 °C (without agitation) to ΔT=0.8 °C with magnetic braking, and that the system recovers around 94% of its electrical demand in a 6-hour cycle under moderate wind conditions.