PERFORMANCE ASSESSMENT OF AN ARDUINO-CONTROLLED SOLAR-POWERED EVAPORATIVE COOLING SYSTEM FOR POST-HARVEST PRESERVATION OF TOMATOES AND HOT PEPPER IN SEMI-ARID NIGERIA

Post-harvest losses of fruits and vegetables remain a significant challenge in developing regions due to inadequate storage infrastructure and limited access to reliable energy. The present designed and developed an Arduino-controlled solar-powered evaporative cooling system for postharvest preservation of tomatoes and hot pepper under semi-arid conditions. The system integrates a natural jute fiber evaporative pad, a solar photovoltaic power supply, a water recirculation unit, and a microcontroller-based control mechanism to regulate the storage microclimate. Performance evaluation was conducted through no-load and load tests. Under no-load conditions, the system consistently reduced internal temperature while increasing relative humidity, reaching up to 98%, thereby establishing a stable cooling environment based on adiabatic evaporation. For the load test, 2 kg of tomatoes and 1 kg of hot pepper were stored inside the chamber and compared with equal quantities kept under ambient conditions. The system maintained high relative humidity levels (approximately 80–98%) and achieved moderate reductions in temperature relative to ambient conditions. Although cooling performance was influenced by ambient humidity, the system effectively minimized vapour pressure deficit, reducing moisture loss and slowing physiological deterioration of the produce. The findings demonstrate that the system having Saturation efficiency (SE) of 95% offers a low-cost, energy-efficient and sustainable approach for postharvest storage. Its capacity to maintain high humidity and moderate temperature conditions supports extended shelf life of perishable produce in environments where conventional Energy is not readily available but has abundant Solar energy.