MODIFICATION OF AN AUTOMATED SOLAR FISH DRYER
Abstract
Fish is a vital protein source in Nigeria’s coastal communities, yet open‐sun drying, still widely
practiced, exposes products to dust, insects, UV degradation, and weather variability, leading to
quality loss and post-harvest wastage. This study presents the modification, automation, and
performance evaluation of an existing solar fish dryer to deliver hygienic, energy-efficient, and
climate-resilient drying suitable for the Niger Delta. The retrofit combined enhanced thermal
insulation (fibreglass), a controlled halogen heating element, an improved airflow path with a
chimney, and a standalone solar PV–battery supply. An IoT-enabled monitoring and control
module (DS18B20/DHT22 sensors with ESP-based telemetry to ThingSpeak) provided real-time
cabinet/ambient conditions and threshold-based relay control for temperature stabilization.
Experimental evaluations comprised no-load and on-load trials using salted and unsalted catfish,
with time-resolved measurements of temperature, moisture loss, battery/array voltages, and
thermodynamic performance (thermal and exergetic efficiencies).The modified system
consistently maintained cabinet temperatures above ambient, confirmed during no-load tests, and
achieved rapid moisture removal during on-load drying. Un-salted samples attained peak
exergetic efficiency of 74% and thermal efficiency of 69%, while salted samples dried faster due
to osmotic effects with slightly lower but stable efficiencies. Overall dryer efficiency reached
83%, improving upon a prior 72% benchmark. Battery discharge analyses showed adequate
operational stability across drying windows despite diurnal variations in solar input. The results
demonstrate that integrating improved thermal design with low-cost automation substantially
enhances drying rate, energy utilization, and product hygiene. The system offers a scalable,
renewable, and cost-effective preservation pathway to reduce post-harvest losses, support
livelihoods, and strengthen food security in humid tropical environments.
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