Design And Development Of A Hybrid Solar/Charcoal Fish Smoke-Dryer

ABSTRACT 

An indirect, natural convection solar-assisted charcoal smoking system was designed and fabricated in one of the host communities of the Federal University of Technology, Owerri where most of the fish farmers and processors adopt the conventional method of drying fishes, that is, using firewood. This method which works well during the dry period of the year is very inconvenient during the rainy season.  Given the excessive heat generated by firewood and its resultant effect on the product during the dry periods of the year produces a lot of discomfort to the processor. In order to improve the quality of dried fish products, working conditions of the rural fish farmers and traders and reduce high incidence of deforestation and bush burning, solar-assisted charcoal fish dryer is hereby designed and the prototype developed, using the local weather parameters.  The fish dryer works on the principle of heat and mass transfer. The ambient air temperature and relative humidity constituted the main drying force, though air flow rate and burner heat contribute significantly to the percentage moisture loss from the fish. The safe moisture content of the scumbia and sardine fish species was found to be 18.98% wb and 18.85%wb respectively. The crude protein content of the two fish species was found to be reduced by 17.7% as against 65 – 75% protein value, while 27.69% of 16 – 34% lipids were reduced and 4.1% ash content was found as against a maximum value of 10%. Statistical analysis and graphical relations illustrated a significant contribution of the solar collector on the dryer chamber temperature as well as reducing the drying time.  The relative maximum charcoal heat energy for smoking and the relative energy developed by the solar collector were found to be 1478.2kJ and 7639.2kJ respectively; the heat source efficiency of the dryer was calculated as 59% and 47% for charcoalsolar and charcoal respectively.