Development of a Multipurpose Small Scale Dryer for Agricultural Products

Abstract

A multipurpose cabinet dryer was designed, constructed and tested using locally available materials. The system comprises a heating chamber, heat exchanger, drying trays, 3-phase blower, three heating elements of 1800 W each, and a control box, which consists of temperature control, contactor, thermocouple, and circuit breaker. The dryer was evaluated based on power consumed, moisture removal, drying rate, and drying efficiency. The result showed that the energy consumed when drying plantain chips, moringa leaves, okra, and locust beans are 346.55, 55.92, 110.63 and 49.64 kJ, respectively. The energy consumed increased with an increase in the moisture removed and drying time. Similarly, the drying rate for plantain chips, moringa leaves, okra, and locust beans was 0.58, 0.09, 0.18, and 0.10 g/min, respectively, which depended on the initial moisture content of the product and the air velocity. The drying efficiency ranged between 62.1 and 65.5%, it reduced with an increase in the amount of moisture removed and the drying temperature. For the products with which the dryer was tested, the drying system promises satisfactory performance for small scale applications.