Simulink Design and Analysis of Universal Solar Dryer with Tracking Device

Abstract

Preserving perishable food is one of the challenges required to overcome food security and season tomatoes and other vegetables wastage. Forced drying of agricultural products, in particular vegetable - such as tomatoes is one modern methods of perishable food drying. Solar drying uses abandoned solar energy during the day. Effective solar drying requires tracking of the sun by the drying tray. Therefore, this necessitates the development of solar dryer with tracker. Aim of this paper is to design a solar tracking for drying tomatoes. This paper however, presents Simulink design of these applications of Flywheel Energy Storage System (FESS) in power system and also analyses the design parameters in order to improve the solar energy tracker. A solar dryer with solar tracking was designed. The drying chamber has overall dimensions of 457.2 mm x 406.4 mm x 558.8 mm with three drying trays having a drying area of 0.25 m2 each. The dryer consists of three major units namely, the drying chamber, the solar tracker and a solar powered control. The control unit has four temperature sensors, and four controlled DC fans for varying the air flow rate from the solar collector. The drying chamber is to be lagged with carbon fibre as an insulator. The solar collector made of Aluminum sheet and the glass on top. Fresh tomatoes were used for performance evaluation testing. Each drying tray was loaded with 5 kg of tomato slices of 8 mm thickness from initial moisture content of 93.3% (w.b.) and dried to a final moisture content of 12% (w.b.) in 13 hours, when operated under natural convection current. The maximum drying rate of tomato slices attained under natural convection and forced circulation were 3.1 and 2.8 kg of water per kg of dry matter-hr. For the open-air sun drying, the maximum drying rates for tomato were 1.5 kg of water per kg of dry matter-hr. The dryer was able to remove 52.8% of moisture while tracking the sun, dry basis, from 4.6 kg of product in one day of 10.00 hours drying time, which is about 0.46 kg/hr drying rate. The efficiency of the dryer was 56.25%.