Solar, Biomass and Hybrid Dryers - BioEnergy Discussion Lists

Package 12: Chimney-type Solar Cabinet DryersThe cabinet dryer developed consists of a rectangular drying chamber supported ona wooden base frame. The base of the drying chamber was made of a papyrus matcovered with black plastic sheeting laid inside the frame. The air inlet into thechamber is from a ventilation slot at the bottom, which is covered by a mosquitomesh to prevent insects from entering the dryer. The front side of the dryingchamber has two hinged doors to provide access for loading and unloading thetrays. An air outlet vent is provided at the top of the chamber to allow the exit ofwarm moist air, which rises by natural convection. ITC designed two versions ofcabinet dryers, one with a 1 m 2 solar collector and the other with a 2 m 2 collector.(a) 1 m 2 solar cabinet dryer(b) 2 m 2 solar cabinet dryerFigure 12.1: The chimney type solar cabinet dryersTable 12.1: Technical Specifications of the Solar Cabinet DryersParameter Dryer model 1 sq. m Dryer model 2 sq. mWidth 1 m 2 mCollector length 1 m 1 mDryer length 1 m 1 mCollector area 1 m2 2 m2Tray area 1.96 m2 3.92 m2Average drying capacity 70 kg 140 kgDesign detailsThe dryers consist of four main parts: a base frame, drying chamber, drying trays,and loading door. The rectangular base frame is built with softwood, and hassupporting legs on which rests a drying chamber. A solar collector is attached to thedrying chamber at the bottom. The drying chamber of the 1 m 2 model measures 1 mlength x 1 m width x 0.75 m height, and contains 4 trays of 1m x 0.495 m to provide a57