A Solar Dryer & Moisture Condensing Cabinet with Thermosyphon Heat Flow

Abstract

In this work, a Solar Dryer & Moisture Condensing Cabinet with Thermosyphon Heat Flow wasdesigned, constructed and performance tested for drying the agricultural production. The cabinet dryer isconstructed as a passive type close system covered with a glass with a horizontal angle of 12o and atransparent acrylic sheet to receive maximum solar energy. A dimension of the dryer cabinet was 83 cm x 77cm x 100 cm containing 5 trays each placed in a horizontal shelf. Shelf 5 was in the top position. The gutterswere placed to receive the condensed moisture from the front and the top pieces of glass and vented outsidethe cabinet. The parameters used to compare the performance of the dryer cabinet were drying duration anddrying rates. The data were collected 6 hours a day from 9 am to 3 pm. The result from the research indicatesthat the Solar Dryer & Moisture Condensing Cabinet with Thermosyphon Heat Flow yielded the products in ashorter drying duration with a higher drying rate compared to a natural drying method of the sunlight. Theresult also reveals that the drying cabinet was used to reduce average 300% (d.b.) moisture of 5 kg ofpeppers in all 5 trays to average 26% (d.b.) in 3 days (18 hrs.) in spites of the fact that all 5 trays were stillplaced in the same shelf compared to that of 52% dried by the sunlight in the same duration. When themoisture of the peppers in each tray was analyzed, the result shows that the peppers on the fifth shelf, thetopmost one, were the driest products with the shortest duration following by the peppers on Shelf 4, Shelf 3,Shelf 2 and Shelf 1 respectively. Thus, the Solar Dryer & Moisture Condensing Cabinet with ThermosyphonHeat Flow can be used to dry 8-10 kg of peppers in 3 days (18 hrs.) depending on solar radiation. Thus, onthe first day the tray of peppers on Shelf 5 could be removed and the trays on the lower shelves were movedup. As such Shelf 1 was replaced with a new tray of peppers. The quality of the products were also in anacceptable criterion. The dried peppers in 5 trays were of a similar colour. They were neither damaged by rainnor eaten by rodents and insects.