DESIGN, IMPLEMENTATION AND TESTING OF AN INDIRECT SOLAR POTATO DRYER

摘要

This paper reports the design, implementation and testing of an indirect solar potato dryer. Indirect solar drying is the new technique of product drying. It is very efficient method than the direct type of solar drying. In this method the atmospheric air is heated in flat plate collector. This hot air then flow in the drying cabinet or drying chamber where potatoes slides are stored. Therefore moisture from the potatoes slides may lost by convection and diffusion. This method of drying is used to avoid direct exposing to the solar radiation. This method mainly reduces the disadvantages of direct solar drying. The experimental set up used for testing the performance of an indirect solar food dryer and determining the influence of various drying methods on the drying behavior of fresh potatoes slides. Evaluation of the dryer was centered on the moisture content reduction and temperature variations. 2 kg of fresh potatoes slides was used for evaluation. Temperatures of the drying chamber (drying cabinet), solar collector and ambient air were taken daily using digital sensors on an hourly basis from 9:00 am to 5:00 pm. Moisture content was taken at the beginning and at the end of each drying day. The test results gave temperature above 65 °C in the flat plate collector (solar collector), 50 °C in the drying cabinet, and the moisture content of 2 kg of fresh potatoes slides reduced to about 66.1% in five days of drying.