COMPARATIVE PERFORMANCE OF CORIANDER DRYER COUPLED TO SOLAR AIR HEATER AND SOLAR AIR-HEATER-CUM-ROCKBED STORAGE

In the present communication, efforts have been made to study the dryi ng characteristics of coriander in a stationary 0.5 tonne/batch capaci ty deep-bed dryer coupled to a solar air heater and a rockbed storage unit to receive hot air during sunshine and off-sunshine hours, respec tively. The drying bed was assumed to consist of a number of thin laye rs of grains stacked upon each other. The theoretical investigation wa s made by writing the energy and mass balance equations for different components of the dryer-cum-air-heater-cum-storage and by adopting a f inite difference approach for simulation. The results revealed that fo r reducing the moisture content from 28.2% (db) to 11.4% (db) the sola r air heater takes 27 cumulative sunshine hours, i.e. about 3 sunshine days, whereas the solar air heater and the rockbed storage combined t ake 31 cumulative hours, i.e. about 2 days and 2 nights at an air how velocity of 250 kg/hm(2). Copyright (C) 1996 Elsevier Science Ltd.