Natural convection solar dryer with biomass back up heater / Mohamed Yasser Mohamed Desa and Azriizwandy Abdul Kadir

A direct type natural convection solar dryer and a simple biomass burner have been combined to demonstrate a drying technology suitable for small-scale processors of dried fruits and vegetable in non-electrified areas of developing countries. From a series of evaluation trials of the system, the capacity of the dryer was found to be 2-3 kg of fresh pineapple arranged in a single layer of 0.01 m thick slices. During the same trail, the drying efficiency of the solar component alone was found to be 20.8%. Key features of the biomass burner were found to be the addition of thermal mass on the upper surface, an internal baffle plate to lengthen the exhaust gas exit path. Further modification to further improves the performance of both the solar and biomass components of the dryer are suggested.