Vol. 12, Issue 12 (2023)

Author(s):
P Vijayakumary, SA Ramjani, J Gitanjali, R Parimala Devi, K Chandrakumar and D Ramesh

Abstract:
Drying plays an important role in processing and preservation of agricultural produce. Drying avoids the growth of microorganisms thereby retains the quality and enhance the shelf life of the products. In this research work an evacuated tube collector (ETC) solar dryer is designed and developed for drying seedless grapes. The collector and dryer are designed based on the sample size, i.e. 5 kg of the grapes and on the criteria of collector surface to volume of dryer ratio. Performance analysis of this system is done on analytical and experimental basis. During the experiment, temperatures of hot and cold air at various places, ambient relative humidity and humidity variation in drying chamber, wind velocity and mass of the grapes are measured throughout the tests on an hourly basis. Average thermal efficiency of the air heating system was found to be 31 percent. The desired moisture content of 20% from an initial moisture content of 80% of grapes was reached within 7 days when dried using evacuated tube solar air collector compared to 20-22 days in open sun drying method.