Experimental and Comparison Studies on Drying Characteristics of Grapes in a Solar Tunnel Greenhouse Dryer and in the Open Sun Drying Method
S. Arun1, K. Vinoth Kumar2, R. Adharsh3
1S. Arun, Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi, India.
2K. Vinoth Kumar, Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi, India.
3R. Adharsh, Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi, India.
Manuscript received on October 03, 2014. | Revised Manuscript received on October 09, 2014. | Manuscript published on October 15, 2014. | PP: 31-35 | Volume-2 Issue-11, October 2014. | Retrieval Number: K07341021114/2014©BEIESP
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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: A natural convection solar tunnel greenhouse dryer was designed and developed in Pollachi region of Tamil Nadu (India) for studying and comparing the drying characteristics of grapes with the open sun drying method during the month of April, 2014. About 30 kgs of grapes were loaded into the dryer and it was repeated for three trails. The drying time and product quality were the main drying parameters which are taken into account. The grapes which has an initial moisture content of 80% was reduced to 10% in solar tunnel greenhouse dryer over a time period of 55 hours whereas the grapes dried in the open sun drying method took 149 hours for the reducing the moisture content of the grapes to the same level. The high temperature and low relative humidity inside the solar tunnel greenhouse dryer helps the dryer to dry the grapes at an earlier time than the open sun method. Also, the greenhouse effect is responsible for the high temperature and low relative humidity inside the dryer that prevents fungal and bacterial infections, damage by birds and animals, etc. which ensures the production of superior quality of grapes in the dryer than in the open sun drying method.
Keywords: Drying time, grapes, moisture content, open sun drying, product quality, solar tunnel greenhouse dryer.