Experimental and Comparison Studies on Drying Characteristics of Red Chillies in a Solar Tunnel Greenhouse Dryer Coupled with and without Biomass Backup Heater
S. Arun1, N. Yashwanth2
1S. Arun, Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi, India.
2N. Yashwanth, Department of Mechanical Engineering, Easwari Engineering College, Chennai, India.
Manuscript received on October 15, 2014. | Revised Manuscript received on October 22, 2014. | Manuscript published on October 25, 2014. | PP:22-28 | Volume-2 Issue-12, October 2014. | Retrieval Number: L08301021214/2014©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 coupled with biomass heater was designed and developed in Nallampalli region of Pollachi, Tamil Nadu (India) and also a natural convection solar tunnel greenhouse dryer without biomass heater was designed and developed in Negamam region of Pollachi, Tamil Nadu (India) for carrying out the experimental and comparison studies of drying characteristics of red chillies during the month of May, 2014. Three experimental runs with about 50kgs of fresh and good quality red chillies were loaded into those two respective dryers. The mass of fuel added to the biomass heater was about 7.5kg/hr. The biomass was ignited for every one hour after 5PM so as to maintain a high temperature inside the dryer. The solar tunnel dryer coupled with the biomass heater dried the red chillies which has an initial moisture content of 72.98% (w.b.) to a final moisture content of 7.5% (w.b.) over a time period of 30 hours whereas the solar tunnel greenhouse dryer without the biomass heater took 56 hours for reducing the moisture content to the same level. The biomass heater is responsible for supplying sufficient heat inside the dryer to maintain a high temperature steadily inside the dryer even during the times when there would be a drop in sunshine (after 5PM). This high temperature and low relative humidity inside the dryer (with biomass heater) accelerated the drying of red chillies which thereby reduces drying time of the red chillies. Also the quality of the red chillies obtained from the solar tunnel greenhouse dryer coupled with biomass heater was found to be superior to that of the red chillies obtained from the solar tunnel greenhouse dryer without the biomass heater which is due to the high temperature and low relative humidity prevailed all the time inside the dryer irrespective of fall in sunshine that prevented the effect of fungal and bacterial infections, damage from birds and animals and windborne problems like dust & dirt.
Keywords: Biomass heater, drying time, moisture content, open sun drying, product quality, red chillies, solar tunnel greenhouse dryer, sunshine.