with the collaboration of Iranian Society of Mechanical Engineers (ISME)

Document Type : Research Article

Authors

Shahid Bahonar University of Kerman

Abstract

Dill is one of the most important plants in the world because of its medicinal properties and it is widely used as a vegetable in the most parts of Iran. In the present study a new solar dryer with finny, perforated absorber plate collector was utilized to dry fresh dill. The dryer was comprised of a solar collector, a product container, a fan and a drying air temperature controller. The temperature controller was used as a control system to regulate the drying air temperature. Thermal performance of the dryer with finny, perforated solar collector was compared with that of a simple flat plate solar collector at different airflow rates. The effect of drying air temperature at three levels (45, 55 and 65 °C), the product size at three lengths (3, 5 and 7 cm) and two different modes of drying (mixed and indirect) on the dryer performance was investigated. The results showed that the finny, perforated absorber plate solar collector could improve the thermal efficiency about 11% in comparison with the flat plate collector and the highest thermal efficiency was achieved at the maximum airflow rate. Meanwhile, increasing the air temperature and decreasing the product size caused a significant reduction in energy consumption. Solar fraction reduced by increasing the air temperature. Finally a maximum dryer efficiency of 70% was observed at air temperature of 65 oC, product size of 3 cm with mixed mode drying.

Keywords

1. Aghkhani, M. H., M. H. Abasspour-fard, M. R. Bayati, H. Mortezapour, S. I. Saedi, and A. Moghimi. 2013. Performance analysis of a solar dryer equipped with a recycling air system and desiccant chamber. Journal of Agricultural Machinery 3: 92-103. (In farsi).
2. Badescu, V. 2006. Optimum fin geometry in flat plate solar collector systems. Energy Conversion and Management 47: 2397-2413.
3. Banout, J., P. Ehl, J. Havlik, B. Lojka, Z. Polesny, and V. Verner. 2011. Design and performance evaluation of a Double-pass solar drier for drying of red chilli (Capsicum annum L.). Solar Energy 85: 506-515.
4. Biondi, P., L. Cicala, and G. Farina. 1988. Performance analysis of solar air heaters of conventional design. Solar Energy 41: 101-107.
5. Dadashzadeh, M., A. Zomorodian, and G. R. Mesbahi. 2008. The effect of drying airflow rates and modes of drying on moisture content reduction for Grapes in a cabinet type solar dryer. Journal of Agricultural Science and Technology 22: 23-34.
6. Dubey, S., S. C. Solanki, and A. Tiwari. 2009. Energy and exergy analysis of PV/T air collectors connected in series. Energy and Buildings 41: 863-870.
7. Duffie, J. A., and W. A. Beckman. 2013. Solar engineering of thermal processes. John Wiley & Sons.
8. Ekechukwu, O. V., and B. Norton. 1999. Review of solar-energy drying systems II: an overview of solar drying technology. Energy Conversion and Management 40: 615-655.
9. Fudholi, A., K. Sopian, M. Y. Othman, M. H. Ruslan, and B. Bakhtyar. 2013. Energy analysis and improvement potential of finned double-pass solar collector. Energy Conversion and Management 75: 234-240.
10. Harmim, A., M. Belhamel, M. Boukar, and M. Amar. 2010. Experimental investigation of a box-type solar cooker with a finned absorber plate. Energy 35: 3799-3802.
11. Ho, C. D., and T. C. Chen. 2008. Collector efficiency improvement of recyclic double-pass sheet-and-tube solar water heaters with internal fins attached. Renewable Energy 33: 655-664.
12. Krokida, M. K., V. T. Karathanos, Z. B. Maroulis, and D. Marinos-Kouris. 2003. Drying kinetics of some vegetables. Journal of Food Engineering 59: 391-403.
13. Liang, R., L. Ma, J. Zhang, and L. Zhao. 2013. Performance analysis of a new-design filled-type solar collector with double U-tubes. Energy and Buildings 57: 220-226.
14. Mahapatra, A., and L. Imre. 1990. Role of solar agricultural-drying in developing countries. International Journal of Ambient Energy 11: 205-210.
15. Montero, I., J. Blanco, T. Miranda, S. Rojas, and A. R. Celma. 2010. Design, construction and performance testing of a solar dryer for agroindustrial by-products. Energy Conversion and Management 51: 1510-1521.
16. Mortezapour, H., B. Ghobadian, S. Minaei, and M. H. Khoshtaghaza. 2012. Saffron drying with a heat pump–assisted hybrid photovoltaic–thermal solar dryer. Drying Technology 30: 560-566.
17. Motevali, A., S. Minaei, M. H. Khoshtaghaza, and H. Amirnejat. 2011. Comparison of energy consumption and specific energy requirements of different methods for drying mushroom slices. Energy 36: 6433-6441.
18. Omara, Z. M., M. H. Hamed, and A. E. Kabeel. 2011. Performance of finned and corrugated absorbers solar stills under Egyptian conditions. Desalination 277: 281-287.
19. Othman, M. Y., B. Yatim, K. Sopian, and M. N. Abu Bakar. 2007. Performance studies on a finned double-pass photovoltaic-thermal (PV/T) solar collector. Desalination 209: 43-49.
20. Pal, U., and M. K. Khan. 2008. Calculation steps for the design of different components of heat pump dryers under constant drying rate condition. Drying technology 26: 864-872.
21. Ramani, B. M., A. Gupta, and R. Kumar. 2010. Performance of a double pass solar air collector. Solar Energy 84: 1929-1937.
22. Sarhaddi, F., S. Farahat, H. Ajam, A. Behzadmehr, and M. Mahdavi Adeli. 2010. An improved thermal and electrical model for a solar photovoltaic thermal (PV/T) air collector. Applied Energy 87: 2328-2339.
23. Setayesh-Mehr, Z., and A. Ganjeali. 2013. Effects of drought stress on growth and physiological characteristics of dill (Anethum graveolens L.). Journal of Horticulture Science 27: 27-35.
24. Stiling, J., S. Li, P. Stroeve, J. Thompson, B. Mjawa, K. Kornbluth, and D. M. Barrett. 2012. Performance evaluation of an enhanced fruit solar dryer using concentrating panels. Energy for Sustainable Development 16: 224-230.
25. Toğrul, İ. T., and D. Pehlivan. 2002. Mathematical modelling of solar drying of apricots in thin layers. Journal of Food Engineering 55: 209-216.
26. Yeh, H. M., C. D. Ho, and J. Z. Hou. 2002. Collector efficiency of double-flow solar air heaters with fins attached. Energy 27: 715-727.
27. Zomorodian, A., and M. Barati. 2010. Efficient solar air heater with perforated absorber for crop drying. Journal of Agricultural Science and Technology 12: 569-577.
CAPTCHA Image