An Experimental Studyon Mixed Mode Solar Dryer with Heat Storage Materials

  • Premkumar S. Department of Mechanical Engineering, SDMIT, Ujire Karnataka, India. (Research Scholar of VTU, Belagavi, Karnataka India)
Keywords: solar dryers, mixed mode solar dryers, heat storage materials


Solar drying is one of the important techniques which are drawing more attention in the recent years. The use of solar dryer helps to preserve the product for a longer time. The present paper focuses on the development of such a technique. In this study, a mixed mode solar dryer with heat storage materials (Pebbles) is developed.  4 kg chillies were used as drying product and experiments were conducted for the metrological conditions of Ujire, Karnataka, India. Design and fabrication of the developed drying system is explained in this paper. The analysis is carried out for its performance is also focused. The obtained results are discussed in detail. Air flow rate maintained was 4 m/s, maximum drying rate obtained was 5.5 grams/min and 4.78 grams /min for upper and lower tray. The results indicate that the upper tray showed better performance than lower tray. Maximum value of overall thermal efficiency of developed drying system was 36.69 %. Use of heat storage materials increases the temperature of incoming atmospheric air so that relative humidity decreases and this increases moisture extraction ability of air. Use heat storage materials also helps to sustain the sudden variation in air temperature at inlet of the dryer cabin.


[1]. D. Jain and G. N. Tiwari, Thermal aspects of open sun drying of various crops, Centre of energy studies, Indian Institute ofTechnology, New Delhi.
[2]. P Garg and J Prakash, Solar Energy, 1st Revised ed. TATA McGraw-Hill Publishing Company Limited, New Delhi, p.191.
[3]. B.A. Ezekoye and O.M. Enebe, Development and performance Evaluation of Modified Integrated Passive Solar Grain Dryer, The Pacific Journal of Science And Technology, Vol-7, No-2.
[4]. A. F. Aloge and R. O. Hammed, Adirect passive solar dryer for tropical crops, African Crop Science Conference, Vol. 8.pp.1643-1646.
[5]. S.H. Senger et al, Low Cost Solar Dryer for Fish, African Journal of Environmental Science and Technology, Vol-3, PP.265-271.
[6]. EHL. P et al, Post Harvesting of Selected Tropical Crops Using a Natural Circulation Solar Dryer, Agricultural Tropical EtSubtropical, Vol-43 (2) 2010.
[7].Prem kumar et al,A Review of the Recent Developments on Solar Dryers, International Journal OF Engineering Sciences &Management Research, ISSN 2349-6193.
[8]. Visavale, G.L., Principles, Classification and Selection of Solar Dryers. In Solar drying: Fundamentals,Applications and Innovations, Ed. Hii, C.L., Ong, S.P., Jangam, S.V. and Mujumdar, A.S.,2012, ISBN - 978-981-07-3336-0, Published in Singapore, pp. 1-50.
[9].M.Mohanraj and P.Chandrashekhar,performance of a forced convection solar Drier integrated with gravel as heat storage Material for chilli drying, Journal of Engineering Science and Technology Vol. 4, No. 3 (2009) 305 – 314,School of Engineering, Taylor’s University College
[10]. S. M. Shalaby, Effect of Using Energy Storage Material in an Indirect-mode Forced Convection Solar Dryer on the Drying Characteristics of Grapes, Journal of Medical and Bioengineering (JOMB) Vol. 1, No. 1, September 2012.
[11]. A.R. Umayal Sundari, et al, Performance of Evacuated Tube Collector Solar Dryer with and Without Heat Sources, Iranica Journal of Energy & Environment 4 (4): 336-342, 2013, Energy & Environment 4 (4): 336-342, 2013, ISSN 2079-2115.
[12]. Bukola O. Bolaji and Ayoola P. Olalusi, Performance Evaluation of a Mixed-Mode Solar Dryer, Technical Report, AU J.T. 11(4): 225-231.
[13]. Premkumar and Dr.E.S. Prakash, Study on Solar Dryer Coupled With FPC, Proc. Of 1st National Conference on Trends and Innovations in Automation, Materials and Thermal Engineering (TIAMTE-2015).
[14]. Mehdi Moradi and Ali Zomorodian, Thin Layer Solar Drying of Cyminum Grains by Means of Solar Cabinet Dryer, American- Eurasian J, Agric& Environ. Sci., 5(3): 409-413, 2009.
[15]. Ahmed Abed Gatea, Design and construction of a drying system, a cylindrical section and analysis of the performance of thermal drying system, African journal of Agricultural Research Vol. 6(2), pp. 343-351, 18 January, 2011
[16]. Francis kofi forson, modelling and experimental Investigation of a mixed-mode Natural convection solar Crop dryer, ph.d thesis De Montfort university, Leicester.
[17] M. S. Sevda and N. S. Rathore, Performance evaluation of the semi cylindrical solar tunnel dryer for drying handmade paper, J.Renewable Sustainable Energy 2, 013107 (2010); doi: 10. 1063/1. 3302139.
[18]. S. Sadodin, T. T. Kashani, Numerical Investigation of a Solar Tunnel Drier for Drying of Copra, ISESCO JOURNAL of Science and Technology, Vol-7, No. -12.
[19]15. BukolaOllalekanBolaji, Exergetic Analysis of Solar Energy Drying Stsyems, 2011,2 92-97.
[20]. Visavale, G.L., Principles, Classification and Selection of Solar Dryers. In Solar drying: Fundamentals, Applications and Innovations (2012)
[21] Francis kofi forson, modelling and experimental Investigation of a mixed-mode Natural convection solar Crop dryer, ph.d thesis De Montfort university, Leicester.
[22]Solar energy, S.P Sukhathme and J K Nayak, Third edition,Tata Mcgraw Hill publications, New Delhi, India.
[23] Premkumar et a.,An Experimental Study to Select Optimum Heat Storage Materials Bed Thickness and Optimum Air Velocity for a Designed Solar Dryer, Journal of Engineering Research and Application, ISSN : 2248-9622, PP 47-51.