An experimental study of a heat pipe evacuated tube solar dryer with heat recovery system

The current study designed, constructed and experimentally evaluated a heat-pipe evacuated tube solar dryer with heat a recovery system in which water was used as working and recovery fluid in the solar and dryer loops, respectively, and air was used as intermediate fluid in the dryer section. The heat recovery system was used to enhance the overall efficiency of the system and to make maximum use of solar energy intake of the dryer. The hot water in the storage tank, which is heated by the solar loop, is sent to the dryer, depending on the system requirement, and its heat in the heat exchanger is delivered to the blown air. The heated air enters the main chamber of dryer, where the drying products exist. This system was tested in the weather conditions of Sanandaj city and the obtained results indicated the effectiveness of heat recovery system. In volumetric flow rate of 0.0328 m3/s, the maximum outlet air temperature of dryer was approximately 44.3 °C. At the end of the day, the exergetic efficiency of the system reaches its maximum rate, approximately 11.7%. Using regression analysis, the most accurate equation for expressing the effectiveness of dryer was obtained.

[1]  G. N. Tiwari,et al.  Analytical studies of crop drying cum water heating system , 1997 .

[2]  Kamal Abdel Radi Ismail,et al.  Performance of a Heat Pipe Solar Collector , 1998 .

[3]  Surendra Kothari,et al.  State of the art of solar cooking: An overview , 2012 .

[4]  R.H.B. Exell,et al.  Solar rice /dryer , 1978 .

[5]  Bukola Olalekan Bolaji,et al.  PERFORMANCE EVALUATION OF A MIXED MODE SOLAR DRYER , 2008 .

[6]  A. El-beltagy,et al.  Solar drying characteristics of strawberry , 2007 .

[7]  T. Abe,et al.  THIN LAYER SOLAR DRYING CHARACTERISTICS OF ROUGH RICE UNDER NATURAL CONVECTION , 2001 .

[8]  Anil Kumar,et al.  Applications of software in solar drying systems: A review , 2015 .

[9]  Saad Mekhilef,et al.  Performance study of different solar dryers: A review , 2014 .

[10]  Yan Su-ying.  Comparative analysis of the instantaneous efficiency about two types of solar collector , 2009 .

[11]  Varun,et al.  Construction and Performance Analysis of an Indirect Solar Dryer Integrated with Solar Air Heater , 2012 .

[12]  D. Jain,et al.  Thermal aspects of open sun drying of various crops , 2003 .

[13]  J. P. Holman,et al.  Experimental methods for engineers , 1971 .

[14]  Satya Narayan Naik,et al.  Solar dryer with thermal energy storage systems for drying agricultural food products: A review , 2010 .

[15]  V. Sharma,et al.  Experimental performance of an indirect type solar fruit and vegetable dryer , 1993 .

[16]  A. Zomorodian,et al.  Optimization and evaluation of a semi-continuous solar dryer for cereals (Rice, etc) , 2007 .

[17]  Abdul Jabbar N. Khalifa,et al.  Testing of the performance of a fruit and vegetable solar drying system in Iraq , 2007 .

[18]  Werner Hofacker,et al.  Die Kaltlufttrocknung von Weizen unter energetischem und mikrobiologischem Aspekt , 2013 .

[19]  P. Barnwal,et al.  Grape drying by using hybrid photovoltaic-thermal (PV/T) greenhouse dryer: An experimental study , 2008 .

[20]  Ahmet Can,et al.  Drying kinetics of pumpkinseeds , 2000 .

[21]  R. Petela.  Exergy of undiluted thermal radiation , 2003 .

[22]  Somchart Soponronnarit,et al.  Closed-ended oscillating heat-pipe (CEOHP) air-preheater for energy thrift in a dryer , 2005 .

[23]  W. Mühlbauer,et al.  SOLAR DRYING OF GRAPES , 1985 .

[24]  Arif Hepbasli,et al.  Exergetic modeling and performance evaluation of solar water heating systems for building applications , 2007 .

[25]  Pankaj Khatak,et al.  Progress in solar dryers for drying various commodities , 2016 .

[26]  D. Kadam,et al.  Convective Flat-plate Solar Heat Collector for Cauliflower Drying , 2006 .

[27]  Fatih Koçyiğit,et al.  Energy and exergy analysis of a new flat-plate solar air heater having different obstacles on absorber plates , 2010 .