Exergy analysis of a solar-powered vacuum membrane distillation unit using two models

A detailed exergy analysis of a solar powered VMD unit was performed using two models: the ideal mixture model and the model using the thermodynamics properties of seawater. The exergy flow rates of process steam, given by the two models differed of about 18%, on average. Despite these differences, the two models agree that during the step of condensation, the most important fraction of exergy was destroyed. Moreover, in this work, two forms of exergy efficiency are calculated. The overall exergy efficiency of the unit with reference to the exergy collected by the solar collector was 3.25% and 2.30% according to Cerci and Sharqawy models, respectively. But, it was 0.182% and 0.128%, when referenced to the exergy of solar radiation, according to Cerci and Sharqawy models, respectively. Besides, the utilitarian exergy efficiency was 9.96%. Since the heat exchanger, the hollow-fiber module and the condenser have a very high exergy performance, then it can be concluded that the enhancement or reduction of exergy losses will be mainly by recovering heat lost in brine discharges and in the rejection of the cooling water. In addition, the influence of the rejection rate on exergy efficiencies was studied.

[1]  Arif Hepbasli,et al.  A key review on present status and future directions of solar energy studies and applications in Saudi Arabia , 2011 .

[2]  Enrico Drioli,et al.  Energetic and exergetic analysis of an integrated membrane desalination system , 1999 .

[3]  Lorna Fitzsimons,et al.  Exergy analysis of water purification and desalination: a study of exergy model approaches. , 2015 .

[4]  Antonio Valero,et al.  Physical Hydronomics: application of the exergy analysis to the assessment of environmental costs of water bodies. The case of the inland basins of Catalonia. , 2009 .

[5]  Slimane Gabsi,et al.  Design of an autonomous solar desalination plant using vacuum membrane distillation, the MEDINA project , 2013 .

[6]  John H. Lienhard,et al.  On exergy calculations of seawater with applications in desalination systems , 2010 .

[7]  S. C. Kaushik,et al.  Energy, exergy and thermo-economic analysis of solar distillation systems: A review , 2013 .

[8]  Guohong Tian,et al.  Exergy efficiency enhancement of MSF desalination by heat recovery from hot distillate water stages , 2013 .

[9]  H. Mehdizadeh,et al.  Membrane desalination plants from an energy–exergy viewpoint , 2006 .

[10]  Cong-zhuo Jin,et al.  Vapour Compression Flash seawater desalination system and its exergy analysis , 2014 .

[11]  N. Hilal,et al.  Membrane distillation: A comprehensive review , 2012 .

[12]  Xiaochang C. Wang,et al.  Development of a method for calculating the entropy increase from organic oxidation in water environment through self-purification , 2016 .

[13]  Kamel Hooman,et al.  Optimised exergy efficiency of a combined flash spray desalinator recovering discharge thermal energy , 2016 .

[14]  G. Tsatsaronis.  Definitions and nomenclature in exergy analysis and exergoeconomics , 2007 .

[15]  Antonio Piacentino,et al.  Advanced energetics of a Multiple Effects Evaporation (MEE) desalination plant: Part I: 2nd principle analysis by a zooming representation at single-effect level , 2010 .

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

[17]  E. Drioli,et al.  Potential of membrane distillation in seawater desalination: Thermal efficiency, sensitivity study and cost estimation , 2008 .

[18]  Hassan E.S. Fath,et al.  Thermo-economic investigation of multi effect evaporation (MEE) and hybrid multi effect evaporation—multi stage flash (MEE-MSF) systems , 2006 .

[19]  Iman Janghorban Esfahani,et al.  Evaluation and optimization of a multi-effect evaporation–absorption heat pump desalination based conventional and advanced exergy and exergoeconomic analyses , 2015 .

[20]  José Carlos Romero,et al.  Exergy as a global energy sustainability indicator. A review of the state of the art , 2014 .

[21]  Enrico Drioli,et al.  Integrated membrane systems for seawater desalination: energetic and exergetic analysis, economic evaluation, experimental study , 2007 .

[22]  Nafiz Kahraman,et al.  Exergy analysis of a combined RO, NF, and EDR desalination plant , 2005 .

[23]  Enrico Drioli,et al.  An exergetic analysis of a membrane desalination system , 2010 .

[24]  Yunus Cerci,et al.  The minimum work requirement for distillation processes , 2000 .

[25]  Lourdes García-Rodríguez,et al.  Exergy analysis of the SOL-14 plant (Plataforma Solar de Almería, Spain) , 2001 .

[26]  Fawzi Banat,et al.  Exergy analysis of desalination by solar-powered membrane distillation units , 2008 .

[27]  Bernard Desmet,et al.  Energetic and exergetic analysis of a triple-effect distiller driven by solar energy , 2005 .

[28]  Slimane Gabsi,et al.  Simulation of solar vacuum membrane distillation unit , 2013 .

[29]  T. Mohammadi,et al.  Analysis of heat and mass transfer in vacuum membrane distillation for water desalination using computational fluid dynamics (CFD) , 2015 .

[30]  Noam Lior,et al.  Energy, exergy, and Second Law performance criteria , 2007 .

[31]  Ibrahim Dincer,et al.  Role of exergy in increasing efficiency and sustainability and reducing environmental impact , 2008 .

[32]  Rahman Saidur,et al.  Exergy analysis of solar energy applications , 2012 .

[33]  Slimane Gabsi,et al.  Simulation of an autonomous solar vacuum membrane distillation for seawater desalination , 2014 .

[34]  Alicia Valero,et al.  Environmental costs of a river watershed within the European water framework directive: Results from physical hydronomics , 2010 .

[35]  Javier Uche,et al.  Chemical exergy assessment of organic matter in a water flow , 2010 .

[36]  Ibrahim Dincer,et al.  A solar desalination system: Exergetic performance assessment , 2015 .

[37]  S. Ji,et al.  Review of thermal efficiency and heat recycling in membrane distillation processes , 2015 .

[38]  Sanjeev Jakhar,et al.  Second law thermodynamic study of solar assisted distillation system: A review , 2016 .

[39]  Noam Lior,et al.  Critical review of membrane distillation performance criteria , 2016 .

[40]  A. S. Nafey,et al.  Exergy and thermo-economic analyses of a combined solar organic cycle with multi effect distillation (MED) desalination process , 2011 .

[41]  Nafiz Kahraman,et al.  Exergy analysis of a MSF distillation plant , 2005 .