Design and test of a single effect thermal desalination plant using waste heat from m-CHP units

Abstract This work refers to an innovative integrated system for the simultaneous production of fresh water and electricity. In particular, a 1 kWe Stirling engine coupled with a thermal desalination plant has been considered for the purpose. The prototype, which refers to the distributed micro cogeneration field, has the final aim of building and testing a single effect distillation plant with a fresh water production of about 150 L/d. Firstly, thermodynamic theories and numerical analysis have been carried out to define the final prototype configuration. Then, an experimental test phase has been carried out to evaluate the actual plant performance. The experimental analysis has been in good agreement with the predicted results. In particular, at nominal operating conditions (@50 °C) the maximum heat transfer rate was higher than the evaporator heat exchanger designed condition (5.5 kWt). Despite the non-ideal plant thermal insulation, fresh water production reached a maximum of about 7 L/h at best operating conditions, proving a good process efficiency. According to the behavior predicted by the model, fresh water production is strongly dependent on the temperature difference between the heating fluid and the salt water in the evaporator tank while it is weakly influenced by the salt content of the treated water. Moreover, the apparatus exhibited a very good response to varying thermal power input thus confirming the opportunity to feed the desalination plant also with different forms of waste heat. More precisely, the plant average efficiency was about 1.3 L/kWh of energy input with minimum and maximum values equal to 1.16 and 1.42 L/kWh. Definitely the proposed solution, studied for a coupling with a 1 kWe Stirling engine, can be easily applied also to the other micro-CHP technologies.

[1]  Massimiliano Renzi,et al.  Study and application of a regenerative Stirling cogeneration device based on biomass combustion , 2014 .

[2]  Arthur H. Chan,et al.  Understanding the water-energy-carbon nexus in urban water utilities: Comparison of four city case studies and the relevant influencing factors , 2014 .

[3]  W. Rohsenow.  A Method of Correlating Heat-Transfer Data for Surface Boiling of Liquids , 1952, Journal of Fluids Engineering.

[4]  Saad Mekhilef,et al.  An overview of different distillation methods for small scale applications , 2011 .

[5]  Han Xu,et al.  Analysis of a 1 kW residential combined heating and power system based on solid oxide fuel cell , 2013 .

[6]  Giovanni Ciampi,et al.  Energy, environmental and economic dynamic performance assessment of different micro-cogeneration systems in a residential application , 2013 .

[7]  Massimiliano Renzi,et al.  Simulation of hybrid renewable microgeneration systems for variable electricity prices , 2014 .

[8]  S. Iniyan,et al.  A review of renewable energy based cogeneration technologies , 2011 .

[9]  Massimiliano Renzi,et al.  Modelling the Italian household sector at the municipal scale: Micro-CHP, renewables and energy efficiency , 2014 .

[10]  Hiroshi Tanaka,et al.  Experimental study of distiller with heat pipe utilizing waste heat from a portable electric generator , 2012 .

[11]  Mohammad Nurul Alam Hawlader,et al.  An experiment with a single-effect submerged vertical tube evaporator in multi-effect desalination , 2003 .

[12]  Rosenberg J. Romero,et al.  Experimental thermodynamic evaluation for a single stage heat transformer prototype build with commercial PHEs , 2015 .

[13]  Antonio Piacentino,et al.  Promotion of polygeneration for buildings applications through sector- and user-oriented “high efficiency CHP” eligibility criteria , 2014 .

[14]  J. Fisher,et al.  Is there a water-energy nexus in electricity generation? Long-term scenarios for the western United States , 2013 .

[15]  Yongping Yang,et al.  Analysis of plate multi-effect distillation system coupled with thermal power generating unit , 2014 .

[16]  A. Campos-Celador,et al.  Parametric study of the operational and economic feasibility of Stirling micro-cogeneration devices in Spain , 2014 .

[17]  J. Lienhard,et al.  Erratum to Thermophysical properties of seawater: A review of existing correlations and data , 2010 .

[18]  Chris Underwood,et al.  Simulation of energy use in buildings with multiple micro generators , 2014 .

[19]  C. Armenta-Deu.  Water distillation: a prototype to determine flow rate gains temperature and salt concentration changes in pressurised system , 2004 .

[20]  M. Biggs,et al.  Dynamic model for the optimisation of adsorption-based desalination processes , 2014 .

[21]  Carlo Roselli,et al.  Load sharing with a local thermal network fed by a microcogenerator: Thermo-economic optimization by means of dynamic simulations , 2014 .

[22]  S. N. Singh,et al.  A small scale Multi-effect Distillation (MED) unit for rural micro enterprises: Part I—design and fabrication , 2011 .

[23]  Ali M. El-Nashar,et al.  Solar barometric distillation for seawater desalting part I: Basic layout and operational/technical features , 2004 .

[24]  Conor J. Walsh,et al.  Reprint of “Desalination using low grade heat in the process industry: Challenges and perspectives” ⋆ , 2013 .

[25]  Andrea Cipollina,et al.  تحلية مياه البحر؛ سيرورات الطاقة التقليدية والمتجددة (Seawater Desalination. Conventional and Renewable Energy Processes) , 2009 .

[26]  S. N. Singh,et al.  A small scale multi-effect distillation (MED) unit for rural micro enterprises: Part-III Heat transfer aspects , 2011 .

[27]  Muhammad Wakil Shahzad,et al.  Multi effect desalination and adsorption desalination (MEDAD): A hybrid desalination method , 2014 .

[28]  Seyed Ehsan Shakib,et al.  Multi-objective optimization of a cogeneration plant for supplying given amount of power and fresh water , 2012 .

[29]  S. Nukiyama.  The maximum and minimum values of the heat Q transmitted from metal to boiling water under atmospheric pressure , 1966 .

[30]  Gavin Towler,et al.  Chemical engineering design : principles, practice, and economics of plant and process design , 2008 .

[31]  K. Youcef-Toumi,et al.  Real-time economic dispatch for the supply side of the energy-water nexus , 2014 .

[32]  Yang Shi,et al.  Combined cooling, heating and power systems: A survey , 2014 .

[33]  Noreddine Ghaffour,et al.  Technical review and evaluation of the economics of water desalination: Current and future challenges for better water supply sustainability , 2013 .

[34]  Anurag Mudgal,et al.  A small scale multi-effect distillation (MED) unit for rural micro enterprises: Part II — Parametric studies and performance analysis , 2011 .

[35]  Gabriele Comodi,et al.  Distributed generation and water production: A study for a region in central Italy , 2011 .

[36]  G. Comodi,et al.  Distributed Stirling Engines for Pipeline Corrosion Protection , 2012 .

[37]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[38]  Modelling radiative heat transfer inside a basin type solar still , 2014 .

[39]  Massimiliano Renzi,et al.  A survey of cogeneration in the Italian pulp and paper sector , 2013 .

[40]  A. Kabeel,et al.  A hybrid solar desalination system of air humidification–dehumidification and water flashing evaporation: Part I. A numerical investigation , 2014 .

[41]  Kim Choon Ng,et al.  Experimental investigation of an adsorption desalination plant using low-temperature waste heat , 2005 .

[42]  Conor J. Walsh,et al.  Desalination using low grade heat in the process industry: challenges and perspectives. , 2012 .

[43]  Y. Çengel,et al.  Thermodynamics : An Engineering Approach , 1989 .

[44]  Seyed Ehsan Shakib,et al.  Simulation and optimization of multi effect desalination coupled to a gas turbine plant with HRSG consideration , 2012 .

[45]  Amro M. Farid,et al.  Quantitative engineering systems modeling and analysis of the energy–water nexus , 2014 .

[46]  Massimiliano Renzi,et al.  Study of an innovative micro-CHP system fuelled by LPG , 2011 .

[47]  Jacobo Porteiro,et al.  Feasibility of using a Stirling engine-based micro-CHP to provide heat and electricity to a recreational sailing boat in different European ports , 2013 .