Comparative energy and exergy performance assessments of a microcogenerator unit in different electricity mix scenarios

Abstract The Directive 2004/8/EC on the promotion of cogeneration proposes a comparative indicator based on primary energy savings, neglecting some important thermodynamic aspects, such as exergy. This study aims to compare and discuss the usefulness of a set of complementary indicators for performance assessments of cogeneration systems, concerning thermodynamic principles based on first and second law (the exergy approach). As case study, a 6 kW electric output micro-combined heat and power unit was experimentally tested and a model of the unit was developed in TRNSYS. Considering as reference a set of different heat and electricity scenarios, including the actual electric mixes of Portugal and Italy, the indicators case incon (PES) and Primary and Total Irreversibilities Savings (PIS and TIS), as well as energy and exergy renewability ratios were assessed and discussed. The results show that the use of MCHP has higher advantages for the Italian electric grid, than an equivalent scenario considering the Portuguese electric network as reference. As result, for a particular scenario analysed, PES and PIS have 3% and 6% for Portugal, and 10% and 18% for Italy, respectively. Furthermore, for one particular scenario evaluated, the indicators energetic and exergetic renewability ratios have 23% and 14%, respectively for the Portuguese electric grid, and 19% and 10% for the Italian electric system.

[1]  Linda Barelli,et al.  An energetic–exergetic analysis of a residential CHP system based on PEM fuel cell , 2011 .

[2]  Carlo Roselli,et al.  Experimental analysis on the dehumidification and thermal performance of a desiccant wheel , 2012 .

[3]  Ibrahim Dincer,et al.  Exergy analysis of two geothermal district heating systems for building applications , 2007 .

[4]  Carlo Roselli,et al.  Experimental investigation to optimise a desiccant HVAC system coupled to a small size cogenerator , 2011 .

[5]  Onder Ozgener,et al.  Monitoring of energy exergy efficiencies and exergoeconomic parameters of geothermal district heating systems (GDHSs) , 2009 .

[6]  D Mertens,et al.  Micro-CHP systems for residential applications , 2006 .

[7]  Z. Lavan,et al.  Second Law Analysis of Desiccant Cooling Systems , 1982 .

[8]  Mehmet Kanoglu,et al.  First and second law analysis of diesel engine powered cogeneration systems , 2008 .

[9]  Svein J. Nesheim,et al.  Efficiencies and indicators defined to promote combined heat and power , 2007 .

[10]  Carlo Roselli,et al.  Experimental validation of constant efficiency models for the subsystems of an unconventional desiccant-based Air Handling Unit and investigation of its performance , 2012 .

[11]  Carlo Roselli,et al.  Experimental analysis of micro-cogeneration units based on reciprocating internal combustion engine , 2006 .

[12]  Ibrahim Dincer,et al.  Understanding energy and exergy efficiencies for improved energy management in power plants , 2007 .

[13]  Viktor Dorer,et al.  Energy and CO2 emissions performance assessment of residential micro-cogeneration systems with dynamic whole-building simulation programs , 2009 .

[14]  A. Bejan.  Advanced Engineering Thermodynamics , 1988 .

[15]  S. P. Lohani,et al.  Comparison of energy and exergy analysis of fossil plant, ground and air source heat pump building heating system , 2010 .

[16]  Christos A. Frangopoulos,et al.  A method to determine the power to heat ratio, the cogenerated electricity and the primary energy savings of cogeneration systems after the European Directive , 2012 .

[17]  S. C. Kaushik,et al.  Exergy analysis and investigation for various feed water heaters of direct steam generation solar–thermal power plant , 2010 .

[18]  Ivar S. Ertesvåg,et al.  Exergetic comparison of efficiency indicators for combined heat and power (CHP) , 2007 .

[19]  Antonio Rosato,et al.  Calibration and validation of a model for simulating thermal and electric performance of an internal combustion engine-based micro-cogeneration device , 2012 .

[20]  Joseph Andrew Clarke,et al.  Developing and testing a generic micro-combined heat and power model for simulations of dwellings and highly distributed power systems , 2008 .

[21]  Adélio Rodrigues Gaspar,et al.  Energy and exergy-based indicators for the energy performance assessment of a hotel building , 2012 .

[22]  Borong Lin,et al.  Renewable energy utilization evaluation method in green buildings , 2008 .

[23]  Ibrahim Dincer,et al.  New energy and exergy parameters for geothermal district heating systems , 2009 .

[24]  Laura Vanoli,et al.  Micro-combined heat and power in residential and light commercial applications , 2003 .

[25]  Ibrahim Dincer,et al.  PERFORMANCE ASSESSMENT OF COGENERATION PLANTS , 2009 .

[26]  S. Lu,et al.  Optimal selection among different domestic energy consumption patterns based on energy and exergy analysis , 2010 .

[27]  Hüseyin Benli,et al.  Experimentally derived efficiency and exergy analysis of a new solar air heater having different surface shapes , 2013 .

[28]  Peter Tzscheutschler,et al.  Experimental analysis of microcogenerators based on different prime movers , 2011 .

[29]  Ibrahim Dincer,et al.  Exergoeconomic analysis of the Gonen geothermal district heating system for buildings , 2009 .

[30]  Carlo Roselli,et al.  Distributed microtrigeneration systems , 2012 .

[31]  S. Ferreira,et al.  Transposition of the EU cogeneration directive: A vision for Portugal , 2007 .

[32]  Pascal Stouffs,et al.  Energy, exergy and cost analysis of a micro-cogeneration system based on an Ericsson engine , 2005 .

[33]  Carlo Roselli,et al.  Desiccant HVAC system driven by a micro-CHP: Experimental analysis , 2010 .

[34]  Mehmet Kanoglu,et al.  Energy and exergy analyses of an experimental open-cycle desiccant cooling system. , 2004 .

[35]  K. Wark,et al.  Advanced thermodynamics for engineers , 1994 .

[36]  Ibrahim Dincer,et al.  Efficiency analysis of a cogeneration and district energy system , 2005 .

[37]  Arif Hepbasli,et al.  Exergetic modeling and experimental performance assessment of a novel desiccant cooling system , 2011 .

[38]  Carlo Roselli,et al.  Desiccant wheel regenerated by thermal energy from a microcogenerator: Experimental assessment of the performances , 2011 .

[39]  H. Torio,et al.  Framework for analysis of solar energy systems in the built environment from an exergy perspective , 2010 .

[40]  C Roselli,et al.  An Experimental and Simulation-Based Investigation of the Performance of Small-Scale Fuel Cell and Combustion-Based Cogeneration Devices Serving Residential Buildings , 2008 .

[41]  Carlo Roselli,et al.  Effect of rotational speed on the performances of a desiccant wheel , 2013 .