Search results for " exergy"

showing 10 items of 27 documents

Ecological indicators – Schrödinger Ratio

2008

Biomass Entropy Entropy production Exergy Eutrophication Lake ecosystems Negentropy Nonequilibrium systems Phytoplankton RespirationEntropyRespirationPhytoplanktonLake ecosystemsBiomassExergyEutrophicationNegentropyEntropy productionNonequilibrium systems
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Exergy analysis of electrodialysis for water desalination: Influence of irreversibility sources

2022

The increasing freshwater demand is pushing the development and adoption of desalination technologies. In this framework, electrodialysis has a consolidated role in brackish water desalination, but to make it competitive with other technologies for the desalination of more concentrated solutions (e.g., seawater), the specific energy consumption should be reduced. Exergy analysis provides a useful tool for determining the contribution of each thermodynamic inefficiencies on the process efficiency and the specific energy consumption. In this regard, this paper presents an exergy analysis of the electrodialysis process. A 1-D model is used for evaluating the performance of industrial-scale sys…

Desalination Electrodialysis Exergy analysis Chemical exergy Irreversibility Specific energy consumptionSettore ING-IND/26 - Teoria Dello Sviluppo Dei Processi ChimiciExergy analysisIrreversibilityFuel TechnologyNuclear Energy and EngineeringRenewable Energy Sustainability and the EnvironmentDesalinationSettore ING-IND/10 - Fisica Tecnica IndustrialeEnergy Engineering and Power TechnologyElectrodialysisSpecific energy consumptionChemical exergy
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Zooming on the exergetic cost formation process of a Multiple-Effects-Evaporation (MEE) desalination plant

2009

In this paper an advanced energetic and thermoeconomic analysis of a Multiple Effect Evaporation (MEE) process is proposed. Starting from the thermochemical fundamentals of desalination processes, a minimum theoretical work of separation is introduced, to be used as reference condition to assess the efficiency of desalination units. The attention is then focused on a forward feed MEE configuration; by abandoning the usual perspective oriented to analyse the system at an “overall plant” level, a zooming strategy is proposed to understand in depth the margins for systems’ improvement. Focusing on a single effect, different subprocesses and their mutual interactions are correctly recognized to…

Desalination exergy saving thermoeconomics cost brine
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Exergy analysis and thermoeconomic cost accounting of a CHP steam cycle integrated with MED-TVC desalination

2016

In this paper exergy analysis and thermoeconomic cost accounting of a CHP steam cycle integrated with MED-TVC plant is performed; the purpose is to show how this methodology provides a rational criterion to allocate production costs on electricity and freshwater. After a brief overview on methodology and a description of reference plant, exergy analysis is carried out in order to calculate exergy flows and plant exergetic performance. A detailed description of the adopted thermoeconomic model is given. Cost accounting is performed considering two scenarios: in the first, the concentrated brine is disposed back to sea, thus being its exergy content definitively wasted; in the second, convers…

Desalination multiple effect evaporation thermal vapour compression dual purpose plant exergy thermoeconomic cost cost accounting reverse electrodialysisSettore ING-IND/26 - Teoria Dello Sviluppo Dei Processi ChimiciSettore ING-IND/10 - Fisica Tecnica Industriale
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On Thermoeconomic Diagnosis of a Fouled Direct Expansion Coil: Effects of Induced Malfunctions on Quantitative Performance of the Diagnostic Technique

2017

Thermoeconomic diagnosis represents a promising technique for the detection of common faults in refrigeration systems, which are responsible of degradation in their energetic performance. Recently, the authors have carried out a sensitivity analysis of the performance of this method to the thermodynamic conditions of inlet air and to the geometry of the direct expansion coil, in case of degradation induced by evaporator fouling. The analysis showed that the method is able to detect this fault, but sometimes its quantitative assessments are not satisfactory. In order to understand more in-depth the origin of such results and identify margins for refinement of the technique, this paper is aim…

EngineeringEngineering drawingThermoeconomic diagnosis;Evaporator fouling;Direct expansion coil;Exergy;Malfunction cost;Fuel impact;Induced malfunction;Intrinsic malfunction020209 energyEnergy Engineering and Power TechnologyMechanical engineering02 engineering and technologyEnvironmental Science (miscellaneous)lcsh:Technologylcsh:HD72-88lcsh:Economic growth development planningFuel impactThermoeconomic diagnosisThermoeconomic diagnosis Evaporator fouling Direct expansion coil Exergy Malfunction cost Fuel impact Induced malfunction Intrinsic malfunctionSettore ING-IND/10 - Fisica Tecnica Industriale0202 electrical engineering electronic engineering information engineeringInduced malfunctionExergyWater Science and TechnologyRenewable Energy Sustainability and the Environmentbusiness.industryDirect expansion coillcsh:TIntrinsic malfunction.Electromagnetic coilEvaporator foulingMalfunction costbusinessJournal of Sustainable Development of Energy, Water and Environment Systems
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Assessing the Robustness of Thermoeconomic Diagnosis of Fouled Evaporators: Sensitivity Analysis of the Exergetic Performance of Direct Expansion Coi…

2016

Thermoeconomic diagnosis of refrigeration systems is a pioneering approach to the diagnosis of malfunctions, which has been recently proven to achieve good performances for the detection of specific faults. Being an exergy-based diagnostic technique, its performance is influenced by the trends of exergy functions in the “design” and “abnormal” conditions. In this paper the sensitivity of performance of thermoeconomic diagnosis in detecting a fouled direct expansion coil and quantifying the additional consumption it induces is investigated; this fault is critical due to the simultaneous air cooling and dehumidification occurring in the coil, that induce variations in both the chemical and th…

Exergy020209 energyevaporator foulingGeneral Physics and AstronomyThermodynamicsair conditioninglcsh:AstrophysicsThermoeconomics02 engineering and technologythermoeconomics; fault diagnosis; evaporator fouling; air conditioning; thermal exergy; chemical exergy; exergy efficiency; dehumidification; coil geometrythermal exergy020401 chemical engineeringlcsh:QB460-466Settore ING-IND/10 - Fisica Tecnica Industriale0202 electrical engineering electronic engineering information engineering0204 chemical engineeringlcsh:ScienceProcess engineeringdehumidificationAir coolingbusiness.industryRefrigerationHumidityfault diagnosifault diagnosislcsh:QC1-999chemical exergyElectromagnetic coilAir conditioningthermoeconomicscoil geometryexergy efficiencythermoeconomicExergy efficiencyEnvironmental sciencelcsh:Qbusinesslcsh:PhysicsEntropy
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Introducing exergy analysis in life cycle assessment: A case study

2018

Life Cycle Assessment (LCA) is a methodology for assessing the potential environmental aspects associated with a product or service along its life cycle. However, in the case of energy technologies, it is suggested that the LCA of a product encompasses also further aspects other than environmental aspects and primary energy calculations. In particular, to optimize the reduction of raw materials during the whole life cycle, it is important to introduce the assessment of the irreversibility, applying the exergy analysis. In this paper, an integrated approach of exergy analysis and LCA is proposed, developing the Life-cycle quality index able to suggest potential exergy inefficiencies and the …

ExergyCumulative exergy demand (CExD)Biomass boilerbusiness.industryApplied MathematicsBiomass boilerExergy analysiLife Cycle Assessment (LCA)Technology obsolescenceModeling and simulationModeling and SimulationEconomicsProcess engineeringbusinessLife-cycle assessmentEngineering (miscellaneous)
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Application of advanced thermodynamics, thermoeconomics and exergy costing to a Multiple Effect Distillation plant: In-depth analysis of cost formati…

2015

Abstract The high thermal energy consumption per m3 fresh water is one of the main barriers to the spread of thermally driven desalination processes and has limited their use to applications in countries with high reserves of fossil fuels or to specific technological solutions like dual purpose cogeneration plants and solar desalination systems. Being energy conversion efficiency a major issue to improve the performance of thermally driven desalination plants, thermoeconomic analysis has been attracting the efforts of researchers for the identification of margins for process improvement. In this paper a rigorous exergy and thermoeconomic analysis is presented for an 8 effect forward feed Mu…

ExergyEngineeringCost formation procebusiness.industryMechanical EngineeringGeneral Chemical EngineeringThermodynamicsThermoeconomicsExergy costingGeneral ChemistryEnergy consumptionDesalinationMultiple effect evaporationChemical exergyCogenerationMultiple-effect distillationSettore ING-IND/10 - Fisica Tecnica IndustrialeGeneral Materials ScienceThermal exergyThermoeconomicSolar desalinationbusinessThermal energyWater Science and TechnologyDesalination
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On thermoeconomics of energy systems at variable load conditions: integrated optimization of plant design and operation

2007

Abstract Thermoeconomics has been assuming a growing role among the disciplines oriented to the analysis of energy systems, its different methodologies allowing solution of problems in the fields of cost accounting, plant design optimisation and diagnostic of malfunctions. However, the thermoeconomic methodologies as such are particularly appropriate to analyse large industrial systems at steady or quasi-steady operation, but they can be hardly applied to small to medium scale units operating in unsteady conditions to cover a variable energy demand. In this paper, the fundamentals of thermoeconomics for systems operated at variable load are discussed, examining the cost formation process an…

ExergyEngineeringPrimary energyRenewable Energy Sustainability and the Environmentbusiness.industryThermoeconomics has been assuming a growing role among the disciplines oriented to the analysis of energy systems its different methodologies allowing solution of problems in the fields of cost accounting plant design optimisation and diagnostic of malfunctions. However the thermoeconomic methodologies as such are particularly appropriate to analyse large industrial systems at steady or quasisteady operation but they can be hardly applied to small to medium scale units operating in unsteady conditions to cover a variable energy demand. In this paper the fundamentals of thermoeconomics for systems operated at variable load are discussed examining the cost formation process and separately the cost fractions related to capital depreciation (which require additional distinctions with respect to plants in steady operation) and to exergy consumption. The relevant effects of the efficiency penalty due to off design operation on the exergetic cost of internal flows are also examined. An original algorithm is proposed for the integrated optimization of plant design and operation based on an analytical solution by the Lagrange multipliers method and on a multi-objective decision function expressed either in terms of net cash flow or primary energy saving. The method is suitable for application in complex energy systems such as ‘‘facilities of components of a same product’’ connected to external networks for power or heat distribution. For demonstrative purposes the proposed thermoeconomically aided optimization is performed for a grid connected trigeneration system to be installed in a large hotel.Energy Engineering and Power TechnologyCost accountingThermoeconomicsGridEnergy conservationVariable (computer science)symbols.namesakeFuel TechnologyNuclear Energy and EngineeringLagrange multipliersymbolsProcess engineeringbusinessSimulation
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Thermoeconomic optimization of a renewable polygeneration system serving a small isolated community

2015

During the last years, special attention has been paid to renewable polygeneration technologies, able of simultaneously producing thermal, cooling, electrical energy and desalinated water from seawater. This paper focuses on an innovative polygeneration system driven by renewable energy sources, including the following technologies: hybrid photovoltaic/thermal collectors, concentrating parabolic trough (CPVT), a biomass heater, a single-stage absorption chiller and a multiple-effect distillation desalination system. The system is designed to cover the base load of an isolated small community. In previous papers, the dynamic simulation model about plant operation is discussed. In this paper,…

ExergyEngineeringSolar desalinationControl and Optimizationexergy analysiSolar heating/cooling Photovoltaic/thermal collectors Solar desalinationEnergy Engineering and Power TechnologyDesalinationlcsh:Technologyjel:Q40Exergoeconomicjel:Qjel:Q43jel:Q42jel:Q41Parabolic troughSettore ING-IND/10 - Fisica Tecnica Industrialejel:Q48jel:Q47Electrical and Electronic EngineeringEngineering (miscellaneous)jel:Q49exergoeconomicsWaste managementphotovoltaic/thermal collectors (PVT)Renewable Energy Sustainability and the Environmentbusiness.industrylcsh:Tsolar heating and coolingPhotovoltaic systemjel:Q0multiple-effect distillation (MED)jel:Q4Renewable energysolar heating and cooling; photovoltaic/thermal collectors (PVT); solar desalination; multiple-effect distillation (MED); exergy analysis; exergoeconomicsBase load power plantExergy efficiencySolar desalinationbusinessexergy analysisEnergy (miscellaneous)
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