Application of Exergoeconomics to the Analysis and Optimization of Process Systems

The definitions and purposes of energy systems and process systems are compared in this paper by considering the role of energy in systems with emphasis on the differences in the methods used to optimize the exergoeconomic benefits of both types of systems.The process system exergoeconomic relationship primarily include the establishment of the Three-link model of process systems,the composition of objective functions,and the corresponding boundary constraint conditions for optimization.The Three-Kink-Method(TLM) which is based on exergoeconomics,can be used to effectively optimize process systems.The TLM used to optimize process systems is outlined in this Some aspects which need further development are also identified.

Closed-loop Supply Chain Systems Constructed by 4PL and Performance Evaluation by Using Exergoeconomics

This paper introduces a new concept of 4PL, which is a contractor of the closed-loop supply chain coordination based on the division of community and the outsourcing development. The concept enriches the connotation of 4PL and broadens the thought for 4PL development. Secondly, according to the characteristics of the closed-loop supply chain in the different duration of the collaborative relationship and the dynamic characteristics of the closed-loop supply chaini we apply the fractal theory to establish a fractal system of 4PL coordinating closed-loop supply chain and propose different strategies for 4PL coordinating with different types of closed-loop supply chains in the various links of the system. Moreover, some strategic and proactive thinking are provided for 4PL＇s practices. Then based on the exergoeconomics theory, the closed-loop supply chain is regarded as a huge energy system with the new view, and the sustainability of the closed-loop supply chain system is discussed under the circumstance of exergoeconomics, and then the metric about “system negative environment effect” is introduced to measure the closed-loop supply chain system performance in the point of energy, a case study illustrates our conclusions.

Probabilistic Exergoeconomic Analysis of Transcorp Power Plant, Ughelli

In this study, the probabilistic exergoeconomic analysis was performed for four industrial gas turbine (GT) units comprising two (GT16 and GT19) units of 100?MW GE engine and two (GT8 and GT12) units of 25?MW Hitachi engine at Transcorp Power Limited, Ughelli. These four industrial GT engine units were modelled and simulated using natural gas as fuel. The design point (DP) simulation results of the modelled GT engines were validated with the available DP thermodynamic data from original equipment manufacturer (OEM). This was done before the off-design point (ODP) simulation was carried out which represents the plant operations. The results obtained from exergy analysis at full load operation show that the turbine has the highest exergy efficiency followed by compressor and combustion having the least. For turbines these were 96.13% for GT8 unit, 98.02% for GT12 unit, 96.26% for GT16 unit, and 96.30% for GT19 unit. Moreover, the combustion chamber has the highest exergy destruction efficiency of 55.16% GT8 unit, 56.58% GT12 unit, 43.90% GT16 unit, and 43.30% GT19 unit respectively. The exergy analysis results obtained from the four units show that the combustion chamber (CC) is the most significant exergy destruction with lowest exergy efficiency and highest exergy destruction efficiency of plant components. The exergoeconomic analysis results from four units showed combustion chamber exergy destruction cost of 531.08 $/h GT8 unit, 584.53 $/h GT12 unit, 2351.81 $/h GT16, and 2315.93 $/h GT19 unit. The probabilistic results and analysis based on the input parameters distributions?were?evaluated and discussed.

Exergoeconomic Evaluation and Optimization of Dual Pressure Organic Rankine Cycle (ORC) for Geothermal Heat Source Utilization

In the present study, a dual-pressure organic Rankine cycle (DORC) driven by geothermal hot water for electricity production is developed, investigated and optimized from the energy, exergy and exergoeconomic viewpoint. A parametric study is conducted to determine the effect of high-stage pressure and low-stage pressure variation on the system thermodynamic and exergoeconomic performance. The DORC is further optimized to obtain maximum exergy efficiency optimized design (EEOD case) and minimum product cost optimized design (PCOD case). The exergy efficiency and unit cost of power produced for the optimization of EEOD case and PCOD case are 33.03% and 3.059 cent/kWh, which are 0.3% and 17.4% improvement over base case, respectively. The PCOD case proved to be the best, with respect to minimum unit cost of power produced and net power output over the base case and EEOD case.

Comprehensive Exergoeconomic Analysis and Optimization of a Novel Zero-Carbon-Emission Multi-Generation System based on Carbon Dioxide Cycle

This paper aims to conduct a comprehensive exergoeconomic analysis of a novel zero-carbon-emission multi-generation system and propose a fast optimization method combined with machine learning.The detailed exergoeconomic analysis of a novel combined power,freshwater and cooling multi-generation system is performed in this study.The exergoeconomic analysis model is established by exergy flow theory.A comprehensive exergy,exergoeconomic and environmental analysis is carried out.Five critical decision variables are researched to bring out effects on the multi-generation system exergoeconomic performance.A novel fast optimization method combining genetic algorithm and Bagging neural network is proposed.The advanced nature comparison is made between the proposed system and four similar cases.Results display that increasing the turbine inlet temperature can improve exergy efficiency and decrease the total product unit cost.The multi-generation system exergy destruction directly determines exergy efficiency and total exergy destruction cost rate.The total product unit cost in the cost optimal design case is reduced by 7.7%and 25%,respectively,compared with exergy efficiency optimal design case and basic design case.Compared with four similar cases,the proposed multi-generation system has great advantages in thermodynamic performance and exergoeconomic performance.This paper can provide research methods and ideas for performance analysis and fast optimization of multi-generation system.

Optimum insulation thickness and exergy savings of building walls in Bamenda: a comparative analysis

The goal of this study is to examine the energetic,entransy,and exergetic methodologies employed to estimate the ideal insulation thickness for construction walls in terms of cost and ecological impact.To achieve these goals,the life cycle cost analysis-based insulating thicknesses of the various methods are evaluated along with the overall costs,yearly cost reductions,and total expenses.The fuel consumption,CO_(2) emissions,and ecological effects are then compared using an environmental analysis based on the three methodologies.The savings of hollow concrete brick(HCB),compressed stabilized earth brick(CSEB),and sundried earth brick(SEB)walls are evaluated along with the insulation thicknesses in terms of cost and ecological impact.As a result,it is determined that the exergetic technique is better suited for optimizing insulating thickness.For CSEB,SEB,and HCB walls,the economic ideal insulation thicknesses are 0.01 m,0.016 m,and 0.02 m,with yearly financial savings of 5$⋅m^(-2),7.5$⋅m^(-2),and 9$⋅m^(-2).For CSEB,SEB,and HCB walls,accordingly,the ecological optimal insulation thicknesses are 0.023 m,0.032 m,and 0.040 m,with net savings of exergetic ecological impact equal to 59 mPts⋅m^(-2),55 mPts⋅m^(-2),and 51 mPts⋅m^(-2).

Energy,Exergy,and Exergoeconomic Analysis of Solar-Driven Solid Oxide Electrolyzer System Integrated with Waste Heat Recovery for Syngas Production

Syngas fuel generated by solar energy integrating with fuel cell technology is one of the promising methods for future green energy solutions to carbon neutrality.This paper designs a novel solar-driven solid oxide electrolyzer system integrated with waste heat for syngas production.Solar photovoltaic and parabolic trough collecter together drive the solid oxide electrolysis cell to improve system efficiency.The thermodynamic models of components are established,and the energy,exergy,and exergoeconomic analysis are conducted to evaluate the system’s performance.Under the design work conditions,the solar photovoltaic accounts for 88.46%of total exergy destruction caused by its less conversion efficiency.The exergoeconomic analysis indicates that the fuel cell component has a high exergoeconomic factor of 89.56%due to the large capital investment cost.The impacts of key parameters such as current density,operating temperature,pressure and mole fraction on system performances are discussed.The results demonstrate that the optimal energy and exergy efficiencies are achieved at 19.04%and 19.90%when the temperature,pressure,and molar fraction of H_(2)O are 1223.15 K,0.1 MPa,and 50%,respectively.

Investigation and optimization of solar collector and geothermal pump hybrid system for cogeneration of heat and power with exergy-economic approach

To use energy systems based on renewable sources,it is very important to consider backup and hybrid sources because renewable energies are not available all the time;therefore,in this system,a geothermal pump is used to preheat the fluid,then the heated fluid is sent to the vacuum tube collector to reach a higher temperature by absorbing solar-thermal energy,and after absorbing solar energy,it goes to the evaporator to produce superheated steam and finally the superheated fluid moves to the steam turbine to produce energy.After the simulation,thermodynamic analysis along with economic analysis has been done.In the base state,the energy efficiency and exergy of cogeneration were 0.566 and 0.156,respectively;the energy efficiency and electrical exergy were better than 0.057 and 0.065;and the overall output and immutable work values were 50 and 671.1 kW,respectively.