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.

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.