The thermodynamic theories and ecological theories can be integrated effectively by exergy(biogeochemical energy of the system) to study the environmental problems of the lakes and reservoirs. In this paper, the appl...The thermodynamic theories and ecological theories can be integrated effectively by exergy(biogeochemical energy of the system) to study the environmental problems of the lakes and reservoirs. In this paper, the applications of exergy in the ecological modelling of lake environment were reviewed. Results showed that exergy can be used as a goal function to estimate the parameters of the ecological model for lakes and reservoirs and to develop the structural dynamic models accounting for the changes in lake ecosystems, and as an ecological indicators for the development and evolution of lake ecosystems.展开更多
Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of op...Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of optimizing the performance of the Brayton cycle. Moreover, four different schemes in the process of multi-objective optimization were suggested, and the outcomes of each scheme are assessed separately. The power output, the concepts of entropy generation, the energy, the exergy output, and the exergy efficiencies for the irreversible Brayton cycle are considered in the analysis. In the first scheme, in order to maximize the exergy output, the ecological function and the ecological coefficient of performance, a multi-objective optimization algorithm (MOEA) is used. In the second scheme, three objective functions including the exergetic performance criteria, the ecological coefficient of performance, and the ecological function are maximized at the same time by employing MOEA. In the third scenario, in order to maximize the exergy output, the exergetic performance criteria and the ecological coefficient of performance, a MOEA is performed. In the last scheme, three objective functions containing the exergetic performance criteria, the ecologi-cal coefficient of performance, and the exergy-based ecological function are maximized at the same time by employing multi-objective optimization algorithms. All the strategies are implemented via multi-objective evolu-tionary algorithms based on the NSGAII method. Finally, to govern the final outcome in each scheme, three well- known decision makers were employed.展开更多
文摘The thermodynamic theories and ecological theories can be integrated effectively by exergy(biogeochemical energy of the system) to study the environmental problems of the lakes and reservoirs. In this paper, the applications of exergy in the ecological modelling of lake environment were reviewed. Results showed that exergy can be used as a goal function to estimate the parameters of the ecological model for lakes and reservoirs and to develop the structural dynamic models accounting for the changes in lake ecosystems, and as an ecological indicators for the development and evolution of lake ecosystems.
文摘Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of optimizing the performance of the Brayton cycle. Moreover, four different schemes in the process of multi-objective optimization were suggested, and the outcomes of each scheme are assessed separately. The power output, the concepts of entropy generation, the energy, the exergy output, and the exergy efficiencies for the irreversible Brayton cycle are considered in the analysis. In the first scheme, in order to maximize the exergy output, the ecological function and the ecological coefficient of performance, a multi-objective optimization algorithm (MOEA) is used. In the second scheme, three objective functions including the exergetic performance criteria, the ecological coefficient of performance, and the ecological function are maximized at the same time by employing MOEA. In the third scenario, in order to maximize the exergy output, the exergetic performance criteria and the ecological coefficient of performance, a MOEA is performed. In the last scheme, three objective functions containing the exergetic performance criteria, the ecologi-cal coefficient of performance, and the exergy-based ecological function are maximized at the same time by employing multi-objective optimization algorithms. All the strategies are implemented via multi-objective evolu-tionary algorithms based on the NSGAII method. Finally, to govern the final outcome in each scheme, three well- known decision makers were employed.
