The emergy theory was used to analyze the emergy structure of the ecosystem at reclamation area in order to find the problem existed in the reclamation ecosystem through compared with the modern agriculture.The resear...The emergy theory was used to analyze the emergy structure of the ecosystem at reclamation area in order to find the problem existed in the reclamation ecosystem through compared with the modern agriculture.The research results show that the propor- tion of assistant emergy input into the system is higher which indicate that the productivity of reclamation land has not resumed and a lot of assistant emergy needed to improve the productivity.The ecosystem overly depend on chemical fertilizer,which is bad to agricul- tural ecosystem;the agricultural ecosystem in reclamation area belongs to traditional agriculture because the main power come from manpower and the usage of organic ferti- lizer is little,through compare the index of emergy with modern agriculture,the value of EyR and ED in reclamation area is less than the modern agriculture.展开更多
This paper applies new maximum-power-point tracking （MPPT） algorithm to a hybrid renewable energy system that combines both Wind-Turbine Generator （WTG） and Solar Photovoltaic （PV） Module （SPVM）. In this paper...This paper applies new maximum-power-point tracking （MPPT） algorithm to a hybrid renewable energy system that combines both Wind-Turbine Generator （WTG） and Solar Photovoltaic （PV） Module （SPVM）. In this paper, the WTG is a direct-drive system and includes wind turbine, three-phase permanent magnet synchronous generator, three-phase full bridge rectifier, and buck-bust converter, while the SPVM consist of solar PV modules, buck converter, maximum power tracking system for both systems, and load. Several methods are applied to obtain maximum performances, the appropriate and most effective method is called gradient-approximation method for WTG approach, because it enables the generator to operate at variable wind speeds. Furthermore MPPT also is used to optimized the achieved energy generated by solar PV modules.Matlab / Simulink approach is used to simulate, discuss, and optimized the generated power by varying the duty cycle of the converters, and tip speed ratio of the WTG system.展开更多
The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipme...The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipment such that the temperature of hot water supply is maintained at a set-point that may be a fixed value or be compensated against the external temperature. This paper presents a novel scheme that can determine the optimal set-point of hot water supply that maximizes the energy efficiency whilst providing sufficient heating capacity to the load. This scheme is based on Adaptive Neuro-Fuzzy Inferential System. The aim of this study is to improve the overall performance of district heating systems.展开更多
基金Henan Province Science and Technology Development Program(0624220093)Key Laboratory of Mine Spatial Information Technologies(Henan Polytechnic University,Henan Bureau of Surveying and Mapping),State Bureau of Surveying and Mapping(KLM200807)
文摘The emergy theory was used to analyze the emergy structure of the ecosystem at reclamation area in order to find the problem existed in the reclamation ecosystem through compared with the modern agriculture.The research results show that the propor- tion of assistant emergy input into the system is higher which indicate that the productivity of reclamation land has not resumed and a lot of assistant emergy needed to improve the productivity.The ecosystem overly depend on chemical fertilizer,which is bad to agricul- tural ecosystem;the agricultural ecosystem in reclamation area belongs to traditional agriculture because the main power come from manpower and the usage of organic ferti- lizer is little,through compare the index of emergy with modern agriculture,the value of EyR and ED in reclamation area is less than the modern agriculture.
文摘This paper applies new maximum-power-point tracking （MPPT） algorithm to a hybrid renewable energy system that combines both Wind-Turbine Generator （WTG） and Solar Photovoltaic （PV） Module （SPVM）. In this paper, the WTG is a direct-drive system and includes wind turbine, three-phase permanent magnet synchronous generator, three-phase full bridge rectifier, and buck-bust converter, while the SPVM consist of solar PV modules, buck converter, maximum power tracking system for both systems, and load. Several methods are applied to obtain maximum performances, the appropriate and most effective method is called gradient-approximation method for WTG approach, because it enables the generator to operate at variable wind speeds. Furthermore MPPT also is used to optimized the achieved energy generated by solar PV modules.Matlab / Simulink approach is used to simulate, discuss, and optimized the generated power by varying the duty cycle of the converters, and tip speed ratio of the WTG system.
文摘The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipment such that the temperature of hot water supply is maintained at a set-point that may be a fixed value or be compensated against the external temperature. This paper presents a novel scheme that can determine the optimal set-point of hot water supply that maximizes the energy efficiency whilst providing sufficient heating capacity to the load. This scheme is based on Adaptive Neuro-Fuzzy Inferential System. The aim of this study is to improve the overall performance of district heating systems.
