Advanced Materials Research Vol. 648

Abstract: The Maximum Power Point Tracking (MPPT) is an important method to improve power conversion efficiency for wind-power generation systems. In this paper, an intelligent global power MPPT method is presented. The comparison result of load power under various wind speed are presented through a real experiment, and it shows that maximum power point can be preferably tracked by the intelligent global power MPPT and makes a significant contribution for energy saving.

Abstract: As a kind of clean energy, gas heat source will play more and more important role in the future heating system. However, the research for the heat source optimization and dispatch of coal fired and gas fired source co-heating system is quite few in china. In this paper, the characteristic of coal fired and gas fired source co-heating system is proposed, and formulas and parameter selection method for the typical heat source operation scheduling schemes were given. By taking an actually heating network as an example, procedure and method for some heat source dispatch schemes are provided, and the optimal operating scheme based on technical and economic analysis is given. The method provided in this paper may supply the theoretical basis for operation scheduling of realistic engineering heating network. It is very meaningful for saving energy and improving environment.

Abstract: Due to huge hydropower energy in the upper Yangtze River basin, discharge projection is very important for integrated water resources development and management under the background of regional climate change. Projections of river discharge at Yichang hydrological station under three greenhouse gas emission scenarios are studied by two kinds of methods. The projection results show that from 2011 to 2050, annual river discharge at Yichang hydrological station has no obvious trends, but future seasonal discharges have different trends under different greenhouse gas emission scenarios, which increase the difficulties of utilization of hydropower energy in the upper Yangtze River basin.

Abstract: The fictitious thermal source (FTS) method has always been the popular analytical way to solve heat transfer of buried pipes. Aiming at complicated conditions, simplified model and procedure based on the FTS method often casts doubts upon the results. Therefore, a numerical simulation method with circle boundary condition is validated comparing to the accurate temperature profile of buried steel pipe without insulation calculated by the FTS method. Then, the simulation method is used to verify calculation error when solving insulated pipes by the FTS method. The comparison shows that it is difficult to obtain accurate temperature profile for buried insulated pipe by the FTS method. However, the average temperature and heat loss are more precise and can be used to solve complicated problems by the analytical method.

Abstract: This article compares the domestic configurations of the boiler feed-water pump for 1000MW units, and takes the technical and economic comparison of the feed-water pump type selection. Analyzed diverse configurations of the boiler feed-water pump set. For example, to 1000MW units boiler feed-water pump set in a factory, obtained relatively optimal configuration of feed-water pump in connection with various technical and economic index.

Abstract: Energy saving has been attached great importance in China. This paper measures the energy-economic efficiency levels of 28 provinces in mainland China from 1985 to 2010 with the SBM model considering undesirable outputs, and then analyzes the regional differences. The empirical results indicate that energy-economic efficiency level of eastern area is in absolute predominance while both the middle and west's levels are lower than the average level of the whole nation. Finally, some practical suggestions are provided to improve the regional energy saving levels.

Abstract: By three-link modal, the energy consumption pattern of oil pipeline system was divided into the energy conversion process, transmission process and technological utilization process. The mathematical model of energy consumption analysis and scheme optimization of pipeline system were established. And on the basis of .Net platform, with the OLE DB database connection technology, The software of energy consumption analysis and comprehensive optimization of oil pipeline system was developed which can be used as a tool to help the pipeline manager to manage the pipeline more effectively.

Abstract: The major factors of the global energy crisis, environmental pollution and climate change, are greatly promote the development and utilization of renewable energy. The large power wind power generation system was constructed based on squirrel-cage induction generator (SCIG), the mathematical models was created With MATLAB/Simulink platform, the SCIG vector control system was designed and the three closed control loop which were torque control loop, speed control loop, power control loop and the optimal control system was integrated at last, the simulation result shows this control system can realize optimal control for large wind energy conversion system which can effectively applied into SCIG wind power generation system for system modification.

Abstract: To decrease the influent load of the wastewater treatment system and increase the overall ability of the wastewater treatment plant to meet the demand for 15% production expansion of the enzyme preparations factory, the purpose of this study was set to decrease COD concentration of the centrate from the sludge treatment system. Three orthogonal experiments and follow-up analysis of experiment results identified the significant impacts factors on COD concentration of the centrate. Afterwards, four full factorial experiments were designed to obtain a set of optimum parameters combination on the condition that no GMO was detected in the dewatered sludge.

Abstract: The sensitivity of net primary productivity (NPP) to future climate change is critical for carbon dynamics and energy saving. Geographically weighted regression, which allows the use of remotely sensed NPP to establish spatial correlations with leaf area index (LAI) and topographically-based climate factors (temperature, precipitation and solar radiation), is introduced in this paper. For most area of North China, the effect of precipitation and LAI on NPP is positive, while that of temperature is negative. Grassland is most sensitive to climate change. LAI will decrease by -21.96%. Similarly, climate change may reduce NPP by -6.29%.