Applied Mechanics and Materials Vols. 541-542

Abstract: Biomass is the great potential and renewable energy, and technologies of its use have become an important topic today. As a way to use biomass fuel, biomass reburning significantly reduce NOx in boilers, and has good application prospects. This article describes the application , background and technical overview of biomass reburning, and focuses on biomass reburning research progress in order to work for the follow-up study providing a valuable reference.

Abstract: Based on the finite-time thermodynamic theory, an operation optimization, of water source heat pump in the combined solar with a dual heat source heat pump which is applied in a greenhouse heating system, is made. According to the ε-NTU method and entropy theory, heat exchange and balance equations are obtained. The function relationship between COP and the indoor temperature T_n, the ambient temperature T_a, low temperature heat source inlet temperature T_ie and high temperature heat source inlet temperature T_ic is also obtained. By means of programming, the impact of parameters on the COP and the way of regulating this water source heat pump system are presented in this article. The results show that: when a separate water source heat pump is running, by adjusting the hot water temperature and the match status of each indoor heating system, the energy-saving operation can be realized.

Abstract: Biomass pyrolysis is a good high-value process of biomass conversion. Study on the pyrolysis products of crushed cotton stalks pyrolysis experiments in the self-made airtight equipment. The effects of three factors (pyrolysis temperature,pyrolysis heating rate and pyrolysis holding time) were investigated by using the mass of the solid products yield as the indexes .Box-Benhnken design ( BBD ) and response surface methodology ( RSM) were adopted to obtain the optimum parameters on the basis of results of single-factor experiments.The results show that: when pyrolysis temperature is 500°C.the heating rate is 9°C/min and holding time is 1h,solid products yield 33.4123%, liquid products yield 36.5699%, and gaseous products yield 30.0178%.

Abstract: Basing on the meteorological data of Panzhihua, such as monthly solar radiation, sunshine duration, sunshine percentage, sunny days, and transmission coefficient, etc, we analyzed the distribution and application potential of solar energy resource . The result is as follows:(1) there are obvious seasonal characteristic for solar energy resource;(2) the solar water heater can meet the requirements of the standard domestic hot water the whole year;(3)it’s necessary to pay attention to usage and control for the sunshade and the day-lighting technology, where the east and west window should be avoided in the architectural design, and the south window with movable level external shading should be set up; (4)the photovoltaic system in the building which can reduce converted units exhaust emissions of 14.20 kg/ WP, produce the environmental benefits of about 1.72￥/ WP, and bring good environmental benefits.

Abstract: The most popular renewable energy are solar and wind. As the problems of energy shortage and environment pollution become more serious, hybridizing energy sources turn to be a crucial solution to reach sustainable development. The present work theoretically concentrates on teasing out a set of complete and clear calculation method for deigning a seawater RO desalination unit powered by Wind-PV energy systems to produce potable water. This paper suggests a series of simple estimation models to help optimize the matching of wind and solar desalination modules.

Abstract: The construction of wind farms grows quickly in China. It is necessary for stakeholders to estimate investment costs and to make good decisions about a wind power project by making a budget for the investment. This paper proposed an evaluation method by integrating the analytic hierarchy process (AHP) with back-propagation neural network (BPNN) to evaluate wind farm investment. In the AHP-BPNN model, the AHP method is used to determine the factors of wind farm investment. The factors with high importance are reserved while those with low importance are eliminated, which can decrease the number of inputs of the BPNN. The experiment results show that the integrated model is feasible and effective.

Abstract: In this paper, with the help of two-parameter Weibull distribution, the monthly, seasonal and annual assessment of wind energy potentiality was made using the wind speed data collected in the last decade, from 2001 to 2010 for the meteorological station of Tindouf region. The vertical extrapolation of Weibull parameters and mean wind speed at a height of 50m and the analysis of temporal energy efficiency using a wind turbine of 600kW rated power from Fuhrländer manufacturer was made. The results show that Tindouf situated in extreme Algerian southwest, in the natural region of the Sahara, on the border with Morocco (west), the non-autonomous territory of Western Sahara (south-west) and Mauritania (south), is one of windiest region in the country, swept by local winds with a good annual mean wind speed =5.67m/s and an annual mean wind power density equal to 200W/m² at 10m, while the highest monthly wind energy produced may be reached in May, the seasonal in Spring and the annual gross electric energy produced is equal to 1.85GWh/year.

Abstract: Based on the analysis of the disadvantages of the several protection schemes for microgrid, the paper proposes a novel current protection scheme for microgrid. The scheme treats the typical microgrid layout as a case study and analyses the principle of operation of adaptive protection in connected mode and islanded mode about three typical faults. In addition, the algorithm and program flow about the adaptive protection, as well as the information feedback mechanism and operation time limit about the bidirectional power flow characteristics have been provided. It improves the technical challenges faced with the protection in different modes to a great extent.

Abstract: In order to develop a new fuel alternative for the diesel engine, experiment of combustion and emission characteristics was carried on a high pressure common rail diesel engine fueled with diesel and acidic oil biodiesel blends, then the results were compared and analyzed. The results indicate that after adding acidic oil biodiesel, the ignition delay is prolonged, combustion pressure, maximum rate of pressure rise and maximum combustion temperature all increase. The maximum combustion heat release rate of blended fuel is higher than diesel at low and middle loads, and lower at high load condition. Compared with diesel, HC emissions of blends decrease dramatically with the increases of blending ratio. NO_X emissions of blends are slightly higher than diesel. CO emissions of blends are almost the same as that of diesel. According to the results, acidic oil biodiesel has wide application prospects as an alternative fuel.

Abstract: A PV inverter Grid-Connected system based on SVPWM is designed here, which is consisted of DC/DC circuit, TMS320F2812 , optical isolating circuit and driver circuit, three-phase inverter bridge, Grid signal acquisition circuit. Besides,program of the system is built with CCS3.3. SVPWM, MPPT, Grid-Connected, control comes true with the help of C language. Improved variable step size perturbation and observation method is applied in MPPT, which saves time of searching maximum power point and avoids oscillation generated. The experimental results show that the system can not only meet the design requirements, the Grid-Connect effect is also ideal.