Advanced Materials Research Vols. 860-863

Abstract: From a carbon cycle perspective, the thermochemical conversion of lignocellulosic biomass is inherently carbon neutral. Pyrolysis of biomass for energy supplying, such as bio-oil and bio-char, has been attracted much attention worldwide. Successful understanding the fundamental issues about the pyrolysis, including pyrolytic behavior and kinetic analysis of lignocellulosic biomass model compounds and real biomass, is essential for the further understanding and optimizing the pyrolysis process. In this paper, pyrolytic behavior of a typical lignocellulosic agricultural residue (wheat straw) and model compounds (cellulose) were measured through thermogravimetric analysis with various heating rates (10, 20, 40 °C·min^-1) under nitrogen atmosphere. The results indicated that the interval of the weight loss for both wheat straw and cellulose moved upwards with the increment of heating rates. The maximum decomposition rates of cellulose were higher than those of wheat straw, and the temperature of maximum decomposition rates increased with the heating rates. Values of activation energy were solved through iso-conversional method. And the average values of activation energy for wheat straw and cellulose were 146.89 kJ·mol^-1 and 134.56 kJ·mol^-1 calculated from Flynn-Wall-Ozawa method, 144.05 kJ·mol^-1 and 130.91 kJ·mol^-1 calculated from Kissinger-Akahira-Sunose method, respectively.

Abstract: Using an atmosphere simulation test platform，the performance of a common rail diesel engine when the engine was fueled with diesel fuel (B0) and different blending ratio of biodiesel (B10, B20, B30)．The results show that at the same altitude(81kPa), with the mixing ratio of biodiesel increases，the common rail diesel engine has higher brake specific fuel consumption and lower power，but it has lower smoke．The biodiesel has a litter influence on the brake specific fuel consumption and power of the common rail diesel engine. The power of B30 is reduced by 4.38% in comparison with B0 maximally. The brake specific fuel consumption of B30 is increased by 4.32% in comparison with B0 maximally. The smoke of B30 are reduced by 22.5％, 38.6%, 57.1% in comparison with B0 maximally.

Abstract: The technology of internet of things (IOT) can be utilizated to realize the monitoring the variation of geothermal field effectively and accurately in true time. Monitoring data shows that the influence range of underground heat exchangers is less than 3 m in certain hydro-geological conditions, and has no heat breakthrough in center hole of the whole area. The imbalance of heat collection and extraction don’t cause the temperature rise in geothermal field in summer and winter. Figures show that the regional shallow geothermal resources supply the heat-exchange area by the means of heat convection of underground water and heat transfer of rock and soil.

Abstract: With the charging and discharging of grid-tied Energy Storage Systems (ESS), distribution network could shift load from peak period or suppress the fluctuation of renewable energy. Constraints of both grid and ESS are analyzed in the present paper, and definition of power supply & storage capacity of distribution network with ESS is proposed, which quantifies the ability of distribution network to shift load or adopt renewable energy generation. Operating optimization model is proposed for the operation of distribution network considering peak load shifting based on power supply & storage capacity, and the model is tested and verified in case study.

Abstract: Economical value including reducing investment in generation side as well as transmission and distribution (T&D) side of the building capacity and decreasing the power expenses for important users brought by BESS are studied.Economic benefits obtained by BESS through decreasing loss of power grid and making use of time of use (TOU) price to reduce electricity tariff are analysed.Considering the primarily capital cost and operation and maintenance (O&M) cost,the capacity optimal allocation model for different types of BESS is developed under optimal conomy condition and genetic algorithm is used to solve it.

Abstract: Microcapsules containing n-octadecane (MicroC18) with n-octadecyl methacrylate (ODMA)-methacrylic acid (MAA) copolymer shell were fabricated through phase separation method, in which the shell-forming copolymers synthesized by free-radical solution polymerization. Meanwhile, theses copolymers were employed as the surfactant during microencapsulation. The crystallization temperature and crystallinity degree of comb-like copolymer display a gradual decrease with an increase the molar ratio of MAA. MicroC18 with spherical profiles and the diameter ranging from 3 to 20 μm were fabricated. In addition, the system pH value plays an important role in the formation process of microcapsules and the optimum value of pH in the range of 8.5-10.5.

Abstract: Hybrid energy storage system, applied in micro-grid, can bring a higher technical performance. A hybrid energy storage system, including batteries and super-capacitors, is presented in this paper. For maintaining the micro-grid stability, the control strategy of the hybrid energy storage system is divided into two layers: central control system and local control system. The central control system is used to calculate the total output power which the micro-grid wants, and the local control system is used to divide the total output power signal into a frequent fluctuant part and a smooth part, and control the super-capacitors inverters and the batteries inverters to output with these two power signals respectively. With the example system in PSCAD/EMTDC, it proves the effectiveness and feasibility of the control strategy.

Abstract: In order to solve the problems of high energy consumption and serious pollution caused by boiler rooms, this paper mainly introduces a preheating boiler feedwater system with air source heat pump, which includes an air source heat pump, plate heat exchanger and so on. The calculating results show that the system can save coal of 35.67 tons, reduce emissions of carbon dioxide of 94.90 tons per year and would recover all the investment eight years later; It has been proved that the system has better characters such as energy-saving, economical efficiency and so on; it is worth popularizing widely in the city as Lanzhou city with heaviest air pollution.

Abstract: High conductivity porosity materials are proposed to enhance the phase change materials (PCM) in order to solve the problem of low conductivity of PCM in the latent heat storage device (LHSD), and two-dimensional numerical simulation is conducted to predict the performance of the PCM by CFD software. During the phase change process, the PCM is heated from the solid state to the liquid phase in the process of melting and from the liquid phase to the solid state in the solidification process. The results show that porosity materials can improve heat transfer rate effectively, but the effect of heat transfer of Al foam is superior to that of graphite foam although the heat storage capacity is almost the same for both. The heat transfer is enhanced and the solidification time of PCM is decreased since the effective thermal conductivity of composite PCM is increased.

Abstract: Vibration-based energy harvester has been widely investigated during the past years. In .order to improve the power-generating ability and enlarge the frequency range of energy harvesters, this paper presents the design and analysis of a new magneto electric energy harvester that uses Terfenol-D/PZT/Terfenol-D laminate to harvest energy from nonlinear vibrations created by magnetic levitation. The mathematical model of the proposed harvester is derived and used in a parametric study. By multi-scale analysis, the frequency-response analysis of the system is obtained and discussed here. It is shown that the systems nonlinearity can broaden the harvesters working bandwidth, thus makes the harvester suitable to work in practical cases.