Advanced Materials Research Vols. 608-609

Abstract: According to the characteristics of photovoltaic array, a novel asymmetric fuzzy PI control method is introduced for MPPT of photovoltaic system. Photovoltaic energy generation system can track the maximum power of PV cell rapidly by using asymmetric fuzzy control. On the base of asymmetric fuzzy control, an added PI control is used to eliminate the power oscillation around maximum power point. Simulation results have verified the good performance of the proposed method

Abstract: This paper analyzes advantages and disadvantages of different maximum power point tracking (MPPT) methods based on mathematical model of photovoltaic cell and its characteristic analysis. According to output characteristics of photovoltaic (PV) array, this paper puts forwards an improved increment conductance (INC) method which can improve the efficiency of photovoltaic cell by increasing power tracking speed under the premise of ensuring stability of the system. This method is verified by means of MATLAB/Simulink.

Abstract: The photovoltaic (PV) industry in China has been developed at a remarkable speed, being supported by the governments and the PV product demand from the international market especially in the developed countries. However, the PV industry in China, now, is coped with a severe challenge due to the several causes. The analysis in the way of SWOT was conducted to figure out the appropriate strategies not only for photovoltaic industry survival but also for the sustainable development.

Abstract: The study is for the water heating mode of a novel building integrated solar thermal system named as building-integrated dual-function solar collector. The novel system avoids summer overheating in hot climate and water-freezing in cold climate, meanwhile remains low operating cost as passive solar heating system. For the novel system at the water heating mode, experiment study was carried out in a hotbox, and dynamic numerical model has been established. The experimental and numerical results show that the characteristic thermal efficiency of the collector achieves 47.386% in water heating mode.

Abstract: With development of solar technology, high absorbance is no longer a hard problem in solar heat utilization. Many solar absorbing coating can easily get absorbance over 90%, but the coating materials and their manufacturing processes may harm seriously to human and environment. A typical plateau butterfly-- Lycaenidae was studied with bionic method in this work. It has considerable solar absorbing capacity for the physical microstructure in its wing scales but not chemicals. The 3D microstructure of the wing scales was measured and analyzed with SEM (Scanning Electronic Microscope) and TEM (Transition Electronic Microscope). The solar absorbing mechanism of the ridge and bottom microstructure was analyzed respectively based on geometrical optics and photon crystal theories. This study may promote solar heat utilization through a bionic structural material way.

Abstract: The model based on matlab S-function of the photovoltaic module describes the relationship between temperature and light intensity of the output characteristics of PV module from the UI and PU curves; This paper further analyzes and discusses the mechanism of hot spot phenomenon of the PV modules and gives reasonable solutions for different situations.

Abstract: Light gases were produced from biomass tar gasification using limonite and dolomite as catalysts. Experiments were performed in a fixed bed reactor with the gasification temperatures of 600–800 °C. Limonite gave the obvious effect on the tar gasification, and the light gases of hydrogen and carbon oxides were mainly obtained. Also, the gas yields depended on the catalytic temperature. Hydrogen yields tend to increasing with temperatures from 650 to 800 °C. The reaction equilibrium was changed by dolomite addition in the reactor system; hydrogen gas was doubled with the limonite and dolomite mixture compared to limonite only.

Abstract: Calcium dioxide can catalyze soybean oil to obtain biodiesel in triglyceride transesterification. Waste mussel shells were utilized as a source of calcium oxide. The shell was calcined in N2 at 1000°C with optimum time of 2 h to obtain active CaO catalysts. Parametric studies have been investigated and perfect conditions were found to be methanol/oil mole ratio, 9:1; catalyst amount, 4wt%; reaction temperature, 65°C; stirring rate of 450 round per minute; reaction time, constant 3h; methyl esters conversion above 98% . Reusability results improved that the prepared catalyst is able to be reemployed up to 9 times. These results indicate waste mussel shell combusted at high temperature can be reused in biodiesel production as a low cost catalyst.

Abstract: Based on Aspen Plus software platform, a simulation of ethanol synthesis from biomass-derived synthesis gas processed on the assumption of both physical and thermodynamic equilibrium. The influences of these conditions such as temperature, reactor pressure and the H2 to (CO+CO2) mole ratio in the feed gas on CO and CO2 conversion and ethanol yield were investigated. The results showed that reaction temperature, pressure and synthesis gas composition have the most important effect on ethanol synthesis behavior. In this process, low temperature and high pressure would be advantageous for ethanol production.

Abstract: Through MFIX software, a three-dimensional numerical gas-solid flow models without chemical reactions is developed to the distributions of solids phase volume fraction and velocities in a 220t/h rectangular cross-section biomass CFB with a height of 3m. The maximum of erosion occurs at the near-wall side at y=0.95m on the front-wall and back-wall. In transition region(0.8-1.4m) of the left-wall and right-wall, typical core-annular regime can be observed, particle in the core region have the tendency to move to the corner. The maximum of erosion occurs at the corner formed between the walls in the role of downward movement of particle. And the lateral movement of particles are obvious enhanced between the core region and back-wall in the role of exit effect, which lead a certain degree of lateral erosion between the core region and back-wall at the left-wall and right-wall.