Advanced Materials Research Vols. 1092-1093

Abstract: A new solar solid adsorption refrigeration system is established in this paper, and the variation relationship between the adsorbent bed temperature and pressure with time are analyzed, and the effects of adsorbent bed condensing pressure on the system performance is researched. Results show that, under the same working conditions, when the condensing pressure is 39 kPa, the daily ice-making capacity of system reach to 5.5 kg with the refrigerating capacity of 2.26 MJ; And when the condensing pressure is 63 kPa, the ice-making capacity of system is only for 3 kg with the refrigerating capacity of 1.48 MJ; The refrigerating capacity of the former is 1.5 times of the latter.

Abstract: The paper firstly introduces the current status of solar energy generation and analyzes the principle,then uses Matlab/Simulink to model and simulate solar energy generation system, finally makes a performance analysis of the simulation results,which is that the influence of different temperature and solar radiation intensity to the voltage-current and power-voltage of solar energy cells.

Abstract: To study the influence of KCl pretreating on the pyrolysis kinetics of soybean stalk, the pyrolysis of soybean stalk pretreated by different concentration KCl solutions were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The Ozawa method was employed to calculate the activation energy. The results showed that the pyrolysis process of the soybean stalk pretreated by 3% and 10% KCl solution can be separated into four stages (water loss, depolymerization and vitrification, thermal decomposition, and carbonization). With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the higher temperature region, and the maximum pyrolysis rate and its corresponding temperature increase too. A small amount of metal salts addition is conducive to the formation of volatile, and a certain amount of metal salts can improve the charcoal yield. More KCl additive makes the lower activation energy value, and the obtained activation energy value increases with the reaction degree.

Abstract: With continuous expansion of the grid, the power system structure is becoming more complicated, leading to more and more uncertainty of the system. Especially, the massive integration of wind power and other renewable energy to the grid brings more challenges. In this paper, by taking use of DSR (dynamic security region) and risk assessment theory, it proposed the transient risk index calculation and integrated analysis method for wind power integration system, which was able to give quantitative indicators of the system day-ahead scheduling plan. The efficiency and practicality of theories mentioned herein were verified by standard numerical examples.

Abstract: The water mass flow and air relative humidity on the performance of air-source heat pump water heater was discussed in this paper. The results show that the energy efficiency of heat pump water heater is improved by correct the water mass flow and discharge pressure can be reduced, the value of the condenser temperature difference between the import and export of water also can be reduced. Increasing the air relative humidity, the more condensated water on evaporator surface effective, the greater the wetting area. In addition, the heat transfer of latent heat can be increased by the growth of air side and refrigerant side heat transfer coefficient.

Abstract: This paper discusses the placement of the wind power plant’ selection process,wind-farm built in Donghai county,Jiangsu province is proposed to select the appropriate wind-farm from the aspects such as macro-sitting and micro-sitting selection.On the basis of the actual measurement data in the site,using histogram and meteorological rose evaluate wind energy resources of the wind-farm,to determine the selection of the wind-farm site and wind turbines and the layout of wind turbine generator system.Special software is adopted to improve the professional evaluation and the effectiveness of the site selection.

Abstract: This research proposes an improved tunable piezoelectric harvester structure which is constructed by a cantilever base beam and piezoelectric elements working in d33 mode. Our previous work on tunable piezoelectric harvester structure showed a frequency variation ratio of 3.17% with piezoelectric elements working in d31mode coupling. In this work, by changing the working mode of the piezoelectric elements from d31 to d33 mode, the frequency variation ratio was shown to be much higher. Theoretical analysis of the improved structure was investigated and verified with simulations. The results showed that the d33 mode coupling surpasses the d31 mode coupling with a frequency variation ratio of 29.74%.

Abstract: In this paper, the high voltage electric field drying characteristic of corn with different electrode forms and different pin electrode numbers are researched, and compared with rice drying under different pin electrode numbers. Results show that the drying effect of pin-disc is the best, then plate-disc, and the plate-mesh is the worst, it is better than the natural control group. The drying speed of the corn is faster than the rice in the pin-disc electric field drying, and the pin-electrode numbers has much influence on the drying effect, pin electrode number is not the more the better, and there is a best number of pin electrode, in this paper, the best number of electrode is three, however the best pin electrode number is different for different materials.

Abstract: This paper proposes the possibility of using the diesel generator with renewable energy sources (RES) and compares the cost of energy of isolated pv-wind-diesel-battery-converter hybrid system with a stand-alone diesel generator for a rural region in Egypt. The isolated system is also evaluated to find out the quantity of air pollution. The system has to supply a load with an average value of 48 kW and a peak value of 71 kW. HOMER software is used to carry out the cost of energy (COE), net present cost (NPC) and environmental emissions (Kg/yr) calculations of optimization model. The simulation results show that the proposed hybrid system is very economical and environment friendly. The COE for the isolated hybrid power system is found to be 0.139 $/kWh which is more than half of the stand alone diesel generator system.

Abstract: Research on wave energy extraction has been conducted in many countries to meet the growing demand for clean energy. To find an efficient and economic way to convert wave energy, an one-base multi-buoy offshore floating Sharp Eagle wave energy converter is designed, consisting of four Eagle head absorbing buoys, one semi-submersible barge, one energy conversion system, buoyancy tanks, underwater appendages and other components. The working principle of the device is described in this paper. To test the hydrodynamic performance of device and make an initial evaluation for the design, a model experiment of 1/13.78th scale was carried out. The influence of wave period, wave height, pressure in hydrocylinders and wave direction is tested. All the efficiencies in different conditions are compared with each other, while the high efficiency and stability of device are verified.