Applied Mechanics and Materials Vols. 291-294

Abstract: A double-axis solar tracking system based on horizontal coordinate is adopted. A method of combining the sun trajectory tracking and light intensity sensor is proposed in this tracking system. Detection results of light intensity sensor were used to determine weather situation, control the start -stop of the tracking system. The sun trajectory was calculated by astronomical algorithms to determine the solar orientation. Different interval times were set in different time periods to improve the tracking accuracy. It enhances solar radiation, improves the power generation efficiency of photovoltaic systems and reduces the cost of photovoltaic power generation. This system is simple and easy to achieve. It has lower cost and reliable performance. It can be used in large-scale photovoltaic power plant projects.

Abstract: A new continuous diffusion furnace is introduced in this paper and its workflow is briefly discussed. Within the analysis and statement about the diffusion principle, both junction depth and sheet resistivity are studied. Numerical analysis has been performed to simulate the temperature distribution in the furnace, with FLUENT software. Finally the values of sheet resistivity are calculated according to both temperature field models of continuous and traditional diffusion furnace respectively. Therefore, the new continuous diffusion furnace is proved to be feasible by the comparison of these values.

Abstract: This paper analyzes the principle of boundary mode flyback topology, presents a five-output auxiliary power supply of 3KW solar power inverter without the optocoupler feedback regulator circuit. The circuit has the characteristics of a simple structure, low cost, high efficiency and high reliability . The multi-output auxiliary power supply of the PV inverter schematic and a high frequency flyback transformer detail design are given. This power supply has been already used in an inverter. The experiment results prove that the auxiliary power supply has a stable work state, a low output ripple, a transformer without fever phenomenon, and meet the requirements of Solar power inverters.

Abstract: The heat loss of vacuum receiver plays critical important role in solar parabolic trough system. In this paper, experimental measurements and calculation models were conducted to investigate the heat loss of solar parabolic trough receiver with receiver length of 10.2 m and diameter of 0.120 m. In general, the heat loss of receiver decreased with the receiver wall temperature, while it can approach minimum under special wind condition. The heat loss of receiver mainly included the heat loss of glass and boundary region, and the heat losses of receiver, glass region and boundary region with tube temperatures of 176.2oC were respectively 987.1 W, 762.2 W and 224.9 W. Outside the glass envelope, the convection and radiation both play an important role in the heat loss of receiver, while the heat transfer is mainly dependent upon the radiation inside the glass envelope. In addition, the heat losses of convection outside the glass and radiation inside the glass from calculation very well agreed with the experimental data.

Abstract: This paper presents experimental performance of a concentrator photovoltaic thermal (CPV/T) dryer for drying of honeysuckle flowers. The dryer consists of a perspex box structure. Heat for drying is provided by the excess heat of concentrator PV module and one fan powered by this concentrator PV ventilate the dryer. To investigate the experimental performances of the solar dryer for drying of honeysuckle flowers, 2 full scale experimental runs were conducted. Of which one experimental runs were conducted by hot air and the drying air temperature varied from 65°C to 80°C, the drying time was 5 hours. The other t experimental runs were conducted for natural sun drying for comparison, and the drying time was 5 hours too. Experiments were conducted for drying of honeysuckle in the month of June, 2012. Various half hourly experimental data namely moisture evaporated, honeysuckle surface temperatures, ambient air temperature and humidity, etc. were recorded to evaluate heat and mass transfer for the proposed system. The experimental results show that the quality of hot air dried products in terms of color, form, texture, etc. was high-quality dried products.

Abstract: In this paper, solar thermal utilization methods in hospitals, schools, hotels and factories in a typical Southern China city, e.g., Dongguan City, were investigated, which lead to the understanding of the heating methods in different types of buildings and the application ratio of different kinds of renewable heating systems, e.g., solar water heater, in all kinds of buildings. These will help reveal the usage of renewable energy for heating and its development in this region of China.

Abstract: This paper studied the thermal and physical properties of a new solar solid desiccant material, including the equivalent thermal conductivity under different moisture content conditions and penetrability under different simulated solar radiation. The results showed that the equivalent thermal conductivity of the material was related to the moisture content and water saturation. In unsaturated state, the equivalent thermal conductivity increased with the increase of the moisture content and presented a linear relation in certain range. When reached saturation, the equivalent thermal conductivity decreased with the increase of the moisture content. These figures could provide the basis for the determination of the thickness of the dehumidification bed and optimization of the design of the dehumidification system.

Abstract: This paper made some researches of modeling on the systems of the photovoltaic（PV） power station, and analyzing the photovoltaic grid-connected generation system. Using MATLAB and PSASP, simulation and analysis of grid-connected characteristics about the large-scale PV power bases were carried out, focusing on the influence of the power flow after the grid connection of large scale PV power bases, the transient stability in the fault condition of the line-side and in the condition of the light disturbance. Specific measures are presented to solve problems. The conclusion of this paper will provide some theoretical basis of improving the stability of grid-connected of the large-scale PV power bases and will also provide some theoretical basis and the guide of grid-connected for the new energy strategy of our country in the future.

Abstract: This paper introduces the design of a solar heating system integrated latent heat store heat exchanger. Aiming at studying the system solar fraction, mathematical models are established for describing solar collector, latent heat store heat exchanger, users’ heating thermal load, and the system in whole. Studies are carried out based on these models. The results show that there are some key influencing factors on solar fraction, including solar irradiance, collector area, collector inclination angle, the difference value between collector inlet fluid temperature and ambient air temperature. Among these, collector inclination angle is the most significant one. If the values between collector inlet fluid temperature and ambient air temperature have big difference, it’ll cause adverse effects. As long as the operation requirements are met, lower collector inlet fluid temperature and suitable ambient air temperature are reasonable conditions for application. The research results provide guide for the system application in engineering.

Abstract: The rural economy is underdeveloped in china, especially in the Loess Plateau, the land is barren and per capita income is not high, prominently they lack the energy. It had been vicious cycle between the biological energy consumption for basic survival and ecological deterioration of the environment. Therefore, it’s a breakthrough in using the new and local energy of exploitation and utilization for solving the shortage of rural energy. This article construct the availability of evaluation index system of Solar with surveying quantitative empirical analysis Anding district in Gansu province of loess plateau areas Northwest China.Conclusion is that the solar level is different in An-Ding district but it has great potential to be developed . The available amount is abundant but the Utilization is inadequate.Due to the poor taste of the local energy, to develop solar energy rational will improve the ecological, address poverty and narrow the economic gap in regions.