Advanced Materials Research Vols. 512-515

Abstract: This paper analyzes the characteristics of solar cells, and establishes the simulation model from its mathematical expressions which can factually reflects the change of solar cells’ parameters. The commonly used method of maximum power point tracking technologies is introduced. A PV system’s most maximum power is simulated by using the fuzzy control method. Simulation results show that the system can work at a stable maximum power point rapidly.

Abstract: A thermal performance mathematical model of Trombe wall combined with solar air collector was established on the base of thermodynamics and fluid dynamics analysis. Then we solved the mathematical model by means of calculating program based on C programming language. The calculating results show the influence law of the area ratio of air opening to air flow channel (A_o/A_f ) and the thickness of air flow channel affected on the heat collecting efficiency of solar wall. With the increasing of A_o/A_f , the efficiency increases firstly, then increases more slowly, and finally comes to steady. The thickness also affects the efficiency in the same way. Though the results still need a further validation by experiments, they are initially proved correct by the qualitative analysis. The theoretical model can be a tool for the structural optimization of the Trombe wall combined with solar air collector.

Abstract: Titanium dioxide was synthesized by a simple micro-emulsion method at low temperature. By using different surfactants and different mass ratios of the titanium source to the surfactant in the micro-emulsion system, we obtained the size controlled micro-structured titanium dioxide. The synthesized materials were characterized by scanning electron microscopy, and X-ray diffraction. The 10~20nm TiO₂ nanoparticles are obtained by adjusting the different surfactants to control the surfactant aggregation. The highest photoelectric conversion efficiency of 7.38% was achieved in the N719-sensitized solar cells in which the nanometer-sized semiconductor TiO₂ was prepared by using TritonX-100 as the surfactant and the aqueous tetrabutyl titanate (TBT) as the titanium source with the ratio of 1:4 (TritonX-100 : TBT).

Abstract: Abstract. In order to solve the traditional sun dried pastures affected by natural conditions, serious winter pastures reserves shortage problem. It’s affect the development of tropical livestock seriously. With Tropical Research No.2 stylosanthes research for the study, we use Hainan island’s abundant solar radiation to design a solar drying equipment for tropical pastures. The main components of the device are solar collectors, drying tower, air blower, temperature and humidity monitoring systems,a preliminary design for the main components of the equipment, and made a part of the efficiency of the various experimental data and mathematical processing methods.Reseach the different positions of drying tower dry conditions of tropical forage, Reseach the influence of environment temperature and solar radiation, drying medium temperature on the quality of tropical pastures.It can provide technical support for the solar drying of tropical pastures and achieve economies of scale.

Abstract: Propose a new type of stand-alone movable wind-solar mutually complementary electricity-generating system with oxygen and water rationing function.The system integrates the wind and solar power systems,control systems and the user load equipments into a movable military square cabinet.It can be an effective solution to the problem of electricity supply for remote areas such as the field of military camps,the plateau and the island.This paper introduces the structure principle of the system and the manner of working,and also briefly describes its data acquisition system and control management process.

Abstract: The article deals with the modeling and simulation aspects of the performance improvement of a solar domestic hot water system. A mathematical model of this system is carried out to predict its operating performance under specified weather conditions of Jeju Island, Korea. The optimum mass flow rate through collector based on the relationship between the useful heat gain of solar collector and the electricity consumption of solar pump is investigated. Besides, the effect of various parameters such as solar collector area, initial water temperature and volume of storage tank is analyzed. The result of the simulation shows that the optimum mass flow rate was determined at kg/s with the new coefficient . At this value, the amount of useful heat gain slightly decreased about 84.3 (Wh) corresponds to 0.16% but the amount of electricity consumption strongly decreased about 227.8 (Wh) corresponds to 48.8% compares with kg/s ( ) was proposed by . Furthermore, the system performance is affected strongly by the change of collector area, initial water temperature and volume of storage tank.

Abstract: We show that the optical absorption in thin-film photovoltaic cells can be enhanced by texturing the silicon absorbing layer into nanostructured array. The optical absorption of the proposed configuration is enhanced by 70% compared to a nonpatterned silicon thin film of the same thickness. Furthermore, the proposed silicon thin film PV cell has a good angle-independent response of up to 60°. The omnidirectional absorbance enhancement of the nanopatterned silicon thin film is attributed to its unusual light trapping mechanism and omnidirectional bandgap.

Abstract: This paper proposes high accuracy modeling approach for PV arrays. The I-V characteristic of PV cell is described by nonlinear equation that’s complicated to be solved by the ordinary mathematical methods. The main theme of this contribution is to use a robust algorithm to solve for all single diode model parameters. Validation of the model with experimental data of Solarex MSX60 solar array is provided.

Abstract: Hexagonal boron nitride (HBN), which has the same crystal structure as graphite, has been used as catalytic material for a counter electrode in dye-sensitized solar cells (DSCs) to investigate its potential application. X-ray diffraction (XRD) has been used to confirm the crystal structure of HBN, scanning electron microscopy (SEM) has been used to characterize the morphology of HBN film on counter electrode, and electrochemical workstation has been employed to obtain the electrochemical impedance spectroscopy (EIS) and corresponding impedance parameters. Results show that the HBN film has rough surface and porous structure with pore size of less than 1 μm. When employed the HBN counter electrode to DSCs, the conversion efficiency (η) is only about a tenth of that of graphite based DSCs. Low efficiency of HBN based DSCs is induced by high charge transfer resistance (Rct) of HBN counter electrode, which means that HBN can hardly provide catalytic activity for the reduction of the triiodide ion. Therefore, the crystal structure is not a crucial factor to select the catalytic material for a counter electrode in DSCs. Moreover, the short circuit photocurrent density (Jsc) and the open circuit voltage (Voc) of device also evidently depend on the characteristics of catalytic material.

Abstract: In this paper a modeling method is investigated that finds the non-linear equation parameters of a photovoltaic (PV) module in order to obtain the desired PV model using any circuit simulator. This modeling method adjusts the I-V curve at three remarkable points: the open circuit voltage, the short circuit current, and the maximum power point [1]. Three models are realized using this technique namely, the single-diode model, the two-diode model, and the three-diode model. The evaluation study of the accuracy of these three models showed relative errors ranging from 32% to 50%. Further, this technique is improved by adjusting the I-V curve at more than three points depending on the number of unknowns to be found for each model, which showed a reduction in the relative error ranging from 0.37% to 38%.