Advanced Materials Research Vols. 724-725

Abstract: The study of heat loss and exergy loss distribution in the power plant system plays a very important role in improving the efficiency of the system. In this paper, a dynamic simulation model of the 5MW solar thermal power system is established. Then, the simulation test with the actual data in a solar thermal power plant is carried out, and we analyze the heat and the exergy loss of the system. The results show that, the heat loss of the condenser is the largest, up to 72%. To increase the thermal efficiency of the system, the energy-saving research for the condenser should be pay attention to. The solar collector field has the most of exergy loss in the system, accounting for approximately 89%. From the exergy efficiency perspective, the solar collector system has huge potential for energy- saving. The thermal efficiency and exergy efficiency of a solar thermal power plant system increases as the load increases, full-load operation of the unit should be maintained as much as possible.

Abstract: In this paper, a novel solar water heating system will be proposed by applying the loop heat pipe to a conventional split solar hot water system, which will have the characteristics of high efficiency, low cost, appearance appealing and building integration. Three types of the system, i.e., the system with evacuated tubes, with single flat-plate glazing cover, and without glazing, will be experimentally investigated and compared on the influence to the dynamic performance of the system. It was found that the system’s operating temperature increased significantly during the start-up stage and gently after until reach relatively constant. The instantaneous efficiency was found to be fluctuated, although it reached stable eventually during the operations for all three types. By using the moving average calculating method, every 10 minutes were applied for the calculation of the average efficiency which had a negative linear relation with the combined factor of (T_mean-T_amb)/I. In general, the solar system with evacuated tubes performed the best with the highest water temperature output, highest system efficiency and lowest heat loss coefficient among the three systems.

Abstract: The new concentrating photovoltaic (CPV) with core technology of III-V multi-junction cells, can significantly reduce the cost of photovoltaic system, and with advantages of high conversion rate, light weight, small size, energy saving and environmental protection, etc, which was widely regarded as the next-generation of solar photovoltaic technology. On the basis of the introduction of related research process, the paper concentrating discuss on the key technologies such as the new efficient multi-junction cells, high performance non-imaging concentrated light technology and sun tracking system, and propose the appropriate technical solutions, which can provide reference for the application and dissemination of the new generation concentrating photovoltaic.

Abstract: Transparent conducting gallium-titanium codoped zinc oxide thin films were grown onto glass substrates with magnetron sputtering technique in ambient argon gas, and the influence of argon pressure on optical properties of the films were investigated. The refractive indexes of the films were calculated. It is found that the refractive index tends to increase with increasing the photon energy. Meanwhile, the dispersion behavior of the refractive index was analyzed in terms of the single-oscillator model and the oscillator parameters were obtained. Furthermore, the optical energy gaps were evaluated by single-oscillator model and Tauc’s relation, respectively. The values of optical energy gap estimated from single-oscillator model are in agreement with those determined from Tauc’s relation.

Abstract: The discovery and heat-collecting principle of solar pond was introduced. Meanwhile, the research development of solar pond technology in experimental study and theoretical study were summarized. The development of solar pond technology in applied study also was described. Finally, the developing tendency of the solar pond technology was prospected.

Abstract: In this paper, the precision test method of single-axis PV track device is proposed by analyzing generator mechanism of PV module. In the process of the rotation of single-axis track device, the change of corner in space is considered. Suitable coordinate system is built in order to evaluate track device precision which normal vector of PV module and solar direction vector can be decomposed in this coordinate system. Meanwhile, the comparison on the tracking precision of PV track devices tested by different devices is made and the test uncertainty is researched as well. Experimental results verify the effectiveness of the method which is proposed in this paper.

Abstract: in order to study the output power of PV plant in depth, effective and reasonable methods of modeling for PV power plant are explored and adaptive neuro-fuzzy inference system (ANFIS) based on Takagi-Sugeno (TS) model is proposed in this paper. According to the power output characteristics of PV system and a variety of factors which impact, three kinds of model of PV plant power output are established based on subtractive clustering ANFIS. After model test and calculation for confidence interval estimate of power output, the results show that the accuracy of the model is able to meet the practical engineering application requirements and the second model is optimal by comparison. In conclusion, ANFIS provides an innovative and feasible model establishment method for the power output of PV plant.

Abstract: Use of automation technology sun tracking is to improve the photovoltaic efficiency of the important ways, according to research the power generating efficiency is increased by 30% to 40%, the existing solar power station solar light tracking for the software control, namely, according to historical data, based on the analysis and calculation of the solar motion law, writing software control, real-time monitoring, cumulative error manual correction, regularly. In order to solve the above problem, this paper describes the design of a novel solar tracking system, sensor, controller, actuator to carefully design and selection, based on the realization of the LOGO! Intelligent controller as the core of hardware platform, the development of the control software, and the system is simulated and validated, finally through the joint hardware and software debugging and practical operation, the system run stable and reliable work, and can switch reset and the weather conditions to realize the automatic open Ing and closing of the automatic tracking system of control function

Abstract: The disposal of PV systems will become a problem in view of the continually increasing production of PV modules. Development for waste PV modules recycling would be extremely effective in coping with this problem. In Europe, the thermal method and chemical method for PV recycling were deeply developed. The thermal treatment was to separate the module components under 600°C. The chemical treatment is to recover silicon wafers out of solar cells, which can be used again in modules. But automated separation of components and advanced chemical process needs to be studied on. In China, mechanical treatment research for PV recycling has just started. PV modules were separated and recycled by abrasive machining under the cryogenic condition and electrostatic separation. The mechanical treatment can't recycle silicon to reprocess new wafers for its low purity. Compared to the advanced technology in Europe, PV recycling in China is primary and badly in need of improving to face the huge PV module recycling demands in future.

Abstract: For the enzymatic saccharification of lignocellulosic biomass, single acid or alkaline pretreatment is not satisfactory because of the low sugar yields together with the neutralization of residual chemicals before enzymatic hydrolysis. Herein, an acid-alkaline two-stage pretreatment process was designed to treat corn stover. During the process, the pretreated liquid from the first stage and the solid residues from the second stage were mixed together for the subsequent simultaneous enzymatic hydrolysis, where a mixture of cellulase with an activity loading of 20 FPU/g substrate, cellobiase with an activity loading of 5 U/g substrate, and xylanase with an activity loading of 200 U/g substrate was used. Compared to the single acid or alkaline pretreatment, the acid-alkaline two-stage pretreatment could significantly improve the enzymatic saccharification, and 91.2% glucose yield with 52.56% of the theoretical total reducing sugar yield was achieved after the subsequent enzymatic hydrolysis.