Advanced Materials Research Vols. 1008-1009

Abstract: According to the theory of solar energy and vibration energy harvesting, an energy harvesting system based on energy conversion scavenging technology has been designed to convert the solar energy and vibration energy into the electric power. Piezoelectric materials and the solar cells are used as core power conversion section, and the system also consists of the lithium battery charge chip, the rectifier, comparators and switch chips as the control segments, combined with the super capacitor, etc. The energy harvesting experiment shows that the lithium battery can be charged through solar and vibration by the solar and vibration energy harvesting system, and the charging chip adopted in this work has input voltage limited current mode which can fulfill intermittent charge smoothly.

Abstract: Through the comparative study of solar capillary low-temperature hot water radiant heating system with air source heat pump system has found that solar energy heat collecting efficiency has a great relationship with the collector temperature for the given system. To reduce the temperature of solar heat collector circulating water can greatly improve the heat collecting efficiency of the heat collector .With the increase of temperature of the water in the heat collector, heat collecting efficiency decrease rate changes linearly. Increasing water storage can improve the heat collecting efficiency, for this heat collecting system, the optimum collector temperature is 32 °C. In this study, COP reached 5 when the low temperature solar hot water capillary system mode is being used, and this result is nearly 5 times higher than that of the air source heat pump mode . Using the low temperature solar water heating capillary system, 27.35 kwh / (m² ·heating season) of electricity can be saved compared with the amount of electricity consumed by air source heat pump. According to the price of current Beijing city , the estimated period of investment payback is 4.8 years .

Abstract: This paper introduces a new type of solar water heater——Parabolic trough solar water heater,the biggest feature of the solar water heater is that the parabolic trough reflector can reflect light onto the tube with reflective principles,which may lead to lots of advantages,such as more strong solar energy flux density,fewer losses,fewer tubes used.In a word,the cost is reduced while the performance is guaranteed.On this basis,we built a collector area of about 1.54 square meters of parabolic trough solar water heaters bench and made experiments to test.Instantaneous average efficiency and daily average efficiency of the water heater can be calculated.Efficiency curve can also be generated.Meanwhile we measured the heat loss coefficient of the water heater.The results showed that the daily average efficiency of the parabolic trough concentrating solar collector is between 30% and 50%,while at higher temperatures the collector showed its good insulation properties.

Abstract: In order to use photovoltaic cell effectively and improve its photoelectric conversion efficiency, the maximum power point of photovoltaic generation system should be tracked rapidly and stably [1]. Taking into account the solar PV systems are often affected by external factors,it is difficult to determine system parameters, and has a strong non-linear,so this paper,a adaptive fuzzy logic control technology for STP0950S-36 type of independent photovoltaic systems to a adaptive fuzzy controller design method, and using MATLAB/SIMULINK,fuzzy logic toolbox for simulation tools such as maximum power point control,adaptive fuzzy control simulation results of MPPT with fixed step method compared to fixed-step method was found to reach steady there is a certain state after the fluctuation,The results show that the method can quickly and correctly track change of MPP in different light intensity and the system has excellent stability performance.

Abstract: We firstly established stimulation model of parabolic trough solar hot water system with TRNSYS software.Based on the simulation model and the weather data of typical meteorological year in Tianjin,research was made on simulation and optimization from three aspects including the type, the inclination and azimuth,the ratio between the tank volume and the collector area,the water temperature ,the load and the tube length.We found that the efficiency and solar fraction of different types is different in 12 months throughout the year;There are great differences in the performance of different inclination and azimuth;The yearly efficiency and solar fraction will increase with the increase of the ratio between the tank volume and the collector area;When the temperature of water increases, the yearly efficiency and solar fraction will decrease and when the water load increases,the yearly efficiency will increase while the solar fraction will decrease;With increasing of the tube length ,the yearly efficiency and solar fraction will decrease.

Abstract: Dye-sensitized solar cell (DSSC) is part of the thin film family that consists of a TiO2 electrode coating which acts as a photo electrode, sensitizer from dye molecules soaked in the TiO2 film, electrolyte layer and a counter electrode. This paper focuses on the usage of a sensitizer from the rose flower and will review some of the research conducted on dye sensitizers from other researcher. Rose flower also known as woody perennial of the genus Rosa, within the family Rosaceae is extracted and were used as sensitizer to fabricate dye sensitized solar cell (DSSC). The photoelectrochemical performance of Rose sensitized solar cell shows parameter of open circuit voltage, V_OC, short circuit current, (I_SC), fill factor (FF), solar cell efficiency (η), and peak absorbance rate as much as 0.13 V, 57.58 µA, 0.58, 0.85% and 3.5 at 550nm respectively. The photoelectrochemical performance of DSSC and the usage of natural sensitizer from Rose flower dye demonstrate good potential to be applied as a sensitizer yet detail investigations are essential in terms of its applicability for long term application.

Abstract: Dye Sensitized Solar Cells (DSSC) is another kind of solar cell from the third generation that forms a photovoltaic. DSSC is designed to reduce cost from usage of expensive material in conventional solar panels. The purpose of this project is to fabricate and compare dye sensitized solar cells (DSSC) by using organic dye from blueberry and blue dye from chemical substances. The DSSC is fabricated using ‘Doctor Blade’ method. Results are based on investigating the electrical performance and characteristic of the fabricated TiO₂ solar cell based on these comparisons of dyes in order to investigate the potential of organic dyes as a light absorbing mechanism. The required data that is investigated are the open circuit voltage, Voc, short circuit current, Isc, fill factors, solar cells efficiency and UV absorption. Result shows good potential in the blueberry dyes as a sensitizer but further investigation is needed in order to fully understand the characteristic of these organic dyes.

Abstract: The recycling energy problem is one of the key problems of the Stratospheric Airship. This paper analyzes the “night power supply system” of the Stratospheric Airship combining the energy storage device and its corresponding solar batteries. Compared with the Li-ion battery, Regenerative Fuel Cells have low energy conversion efficiency, resulting that the solar batteries combined with them for “night power supply system” have to be much heavier. Unless the specific energy and energy conversion efficiency of the Regenerative Fuel Cells improve obviously, it will not show much progress compared to Li-ion battery.

Abstract: This study adopted analytical hierarchical process (AHP) to evaluate the significance of the criterion of policy regarding promoting biomass energy, taking environmental social groups’ points of view into consideration. The analytical results of the study are as follows. The experts from environmental social groups suggested that the most important major criteria are in the order as follows: policy criterion layer, technical criterion layer, economy criterion layer, and energy education criterion layer. As for the global weights of the criteria, the criteria with top five weights are in the order as follows: “active development of green energy industry by government”, “supply and consumption method of low-carbon and low-pollution energy”, “increase of percentage of power generation from renewable energy in total power supply”, “encourage manufacturers to develop new biomass power generation technology”, and “continually develop the technology projects which has potential and prospects in the future”.

Abstract: A field experiment was carried out to study the growth characteristics of switchgrass cultivated in saline-alkali lands. The results show that: the survival rate, plant height, tiller numbers per plant and biomass yield of switchgrass significantly reduce with the increasing magnitude of salinity-alkalinity stresses. Switchgrass can grow in saline-alkali environments, the survival rate is more than 85%, and the overwintering rate is more than 95%. Switchgrass plants grow better in mild and moderate saline-alkali lands, and it achieve the highest biomass yield and theoretical ethanol yield of 14.3 t/ha and 5958.8 l/ha respectively, in the third year. With saline-alkali stress, ash and lignin content of switchgrass biomass increase, calorific value, cellulose and hemicelluloses content of switchgrass biomass decrease, and fuel quality of switchgrass biomass reduce to a certain extent.