共查询到20条相似文献，搜索用时 15 毫秒
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Bekir Sami Yilbas 《国际能源研究杂志》2019,43(1):4-8
In order to minimize dust effects on optical surfaces related to the solar energy harvesting, adhesion between the active surface of energy harvesting device and the dust particles needs to be lowered. Consequently, the pinning force for the dust particles reduces, and the dust particles can be removed via creating the self‐cleaning effect. The wetting state of the active surface becomes critical towards reducing the pinning force. In this case, hydrophobic surfaces remain favorable reducing the dust adhesion on the surfaces. In the present perspective, characteristics of the environmental dust particles and their effects in humid air ambient are presented. The methods for dust removal from the surfaces and the optical transmittance reduction by the dust particles are discussed. The challenges and future perspectives of surface texturing towards achieving hydrophobicity and optical transmittance are also introduced. 相似文献
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A. S. Abdelrazik K. H. Tan Navid Aslfattahi R. Saidur Fahad A. Al-Sulaiman 《国际能源研究杂志》2020,44(14):11487-11508
The present work investigates the effect of the nanoparticles concentration on the optical and stability performance of a water-based nanofluid in solar photovoltaic/thermal (PV/T) systems experimentally and numerically. A novel nanofluid is formulated with the inclusion of the reduced graphene oxide decorated with silver (rGO-Ag) nanoparticles in water. Five different concentrations of nanoparticles in the range from 0.0005 to 0.05 wt% is suspended in water to prepare the samples. Optical properties are measured using UV-Vis. The UV-Vis absorption analysis reveals that all samples show consistent optical absorption coefficient (α) at higher value (more than 3 cm−1) in the range of 1.5 to 4 eV. The application of optical filtration (OF) using water/rGO-Ag nanofluid in hybrid PV/T system presented more solar energy absorption through the OF. The hybrid system shows better performance at concentrations less than 0.0235 wt% compared to the PV system without integration with optical filtration. The hybrid solar PV/T system with OF using water/rGO-Ag nanofluid is able to produce thermal energy with efficiencies between 24% and 30%. 相似文献
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Redhwan A. Moqbel Mohamed A. Gondal Talal F. Qahtan Mohamed A. Dastageer 《国际能源研究杂志》2018,42(4):1487-1495
The large‐scale applications of cadmium sulfide (CdS) nanoparticles (NPs) as a photo‐catalyst are limited by their poor stability (high aggregation tendency) and consequent reduction in the surface area and increased rate of recombination of photoinduced electron‐hole pairs, despite its inherent positive feature of being visible light active. It has been reported that the photocatalytic performance of CdS can be considerably improved if CdS is made as a composite material with reduced graphene oxide (rGO) in an optimum ratio. In this work, for the first time, we adopted the technique of pulsed laser ablation in liquids (PLAL) to synthesize highly pure CdS NPs and the required CdS/rGO nanocomposites using high purity (99.9%) microstructured CdS and graphene oxide as chemical precursors. PLAL is a simple and rapid 1‐step synthesis process (where the reaction time is reduced from several hours to a few minutes), which does not require high temperature, toxic chemicals, and the final treatment to remove the unwanted by‐products. The optical and morphological characterizations revealed that the anchoring of CdS on rGO transformed the CdS/rGO composite into an efficient photo‐catalyst by enhancing the following positive attributes required for a good photo‐catalyst: (1) The inherent tendency of aggregation of CdS is considerably reduced; CdS NPs with an average grain size of 20 nm are well placed on the rGO sheets; and hence, the surface area of the catalyst was significantly increased to provide more active sites. (2) The reduced rate of photoinduced electron‐hole recombination manifested in the photoluminescence spectrum indicated the effective charge separation. (3) The enhanced light absorption in the visible/infrared region ensured the effectiveness of this material in naturally abundant solar radiation. In the CdS/rGO composite, the rGO sheets play the role of a supporting matrix, cocatalyst, and electron acceptor for CdS. To evaluate the photo‐catalytic performance of CdS/rGO, we applied it as a visible light‐driven photo‐catalyst for degrading methylene blue dye and found that CdS/rGO nanocomposite was more efficient than pure CdS in the visible spectral region. Therefore, PLAL provides a simple and 1‐step route to synthesize high‐purity visible light–driven photo‐catalysts and solar cell material. 相似文献
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Normal luminescent solar concentrators (LSC) have a great limitation in their light transportation because the light produced by the recently reported LSCs is not a point light source. In order to enable LSCs to use optical fibers as the effective remote light transport media, a new design of LSC, which uses three color luminescent fibers for solar absorption and uses clear optical fiber bundles to transport the absorbed sunlight into a remote place, is fabricated and tested. Radiation flux ratios with a mean value of 5.7%, the luminous flux up to 114.1 lumens, and the light efficiency of 0.56% have been achieved during the trial run. The luminous efficacy as 0.643 lm W−1 is higher than that of combusting candles (0.3 lm W−1) but lower than that of the incandescent light bulbs (16–40 lm W−1). Further, since the sun light is free, different from electrical light sources, the luminous efficacy of the new LSC does not result in any electricity consumption when it is under operation. A color analysis and spectrum test proves that the light produced by the new LSC performs a great match to the direct sun light in color. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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The transmission properties of water and sodium chloride water solutions with various salt concentrations were investigated. This paper concerns the measurement of the spectral transmittance and the calculation of the total transmittance for water and NaCl water solutions. The spectral transmittance of the NaCl water solutions over the infrared and nearby regions increased with increasing salt concentration for constant specimen thickness and air mass. The spectral transmittance was found to be useful for precisely calculating the thermal performance of a solar pond, and by using an effective absorption coefficient, a five-partition method dividing the wavelengths into five bands by which the total transmittance up to a water depth of 3 m could be calculated, was found to be important as a practical method of solar pond technology. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 26(1): 1–15, 1997 相似文献
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Energy harvesting from pavements has been a topic of extensive research in the recent past. This domain has attracted not only the research community but also the industry and governmental authorities. The various sources exploited for energy harvesting from pavements and roadways are solar radiation, mechanical energy dissipated due to moving vehicles and pedestrians, geothermal energy, rainwater, and wind. This article presents an exhaustive and updated review of all potential means of energy harvesting from these sources. Following the introductory section, the article sequentially covers the energy harvesting methods and their research progress, materials, development of practical systems, commercial status, comparison of technologies, challenges, and concluding remarks. This study reveals that there is wide scope for further research and feasibility studies, which could lead to a wide‐spread implementation of the various technologies for energy harvesting from pavements and roads. 相似文献
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利用EnergyPlus建立通风型非晶硅光伏窗传热、采光、发电的综合模型,研究不同透过率下非晶硅光伏窗的热光电性能。使用实验数据验证所建模型的准确性,并用验证的模型分别研究不同气候区非晶硅光伏窗透过率对发电量、室内照明能耗、空调能耗、综合能耗的影响。结果表明:适宜透过率的光伏窗产生的电量能对建筑空调采光能耗进行补偿,使整体能耗最少。广州、昆明、长沙、北京、哈尔滨5个城市综合能耗最少时的最佳透过率分别为0.22~0.25、0.25、0.25~0.30、0.25~0.30、0.35。 相似文献
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一座典型建筑物的窗户覆盖透明蜂窝后的热环境分析 总被引：1，自引：0，他引：1
透明隔热材料（ＴＩＭ）的热损系数Ｕ值低于１．５Ｗ／ｍ２·Ｋ，太阳辐射的透过率大于７０％，在被动式太阳房中具有良好的应用前景。粗略地模拟了当建筑物的南窗很大并覆盖透明蜂窝时，在夏季和冬季的日照和气候条件下室内温度的动态变化。结果显示该房具有良好的热性能。 相似文献
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针对线性菲涅尔反射式（LFR）聚光集热系统镜面积尘所引起的光学损失问题,建立镜面积尘的系统三维模型,利用蒙特卡洛光线追迹法进行光学仿真模拟,研究灰尘颗粒形状、粒径以及镜面积尘密度对光线路径、系统能流密度和聚光效率的影响,并利用LFR能流密度测试系统来验证仿真模拟方法的可靠性。结果表明,球体颗粒对光线有汇聚作用,入射至正方体颗粒的光线会被完全吸收,镜面积尘密度增加1 g/m2,吸热管周的平均能流密度降低625.17 W/m2,系统的聚光效率下降5.53%,且镜面积尘颗粒的粒径越小,吸热管周的能流密度下降越严重,不同积尘密度下仿真模拟与试验测试的能流密度变化趋势一致,两者之间误差为9.6%。 相似文献
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采用直流及中频反应溅射在铜基底上沉积SiCrOxNy光谱选择性吸收涂层。对该涂层的光学性能进行表征,其吸收比为0.938,80℃发射比为0.07。经300℃,200 h热处理后,吸收比无明显变化,发射比小幅升高;俄歇电子能谱(AES)分析显示,界面处元素扩散和Cu基底氧化是涂层光学性能下降的主要原因。在35℃下进行5%盐雾腐蚀试验,腐蚀初期涂层发射比迅速升高,腐蚀36 h后吸收比衰减加速,涂层表面开始出现剥落现象;致密的SiO2减反射层对增强涂层耐盐雾腐蚀性能有明显效果。 相似文献
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庞杰;何易卓;方志刚 《节能》2022,41(7):43-48
为解决小型用电设备供电问题,通过分析现有对发电地砖的相关研究,设计了一种基于双向机械式整流装置的机械电磁式发电地砖,以回收地砖顶板上下移动产生的动能。根据机电相似原理建立了发电地砖的仿真模型,在Matlab/Simulink中进行了仿真分析,分析了回位弹簧刚度和负载电阻对系统输出功率以及能量回收率的影响,并对刚度和电阻值进行了优化。结果表明：在所得最优条件下,系统的平均输出功率为4.4 W,能量回收效率为68.25%,证明了该发电地砖具有较高的使用价值。 相似文献
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Solar energy is one of the most promising forms of renewable energy for solving the energy crisis and environmental problems. Dust deposition on photovoltaic mirrors has a serious negative impact on the photoelectric conversion efficiency of solar power stations. In this paper, the influence mechanism of the dynamic and static liquid bridge forces on particle deposition behaviors on solar photovoltaic mirrors is investigated. In addition, the expression and physical meaning of the particle critical separation velocity are proposed. The research results show that the static liquid bridge force can be the primary deposition force causing dust particles to adhere to photovoltaic mirrors. However, the dynamic liquid bridge force can act as a resistance force for the particle motion process and even make dust particles roll along and finally stay on the mirror. The contact force is the primary separation force that causes dust particles to flow away from the mirror. Whether dust particles adhere to the mirror depends on the relative size of the deposition and separating forces. The particle critical separation velocity describes the relative size of the collision-rebound effect and mirror adhesion effect and is expressed in Eq. (16). These research findings can provide theoretical guidance for mirror cleaning methods in the operation process of photovoltaic mirrors. 相似文献
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利用分光光度计对建筑材料表面,对紫外到近红外线范围(240～15000nm)内的正分光透射比、正分光反射比进行测定.另外,还利用积分球对紫外到红外线范围(240～2200nm)内的漫射比谱进行测定,同时将测定结果与正分光透射比、反射比进行比较,并计算出太阳吸收比及热放射比. 相似文献
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基于菲涅尔透镜的聚光特性和极轴跟踪原理,提出一种能实现定焦点聚光的太阳能聚光器,详细分析聚光器的定焦点聚光原理,并搭建实验平台对其聚光焦斑位置偏差进行红外热成像分析。实验结果表明,全天聚光焦斑相对位置偏差最大值为5.72%,且焦斑基本分布于以基板中心为圆心、半径50 mm的圆环区域内,即实现定焦点聚光。同时利用TracePro值为3.56%,且焦斑分布情况与实验基本一致。结合全年太阳赤纬角的变化,对真太阳时为08:00～16:00的聚光焦斑位置偏差情况进行模拟分析,结果表明该聚光器的全年聚光焦斑相对位置偏差最大值为4.84%,进一步验证了聚光器能实现全年定焦点聚光。 相似文献