平板型太阳能集热器性能研究分析

平板太阳能集热器构件材料和安装角度是影响集热器的集热效率的关键。研究通过改善透明盖板的性能和确定一种合理计算最佳倾角的简便方法来提高集热效率的方法。在理论的基础上,通过集热器的数学模型,比较了不同盖板对集热参数和效率的影响。根据前人总结的最佳倾角的公式,再结合地区的气象参数,比较精确地确定了安装角度的便捷公式。     

掺W对染料敏化TiO2电极光电性质的研究

用双靶直流磁控共溅射方法在FTO透明导电玻璃上沉积掺W的TiO2薄膜.采用原子力显微镜、喇曼光谱仪和透射光谱仪对其表面形貌、晶体结构及光学性能进行了分析.研究发现适量的掺w有利于改善TiO2薄膜的表面结构,并有利于提高染料敏化电池的短路电流;但过量的掺w减弱了锐钛矿相,TiO2薄膜转变为金红石相结构;适量W掺杂TiO2薄膜经敏化组装的太阳能电池,有利于提高其短路电流及光电能量转换效率,不利于提高其开路电压.     

PCB钻孔用涂胶铝基盖板的制备及其性能分析

以聚乙二醇（PEG）、聚环氧乙烷（PEO）、粘结树脂等为基本涂层材料,以铝箔为基材,成功制备了高性能的PCB钻孔用铝基盖板材料。对PCB铝基盖板产品的外观、热熔性、水溶性等基本性能进行了测试和分析表明：铝基盖板上的涂层表面较为平整且无相分离结构,便于钻孔;铝基盖板涂层的吸热性能良好,有利于在打孔时带走钻头的热量,降低钻头的温度,保护钻头;涂层的水溶性能也较好,即使在钻孔时被钻头带入PCB板材,也容易用水冲洗掉。利用涂胶PCBX铝基盖板进行钻孔测试发现,所制备的PCB铝基盖板产品在断刀率、耐磨耗、孔位精度等方面均要优干常规铝箔．可见,涂胶蓑板的基本性能完全满足PCB用高性能铝基盖板的要求．     

手机彩屏的种类及特点

随着移动多媒体时代的到来,人们对手机显示屏性能的要求也越来越高,市场上争奇斗艳的彩屏手机可谓让人眼花缭乱。购买手机时,单说选彩屏手机似乎太笼统了,要知道,“彩屏”两个字还有很多学问呢。目前,彩屏手机所采用的液晶显示器(LCD)主要有以下几种:STN、TFT、UFB、TFD和GF。下面详细介绍其特点,或许能对大家购机有一定帮助。STN(Super Twisted Nematic)的中文含义是超扭曲向列,是由TN(Twisted Nematic扭曲向列)型液晶发展而来的。在两片玻璃中间填充向列型液晶材料,玻璃的表面上镀有一层导电的透明薄膜和表面配向剂,透明薄膜作…     

AZO透明导电薄膜的工艺优化及其在叠层硅薄膜太阳能电池上的应用

本文利用直流磁控溅射法在玻璃衬底上制备了低电阻率、高透光率的掺铝氧化锌（ZnO:Al）透明导电薄膜,经过稀盐酸腐蚀制绒后,作为前电极应用于叠层硅薄膜太阳能电池。详细讨论了溅射和腐蚀工艺参数对薄膜光电性能的影响。优化工艺制备出的AZO薄膜具有高散射能力的表面形貌,其透光率在81%以上（380~1100nm范围）,方块电阻和雾度分别为11Ω/□和41.3%。AZO薄膜作为前电极应用于a-Si:H/μc-Si:H双结薄膜太阳能电池,小面积电池的初始转换效率达到了12.5％。     

ITO薄膜的电阻并联效应研究

采用电子束蒸发镀膜方法在K9玻璃基底上分别镀制了ITO/SiO₂/ITO,ITO/Ti₂O₃/ITO和ITO/MgF₂/ITO结构的多层薄膜,用四探针方块电阻仪测量薄膜表面的方块电阻,用原子力显微镜观测样品的表面微观形貌。结果显示,当ITO薄膜的粗糙度较大且介质薄膜的物理厚度小于100nm时,各层ITO薄膜之间通过山峰状的凸起结构相连通,导致样片表面的方块电阻测量值与各层ITO薄膜电阻的并联值相当。这表明,当ITO薄膜的粗糙度较大且介质薄膜厚度较小时,各层ITO薄膜表现出电阻并联效应。利用多层ITO薄膜的电阻并联效应设计并制备了450～1200nm超宽光谱透明导电薄膜,用四探针方块电阻仪测量了试验样片的表面方块电阻,用紫外-可见-近红外分光光度计测试了样片的光谱透射率。结果显示,在相同表面方块电阻条件下,相比于单层ITO薄膜,利用ITO薄膜电阻并联效应所制备的多层透明导电薄膜具有更高的光谱透射率。     

薄膜厚度对ZnO：Zr透明导电薄膜光电性能的影响

利用射频磁控溅射法在室温水冷玻璃衬底上制备出了可见光透过率高、电阻率低的ZnO:Zr透明导电薄膜.讨论了厚度对ZnO:Zr透明导电薄膜光学、电学性能的影响.当薄膜厚度为213 nm时,薄膜电阻率达到最小值1.81×10-3 Ω·cm.所制备的薄膜样品都具有高透光率,其可见光区平均透过率超过了93.0%.当薄膜厚度从125 nm增加到350 nm时,薄膜的光学带隙从3.58 eV减小到3.50 eV.     

不同衬底沉积Ti-Al共掺杂ZnO薄膜的性能对比研究

利用直流磁控溅射法,在玻璃衬底和Si片衬底上分别沉积出了Ti-Al共掺杂ZnO透明导电薄膜(TAZO),并对这两种衬底上的薄膜的应力、结构和光电性能进行了对比研究.结果表明:玻璃衬底和Si片衬底上沉积的TAZO薄膜均为具有c轴择优取向的六角纤锌矿结构多晶薄膜,Si片衬底的TAZO薄膜的导电性能优于玻璃衬底上的TAZO薄...     

柔性ITO薄膜表面无敏化法选择性化学镀镍研究

通过化学镀镍对聚对苯二甲酸乙二醇酯(PET)基体表面氧化铟锡(ITO)薄膜进行金属化处理从而提高其导电性能。该化学镀镍工艺不同于传统工艺,无需敏化,直接经过活化还原后实现在柔性ITO薄膜表面选择性化学镀镍。采用扫描电子显微镜(SEM)、结合力测试和导电性测试对镀层形貌和性能进行表征。结果表明,ITO表面镀镍层均匀致密、附着力好,PET基体无镍层覆盖,具有高度的选择性,且极大提高了柔性ITO薄膜的导电性和疏水性能。     

太阳能选择性吸收薄膜的微结构分析

本文介绍了在铝衬底上采用阳极氧化,电解着色方法制备的太阳能选择性吸收薄膜,并运用扫描电子显微镜和扫描俄歇电子能谱仪对薄膜结构进行了表面形貌和元素分布的深度剖析,测定了涂层的反射率和吸收率,获得了性能较好的涂层试样。     

Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator

In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.     

Performance Study of Thermoelectric Solar-Assisted Heat Pump with Reflectors

The simultaneous conversion of solar radiation into thermal and electrical energy in a thermoelectric (TE) solar-assisted heat pump is, for the purposes of this study, referred to as hybrid conversion. To capture more thermal and electrical energy, flat-plate reflectors have been mounted on a TE solar collector. To obtain higher solar radiation intensity on the TE solar collector, the position of the reflectors has been changed and the optimal position of the reflectors determined by both experimental measurements and numerical calculation so as to obtain maximal concentration of solar radiation intensity. The calculated values have been found to be in good agreement with measured ones. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the TE solar-assisted heat pump with reflectors. For the optimum position of the reflectors, the coefficient of performance (COP) of the system formed from a TE solar collector integrated with a heat pump (TESC-HP) was 5.60. The power output and conversion efficiency of the TE modules can reach 10.09 W and 2.40%, respectively, being improved by 34.5% and 18.2%, respectively, compared with the TESC-HP without reflectors.     

Feasibility Study on the Use of a Solar Thermoelectric Cogenerator Comprising a Thermoelectric Module and Evacuated Tubular Collector with Parabolic Trough Concentrator

We have designed a new solar thermoelectric cogeneration system consisting of an evacuated tubular solar collector (ETSC) with a parabolic trough concentrator (PTC) and thermoelectric modules (TEMs) to supply both thermal energy and electricity. The main design concepts are (1) the hot side of the TEM is bonded to the solar selective absorber installed in an evacuated glass tube, (2) the cold side of the TEM is also bonded to the heat sink, and (3) the outer circulated water is heated by residual solar energy after TEM generation. We present an example solar thermal simulation based on energy balance and heat transfer as used in solar engineering to predict the electrical conversion efficiency and solar thermal conversion efficiency for different values of parameters such as the solar insolation, concentration ratio, and TEM ZT values.     

Overall efficiency enhancement and cost optimization of semitransparent photovoltaic thermal air collector

A semitransparent photovoltaic‐thermal (PV/T) air collector can produce electricity and heat simultaneously. To maximize the thermal and overall efficiency of the semitransparent PV/T air collector, its availability should be maximum; this can be determined through a Markov analysis. In this paper, a Markov model is developed to select an optimized number of semitransparent PV modules in service with five states and two states by considering two parameters, namely failure rate ( λ ) and repair rate (µ). Three artificial neural network (ANN) models are developed to obtain the minimum cost, minimum temperature, and maximum thermal efficiency of the semitransparent PV/T air collector by setting its type appropriately and optimizing the number of photovoltaic modules and cost. An attempt is also made to achieve maximum thermal and overall efficiency for the semitransparent PV/T air collector by using ANN after obtaining its minimum temperature and available solar radiation.     

Performance Study of a Double-Pass Thermoelectric Solar Air Collector with Flat-Plate Reflectors

In this paper the results of the influence of flat-plate reflectors made of aluminum foil on the performance of a double-pass thermoelectric (TE) solar air collector are presented. The proposed TE solar collector with reflectors was composed of transparent glass, an air gap, an absorber plate, TE modules, a rectangular fin heat sink, and two flat-plate reflectors. The flat-plate reflectors were placed on two sides of the TE solar collector (east and west directions). The TE solar collector was installed on a one-axis sun-tracking system to obtain high solar radiation. Direct and reflected incident solar radiation heats up the absorber plate so that a temperature difference is created across the TE modules to generate a direct current. Only a small part of the absorbed solar radiation is converted to electricity, while the rest increases the temperature of the absorber plate. Ambient air flows through the heat sink located in the lower channel to gain heat. The heated air then flows to the upper channel, where it receives additional heating from the absorber plate. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the double-pass collector system with reflectors and TE technology. It was found that the optimum position of the reflectors is 60°, which gave significantly higher thermal energy and electrical power outputs compared with the TE solar collector without reflectors.     

A General Model for the Electric Power and Energy Efficiency of a Solar Thermoelectric Generator

A general model for the electric power and energy efficiency of a solar thermoelectric generator is discussed, considering the influences of the input energy, the thermal conductivity, the absorptivity and emissivity of the heat collector, and the cooling water. The influences of these factors on the performance of the thermoelectric device are discussed, considering the thermoelectric generator as a whole, including the heat collector, the thermoelectric device, and the cooling. Results show that high input energy, and high absorptivity and low emissivity of the heat collector, are helpful for obtaining a high-performance thermoelectric generator. A high thermal transfer coefficient of the cooling water can increase the temperature difference across the thermoelectric device but results in greater accessory power requirements if increased further.     

太阳能热水系统中蓄热水箱温度分层研究及发展趋势

太阳能热水系统中蓄热水箱合理的温度分层,一方面可以降低集热器进口温度,减少热量损失,提高集热器效率;另一方面可以提高储罐内可用能量,减少辅助热量,缩短系统从开启到有可用能的时间,从而提高可用能的品质,是提高太阳能热水系统性能的关键问题之一。目前实现水箱温度分层的主要方法有改进水箱内部结构和进出口结构两种。综合国内外文献,从太阳能储热水箱温度分层的研究现状和改进方法两个方面介绍并分析了蓄热水箱的内部结构、进口结构等因素对蓄热水箱温度分层的影响,并展望了温度分层型蓄热水箱的研究趋势。     

全玻璃真空管太阳能集热器研究方法概述及计算模型分析

基于实验测试、数学模拟、模型分析等方法,介绍了国内外全玻璃真空管太阳能集热器的研究现状和发展趋势。分析各影响因素对集热效率的影响,确定最佳倾角,提高集热性能和优化结构是集热器研究的重点。在此基础上重点介绍了真空管式太阳热水器能量收益和效率模型、标准光-热性能计算模型、自然对流的冷热水循环计算模型和强制循环太阳能热水系统计算模型。     

Optical Design of Silica Aerogels for On-Demand Thermal Management

Silica aerogels, a type of porous material featuring extra low density and thermal conductivity, have drawn increasing interest from both academia and industry owing to their excellent thermal insulation performance. However, thermal insulation is always the single consideration when silica aerogels are used for thermal management. In this study, the on-demand thermal management (ODTM) of silica aerogel with either passive thermal insulation, passive heating, or passive cooling in different environments is revealed. The ODTM behavior of silica aerogels can be simply fulfilled through their optical property variations such as solar light transparency and infrared emissivity, which are controllable via the microstructures of the building blocks and surface composition design. Robust solar heating of 25 °C higher than the ambient in the daytime and sub-ambient cooling of 7 °C at night is achieved with the traditional transparent silica aerogel. Interestingly, sub-ambient cooling of 5 °C in the daytime and a warmer state on cold nights is achieved by modifying its solar transmittance and infrared emissivity. This study guides a comprehensive understanding of the thermal management behavior of silica aerogels and leads to ODTM applications of silica aerogels by tailoring their optical and thermal conductivity properties.     

基于OMRON PLC的太阳能集热系统设计

本文详细介绍了基于OMRON PLC的太阳能集热器控制系统的设计方案,采用CJ1系列PLC作为核心控制器,采用复杂的数学公式计算出太阳角度,通过PLC和NC位置控制模块输出脉冲信号控制步进电机,并设计聚焦反馈系统形成闭环控制,使集热管始终处于焦点位置,极大的提高了太阳能系统的集热效率。控制系统充分利用PLC的功能块功能,使控制系统的开发周期短,维护方便。