Preparation and solar reflectance spectra of chameleon-type building coatings

In this paper, the preparation of chameleon-type building coatings was investigated. The reversible thermochromic properties of the chameleon-type building coatings at normal temperatures were measured, and their solar reflectance spectra were measured. The results showed that the colors of the chameleon-type building coatings could be changed reversibly between red, violet etc. below 18°C and white above 18°C. The solar reflectance spectra of the coatings showed that they could absorb more solar energy below 18°C than above 18°C, which indicated that the coatings had transformed between light-absorbing and light-reflecting at normal temperatures. The characteristics of the coatings could be used to create a thermally comfortable building environment.     

吸能超双疏防覆冰涂层对风机叶片防覆冰影响研究

为了解决风机叶片的覆冰问题,对风机叶片基材涂覆吸能超双疏防覆冰涂层,研究吸能超双疏防覆冰涂层的接触角、滚动角、覆冰减少率、冰粘结力、低温脱冰性能和表面温升。通过实验表明:吸能超双疏防覆冰叶片样板具有超疏水、超疏油性能,覆冰比空白叶片样板减少了55%,水平粘结力比空白叶片样板减少了99%,垂直粘结力减少了89%;吸能超双疏防覆冰涂层表面有温升效果,-2℃环境温度下,晴天天气涂层表面温升为4.2℃,多云天气涂层表面温升为2.4℃,阴天天气涂层表面温升为1.7℃。因此,超双疏防覆冰叶片具有超双疏、减少覆冰量、降低冰附着力和低温脱冰的性能,改善了风机运行中叶片覆冰的问题。     

Analyses of reversible solid oxide cells porosity effects on temperature reduction

This study is based on reversible Solid Oxide Cells (rSOCs) numerical and experimental analysis. To increase the cell application and accommodate a variety of excellent materials to be adopted in this innovation, the operating temperatures has to be lowered. Porosity control is used to substitute the high operating temperatures. Pretreatment and sintering procedures are used to adjust a button cell porosity. Experimental results include property measurements for porosity and ionic conductivity to understand the cell performance. A cell sintered at 1400 °C with 36.2% porosity renders superior results compared to the other conditions. Improved performance has been noted on 40-30% porosity decrease. COMSOL Multiphysics is used to simulate the experimental procedures. Butler–Volmer equation is implemented to predict the cell current density distribution, and Modified Stefan-Maxwell diffusion model incorporating Knudsen diffusion equation has been used for multicomponent diffusion.     

Questionable effects of antireflective coatings on inefficiently cooled solar cells

A model for temperature effects in p–n junction solar cells is introduced. The temperature of solar cells and the losses in the solar cell junction region caused by elevated temperatures are discussed. The model developed is examined for low-cost silicon solar cells. Plots of output power and efficiency as functions of the time throughout the day are presented. In order to improve the shape of the output power and efficiency curves throughout the day the coherence between technical parameters of the solar cells and the climate in the operation region is observed and examined. It is shown how the drop in output power around noon can be avoided by fitting technical parameters of the solar cells to the climate.     

可逆流光伏与市电联合供电能量管理研究

针对光伏直流供电系统的能量变动性,提出了使用市电作为直流负载的能量补偿来源。系统由光伏电池、市电、移相全桥变换器、PWM整流器组成。在光伏发电能量大于负载所需时,将多余的能量馈送电网;在光伏发电能量不足时,由市网补充。系统的核心是实现光伏、市电、负载三者之间的能量管理。文章首先对整个供电系统进行了分析,然后讨论了系统的不同工作模式,最后提出了市电的能量补偿控制策略。仿真和实验表明所提的系统结构和控制策略能够实现市电与光伏供电系统的稳定联合供电。     

A correlation between normal and hemispherical emissivity of low-emissivity coatings on glass

Transparent low-emissivity coatings are commonly used to reduce the thermal conductance of windows. It is important to be able to characterize and compare the wide variety of these coatings that are now available. The property that best describes the effectiveness of a coating in suppressing radiative heat transfer is the total hemispherical emissivity. It is much simpler, however, to measure the normal emissivity. This paper shows that a correspondence exists between these two properties which applies to most types of low-emissivity composite coatings. An empirical expression for this correspondence is provided.     

长方体建筑物屋顶典型位置湍流特性研究

针对长方体建筑物屋顶6个典型位置开展流场数值仿真,获得了不同尺寸建筑物屋顶各典型位置高度2 m处的湍动能随建筑物长度、高度的变化规律。对于建筑物迎风面拐角点,低建筑物湍动能随建筑物高度变化的敏感性比高建筑物显著;随建筑物长度增加,迎风面边界中心点的湍动能峰值向建筑物高度降低的方向移动,且湍动能峰值随着建筑物长度的增加逐渐升高。除了工程上通常关注的典型点外,还获得了建筑物屋顶其他4个特征位置处的湍动能随建筑物尺寸大小的变化规律。该研究对建筑用风力机微观选址及安装技术参数确定具有一定的理论和实用价值。     

A study on the interaction mechanism between thermal radiation and materials

Introduction When thermal radiation is incident onto material, the incident thermal radiation exerts forces on charges and the forced charges generate a radiation field that affects the incident electromagnetic field. The relationship between the incident electromagnetic field and materials (namely interaction) is of extensive interests in the field of thermal radiation. The interaction between thermal radiation and materials is of universal existence in solid, liquid and gas. Among them, the…     

Fast and reversible lithium-induced electrochemical alloying in tin-based composite oxide hierarchical microspheres assembled by nanoplate building blocks

To benefit from the large capacity gain advantages offered by lithium-induced electrochemical alloying and to overcome poor kinetics, a novel concept to tackle such issues by using porous hierarchical microspheres with an interconnected network of nanoplate building blocks, has been introduced and demonstrated with Sn_1.0P_1.17O_4.72 glass as an example. Such desired three-dimensional microarchitectures with exciting nanosize effects can be exploited to fabricate next generation of lithium-ion batteries where outstanding rate capability and sustained reversible capacity are achieved.     

民用建筑热压自然通风有效热量系数的研究

对具有内热源的民用建筑采用CFD技术,分别改变热源强度、面积比、热源高度、双热源间距、进出风口中心高差、进风口面积,对不同工况下的热压自然通风流场进行数值模拟,得出了有效热量系数的影响因素及其变化规律。     

硅基薄膜叠层太阳能电池减反射膜的效果评估

减反射膜涂覆在硅基薄膜太阳能电池的前板玻璃表面,通过减少对太阳光的反射而提高光电转换效率;然而,减反射膜的热固化工艺会影响减反射膜的最终效果,而无法区分减反射作用和热固化过程对电池效率的影响。文章设计了一种简单有效的评估测试方法,即将未镀减反膜的玻璃和镀减反膜的玻璃分别与电池叠放,来测试电池的量子效率和电流-电压性能,排除热固化工艺对电池性能的影响,以了解减反射膜对电池的作用效果。     

生物质颗粒微观成型机理研究

为研究生物质平模成型机的攫取成型机理,将棉花秸秆原料压缩成颗粒,通过场发射扫描电子显微镜对生物质平模成型机的供料区、压紧区、压实区、成型区的原料及压辊磨损前后期成型颗粒的组织进行微观形貌观察研究,对比不同阶段物料的微观形态。结果表明:随着压辊转动,散乱的物料方向变化明显,物料间相互填充,空隙减小。压实区物料主要发生弹性与塑性变形,微观结构被破坏,纤维层与层之间紧密胶合,方向形态基本稳定,以有序的排列进入成型孔。颗粒密度通过成型孔进一步增大,颗粒间结合得更加紧密。压辊磨损后期的成型颗粒纵横方向性较前期的混乱,同时生产效率降低、成型密度减小。研究结果旨在为生物质平模成型机优化设计提供理论参考。     

Economic effects of energy efficiency improvements in the Finnish building stock

This study estimates the economic effects of investing in energy efficiency in buildings on a national level. First conservation potentials in space heating for two different scenarios with different levels of investment in energy efficiency are quantified. This was done relying on statistical data and future projections of the development of the building stock. Then economic modeling was used to estimate the effects on energy sector and the economy at large. The results show that a rather modest increase resulting in a few percent rise in annual construction and renovation investments can decrease total primary energy consumption 3.8–5.3% by 2020 and 4.7–6.8% by 2050 compared to a baseline scenario. On the short term a slight decrease in the level of GDP and employment is expected. On the medium to long term, however, the effects on both would be positive. Furthermore, a significant drop in harmful emissions and hence external costs is anticipated. Overall, a clear net benefit is expected from improving energy efficiency.     

基于太阳能光伏技术的节能建筑系统的设计与研究

介绍了太阳能光伏发电技术的原理及独立光伏系统和并网光伏系统的组成,总结了两种光伏系统中各组成部分的作用。分析了目前建筑耗能和建筑节能的现状,指出光伏技术与建筑的一体化方案势在必行。分析比较了几种常用的太阳能光伏利用与建筑一体化的实施方式,总结了各种方式的特点。最后提出了几条光伏建筑一体化的基本设计原则。     

Comparative effects of building envelope improvements and occupant behavioural changes on the exergy consumption for heating and cooling

Much focus is put on measures to improve the building envelope system performance to reduce the impact of the building sector on the global environmental degradation. This paper compares the potential of building envelope improvements to those of a change in the occupant's behavioural pattern. Three cases of improvements together with a base case were analysed using exergy analysis, because the exergy concept is useful to understand the underlying processes and the necessary adjustments to the calculation of the heat-pump system. The assumptions for the occupant behaviour were set up based on our field measurements conducted in a dormitory building and the calculation was for steady-state conditions. It was found that the potential of occupant behavioural changes for the reduction in exergy consumption is more affected by the outdoor temperature compared to building envelope improvements. The influence of occupant behaviour was highly significant (more than 90% decrease of exergy consumption) when the temperature difference between indoors and outdoors is small, which is the case for long periods in regions with moderate temperatures during summer and/or winter. Nevertheless, both measures combined lead to a reduction from 76% up to 95% depending on the outside conditions and should be the final goal.     

既有建筑外保温系统性能检测与评定标准探究

在既有建筑围护结构中,较为常见的系统为外墙外保温系统,但此类系统通过使用却暴露出一些不容忽视的问题。因此,为了使建筑物展现出良好的保温效果,有必要对外墙外保温系统的性能进行准确检测,并选择有效的评价方法。基于此,论述了既有建筑外保温系统性能检测所包含的主要内容,指出了外保温系统的评价方法、评价标准与评价定级,其中评价定级涉及5个方面,即外墙外保温系统连接安全性评价、防火安全性评价、保温功能评价、美观耐久性评价及综合性能评价,最后以阐明如何评价外保温系统的连接安全性为目的,对具体的案例进行了深入剖析。     

Interaction mechanism of hydrogen storage materials with layer-by-layer applied protective polyelectrolyte coatings

Metal hydrides are promising compounds for the storage of hydrogen especially in the transport sector. Their high reactivity with moisture and difficult handling in ambient atmosphere prevents their easy application in tanks and thus the market penetration of this very promising and clean technology. In the present work we investigated the way to protect sodium borohydride with organic polyelectrolytes like polyethyleneimine (PEI) and dicarboxy terminated poly(acrylonitrile-co-butadiene-co-acrylic acid) (PABA) with emphasis on the interaction of those polyelectrolytes with the SBH. The polyelectrolytes protect SBH either by electrostatic adsorption or by reacting with it, depending on the reactive groups present in their structure. PABA undergoes only an electrostatic interaction with the SBH substrate. PEI on the other hand interacts chemically with the SBH substrate and forms complexes with groups on the SBH surface. Both polyelectrolytes can be applied in a layer-by-layer approach on the SBH in order to protect it. Regarding the best order of the layer application XPS results yield that the formation of the boron-amino-complexes between the PEI and the SBH is independent of the order in which the PABA and PEI layers are applied. However, the rearrangement of the SBH surface groups due to the application of the PEI films has been found to be considerably influenced by the order of application. The effect of a PEI film has been mostly compensated by the subsequent application of a PABA film, while the application of PEI had a much larger influence on the surface of a PABA coated SBH sample. Thus, the best order of the layer application with respect to the application according to XPS is to deposit the PEI layer at first and the PABA layer afterwards.     

建筑物冬季供暖空调逐时负荷

对华北地区冬季建筑物南外窗的逐时日射得热和相应的室内空气得热进行了分析和计算,结果表 明在大部分的日照时刻南外窗(玻璃幕墙)的逐时日射得热及室内空气逐时得热已超过其本身的逐时负 荷。中央空调系统应采用合理的空调分区和有效的调控设备利用这部分热能,以避免造成建筑物冬季 南向房间过热和能源浪费。     

土壤新风换热系统在博物馆建筑中的应用研究

土壤新风换热系统是利用浅层地表土壤中所蕴藏的冷热量,对室外空气进行冷却和加热的系统。文章归纳整理出了湿陷性黄土热物性的计算方法以及土壤温度分布计算模型,并分析了西安地区土壤温度的变化特性;针对地下埋管土壤新风换热系统,给出了其在连续运行和间歇运行工况下的数学计算模型,并分析了系统在西安典型气象条件下的夏季降温、冬季升温性能。在理论研究的基础上,完成了西安汉长安城直城门项目的地下埋管土壤新风换热系统设计,并利用上述项目的设计数据和预算定额从初投资、运行费用等方面对地下埋管土壤新风换热系统的经济性进行了探讨。     

信息化要素与能源要素之间的关系研究

关于信息化要素与能源要素关系的研究还相对较少。本文选取了27个行业1986～2012年的数据对两者之间的关系进行了验证。检验结果显示,我们国家从80年代中期至今,信息化资本要素与能源要素之间呈现互补关系。有6个行业,分别是普通机械制造业、电气电子机械制造业、运输设备制造业、交通运输仓储及邮电通讯业、电力、批发和零售贸易及餐饮业,在这些行业中信息化要素与能源要素之间呈现替代关系;其余行业中,信息化要素与能源要素之间呈现互补关系。