墙体节能在5万亿建筑节能市场中份额突出

“建筑节能的潜力和空间在节能服务业中位居前列.行业专家预计到2020年底,建筑节能改造和新建建筑保温节能市场空间合计约达5万亿元.其中墙体节能材料在其中占有的份额较重.”中国硅酸盐学会混凝土与水泥制品分会泡沫混凝土专业委员会专家委员、北京华丽联合高科技有限公司副总经理于崇明对记者如是说.     

聚氨酯硬质泡沫塑料在节能复合墙体中的应用

介绍了在严寒地区建筑工程中应用聚氨酯硬质泡沫改造墙体保温节能的情况。     

温度波作用下建筑内墙定型相变材料板的热特性

通过数值模拟研究了正弦温度波作用下建筑内墙定型相变材料板的热特性并与传统的墙体材料——砖和泡沫混凝土板相比较.利用焓法建立的一维瞬态模型采用全隐差分格式迭代求解.计算结果表明,与砖和泡沫混凝土板相比,定型相变材料板表面温度变化不仅波幅有较大的衰减,时间延迟也较明显;相变温度是影响波幅衰减程度的重要因素;对于一定的温度波,相变材料潜热、导热系数和表面换热系数均存在极限值,超过此值,相变材料板表面温度受室内温度波动的影响很弱;相变材料板厚度对表面温度波动几乎无影响;相变温度区间的扩大使表面温度有轻微的波动.所得结果为太阳能建筑及相关领域中相变材料的选择与应用提供参考.     

蒸压加气混凝土砌块墙体质量控制

蒸压加气混凝土砌块墙体质量主要控制墙面裂缝与抹灰空鼓,指出要从设计构造、砌块性能、选用材料和施工工艺等方面采取预控措施,才能提高蒸压加气混凝土砌块墙体质量。     

塑性混凝土防渗墙在地震区大坝中的应用

塑性混凝土是近年来发展的一种新型防渗墙体材料,通过对比计算分析,提示了塑性混凝土应用于地震区大坝坝基及坝体的优越性,较详细地介绍了塑性混凝土在册田水库南副坝的应用及运行情况,并建议在我国推广应用这种新型墙体材料。     

基于泡沫混凝土和U型钢的煤矿巷道支护体系研究

针对煤矿软岩大变形巷道,提出了由钢网、锚杆、锚索、喷射混凝土、可压缩U型钢、泡沫混凝土阻尼层、裂隙岩缓冲层组成的组合支护体系。运用了数值分析和现场监测的技术手段。数值分析结果表明,泡沫混凝土能吸收围岩的大部分变形,U型钢的收缩率显著降低,U型钢的平均轴力与泡沫混凝土厚度呈二阶方程关系。在工程实践中,当泡沫混凝土厚度超过30 cm时,阻尼效应不再明显。现场监测结果表明,围岩位移及U型钢受力在组合支护体系初始阶段20 d内均呈增大趋势,但增大趋势减弱。     

基于Ansys的相变墙体节能效果分析

基于Ansys软件建立数学模型,计算分析不同厚度的混凝土分别与不同厚度定形相变材料组成的相变墙体的传热特性和节能效果。计算结果表明,相对于两种不同厚度混凝土墙体,增加定形相变材料起到了很好的节能效果;定形相变材料的最优厚度需要从各方面综合考虑确定;随着定形相变材料的厚度的增加,墙体内表面温度波动幅度近似呈线性减小。     

自保温墙体材料的应用研究现状及发展趋势

对目前我国常用的蒸压加气混凝土类、轻骨料混凝土类、石膏类、烧结类等自保温墙体材料的应用和研究现状进行了全面的介绍和总结,并对自保温墙体材料行业的发展趋势提出了要因地制宜开发新型自保温墙体材料、提高保温性能、改善物理性能、优化结构设计、研发配套砂浆、完善相关标准等合理性建议。指出自保温墙体材料行业的发展一定要契合绿色、节能、环保、可持续发展的主题,才会有广阔的应用市场和发展前景。     

泡沫混凝土作为原位土壤热修复隔热层的研究

原位热修复场地表层土壤采用有效的隔热措施,有助于实现节能降耗.泡沫混凝土是一种新型轻质保温材料,导热系数低,可作为原位热修复场地的表面阻隔材料.通过计算敷设的泡沫混凝土在不同环境条件下的散热损失,分析、讨论其隔热性能和特点,得到以下结论:泡沫混凝土作为原位热修复工程场地表层阻隔材料,在不同环境条件下,均可起到较好的隔热...     

浮石混凝土和火山渣混凝土多排孔小型砌块墙体热阻的实验研究

利用大型双试件保护平板法实验装置，对浮石混凝土和火山渣混凝土多排孔小型砌块墙体的热阻进行了实验研究，认为：浮石和火山渣混凝土小型砌块与红砖墙体对比，具有容重小、保温性能好、施工简单快捷、原材料较丰富等优点，具有很好的推广应用前景。     

Life cycle energy analysis of a residential building with different envelopes and climates in Indian context

In this paper life cycle energy (LCE) demand of a residential building of usable floor area about 85.5 m² located at Hyderabad (Andhra Pradesh), India is evaluated under different envelopes and climates in Indian context. The house is studied with conventional (fired clay) and alternative wall materials (hollow concrete, soil cement, fly ash and aerated concrete) under varying thickness of wall, and insulation (expanded polystyrene) on wall and roof. The house is modelled for five different climatic zones of India, i.e. hot and dry, warm and humid, composite, cold and moderate. Study suggests that alternative wall materials alone (without insulation) reduce LCE demand of the building by 1.5-5%. Aerated concrete (AC), as wall material, has better energy performance over other materials. LCE savings are significant when insulation is added to external wall and roof. It varies from 10% to 30% depending on the climatic conditions. Maximum LCE savings with insulation are observed for warm and humid climate and least for moderate climate. For same thickness of insulation, LCE savings are much more with roof insulation than wall insulation. But wall insulation is found to be preferable to a thicker wall. It is also observed that there is a limit for thickness of insulation that can be applied on external walls and roof from life cycle point of view. This limit is found to be about 10 cm for composite, hot and dry, warm and humid, and cold climates and 5 cm for moderate climate.     

Investigation of the effect of metal foam characteristics on the PCM melting performance in a latent heat thermal energy storage unit by pore-scale lattice Boltzmann modeling

Latent heat thermal energy storage (LHTES) has many advantages such as high energy density and phase change at a nearly constant temperature compared with sensible thermal energy storage or chemical energy storage techniques. However, one of its major drawbacks is the low thermal conductivity of phase change materials (PCMs) which impedes the heat transfer efficiency. High thermal conductivity metal foams could be added into the LHTES to enhance the heat transfer speed. Under this case, the investigation of the effects of metal foam porosity and pore size on the melting process is essential for improving the heat storage capability of LHTES. In this article, a pore-scale modeling of melting process in a LHTES unit filled with metal foams is carried out by enthalpy-based multiple-relaxation-time lattice Boltzmann method. The quartet structure generation set is used to generate the morphology of metal foams. In addition, a Compute Unified Device Architecture (CUDA) Fortran code is developed in this work for executing highly parallel computation through graphics processing units. The melting process in the PCMs is investigated in terms of porosity, pore size, nonuniform metal foam, hot wall temperature, and initial subcooled temperature to optimize the design of LHTES filled with metal foams.     

Modeling and prediction of the effective thermal conductivity of random open-cell porous foams

Although highly desirable, accurate prediction of the effective thermal conductivity of high-porosity open-cell porous foam materials has remained to be a challenging problem. Aiming at this thorny obstacle, we have developed a random generation-growth method to reproduce the microstructures of open-cell foam materials via computer modeling, and then solve the energy transport equations through the complex structure by using a high-efficiency lattice Boltzmann method in this contribution. The effective thermal conductivities of open-cell foam materials are thus numerically calculated and the predictions are compared with the existing experimental data. Since the porosity is high, the predicted thermal conductivity caused by thermal conduction is lower than the measured data when the thermal conductivity of either component is very low and the radiation heat transfer is non-negligible. After considering the radiation effect, the numerical predictions agree rather well with the experimental data. The radiation influence is diminishing as the material porosity decreases. In general the effective thermal conductivity of open-cell foam materials is much higher than that of granular materials of the same components due to the enhanced heat transfer by the inner netlike morphology of the foam materials.     

Experimental study of small-scale solar wall integrating phase change material

Solar walls have been studied for decades as a way of heating building from a renewable energy source. A key ingredient of these wall is their storage capacity. However, this increases their weight and volume, which limits theirs integration into existing building. To aleviate this problem, storage mass is replaced by a phase change materials. These allow to store a large amount of energy in a small volume, which brings the possibility of retrofit trough use of light prefabricated module.This article presents an experimental study of a small-scale Trombe composite solar wall. In this case, the phase change material was inserted into the wall in the form of a brick-shaped package. While this material can store more heat than the same volume of concrete (for the same temperature range), it shows a very different thermal behavior under dynamic conditions. A particular attention is focused on the delay between the absorption of solar radiation and the energy supplied to the room. The energy performance of the wall from heat flux measurements and enthalpy balances are also presented.     

天生桥水电站副坝基础塑性混凝土防渗墙设计与实践

论述了天生桥水电站副坝基础塑性混凝土防渗墙的设计和施工特点,针对古河道深厚覆盖层的地质条件,采用塑性混凝土防渗墙的防渗型式,结合有限元计算和配合材料试验。提出了塑性混凝土防渗墙的配合比,采用人工成槽和机械成槽并举,成功解决了基础防渗问题,取得了显著的效果。     

全户内变电站装配式建筑墙体细化设计与应用

  [目的]  为促进变电站建设的规范、统一，提高建设效率，国家电网编制了通用设计并推广装配式建筑。在应用通用设计时简单套用标准图集，对具体工程可能会造成不必要的浪费，必须针对工程项目实际，结合建筑材料的发展，进行优化和细化设计。  [方法]  结合工程实例，根据功能需要和建筑材料性能，在满足结构、功能要求前提下，按照建筑、节能降噪、防火等要求，对全户内变电站装配式建筑墙体进行优化和细化设计研究，经过计算，确定了墙体构造、用材、厚度等具体设计参数。  [结果]  研究表明:细化设计方法通过多项工程实例检验，细化设计后节省了建材，节约了建筑占地，达到了节能目的。  [结论]  提出的细化设计方法可为同类工程设计和建设管理者提供借鉴和参考，值得推广应用。     

泡沫铜多孔材料的液体渗透特性研究

目前对波形板汽−水分离装置的研究多集中于结构参数和入口参数的分析,而从其材料特性角度探讨提高分离效果的研究鲜有报道。以去离子水为介质,探讨了泡沫铜多孔材料孔隙率、有效半径以及浸润性对其渗透特性的影响。将修正后的弯毛细管模型与达西定律相结合,建立了泡沫铜渗透率、孔隙率以及有效半径之间的定性关系,即随着泡沫铜孔隙率和有效半径的增加,其渗透性能逐渐增强,这一结论与实验结果符合良好。此外,通过对泡沫铜材料进行浸润改性,分析了浸润性对其渗透性能的影响,结果发现,随着表面能的提高,泡沫铜的渗透性能逐渐增强。     

Two novel high-porosity materials as volumetric receivers for concentrated solar radiation

This article reports on two novel porous materials, which have been foreseen as volumetric receivers for concentrated solar radiation: a double-layer silicon carbide foam and a screen-printed porous silicon carbide material. Volumetric receivers are used in the solar tower technology. In this technology ambient air flows through the porous solid, which is heated by concentrated solar radiation. A heat exchanger then transfers the energy to a conventional steam turbine process. The general thermophysical and permeability properties of materials required for this application are reviewed. Experimental set-up and results of pressure loss and laboratory scale tests in concentrated solar radiation are reported. For the foam, efficiency data could be determined from the test results. Finally, a comparison is presented between the efficiency properties of the foam and those of materials used for the same application until now. This comparison shows, that the efficiency of the double-layer foam material is significantly higher. Up to now, porous materials consisting of a parallel channel geometry with thin walls showed disadvantageous permeability properties. By applying a new manufacturing process and modifying the channel geometry, the permeability properties of the printed material could be significantly changed, so that it now meets the requirements for an application as a volumetric receiver.     

均匀及梯度泡沫金属复合PCM熔化特性模拟研究

基于六面通圆孔的均匀泡沫金属结构,构建了泡沫金属复合相变材料(PCM)三维模型,采用高性能计算显卡(GPU)加速的多松弛时间格子玻尔兹曼方法模拟了均匀及梯度泡沫金属复合PCM的瞬态熔化过程。结果表明：随着均匀泡沫金属孔隙率的降低,复合PCM的传热速率提高,潜热储能的能力减弱;对于固定平均孔隙率的不均匀泡沫金属,孔隙率沿导热方向上递增的模型具有最佳的强化传热效果,其完全熔化时间比填充均匀骨架模型和孔隙率在导热方向上递减的骨架模型分别缩短了4.2%和25%,当孔隙率梯度变化方向与导热方向一致时,在高温壁面附近填充低孔隙率泡沫金属能显著强化传热;当两者方向垂直时,熔化速率取决于平均孔隙率,与梯度分布几乎无关。     

THE PERFORMANCE OF A COLLECTOR-STORAGE WALL IN ALEXANDRIA,EGYPT

This investigation presents an analysis of the performance of a collector-storage wall composed of concrete using the weather data of Alexandria, Egypt. An energy balance on the collector-storage wall is used to predict the energy flows into and out of the wall. The numerical model is then incorporated into TRNSYS to determine the thermal performance of the wall. The effect of the wall thickness, the number of glazing, the building capacitance, and the night insulation resistance on the performance of the collector-storage wall in Alexandria, Egypt are studied.