Analysis of the Performances of a New Type of Alumina Nanocomposite Structural Material Designed for the Thermal Insulation of High-Rise Buildings

The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.

Carbon foams prepared from coal tar pitch for building thermal insulation material with low cost

A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.

Comparison of the thermal properties of clay samples as potential walling material for naturally cooled building design

The thermal properties of different clay samples obtained from locations in Akwa Ibom State, Nigeria were investigated and compared, and in order to establish their suitability as building material from energy conservation point of view. The results showed that stoneware clay has the highest solar radiation absorptivity of 22 32 m -1 while kaolin clay has the lowest radiation absoptivity of 14 46 m -1 A model for the prediction of temperature variation with thickness of the samples was developed. Results showed that kaolin would make the best choice for the design of a naturally cooled building.

Experimental study on the influence of temperature and humidity on the thermal conductivity of building insulation materials

At present,thermal conductivity is usually taken as a constant value in the calculation of building energy con-sumption and load.However,in the actual use of building materials,they are exposed to the environment with continuously changing temperature and relative humidity.The thermal conductivity of materials will inevitably change with temperature and humidity,leading to deviations in the estimation of energy consumption in the building.Therefore,in this study,variations in the thermal conductivity of eight common building insulation materials(glass wool,rock wool,silica aerogel blanket,expanded polystyrene,extruded polystyrene,phenolic foam,foam ceramic and foam glass)with temperature(in the range of 20-60°C)and relative humidity(in the range of 0-100%)were studied by experimental methods.The results show that the thermal conductivity of these common building insulation materials increased approximately linearly with increasing temperature with maxi-mum growth rates from 3.9 to 22.7%in the examined temperature range.Due to the structural characteristics of materials,the increasing thermal conductivity of different materials varies depending on the relative humidity.The maximum growth rates of thermal conductivity with humidity ranged from 8.2 to 186.7%.In addition,the principles of selection of building insulation materials in different humidity regions were given.The research re-sults of this paper aim to provide basic data for the accurate value of thermal conductivity of building insulation materials and for the calculation of energy consumption.

A New Type of Paper-frame Cavernous Material and Its Application in Energy Efficiency in Buildings

This paper introduces a new type of paper-frame cavernous material, which is a made-up hollow material, by using silicate-cinder size to drench and daub. It possesses excellent performances such as light-weight, high-intensity, fire-resistance, sound-insulation, heat-insulation and no-pollution. Composed with concrete materials, a new type of bearing and energy-efficient block can be gained, which is kind of excellent wall materials and has a wide application prospect.

Influence of materials’hygric properties on the hygrothermal performance of internal thermal insulation composite systems

Internal thermal insulation composite system(ITICS)can be an important measure for the energy-saving retrofitting of buildings.However,ITICS may cause harmful effects on the hygrothermal performance of building envelopes.This work investigated the influence of the materials’hygric properties on the hygrothermal perfor-mance of a typical ITICS in different climate conditions in China.Two base wall materials,the traditional concrete and a new type aerated concrete,were tested and compared for their hygric properties firstly.The influence of the hygroscopicity of exterior plasters,the permeability of insulation materials and the climate conditions were then analyzed with WUFI simulations.The hygrothermal performance was evaluated with consideration of the total water content(TWC)of the walls and the moisture flux strength,the relative humidity(RH)and the mould growth risk at the interface between the base wall and the insulation layer(B-I interface).The numerical analysis implies that the TWC of internal insulated walls depends mainly on the hygroscopicity of exterior plaster and the wind-driven rain intensity.The upper limits for the water absorption coefficient of exterior plasters used in Bei-jing,Shanghai and Fuzhou are 1e-9,1e-10,1e-10 m^(2)/s respectively.When such limits are guaranteed,a vapour tight system created by using insulation materials with a large vapour resistance factor or adding a vapour barrier can improve the hygrothermal performance of ITICS,especially for concrete walls in cold climate.

Dynamic performance and energy efficiency of reflective and insulative composite coating on building exterior wall

Reflective and insulative composite coatings are a new energy-saving material with high solar reflectance and extremely low thermal conductivity for buildings.The optimization and impact of high solar reflectance and low thermal conductivity on the insulating capacity of walls remain uncertain.This work investigates the dynamic thermal performance and energy efficiency of a reflective and insulative composite coating in regions with hot summer and warm winter.A simplified thermal resistance-heat capacitance model of an exterior building wall is established to predict thermal performance.The dynamic temperature and heat flow of the wall are predicted to reduce heat loss through the interior surface of the wall and compared to the conventional coating.The specific impact of the thermal conductivity and solar reflectance of the coating on the heat loss is further investigated to minimize heat loss of the wall.This research shows that the composite coating shows better performance on adjusting outdoor climate change than the other coating.Compared with cement,it reduces the maximum temperature of the exterior surface of the wall by 7.45°C,and the heat loss through the interior surface of the wall by 38%.The heat loss is reduced with the increase of solar reflectance and the reduction of thermal conductivity.The results can provide a useful reference and guidance for the application of reflective and insulative composite coating on building exterior wall to promote their energy-saving use on building envelopes.

Performance of aerogel as a thermal insulation material towards a sustainable design of residential buildings for tropical climates in Nigeria

The building sector accounts for nearly 40%of global energy consumption.In Nigeria,more than two-thirds of the consumption comes from residential buildings.Energy efficiency measures through the adoption of insulation materials are tools that could crash the peak demand of energy in buildings while improving its thermal comfort and aerogel is considered as the most effective material for insulation,owing to its unique thermal properties.In this paper,we present the performance of aerogel as a thermal insulation material towards a sustainable design of residential buildings for tropical climates in Nigeria.First,a typical residential building in the tropical region was modeled with conventional materials utilized in the region and was later modified through the application of aerogel material on various surfaces of the model.A whole building energy simulation was then carried out in each variation and the outcome was compared to effectively conclude on the significance of aerogel in terms of thermal comfort improvement and energy consumption reduction.Results show that aerogel had the highest influence when inserted in the attic and floor slabs of the designed model.A reduction of more than 6%was attained in the recorded indoor mean air and operative temperatures while still maintaining an acceptable humidity range.Concerning energy consumption,a reduction of more than 15%was achieved.However,the high price of aerogel may hinder its application on the studied building but could be a good investment where climate change and sustainability are of high importance and less concern is given to expenditure.Aerogel demonstrated significant potential with respect to both thermal comfort improvement and energy consumption reduction on the designed model.The outcome of the study is hoped to serve as a base reference for the insulation of residential buildings with similar climate and characteristics to the adopted case building.

外墙保温材料用防火粘结剂的制备及性能分析

为了促进建筑外墙用保温材料应用,防火等级高的保温材料是实现建筑外墙保温系统安全构建的必要举措,而防火粘结剂则是保温材料性能发挥的关键。研究主要以环氧树脂浆料、丙烯酸树脂乳液为主要原料,高分子复合乳液、固化剂、增塑剂、乳化剂等为助剂,制备了一种新型建筑外墙用保温材料防火粘结剂,并对粘结剂的性能进行了分析,结果表明,产物所有性能指标均符合要求,且与传统粘结剂相比,防火性能、耐水性能、耐久性能提升明显,可适用于我国房屋建筑用保温材料工程中。

建筑外墙保温板接缝专用改性聚醚密封胶制备及特性研究

为提升建筑外墙保温板的使用寿命,制备装配式建筑外墙保温板接缝用改性聚醚密封胶,并通过试验分析该密封胶性能。以封端硅烷偶联剂和异腈酸酯基硅烷作为改性剂,聚醚元醇作为基料制备改性聚醚密封胶,应用在装配式建筑外墙保温板接缝中。依据标准测试该密封胶的表观性能,研究养护时间、紫外光照对该密封胶的粘接强度影响,分析催化剂和填料用量对于该密封胶表观性能与拉伸性能影响。试验结果表明,该密封胶表观性能符合标准,养护7 d后粘接性能基本稳定,催化剂用量20%,填料用料30%时表观性与拉伸性能最好。

节能墙体隔热材料在住宅建筑设计中的研究

现今新型建筑节能墙体材料常运用于住宅建筑中,故本研究针对新型建筑节能材料特点,分析其在住宅建筑的应用,并对不同规模的墙体总厚度在不同室外环境温度下的能耗对比。试验结果表明,墙体总厚度在105mm条件下,当室外环境温度为40℃时,空调的降温能耗相差3.2℃,此时差值最大,空调降温能耗的降低趋势均减缓,建筑的节能效果明显降低。在室外环境为–30℃时,空调的取暖能耗相差为4.8℃,取暖能耗均呈现降低的趋势。由此可见,在外界环境高、低气温环境下均能获得较为显著的建筑节能效果,但墙体总厚度超过105mm时其实用价值不大。

建筑外墙外保温系统节能施工技术探析

伴随当下社会的不断进步,科学技术的日益提高同样促使建筑行业迈入了一个崭新的台阶,这也就促使人们开始将目光转移到居住环境上来,尤其是房屋建筑方面的需求也越来越高。当前,与建筑物外保温有关的技术已引起社会各方的高度重视,它直接影响着人类是否能够获得一个更为舒适的居住环境。作者从建筑外墙外保温系统节能技术的概况入手,对外墙外保温系统的施工工艺进行了较为系统的讨论,希望可以为提高我国建筑外墙外保温工程的品质,同时也为相关研究提供一些借鉴。

新型装配式保温装饰墙体系统的隔声性能研究

装配式建筑模式具有成本低、环保性强、可节约能源等优势和特点,因此对新型装配式建筑进行设计对于环保事业的发展与公众居住健康有十分重要的意义。文章基于上述背景,对新型装配式保温装饰墙体的系统隔声性能进行详细分析,根据墙体系统的各个节点构造与设计保障其隔声性能,以期对装配式轻质墙体系统的发展有所借鉴和参考。

新型动态保温相变Trombe墙体热性能的实验研究

通过测试一间有一面是相变材料另一面是保温材料的新型动态Trombe墙体的房屋全尺寸模型,对该墙体的热性能进行实验研究。以墙体和房间的空气温度以及通过墙体的热流量和气流速率来评估其性能。结果表明:在相变过程中,温度变化相对平缓;墙体从玻璃获得的热量占其获得总热量的26.2%,且利用其储存的90.1%的热量对房间进行加热;在相变材料放热期间,该墙体可降低室内温度的分层且房间中部的温度至少比室外温度高3.2℃。

一种废玻璃和废陶瓷再生的新建筑保温材料性能测试及应用

以废玻璃和废陶瓷为基材,氯化钠为相变材料制备了一种新型再生相变蓄热材料。试验对再生相变蓄热材料的配比和制备条件进行优化,并对蓄热材料的蓄热性能和热循环性能进行表征。试验结果表明,基体材料与相变材料质量比为6∶4,烧结温度为950℃,烧结时间为60 min,制备的再生相变蓄热材料性能最佳。此时再生相变蓄热材料体积密度约为1.88 g/cm3,抗折强度约为40 MPa,峰值温度为797.7℃,相变潜热为60.52 J/g,蓄热密度为230.213 J/g,导热系数为0.73 W/(m·K),蓄热性能表现良好,满足GB 50411—2019标准要求。经过多次循环后,再生相变蓄热材料整体失重率始终低于1%,表现出良好的热循环性能。

玻璃幕墙节能技术在住宅建筑外墙保温中的应用分析

传统住宅建筑外墙保温方法直接对建筑外墙温度控制参数进行优化未对住宅建筑外墙传热模型进行构建,造成传统方法部分指标不满足保温性能要求。提出玻璃幕墙节能技术在住宅建筑外墙保温中的应用分析。对住宅建筑外墙传热模型进行构建,为进一步确定玻璃幕墙节能技术的保温方式奠定基础,基于玻璃幕墙节能技术优化建筑外墙温度控制参数,解决热传导过快问题,从而实现住宅建筑外墙保温,设计对比实验,实验结果表明该研究方法更符合住宅保温性能指标要求。

粉煤灰/废砖粉制备多孔建筑材料的技术要点探究

粉煤灰/废砖粉可以作为原材料生产多孔建筑材料,其性能有待进一步研究。该文以粉煤灰为材料,以钢渣废砖粉为协同材料,以多孔外墙建材为生产方向,采取文献梳理、建材生产实践的方法,逐一梳理粉煤灰用于多孔建材生产的技术要点。通过研究发现,烧制温度取1205℃,最佳值是1218℃;恒温保持时间的最佳值为12.5 min;SiC用量最佳值为0.78 wt.%;钢渣协同生产的最佳占比为5 wt.%。实验结果显示,粉煤灰可用于多孔建筑材料的生产,在烧制温度、恒温时间、SiC与钢渣用量各个方面,分别给出的生产方案,能够有效控制多孔外墙建材的表观密度p值,使其不超过1 g/cm3,符合多孔外墙建材的生产规范。

现浇混凝土保温复合填充墙与剪力墙弱连接节点分析研究

近些年剪力墙住宅愈发增多,研究提出了一种薄弱位置的节点设计方案,该节点可用于剪力墙结构中部分现浇混凝土保温复合填充墙与剪力墙、梁等结构构件的弱连接,同时还可利用土木结构非线性软件进行有限元计算分析。结果表明:通过对比弱连接节点及结构构件的剪应力可知,混凝土现浇外墙与周边结构构件的弱连接剪应力远大于主体混凝土梁在对应工况下的剪应力,该弱连接节点可以满足先于主体混凝土梁破坏的要求,故节点构造切实可行。

城市更新项目中外墙保温技术应用

本文主要探讨了城市更新项目中老旧小区外墙保温技术的应用。通过分析老旧小区建筑外墙节能保温的现状,阐述了外墙保温技术的意义和重要性。本文从建筑外墙保温构造做法、工艺流程、施工中容易忽略的问题及保温施工通病及措施等四个方面,介绍了各种节能保温技术的具体应用方法和效果。最后,总结了城市更新项目中老旧小区外墙保温技术的发展趋势和未来发展方向。