建筑反射隔热涂料自然老化性能研究

对我国市场上现有冷屋顶反射隔热涂料的自然老化性能进行了深入、系统性研究,并探索了影响冷屋顶反射隔热涂料长期性能的主要影响因素。结果表明反射隔热涂料的太阳光反射比取决于涂料本身的物理、化学性质和曝露地区的环境、气候(包括降雨、空气中颗粒物浓度、风速及温湿度)等条件,而与样品的基材种类、曝晒角度关系不大;老化前后,样品热发射率变化不大,随老化时间延长也未见明显下降。     

夏热冬冷地区建筑反射隔热涂料应用技术

文章介绍建筑反射隔热涂料在夏热冬冷地区应用的几个技术问题,包括应用形式、建筑节能计算中等效涂料热阻的取值和工程质量控制方法等。目前建筑反射隔热涂料在夏热冬冷地区应用时,为满足冬季保温要求而多采取和浆料类保温层复合成保温层-建筑反射隔热涂料节能系统的形式进行应用;JGJ/T 359-2015规程规定采用"污染修正后的太阳辐射吸收系数"计算用于建筑外墙和屋面的建筑反射隔热涂料的等效热阻;对工程进行太阳光反射比性能项目的现场检测能够对规程质量进行有效的控制。     

建筑反射隔热涂料自然老化性能的研究

建筑反射隔热涂料能有效的反射、阻隔太阳光的能量,明显降低屋顶和室内温度,降低空调设备等能耗。反射隔热涂料自然老化性能是指其在一定的使用周期内能否达到预期反射隔热效果的关键指标。通过在西安地区进行反射隔热涂料的自然老化试验研究,分析其太阳光反射比的变化规律,为其在西安地区的推广应用及相关标准技术指标的制定提供试验依据。     

建筑反射隔热涂料的关键技术及其应用

建筑反射隔热涂料由于具有较高的太阳光反射比、近红外反射比和半球发射率,建筑物外墙和屋面涂装建筑反射隔热涂料后可以有效反射、阻隔夏季的太阳热辐射,减少建筑物表面对太阳幅射能量的吸收,降低围护结构表面的温度,实现围护结构的节能,因而近年来建筑反射隔热涂料在夏热冬冷和夏热冬暖地区得到了较快的发展。介绍了建筑反射隔热涂料的特点、隔热机理和研制的关键技术,并介绍了将于2016年2月1日起实施的JGJ/T 359—2015《建筑反射隔热涂料应用技术规程》规定的建筑反射隔热涂料应用技术要点。     

高反射涂料自然老化后的隔热性能

为研究高反射涂料在夏热冬冷地区一年自然老化后的隔热性能,以重庆市某办公建筑两间建筑外形、围护结构和朝向均相同的顶层房间为研究对象,在屋顶上涂敷普通灰色涂料、白色高反射涂料分别作为基准屋顶、高反射屋顶,分别选取2014年7月和2015年7月的连续3个晴朗日进行夏季隔热性能实测。研究结果表明:经过一年自然老化后的高反射屋顶反射率下降,隔热性能有所降低,在相同空调工况下,内外壁面降温幅度分别减小3.2℃和4.2℃,空调耗电量降低0.03kWh/m2·d;非空调工况时,室内空气温度降温幅度减小2.5℃。     

建筑用隔热涂料热工性能评价方法分析

外墙及屋面通过采用热反射隔热涂料来提高太阳光反射比和半球发射率,从而达到了隔热降温效果,结合上海的气候特点对此进行了理论分析。参考国内外隔热涂料相关标准,提出了涂层稳态表面温度、等效热阻、热惰性修正系数等评价指标及方法,为隔热涂料的效果评价提供了理论依据。     

颜填料对水性反射隔热涂料太阳光反射比的影响

采用JG/T 235—2014《建筑反射隔热涂料》测试方法表征了水性反射隔热涂料的太阳光反射比和近红外反射比,着重研究了钛白粉、常用填料、空心玻璃微珠和普通色浆对涂料太阳光反射比的影响。     

彩色热反射装饰砂浆的性能研究

通过在装饰砂浆中添加冷颜料,可得到高性能的彩色热反射装饰砂浆。同传统的彩色砂浆相比,热反射砂浆在保证色彩的同时,具有较高的太阳光反射比和近红外反射比,对于降低墙体表面温度具有明显效果。添加3%铁黑的装饰砂浆表面太阳光反射比仅为0.101,而添加相同掺量铁铬黑冷颜料的装饰砂浆表面太阳光反射比达到0.410。经分析可以发现,热反射砂浆表面L*(明度)值越高,太阳光反射比也相应增大,并得出了两者之间的经验公式。     

热反射涂料屋面与种植屋面室内空调能耗实测对比

为对比研究建筑应用热反射涂料屋面和种植屋面的室内空调能耗水平,选取厦门市同安区某宿舍楼内三个户型和面积一致、围护结构材料相同且同一朝向的顶层相邻房间作为测试平台进行现场测试,测试结果表明:夏季空调24小时运行工况下,热反射涂料屋面和种植屋面房间日均耗电量分别比普通涂料屋面房间少0. 037 k W·h/m~2、0. 036 k W·h/m~2;夏季空调夜间运行工况下,热反射涂料屋面和种植屋面房间日均耗电量分别比普通涂料屋面房间少0. 056 k W·h/m~2、0. 097 k W·h/m~2。热反射涂料屋面和种植屋面均可减少室内空调耗电量,具有一定的节能效果,种植屋面房间在夜间节能效果更明显。     

除了节能,反射涂料还有哪些好处

多年来,反射涂料在改变耗能多、传统的深色屋面,使之成为更加环境友好的冷屋面进程中功不可没.随着白色热塑性聚烯烃(TPO)和聚氯乙烯(PVc)等高反射性屋面卷材产品越来越多地被使用,业内许多观察家预言,建筑涂料将不会继续在屋面工程中占有一席之地.然而,反射涂料的主要用途,除了把深色屋面变成白色以减少空调运行的能耗外,它还可以组建白色冷屋面系统,在其他很多方面发挥作用.     

Estimating the effect of using cool coatings on energy loads and thermal comfort in residential buildings in various climatic conditions

The impact from using cool roof coatings on the cooling and heating loads and the indoor thermal comfort conditions of residential buildings for various climatic conditions is estimated. The energy cooling loads and peak cooling demands are estimated for different values of roof solar reflectance and roof U-value. The results show that increasing the roof solar reflectance reduces cooling loads by 18–93% and peak cooling demand in air-conditioned buildings by 11–27%. The indoor thermal comfort conditions were improved by decreasing the hours of discomfort by 9–100% and the maximum temperatures in non air-conditioned residential buildings by 1.2–3.3 °C. These reductions were found to be more important for poorly or non-insulated buildings. For the locations studied, the heating penalty (0.2–17 kWh/m² year) was less important than the cooling load reduction (9–48 kWh/m² year). The application of cool roof coatings is an effective, minimal cost and easy to use technique that contributes to the energy efficiency and the thermal comfort of buildings.     

冷屋面节能实效研究

针对夏季北京地区建筑屋面涂覆太阳热反射涂料后的隔热节能效果进行理论分析和实证研究,结果表明:冷屋面温度及得热量明显降低,可减少夏季建筑空调负荷,具有明显的节能效果。     

Effect of roof solar reflectance on the building heat gain in a hot climate

The effect of the roof solar reflectance on the thermal performance of a building is often ignored. However, there are significant differences in heat gain from light and dark-coloured roof surfaces. In this paper an equation for the average daily downward heat flow of a sunlit roof is derived. Using building simulation, it is first shown that the thermal mass of the roof does not significantly affect the overall daily heat gain (although it causes a time lag and reduction in peak heat flow). As a consequence the daily heat gain from the roof may be estimated by integrating the equation for the steady-state downward heat transfer over the day. For north Australia the derived equation suggests that a light-coloured roof has about 30% lower total (air temperature difference and solar-driven) heat gain than a dark-coloured one. The effect of aging (change in solar reflectance with time) is considered in the calculations and a relationship between the solar absorptance of new and aged material is suggested. A classification of roof colours with respect to their solar absorptance (dark, medium, light and reflective) is proposed to enable a quick and simple assessment of the effect of roof colour on the heat gain and R-value.     

避雷器的污秽性能和5000h气候老化试验

阐述了避雷器的污秽性能及长期气候特性,分析了避雷器有关标准要求和5000h气候老化试验。结果表明:在持续施加工作电压、阳光辐射、人工雨、加热、潮湿和盐雾等综合效应的作用下,憎水性、迁延性及耐漏电起痕特性均有较好的表现;建议在典型的自然环境条件下,建立户外自然污秽试验场,以研究带电情况下避雷器的长期特性。     

Chemical and microbial effects of atmospheric particles on the performance of steep-slope roofing materials

The reflectivity of a roof is a critical component in design of strategy to reduce overall building energy usage. Airborne particulate matter that settles on a roof can either reflect or absorb incoming solar radiation. The light scattering and absorption processes occur within a few microns of the surface that affects the solar reflectance of the roof. The long-term loss of roof reflectivity appears driven by the ability of the atmospheric particulate matter to cling onto the roof and resist being washed off by wind and or rain. Contaminants collected from samples of roof products exposed at seven California sites for about one and a half years were analysed for major and trace elements and carbons to assist characterization of the chemical profile of the atmospheric particles that soil each roof sample. The chemical composition of the accumulated particles was very similar across the state of California; there was no clear distinction from one region to another. Elemental carbon did not contribute significantly to the loss of solar reflectance as initially expected. Dust particles and organic carbon compensated for the loss of solar reflectance due to elemental carbon possibly because some crystalline forms of these elements were light reflecting and contributed to the solar reflectance. Differences in microbial communities and biomass were seen between the various materials. Abundance of microbial biomass on roof tiles appears to be related to the composition/surface structure of the tile. Cyanobacteria or fungi represent the dominant player.     

古代砖砌体风化性能分析及风化程度评定

自然界中气温、降水的长期作用导致古代砖砌体风化,风化损伤材料和砌体力学性能。实验采用大气环境实验舱实现自然风化作用人工模拟,根据不同饱水度和冻融次数,实验舱设定了7种非饱水冻融工况,对7种工况影响下的砖、灰浆、砌体抗压、砌体抗剪试件试件强度变化规律进行实验分析。实验表明,饱水度是反映材料冻融性能的重要指标;不同饱水度下的冻融试件强度呈现先升后降的趋势;试件在饱水度为53%的冻融作用下,砌体构件具有最佳抗力;提出古代砖砌体构件风化程度评定标准。实验对古砖砌体结构保护工作具有指导和应用价值,定期评定古塔砌体风化程度,时刻掌握古塔构件结构安全性能的变化规律,科学保护古塔。     

PVC-U排水管材户外老化影响因素综述

分析了PVC-U排水管材户外老化影响因素,主要原因为PVC分子结构缺陷、紫外光老化、产品质量问题及环境污染。     

Ce^(3+)和Fe^(3+)共掺杂CaAl_(2)O_(4)高近红外反射颜料的制备与表征

离子掺杂能够调谐颜料的反射性能和颜色。采用溶胶-凝胶法制备了一系列新型低毒的Fe^(3+)、Ce^(3+)共掺杂Ca_(1-x)Ce_(x)Al_(2-y)Fe_(y)O_(4)(x=0、0.15;y=0.15、0.25、0.35)高近红外反射无机颜料。采用X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外/可见/近红外光谱仪及Color CIE色度分析软件对所合成复合颜料的晶体结构、微观形貌、光学性质(反射性能)和颜色等进行了表征。XRD分析表明,煅烧温度为1100℃时,所合成的样品为磷石英结构;光学性能分析表明,随着Fe^(3+)掺杂量的增加,颜料的颜色由白色逐渐变为黄色再变为深棕色。Fe^(3+)、Ce^(3+)共掺杂所制备的颜料在780~2500 nm波长范围内具有较高的近红外反射率(NIR≥61.5%)。该Ca_(1-x)Ce_(x)Al_(2-y)Fe_(y)O_(4)“冷”颜料粉体在建筑涂料等方面具有广阔的应用前景。     

Effects of coefficients of solar reflectivity and infrared emissivity on the temperature and heat flux of horizontal flat roofs of artificially conditioned nonresidential buildings

Nonresidential buildings such as shopping centers, supermarkets and factories are constructions characterized as having large roof surfaces in comparison to their external wall surfaces. When conditioned artificially, these buildings become great consumers of electricity. To reduce this consumption, insulation materials are usually used. Notwithstanding the effectiveness of such a procedure, both the cost and environmental issues (the heat-island effect) have been considered as limiting factors for its usage. In this study, we analyze the effect of the application of selective coatings (with very high reflectance for solar radiation and high emittance for infrared radiation) on the surface temperature of the roof and the heat flux that crosses it. Two roof concepts were considered, namely metal roofs both with and without conventional mass-insulation, i.e. an insulating board on the internal side or between two metal foils. The methodology adopted to solve the proposed problem was based on the heat transfer analysis of a roof composed of multiple layers. External air temperature and solar radiation are considered time-varying. The results obtained show the benefits of selective coatings in terms of reductions in both roof temperature and heat flux and, consequently, alleviation of the urban heat-island effect and reduction of electricity consumption.