浅谈屋面节能

结合屋顶保温节能的效益,分别介绍了平改坡、绿色屋顶、冷屋顶、金属屋面等几种节能屋面的节能效果及优点,阐述了屋面节能方面的技术理论,以期创造高效低耗,无废无污,健康舒适,生态平衡的建筑环境。     

ASTM制定种植屋面建议标准

<正>建筑的可持续发展越来越受到关注,使人们对于用花草植物代替传统屋面材料的种植或绿色屋面产生了浓厚兴趣。一项新的ASTM(国际)建议标准将涉及设计屋面的一个重要方面,即为其选用适当的防水卷材。     

种植屋面的能耗模拟分析——以长沙某办公建筑模型为例

随着建筑规模和体量的增长,建筑能耗日益攀升.屋顶作为建筑围护结构的主要构件,是建筑节能设计的主要对象之一.与传统屋顶相比,种植屋面能有效缓解城市热岛效应、降低建筑能耗.该文采用Energy Plus能耗模拟软件对长沙某办公建筑模型进行全年能耗模拟,分析了植物叶面积指数、基质层厚度、保温层厚度对种植屋面节能率的影响.结果表明:叶面积指数越大,供冷能耗越小;基质层和保温层越厚,供热能耗越小.     

城市建筑物屋面绿化工程的绿色价值评价研究

对裸露屋顶进行绿化,可大大提高城市绿地覆盖率、改善城市气候、缓解热岛效应、美化环境.论述了城市建筑物屋面绿化技术的发展,揭示了绿色价值的内涵,从财务收益、资源消耗、环境负荷和外部收益4个维度,确立了建筑物屋面绿化工程的绿色价值的评价方法,使建筑屋面绿化技术的综合效益有了一个具有可比性的统一量化的指标值,便于建筑物屋面绿化技术在我国的发展和大规模展开.结合工程实例,运用建立的模型,对屋面绿化工程费用情况进行评价,得出经济合理的屋面绿化方式.     

法国“波形沥青瓦、波形沥青防水板”轻型屋面材料问世

建筑能耗在我国总能耗中所占的比例很大,尤其屋面的传热系数为国外的3-6倍。目前国家大力提倡节能减排,建筑的节能,尤其建筑屋顶的节能越来越被重视。因此,提高屋面的通风除湿性能,对提高抵抗夏季室外热作用的能力尤其重要,这也是减少空调耗能,改善室内热环境的一个重要措施。     

如鸟斯革,如翚斯飞——中国木构建筑屋面形态及其审美意匠

中国传统建筑屋顶形式的选用有着严格的规定,是区分建筑等级的最显著标志。其硕大的屋顶,经过曲面、曲线的处理,再加上一些装饰,俨然成了中国古代木构建筑最富有情趣的一个部分。本文通过阐述屋面的形成与发展的成因,分析中国传统木构建筑的屋面结构、实体造型,描述了屋面形态的美学特征。力图在开拓建筑艺术的审美广度的同时,挖掘建筑的审美深度。对凝聚其中的审美意匠作一定程度的探讨。     

屋顶隔热构造的热工性能分析

本文介绍位于福建省建筑科学研究院金山基地试验楼屋顶的四种隔热保温构造形式,在2003年和2004年夏季进行的热工效果测试和分析,介绍四种不同方案的空调耗能指标的对比试验结果。本文还对我省屋面构造作法提出看法和建议。     

BIM技术在低能耗建筑设计中的协同作用——以建筑方案设计优化为例

文中利用响应面设计方法进行试验设计与分析，结合建筑信息模型及建筑性能模拟软件的耗能指标分析结果，得到建筑耗能设计影响因子的显著程度。研究发现，墙传热系数与窗传热系数对能耗指标影响显著；窗墙比和屋面传热系数的P值大于0.05，说明窗墙比和屋面传热系数对能耗指标影响不显著。此外，窗墙比和屋面传热系数的交叉作用P值小于0.05，说明两者交叉作用对能耗指标影响显著。通过模型的计算优化，得到能耗指标最少的热环境下的模拟参数设定，即窗墙比0.50、墙传热系数0.67、窗传热系系数5.50、屋面传热系数0.73。     

建筑屋面节能技术

中国建筑节能技术正处在发展的初期 ,建筑能耗很高 ,能源利用率还很低 ,我国南方地区在夏季太阳辐射和室外气温的综合作用下 ,从屋顶传入室内的热量要比从墙体传入室内的热量多得多 ,因此 ,建筑屋面的隔热节能尤为重要。论述了倒置式屋面、屋面绿化、蓄水屋面、平改坡等几种屋面节能技术。     

光伏幕墙屋面系统技术的应用研究

现代建筑技术的发展使人们对住宿条件的要求有了新的认识,光伏建筑一体化的建筑概念,促进了光伏幕墙的推广与发展。光伏幕墙系统是通过将建筑物屋顶和墙面围护结构与光伏发电集成起来,使建筑物能利用太阳能资源产生电能,起到节能环保的作用,达到绿色建筑的要求。本文通过对光伏幕墙屋面系统技术的了解,分析光伏幕墙屋面系统技术在房屋建设中的应用。     

A green roof model for building energy simulation programs

A physically based model of the energy balance of a vegetated rooftop has been developed and integrated into the EnergyPlus building energy simulation program. This green roof module allows the energy modeler to explore green roof design options including growing media thermal properties and depth, and vegetation characteristics such as plant type, height and leaf area index. The model has been tested successfully using observations from a monitored green roof in Florida. A preliminary set of parametric tests has been conducted on prototypical 4000 m² office buildings in Chicago IL and Houston TX. These tests focus on evaluating the role of growing media depth, irrigation, and vegetation density (leaf area index) on both natural gas and electricity consumption. Building energy consumption was found to vary significantly in response to variations in these parameters. Further, this response depended significantly on building location (climate). Hence, it is evident that the green roof simulation tool presented here can serve a valuable role in informing green roof design decisions.     

Experimental measurements and numerical modelling of a green roof

Green roof utilisation has been known since ancient times both in hot and cold climates. Nowadays, it has been reconsidered at issue of energy saving and pollution reduction. In this paper, some measurement sessions on a green roof installed by the Vicenza Hospital are described. A data logging system with temperature, humidity, rainfall, radiation, etc. sensors surveyed both the parameters related to the green roof and to the rooms underneath. The aim is to evaluate the passive cooling, stressing the evapotranspiration role in summer time. Furthermore, the enhanced insulating properties have been tested during winter time. A predictive numerical model has been developed in a building simulation software (TRNSYS) to calculate thermal and energy performances of a building with a green roof, varying the meteorological dataset for a specific geographic zone.     

Modeling the heat diffusion process in the abiotic layers of green roofs

Green roofs have been increasingly installed to alleviate some common environmental problems. The thermal benefit of living vegetation on rooftop has been extensively studied. The individual and joint contribution of the non-living green roof layers, namely soil, rockwool (water storage) and plastic drainage layers, to thermal performance of green roof has seldom been assessed. This study evaluates the insulating and cooling effects of these abiotic materials. A one-dimensional theoretical model was developed to assess the heat diffusion process in the layers. The model was validated with empirical results from three experimental plots. A calibration procedure was successfully applied to determine key model parameters. The model can capture the most critical features of temperature variations and thermal performance of common abiotic green roof materials. The appreciable water-retention capacity of rockwool plays the dual role of supplying water to the soil to enhance evaporative cooling, and increasing the specific heat capacity of the green roof. The plastic drainage sheet with ample air spaces serves as an excellent thermal insulator. The model remains robust despite seasonal and weather variabilities. Our research findings contradict with some researches in the temperate region that the thermal dissipation in green roofs with dense vegetation is lower than thermally insulated bare roofs. The theoretical model could be used to simulate the micro-environmental conditions and predict the thermal performance of different materials to improve green roof design.     

Modeling the reduction of urban excess heat by green roofs with respect to different irrigation scenarios

Urban heat reduction by evaporative cooling from extensive green roofs is explored by applying irrigation scenarios to green roofs located in different climate zones using a coupled atmosphere-vegetation-substrate green roof model. The model,which is integrated in the building energy simulation software Energy Plus,is validated with eddy covariance surface energy fluxes from a green roof in Berlin,Germany. The original model wasmodified to include interception and an improved runoff calculation. Three irrigation scenarios were defined( no irrigation,sustainable irrigation by harvested runoff water,unrestricted irrigation) to study the heat reduction potential in terms of surface energy partitioning and sensible heat fluxes( QH). The irrigation scenarios are compared to two white roofs( albedo equal to 0. 35 and 0. 65) and a black roof.High correlation of sensible and latent heat( QE) fluxes between measured and modelled data for the original and the modified version of the green roof model were observed( for the original model,R~2= 0. 91 and 0. 81 for QH and QE,respectively,while for the modified version R~2= 0. 91 and 0. 80,respectively). The modified version was applied to study irrigation,due to lower systematic errors for QH,QEand better performance for the substrate moisture content. In comparison to a black roof the green roof reduces urban excess heat by 15%-51%with sustainable irrigation,by 48%-75%with unrestricted irrigation,but drops to 3% for unirrigated roofs in the different cities. Sustainable irrigation can be effective in climates with high annual( or summerly) precipitation.     

Assessment of green roof thermal behavior: A coupled heat and mass transfer model

Green roofs have a positive effect on the energy performance of buildings, providing a cooling effect in summer, along with a more efficient harnessing of the solar radiation due to the reflective properties found inside the foliage. For assessing these effects, the thermodynamic model was developed as well as the thermo-physical properties of the green roof components were characterized. Its typologies and vegetation styles should also be studied. The proposed model is based on energy balance equations expressed for foliage and soil media. In this study, the influence of the mass transfer in the thermal properties and evapotranspiration were taken into account. We then added the water balance equation into our model and performed a numerical simulation. By assuming the outdoor conditions, the roof support temperature and the drainage water as inputs, the model evaluates the temperatures evolution at foliage and soil ground levels. A parametric study was performed using the proposed model to classify green roofs depending on the considered climate condition. Comparisons were undertaken with a roof slab concrete model; a significant difference (of up to 30 °C) in temperature between the outer surfaces of the two roofs was noticed in summer. The model was experimentally validated according to green roof platform, which was elaborated. The mass transfer effect in the subtract was very effective in reducing the model errors. Simulation results show that the use of vegetation in the roof building improves not only thermal comfort conditions, but the energy performance of a building.     

Investigation of green roof thermal performance in temperate climate: A case study of an experimental building in Florianópolis city, Southern Brazil

Green roofs have been investigated as a bioclimatic strategy to improve the energy efficiency of buildings. Quantitative data on this subject are still needed for many specific climatic conditions. This paper deals with the investigation of the green roof thermal performance of an experimental single-family residence in Florianópolis (SC, Brazil), a southern city with a temperate climate. Field measurements during a warm period (01-March-2008-07-March-2008) and during a cold period (25-May-2008-31-May-2008) included internal air temperature of rooms, internal and external surface temperature of three types of roofs (green, ceramic and metallic), heat fluxes through these roofs, green roof's temperature profile, water volumetric content in substrate layer and meteorological data. During the warm period, the green roof reduced heat gain by 92-97% in comparison to ceramic and metallic roofs, respectively, and enhanced the heat loss to 49 and 20%. During the cold period, the green roof reduced heat gain by 70 and 84%, and reduced the heat loss by 44 and 52% in comparison to ceramic and metallic roofs, respectively. From the derived data it has been confirmed that green roof contributes to the thermal benefits and energy efficiency of the building in temperate climate conditions.     

国内外屋顶的绿化设计

屋顶绿化是建筑节能的一种有效措施,具有显著的生态效益和景观价值,已越来越多地引起了建筑领域及相关人员的广泛关注。通过系统分析屋顶绿化在促进建筑节能、改善环境和蓄积雨水等方面的作用和效果,研究总结了国内外屋顶绿化设计的方法及其主要影响因素,包括配置模式、植被材料和栽培基质等方面的研究成果,对国内外屋顶绿化政策和实践的发展进行了回顾和比较。     

Modeling impacts of roof reflectivity,integrated photovoltaic panels and green roof systems on sensible heat flux into the urban environment

This study presents results of a modeling effort to explore the role that sustainable roofing technologies play in impacting the rooftop energy balance, and the resultant net sensible heat flux into the urban atmosphere with a focus on the summertime urban heat island. The model has been validated using data from a field experiment conducted in Portland Oregon. Roofing technologies explored include control dark membrane roof, a highly reflective (cool) roof, a vegetated green roof, and photovoltaic (PV) panels elevated above various base roofs. Energy balance models were developed, validated with experimental measurements, and then used to estimate sensible fluxes in cities located in six climate zones across the US.     

Do green roofs really provide significant energy saving in a Mediterranean climate?Critical evaluation based on different case studies

Green roofs represent a growing technology that is spreading increasingly and rapidly throughout the building sector. The latest national and international regulations are promoting their application for refurbishments and new buildings to increase the energy efficiency of the building stock. In recent years, vegetative coverings have been studied to demonstrate their multiple benefits, such as the reduction of the urban heat island phenomenon and the increase in the albedo of cities. On the contrary, this study aims to verify the actual benefit of applying a green roof on a sloped cover compared with installing a highly insulated tiled roof. The EnergyPlus tool has been used to perform dynamic analyses, which has allowed to understand the behavior of two different stratigraphies in accordance with weather conditions, rain, and irrigation profiles. Results have shown that the installation of a green roof cannot always be considered the best solution for reducing building energy consumption, especially if compared with a classic highly insulated clay tile roof. In terms of summer air conditioning, the maximum saving is 0.72 kWh/m2. The presence of water in the soil has also been proven a crucial factor.     

关于屋顶绿化节能技术化问题

建筑节能提倡采用生态节能技术，尤其是建筑绿化节能技术。围绕屋顶绿化的节能技术化问题进行讨论，分析了屋顶绿化节能效果影响因素，提出了屋顶绿化节能性能参数的确定方法。