室内气温对绿化屋顶当量热阻的影响

绿化屋顶在节能设计中以附加当量热阻增大屋顶总热阻值,有效减少由屋顶进入室内的热量,降低室内空气温度。但根据已有的实验研究,绿化屋顶隔热特性与室内气温是耦合关系,随室内气温的变化,绿化屋顶会呈现出不同的隔热特性。用实验测试与数值模拟相结合的方法,分析在不同室内气温下绿化屋顶、参照屋顶与等效保温屋顶内表面温度与热流的变化。结果表明:室内气温会显著改变绿化屋顶的隔热性能,其当量热阻为与室内温度正相关的变量。在被动式建筑中,绿化屋顶更能充分发挥隔热功效,且具有不向室内传热的特性。     

屋顶绿化传热临界温度

根据实验研究结果,分析了屋顶绿化在被动式室内热环境状态下的热流特点。研究结果表明,不能采用等效热工参数评价其隔热性能。采用屋顶绿化实验方法,证明了屋顶绿化在室内人体可接受的热环境范围内存在着不向室内传热的临界温度状态。通过屋顶内表面热流与室内外温差的相关性分析,得出屋顶绿化的传热临界温度低于室外平均气温1.5℃。     

藤架式屋顶绿化对建筑热环境影响研究

本文将位于夏热冬暖区的厦门市近郊藤架式屋顶绿化作为对象研究,实测屋顶绿化房间和紧邻无绿化措施房间的数据,采集两个房间室内和室外空气温度、楼板温度、PMV等多项影响人体热舒适的参数。通过实际测试与CFD模拟综合对比,分析夏季藤架式屋顶绿化对建筑顶层房间热环境的影响。数据显示,藤架式屋顶绿化使屋顶表面温度最大降低12.35℃,室内空气温度日均降低0.68℃,分析得出藤架式屋顶绿化在一定程度上改善了顶层建筑热环境,是一种有效改善居民生活热环境的途径。     

粗放型屋顶绿化隔热效果分析

以自然通风层的屋顶绿化为研究对象,对有无绿化屋顶内表面温度进行比较,采用实测数据统计分析的方法,以全夏季为研究周期,按不同温度区间分析屋顶内表面温度的分布特性,比较2种状态下屋顶内表面温度的分布频率以及总温度,得到绿化屋顶内表面温度<34 ℃出现的频率占总周期的90％,是无绿化屋顶的1.6倍,大于36 ℃高温的频率为无绿化屋顶的4.6%,绿化屋顶内表面大于30 ℃的温度总量约为无绿化屋顶的1/3,且绿化屋顶的隔热性能与室外气温有较强的正向性,随着气温的升高,绿化屋顶的隔热性能体现得更加充分。     

屋顶铝箔防水卷材保温性能研究

指出屋顶作为建筑物外围护结构之一,在建筑节能方面具有重要作用,通过对铝箔防水卷材屋顶的热工实验和计算,分析得到铝箔的等效保温作用,使得屋顶获得更佳的节能作用。     

内蒙古草原民居外围护结构热惰性研究

对内蒙古西部草原民居外围护结构的热惰性指标(D)进行研究,分析有无保温、不同墙厚、不同保温层厚度时热惰性指标D值对采暖能耗和室内热舒适值(PMV值)的影响。采用MATLAB软件,用最小二乘法将D值与采暖能耗和PMV进行曲线拟合。结果表明:无保温时D的最佳取值为6.75,有保温时D的最佳取值为6.54;无保温时,小窗墙比对采暖能耗的影响明显优于大窗墙比时的情况,而PMV值的结果正好相反;有保温时,小窗墙比不仅能降低采暖能耗,而且可以提高PMV值;保温材料的综合保温效果为:PUR最佳,XPS次之,EPS最差。     

轻型屋顶景天绿化的降温效果

屋顶绿化是对城市土地资源的有益补充，具有地面绿化一样的美化环境、净化空气、降低噪音、减少环境污染、提高城市排蓄水功能和缓解热岛效应等作用。而且还有地面绿化不具备的独特作用即：改变现代城市乌瞰形象、丰富城市立体景观，隔热降温、隔热保温、改善建筑物环境小气候，提高建筑物防水层使用寿命、节约能源等。日本研究表明，屋顶绿化具有降低屋面温度的良好作用。我国重庆大学开展屋顶绿化对屋面温度的影响研究，并建立了相关数学模型。但这些研究很少涉及屋顶绿化中最大的难题——轻型屋顶绿化，特别是轻型屋顶绿化对降低屋面温度从而影响室内温度的报道。     

南方民宅屋顶架空绿藤棚对室内外热环境的影响

为确切了解夏季屋顶架空绿藤棚对南方民宅室内外热环境的防热效果,本文以厦门兑山村的典型民宅为研究对象在2014年8月9日~10日进行实测研究,对比包括"遮蔽房和无遮蔽房的空气温度、相对湿度、黑球温度、风速、顶棚表面温度、室内热舒适PMV值、屋顶地表温度、屋顶室外热舒适SET值",实验结果遮蔽房的室内PMV平均值为2.08,比无遮蔽房低0.84,尤其是20:30~次日10:30能提供14 h左右的PMV值1.3~2.0相对好的热舒适环境,午后室内PMV值下降相对无遮蔽房更明显且快速。绿藤棚灰空间的WBGT值低于32℃且显著低于露台,绿藤棚灰空间的SET值白天在30~35℃感受稍热,明显低于露台区域的30~38.55℃。结论证明绿藤棚的防热效果对于屋顶空间及遮蔽房都有明显作用,辅助降低空调能耗。     

遮阳网与绿化层的隔热效果测试分析

为了研究遮阳网和绿化层的隔热降温效果,对某小区住宅楼有、无绿化屋顶进行了连续测试。分析测试结果发现:仅绿化层作用下,平均温度和最高温度分别降低23.8%、36.9%;仅遮阳网作用下,平均温度和最高温度分别降低33.3%、38.7%;绿化层和遮阳网共同作用下,平均温度和最高温度分别降低35.6%、45.5%。对屋顶进行绿化和加设遮阳网都能有效地改善阳光直射屋顶而导致的屋顶过热现象,两者共同作用下的隔热效果更好,可进一步降低室内空调能耗,达到建筑节能的效果。     

立体绿化住宅建筑热工性能研究

以黄冈居然之家垂直森林城市综合体项目为研究对象,使用Revit建模软件建立围护结构模型,通过Ecotect能耗模拟软件完善模型,并设置环境参数对房间负荷进行热环境分析,研究建筑模型分别在普通墙体和普通屋顶、绿化墙体和绿化屋顶两种不同类型的外部围护结构条件下,室内空调的耗能情况。结果表明,在建筑外覆盖绿色植被,可一定程度上增强建筑物外部围护构件的抗热性能和保温性能;立体绿化可减小建筑模型的全年负荷,还可消耗CO_2,缓解热岛效应。     

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.     

南方民宅屋顶架空遮阳网对室内外热环境的影响

为了解南方民宅屋顶自发搭建的黑色遮阳网对室内外热环境的防热效果,以两个典型民宅为研究对象对其进行实测研究,一个是厦门集美兑山村民宅,另一个是厦港片区民宅为研究对象,在晴热天气测试其室内外气候参数,对比包括遮蔽房和无遮蔽房的空气温度、湿度、黑球温度、风速、顶棚表面温度、室内热舒适PMV值、屋顶地表温度、屋顶室外热舒适SET值,结果表明黑色遮阳网对室内的遮蔽房具有明显的防热效果,白天及其他大部分时间遮蔽房比无遮蔽房的空气温度、黑球温度、顶棚表面温度、室内PMV值都明显较低,并且下午随着日照减弱各个指标的降温也更快、幅度更大、显著缩短高温的持续时间;证实黑色遮阳网的防热效果对于屋顶灰空间作用不明显,却对于灰空间下方的遮蔽房间有明显作用。     

南方民宅屋顶铁皮棚对室内外热环境的影响

为揭示南方民宅屋顶自发搭建附加铁皮棚对室内外热环境所产生的影响,以厦门集美兑山村民宅为研究对象,在盛夏天气对典型民宅进行室内外气候参数测试,对比分析"有无屋顶铁皮棚遮蔽的屋顶空间的地表温度、WBGT和SET值","有无屋顶铁皮棚遮蔽的房间室内热舒适度PMV值和顶棚表面温度"等热舒适指标。结果表明:铁皮棚下方遮蔽房的室内PMV平均值为2.84,比无遮蔽房低0.3;屋顶灰空间的WBGT值为安全范围,全天低于32℃,无遮蔽区域则超出32℃,不安全;灰空间SET值白天30~32℃,感觉温暖,而无遮蔽区域为36~38℃,感觉非常热乃至生理调节失效;结论证实民宅屋顶附加铁皮遮阳棚不仅能显著改善白天屋顶铁皮棚灰空间的热舒适度,而且具有改善其下方遮蔽房间热环境。     

Seasonal heat flux properties of an extensive green roof in a Midwestern U.S. climate

Green roofs, or vegetated roofs, can reduce heat flux magnitude through a building envelope as a result of insulation provided by the growing medium, shading from the plant canopy, and transpirational cooling provided by the plants. This study quantifies the thermal properties of an inverted 325 m² retro-fitted extensive green roof versus a traditional gravel ballasted inverted roof in a Midwestern U.S. climate characterized by hot, humid summers and cold, snowy winters. In autumn, green roof temperatures were consistently 5 °C lower than corresponding gravel roof temperatures. Even during chilly and moist conditions, the heat flux leaving the building was lower for the green roof than the gravel roof. Temperatures at the top of the insulation layer were more variable for both green roof and gravel roof on winter days with no snow cover than on days with snow cover. Variation in temperatures between roof types in spring was similar to those in autumn. Peak temperature differences between gravel and green roof were larger in summer than other seasons (sometimes by as much as 20 °C). Over the course of a year (September 2005-August 2006), maximum and minimum average monthly temperatures and heat fluxes were consistently more extreme for the gravel roof than the green roof.     

冷屋面在建筑节能中的应用

国内外对冷屋面用反射型隔热涂料节能效果的评价方法,有涂层稳态表面温度、等效热阻以及建筑能耗模拟分析等。其中,等效热阻法在建筑节能设计中应用简便、易操作。从理论和上海静安科技馆40mmPU屋面的应用实例证实,热反射隔热屋面节能效果显著。     

基于屋顶绿化热工性能研究节能降温效应

随着建筑能耗比例持续增高,屋顶绿化作为节能设计重点技术之一,具有巨大的节能潜力。通过屋顶绿化的构造及各层参数来分析屋顶绿化的隔热原理,并结合外表面温度、内表面温度和当量热阻3个影响因素阐释屋顶绿化对室内空调能耗的影响。以杭州市某住宅项目为研究对象,运用PHOENICS软件模拟整个住区环境的建筑实况,验证有无屋顶绿化时室内温度差值,来证明屋顶绿化确实减少室内空调运行能耗,一定程度上缓解周围热岛,为夏热冬冷地区隔热节能设计提供理论基础。     

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.     

Study on the thermal performance of the Chinese traditional vernacular dwellings in Summer

Based on the field measurements of the thermal environment parameters and a long-term auto-recorder of the indoor and outdoor temperature at four typical traditional vernacular dwellings at Wannan area in summer, some wrong viewpoints about Chinese traditional vernacular dwellings are clarified. Also, with the analysis of the fine structures design such as the dooryard, the structure of the double-pitched roof and the eaves by the measurements of temperature, wind velocity, etc. some design principles of the traditional vernacular dwellings in Wannan area are revealed, of which sun shading and insulation are of great importance while the natural ventilation is just considered as an auxiliary approach. So the strategy of ventilation design is to restrain the natural ventilation at daytime and to boost it at night. Moreover, the thermal sensation votes (TSV) of the occupants and the predicted mean votes (PMV) are compared and the evaluation standard in a naturally ventilated environment is also discussed.     

粗放式屋顶绿化的热惰性

屋顶绿化的热工性能是进行建筑节能工程设计和评价的依据,但目前对屋顶绿化热工性能的研究很少关注热惰性。以一种粗放式屋顶绿化在自然通风状态下连续5个月的对比测量数据为依据,采用统计分析方法研究了屋顶绿化对气候热作用波动的衰减和延迟特性。结果表明,绿化屋顶与裸屋顶相比,对气候热作用波动的平均衰减倍数提高了1倍以上,延迟时间有所减少。