居住建筑室内自然通风效果关键影响因素分析——以重庆地区为例

自然通风是一种在不消耗能源的情况下改善室内环境的通风方式,尤其在公共卫生事件情况下,自然通风是最有效、最简单的防护措施,但由于自然通风受到气候、地理等条件的影响,其应用效果往往受到限制.以重庆地区为例,以居住建筑为研究对象,通过对气候条件的分析和对典型建筑的状态模拟,发现建筑位置布局、建筑朝向、室内布局、外窗大小及形式是影响居住建筑室内自然通风的关键因素.     

基于CFD的村镇住宅利用天井自然通风研究

通过CFD技术模拟天井对一种村镇住宅的自然通风效果。通过模拟不同风速、风向,其结果显示:天井为背风面房间的自然通风提供有利条件;建筑朝向以及外界风向对天井的通风效果有着较大的影响。同时,结合杭州气象条件,通过对有无导流构造的通风模拟,可以看出导流构造对于天井通风的影响。最后得出,结合恰当的建筑朝向以及适当的导流构造如老虎窗、一定外形的屋面等,结合天井,可有效改善住宅的自然通风状况。     

基于CFD模拟的绿色高层大跨建筑“形体—风适应”研究

自然通风是一项重要的绿色建筑被动式技术措施,一方面能降低室内污染物浓度,提高建筑室内舒适度,另一方面能降低空调和机械通风能耗,节能减排。采用基于计算流体力学的PKPM-CFD软件,以高层大跨建筑为建模原型,并连续变化建筑朝向,以长沙地区各个朝向的逐时风况作为输入条件进行自然通风模拟,得出不同朝向的平均换气次数,分析得出,长沙地区最有利于自然通风的朝向为西南向。风向对自然通风会产生很大的影响,风向最好垂直于建筑。影响自然通风的因素是多方面的,应当综合考虑。     

夏热冬暖地区某开敞式大空间建筑的节能改造技术分析

为了探讨夏热冬暖地区开敞式大空间建筑的节能改造措施,以广州市某实际工程为例,应用Fluent软件,对自然通风、置换通风、遮阳、屋顶淋水降温的节能效果进行了定性分析,并应用DeST软件模拟了全年能耗。分析了自然通风与空调系统联合工作时的室内温度和速度场,并给出了室内温湿度的实测数据。结果表明:在该工程中,自然通风、置换通风、遮阳挡板和屋面淋水技术可明显改善室内热环境,同时降低建筑能耗;下沉式地面有利于增强室内置换通风效果;通过采用被动节能技术合理设计后,建筑节能率达61.9%。     

低碳理念下村镇住区自然通风技术措施研究

由于拥有广阔的自然环境,建筑密度又低,故农村住宅利用自然通风的优势明显,且意义重大。本文结合山东省的气候特征,对农村建筑自然通风进行探讨,提出农村住宅朝向的合理范围,论证了建筑间距与自然通风的影响关系,分析了群体各种组合方式的特点和通风效果,以期对村镇建筑的自然通风设计有所借鉴意义。     

建筑朝向对自然通风的分析及确定

通过分析气流组织、风影区长度、室内平均风速、室内通风量以及室内空气的均匀性等影响自然通风效果的因素,确定在群体性建筑自然通风时,建筑来流入射角的取值。在此基础之上,确定了风向季节变化区的建筑朝向,并且综合考虑多项因素,最终确定建筑朝向。     

造船厂焊接车间通风方式的研究

从工程应用的角度,结合实际调研,通过CFD模拟计算探讨了自然通风和辅助机械通风方式对造船厂焊接车间通风效果的影响.     

建筑平面布局与朝向设计对室内通风的影响

建筑平面布局和朝向对室内通风都有极大的影响,合理的建筑设计可增强室内自然通风,使室内环境的舒适性得到明显的改善.本文着重从建筑平面布局和朝向两个方面进行研究,对建筑布局、建筑平面、室内设计细节以及来流入射角对室内通风的影响进行了较为详细的探讨.     

基于FLUENT模拟的通风屋顶流场分析

通风屋顶作为一种传统的自然通风方式,对于降低建筑能耗和节约能源有非常重要的作用,针对通风屋顶的通风桥进行研究,运用FLUENT软件模拟分析其内部温度场和流速场的分布和变化。     

建筑平面布局和朝向对室内自然通风影响的数值模拟

合理的建筑设计可增强室内自然通风,使室内环境的舒适性得到明显的改善。为了对比建筑设计对室内自然通风效果的作用,结合重庆市的最佳户型评选活动的部分建筑户型,利用数值分析的方法,对建筑进行了建筑布局和建筑朝向的不同设计情况下室内速度场分布、温度场分布和室内PMV分布的分析。分析表明,通过改变建筑朝向和局部改变建筑布局设计,室内产生的最大气流可从0.24 m/s增强到0.82 m/s,显著改善了室内的自然通风效果;半小时后室内温度较原朝向降低0.9℃,室内的PMV值更接近舒适。由此可见,建筑布局和建筑朝向的合理设计,是保证建筑良好室内舒适环境的前提。     

自然通风环境下办公建筑中庭空间热舒适性模糊优化研究

：随着绿色建筑设计理念深入人心,办 公建筑的中庭空间因其特有空间特质受到越来 越多的关注。通常办公中庭空间中的节能性与热 舒适性是一对矛盾体,而自然通风作为被动节能 技术之一,不仅能够促进中庭空间的内外空气 循环,改善室内空气质量,而且降低能耗和提升 热舒适性,较好地解决这一矛盾。以江雅园办公 楼中庭空间为案例进行研究,从中庭屋顶形态、 中庭高度及进风口开启方式三个变量因素出发, 引用模糊评估方法寻找出中庭空间自然通风热 舒适性最佳方案,结论显示在多个组合方案中 斜屋顶形态+进风口全部开启的方案热舒适性最 佳,同时也证明屋顶形态与通风方式的变化对自 然通风舒适性的影响较大,而中庭空间高度的变化对自然通风舒适性影响较小。本研究希望建立一套以风速和温度为评价指标的模糊体系,为自 然通风的热舒适性的评价提供一种客观的评估手段,从而为方案阶段的中庭空间设计提供一种 有效的优化方法。     

Passive cooling in hot,arid regions in developing countries by employing domed roofs and reducing the temperature of internal surfaces

Natural ventilation due to wind effects through buildings employing domed roofs was estimated by a flow network analysis. The dome was assumed to have an opening at its crown. When compared with flat roofs, the domed roofs always increase the air flow rate through the building. The increase in natural ventilation becomes significant in buildings with doors and windows all in one wall, or whenever the wind effects on the building envelope do not produce large pressure differences at the openings.The large air flow rate in the buildings with domed roofs may be utilized to store night air coolness in the structure more effectively and keep the mean radiant temperature of the interior surfaces low for thermal comfort in summer. The lowest internal surface temperatures can be obtained when the surfaces are kept moist and evaporatively cooled.Through a one-dimensional energy analysis the inside surface temperature of a horizontal slab was estimated for various slab materials and thicknesses and external and internal conditions. The inside surface temperature was compared with the case of employing a roof pond. It was found that lower temperatures can be obtained by evaporatively-cooled moist internal surfaces than that which can be obtained by unshaded roof ponds: For a building whose internal surfaces (walls and ceiling) are kept moist a large ventilation rate is needed to prevent water vapor build-up in the space. A domed roof with a hole in its crown can produce the necessary ventilation for such a building.     

Model development and experimental validation of a floriculture greenhouse under natural ventilation

Greenhouse technology is an effective method of cultivation of flowers, crops, etc. under controlled environment. For any greenhouse, ventilation performance is a major factor in production, influencing the yield and quality of the products. Natural ventilation can be effectively used to maintain greenhouse microclimate, conducive to plant growth, when the ambient conditions are not extreme. The present paper discusses the modeling aspects of a floriculture greenhouse suitable for operation in typical Indian climate under natural ventilation. Combined ridge and sidewall ventilation is considered in the model. The model is validated against the test results of an experimental greenhouse. Parametric analysis is also done to understand the effects of variations in parameters such as wind speed, solar radiation intensity, effective greenhouse height etc. The study reveals that the performance of a greenhouse under natural ventilation is influenced considerably by parameters such as intensity of solar radiation, effective distance between the side and the roof vents, free wind speed etc.     

太阳能通风器的研究应用

在建立太阳能通风数学模型的基础上,通过具体实验研究特定太阳能通风器在特定环境下的通风性能,分析了特定材料的太阳能通风器在通风性能以及在不同地区工程中应用的可行性,以期推广通风器的应用,节约能源,实现可持续发展。     

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。     

Experimental performance investigation of natural,mechanical and hybrid ventilation in urban environment

An experimental investigation of the performance of natural, mechanical and hybrid ventilation systems was carried out in an urban measurement campaign during summer period 2002 in Athens, Greece. Three building apartments characterized by different geometry and located in two street canyons with different orientation were studied. The aim was to show the impact of the urban environment on the ventilation efficiency of natural and hybrid systems. The tracer gas decay method has been applied during the experimental procedures with one (N₂O) and two tracer gases (N₂O and SF₆). Based on the results of air-exchange rates using multizone methods from a previous study, a further analysis is performed in the present work for the evaluation of the performance of different ventilation systems in urban conditions, with emphasis on the ventilation efficiency. A methodology to estimate the air-exchange efficiency, on the basis of room mean age of air, in multitracer gas experiments is introduced. In spite of the reduced wind speeds due to the canyon effect, appreciable ventilation rates can be obtained with natural ventilation, especially when cross-ventilation with two or more windows is measured. For single-sided ventilation or under calm conditions, hybrid ventilation has only a slight advantage over natural, either in terms of air-exchange rates or of air-exchange efficiencies.     

北京某商业步行街采光顶光热性能分析

为了对商业广场风雨步行街采光顶的光热性能进行整体评价,提出兼顾舒适、经济、节能三者的优化设计方案,现以北京某商业广场风雨步行街为实例,运用模拟计算软件对其步行街采光顶在无遮阳、采用内遮阳(实际采用的遮阳方式)、采用外遮阳这3种情况下分别进行模拟计算,分析其3种情况下步行街室内的采光效果、透入太阳辐射热程度,最后提出优化建议。     

A naturally ventilated cavity roof as potential benefits for improving thermal environment and cooling load of a factory building

The impact of natural ventilation of a roof cavity on improvement of the thermal environment and reduction of cooling load of a factory building is discussed. A computer program was developed with the logic in a companion paper [1] to observe the effect of cavity ventilation on the operative temperature of the occupied zone in the factory. Comparisons were made between factories with a cavity roof and a single roof in the Japanese climate. Results showed that the cavity roof was superior to the single roof in lowering the operative temperature by about 4.4 °C. When the factory was air conditioned, the cooling load reduction reached approximately 50% during the summer to maintain an operative temperature of 26 °C. Results showed that a naturally ventilated cavity roof has excellent potential for improving the indoor thermal environment and energy savings of factory buildings without complicated cooling installations and life time power consumption.     

Wind-induced natural ventilation of re-entrant bays in a high-rise building

This paper reports a systematic computational study of wind-induced natural ventilation and pollutant transport of re-entrant bays on a total of 30 generic building models of different building heights and with bays of different dimensions. Mean wind flow around each building model and wind-induced flow inside re-entrant bays are computed. To determine the ventilation efficiency of the bay, the computed flow field is used to disperse a scalar pollutant initially occupying the entire bay at a uniform concentration. The subsequent time decay of pollutant concentration inside the bay is studied and the ventilation efficiency is quantified by the retention time. The results show that wind-induced flow inside the bay, especially on the building side face, is complex and highly three-dimensional. Air exchange rates through the roof opening and vertical side opening are analyzed for each bay and their relationship to the ventilation efficiency is discussed. The bays on the building side faces are much worse ventilated than those on the windward or leeward building face. The deeper the side bay, the worse is the air exchange and ventilation. The building height is found to have a governing effect on the ventilation of the windward and leeward re-entrant bays.