自然通风技术的应用

介绍了自然通风常见的基本形式.从节能、舒适性、可控制性和可靠性等方面分析了自然通风技术的应用,指出了自然通风存在的问题与发展,并给出几种自然通风技术的发展应用.自然通风是一个整体建筑设计概念,需要各专业研究设计人员的相互配合.     

太阳能烟囱强化自然通风的研究进展

阐述了太阳能烟囱技术的技术原理及研究进展,在国内外大量学者试验研究、理论分析及模拟研究的基础上,提出了当前研究存在的问题,并对太阳能强化自然通风技术的继续研究提出了相关建议。     

自然通风房间热环境的耦合模拟计算方法

分析了自然通风房间的自然通风量和室内空气温度的相互影响作用关系,采用宏观计算模型,建立了自然通风系统和建筑热过程系统的耦合影响作用模型,通过计算结果和实测值的对比,证明该模型提供了一种可以较为准确地模拟自然通风房间热环境的方法。     

太阳能烟囱强化自然通风实验研究

实验探讨了高2000mm,长1000mm的竖直集热板屋顶式太阳能烟囱模型,在改变宽度及热流密度的情况下,研究其诱导的空气量及内部空间气流温度场和速度场的变化.结果表明,在研究范围内自然通风量随烟囱宽度、热流密度的增加而增大,气流速度随热流密度的增加而增大,随烟囱宽度的增加而降低.气流温度及速度在烟囱热壁近壁面处高于其在远离壁面处,在热壁近壁处形成了温度和速度边界层.     

谈建筑中自然通风技术的作用原理

在公共建筑中,自然通风技术正在被日益广泛地采用,降低了能耗,提升了建筑内部环境空气质量,最大限度地使室内的人员舒适并保护他们的健康。     

自然通风的策略形式及模拟分析

介绍了自然通风的策略形式 ,阐述了采用网络法和CFD对自然通风的模拟分析。最后提出了自然通风的策略选择和模拟分析中要注意的几个问题。     

大开口自然通风实验研究及数值模拟分析

论述了大开口自然通风风洞实验所要遵守的相似理论,采用风洞实验的方法对通过大开口自然通风的流动特性进行了研究,并将实验数据与相同工况下数值模拟数据进行了对比分析,结果表明二者存在一致的规律性,单区模型中线上的风洞实验数值与数值模拟数据吻合的最好。对建筑内部流场的分析显示,单区大开口自然通风室内流场速度分布很不均匀,惯性力作用不能忽略;经过开口后的气流很难立即恢复到均匀流或渐变流状态,在应用能量守恒方程计算其自然通风量或流量系数时,计算断面选取位置会对取值产生影响。     

绿色建筑中的自然通风

分析了现代建筑中造成室内空气品质恶劣的主要因素,提出了应当在绿色建筑中着力推广采用自然通风系统。同时,还分析了在绿色建筑中采用自然通风系统迫切需要解决的几个技术问题。     

夏热冬暖地区的建筑自然通风优化设计研究

随着能源危机的加剧,建筑能耗和环境问题的日益严重,可持续发展的理念已成为人类的共识,绿色建筑是建筑行业发展的必然趋势。可从建筑的通风系统入手,优化机械通风系统的使用,减少环境污染,同时提高人们的生活质量,实现与自然和谐发展的目标。     

室内自然通风环境热舒适性研究

通过建立室内自然通风模型,研究了系统在不同温度、不同进风口风速及不同外窗开度情况耦合工况下,人体热舒适感受能够承受的温度上限和空气流速与外窗开度的适用范围。结果表明,室内热舒适性会随室外温度升高而明显恶化,温度达28.5℃时超过热舒适性指标国家标准推荐值;各因子中,风速及温度对室内热舒适性影响比重相对较轻,外窗开度的影响最大;20%为外窗开度下限,随开度的增大室内热舒适性增强;风速增加带来的不适\"吹风感\"也需考虑,该个体差异性感受会使得室内热舒适性迅速下降。     

济南办公建筑自然通风工况下自然室温的研究

针对济南地区一办公房间,讨论不同的换气次数、围护结构和建筑朝向对自然室温影响的变化规律。指出夜间通风和节能50%的围护结构能获得适宜的自然室温,建筑朝向对自然室温的影响较小。     

被动式生态建筑中庭的自然通风设计策略

分析中庭设计存在的问题,将被动式生态设计与中庭结合,归纳总结了寒冷气候区、温和气候区、干热气候区、湿热气候区等4种典型气候类型对中庭被动式生态自然通风设计的影响,提出有效的通风策略和中庭自然通风的季节性调控技术。另外,还提出自然通风控制技术和构造策略,提供了一些新的视角,赋予中庭空间新的意义,为生态建筑中庭的自然通风设计提供参考。     

太阳能烟囱的通风效应及应用研究

对太阳能烟囱自然通风模型进行了理论分析和数值计算，得出了通风量与烟囱高度、宽度及太阳辐射强度之间的关系。最后提出了太阳能烟囱在应用中应注意的几个问题。     

Synergic effects of thermal mass and natural ventilation on the thermal behaviour of traditional massive buildings

The energy policies about energy efficiency in buildings currently focus on new buildings and on existing buildings in case of energy retrofit. However, historic and heritage buildings, that are the trademark of numerous European cities, should also deserve attention; nevertheless, their energy efficiency is nowadays not deeply investigated. In this context, this study evaluates the thermal performance of a traditional massive building situated in a Mediterranean city. Dynamic numerical simulations were carried out on a yearly basis through the software DesignBuilder, both in free-running conditions and in the presence of an air-conditioning (AC) system. The results highlight that the massive envelope of traditional residential buildings helps in maintaining small fluctuations of the indoor temperature, thus limiting the need for AC in the mid-season and in summer. This feature is highly emphasised by exploiting natural ventilation at night, which allows reducing the building energy demand for cooling by about 30%.The research also indicates that, for Mediterranean climate, the increase in thermal insulation does not always induce positive effects on the thermal performance in summer, and that it might even produce an increase in the heat loads due to the transmission through the envelope.     

Experimental study for natural ventilation on a solar chimney

Thermal performance of a solar chimney for natural ventilation was experimentally investigated. The experimental model was implemented on full scale and real meteorological conditions, so that experimental results will be compared with the simulation results. The results show that for a maximum irradiance of 604 W/m², occurring around 13:00 h on September 15th, 2007, a maximum air temperature increment of 7 °C was obtained through the solar chimney. Also, a volumetric air flow rate ranging from 50 to 374 m³/h was measured on that day. Thus, an average air flow rate of 177 m³/h was achieved from 0:00 h to 24:00 h. The experimental solar chimney discharge coefficient, C_d, was 0.52. This coefficient is useful to determine the mass flow rate in the solar chimney design. It was observed that the air flow rate through the solar chimney is influenced by a pressure difference between input and output, caused by thermal gradients and wind velocity, mainly.     

Prediction of hybrid ventilation performance using two simulation tools

This paper describes the results of a collaboration between ENTPE-LASH and LEPTAB within the framework of the IEA Annex 35 “Hybrid Ventilation in New and Retrofitted Buildings”. The aim of the work is to carry out a cross-simulation study and to identify optimal control strategies for ventilation systems in order to provide a comfortable thermal indoor environment and a good indoor air quality with energy efficiency. Two models were developed by ENTPE-LASH and LEPTAB in order to carry out hybrid system simulations taking into account air flows, heat transfers and CO₂ concentrations, and numerical results are compared in this study. The models were first adjusted to an experimental cell, HYBCELL, created in the same project. The simulations were carried out using a fictive classroom. The test room was assumed to be in Copenhagen and to be equipped with a natural ventilation system (two inlet grilles and an exhaust chimney) or with mechanical ventilation systems (fans with or without heat recovery). This work also reveals what are the differences in results between the two tools and outlines some conclusions on relative performance of the specific control strategies chosen in this study.     

A numerical study of solar chimney for natural ventilation of buildings with heat recovery

The performance of a glazed solar chimney for heat recovery in naturally-ventilated buildings was investigated using the CFD technique. The CFD program was validated against experimental data from the literature and good agreement between the prediction and measurement was achieved. The predicted ventilation rate increased with the chimney wall temperature. The effects of solar heat gain and glazing type were investigated. It was shown that in order to maximise the ventilation rate in a cold winter, double or even triple glazing should be used. Installing heat pipes in the chimney for heat recovery not only increased the flow resistance but also decreased the thermal buoyancy effect. To achieve the required air flow rates in naturally-ventilated buildings with heat recovery, use should be made of wind forces.     

Buoyancy-driven single-sided natural ventilation in buildings with large openings

Full-scale experimental and computational fluid dynamics (CFD) methods were used to investigate buoyancy-driven single-sided natural ventilation with large openings. Detailed airflow characteristics inside and outside of the room and the ventilation rate were measured. The experimental data were used to validate two CFD models: Reynolds averaged Navier-Stokes equation (RANS) modeling and large eddy simulation (LES). LES provides better results than the RANS modeling. With LES, the mechanism of single-sided ventilation was examined by turbulence statistical analysis. It is found that most energy is contained in low-frequency regions, and mean flow fields play an important role.     

自然通风条件下建筑围护结构及室内空气的温度计算

建立太阳照射和自然通风条件下建筑与室内、外环境的空气平衡方程与热平衡方程,以及沿围护结构厚度的非稳态一维导热方程,求解得到建筑围护结构和室内空气的温度。选取广州夏季某一天的气象参数,计算围护材料分别采用钢筋混凝土、灰砂砖砌体、浮石混凝土、橡木和平板玻璃情况下,从7时至19时一单室建筑围护结构及室内空气的温度。