建筑外围护结构整体气密性能国内外标准综述及分析

空调系统能耗已成为建筑能耗的一个主要组成部分,建筑物由于围护结构漏风造成的空调能耗损失很大,建筑物围护结构漏风还会造成许多直接或者间接的危害,故加强围护结构的气密性检测必须得到重视。通过综述国内外关于建筑物外围护结构气密性相关标准,比较了国内外标准的异同,并且针对我国建筑外围护结构气密性的现状及加强改进方面提出了一些建议。     

通风管道气密性国内外标准综述及分析

当今,空调系统能耗无疑成为建筑能耗的一个主要组成部分,越来越多的学者将降低空调系统能耗作为建筑节能的一个主要的、有效的手段,而空调系统由于漏风现象造成的能耗损失是惊人的,空调系统风管漏风还会造成许多直接或者间接的危害,故加强风管的气密性检测必须得到重视和强制性地实施。通过综述不同国家建立的关于风管气密性的相关标准,比较了国内外标准的异同,并且针对我国暖通空调系统风管气密性的现状及加强改进给出了一些建议。     

Feuerstätten in Häusern mit mechanischen Lüftungsanlagen ndash; Anforderungen und Lösungen

Burning appliances in buildings with ventilation installation ndash; requirements and solutions. There are permission criteria of the building supervisory board for room air‐independent burning appliances for liquid and solid fuels. With solid fuel burning appliances, these refer to higher tightness requirements, lower CO emissions and the demand of a self‐closing door. When critically analysing the permission criteria, it can be found that the limit values of leakage flow rate and CO emission cause an exchange of air of over 1.5 h^‐1 in a medium size installation area. Intermittently heated storage stoves are favourable for such cases of application because waste gas accumulation in the living space outside of the heating phase of the burning appliances can be diminished by the ventilation system. Special attention has to be put on the combustion air guidance in parallel and concentric air‐waste gas‐systems. On winter conditions, circulation flows arise outside of the operation of the burning appliances if the flow path combustion air guidance / room heater / flue duct is not interrupted by shut off dampers. The consequences are lower deviation of the dew point and dampness formation with appearances of icing in the unheated storey below the roof as well as in the area of the roof and floor breakthrough. Regarding the leak test of installed facilities and their monitoring, requirements and solutions have to be specified.     

泥水盾构带压开舱时泥膜的微观孔隙及渗透性研究

泥膜的良好闭气性是保证泥水盾构带压开舱安全顺利实施的关键之一,要想提高泥膜的闭气性,首先应了解泥膜在带压开舱过程中的孔隙结构及渗透性变化。以南京纬三路过江通道在江底砂卵石地层中进行带压开舱为背景,在自制的试验装置中进行泥浆成膜和泥膜闭气试验,然后观测泥膜的孔隙结构和孔径变化,最后分析泥膜渗透系数的变化。研究结果表明:试验泥浆在0.2 MPa气压作用下6 h,在试验地层表面形成的泥膜厚度约为5.0 mm、孔隙率约为67%,在闭气过程中泥膜会发生压缩,且第一次单位压力引起的压缩量最大;随着闭气压力的增大,大孔隙组被优先压缩;泥膜基本单元体为骨架状结构,孔隙主要是粒间孔隙与架空孔隙,孔隙分布不连续、连通性差;孔径分布范围较广,其中在0.1~3.0μm的孔隙组占有绝对优势;本次试验中压缩后泥膜的渗透系数在10-9 cm/s量级。研究结果有助于明确泥膜在闭气过程中的变化,对后续提高泥膜闭气性的研究有重要的参考意义。     

Inverse design of an indoor environment using a filter-based topology method with experimental verification

In order to create a healthy, comfortable, productive, and energy-efficient indoor environment, the computational fluid dynamics (CFD)-based adjoint method with an area-constrained topology method can be used to inversely design the optimal number, size, location, and shape of air supply inlets and air supply parameters. However, this method is not very mature, and the distribution of retained inlets is always scattered. To solve that problem, this investigation introduced a filter method that smooths the intermediate results during the inverse design process. Using a three-dimensional, non-isothermal, asymmetrical office with pre-set air supply inlets as an example, this study verified the performance of the proposed filter-based topology method. The verified method was then used to solve a multi-objective design problem and design an optimal indoor environment for a room. The results indicate that the proposed method was able to find the optimal number, location, and shape of air supply inlets and the optimal air supply temperature, velocity, and angle that led to a thermally comfortable, healthy, productive, and energy-efficient indoor environment. Finally, this investigation installed the optimal inlets in an environmental chamber to mimic the room. The measured air temperature, velocity, and mean age of air in several typical locations in the environmental chamber matched the CFD simulation results very closely.     

Ventilation by natural convection of a one-story building

The objective of the present paper is to study passive ventilation of a one-story detached building. The flow of air is induced by a hot element of the building heated by solar energy. The hot element could be a part of a roof or a wall of the building, or a chimney through which the air is sucked from the building.The method does not require electrical power or mechanical installations, thus it can be applied in remote areas and buildings that are not connected to electric power, like desert-located buildings. The method may be used also for removal of toxic gases, like radon, from the ground floor of the building, without additional expenses.Experiments and simulations have been performed, in steady and transient states, in a scaled-down laboratory model. The results obtained from the simulations and fully supported by measurements and visualization, indicate that it is possible to obtain effective ventilation by the proposed method. Numerical simulations for steady and transient ventilation in real-size buildings are presented and discussed.     

建筑外围护结构整体气密性能检测关键技术

建筑外围护结构整体气密性能是低能耗建筑的一项重要技术指标,但是我国尚未建立相关的测试标准和测试方法。在国外建筑外围护结构整体气密性能检测标准的基础上,通过大量工程测试应用实践,结合我国建筑发展特点和科学技术水平,研究提出我国建筑外围护结构整体气密性能检测中关键问题的解决方法,提高相关测试方法和测试数据的科学性与真实性,为今后我国建筑外围护结构整体气密性检测标准的编制和测试方法的应用提供参考和借鉴。     

加压送风系统关闭风口漏风量计算的方法

根据流体力学的理论,建立了加压送风系统关闭风口漏风量的数学计算模型,并建立了关闭风口两侧静压差、各管段沿程阻力、静压复得量等6项中间参数的子项模型。以优化防烟方案为物理模型,按是否考虑静压复得、采用不同等级气密性风口、改变主风道断面积等条件,组合成5类范例,并进行了数值计算。结果表明:附加系数法和直接导用气密性标准的计算方法都有明显缺陷;当风口的气密性标准较高时,可采用忽略静压复得量的简化算法。     

杭州庆春路过江隧道施工风险控制实例分析

 介绍杭州庆春路过江隧道施工过程中的风险控制,分析盾构出洞时洞门涌泥水及加固区土体坍塌的原因、规避及处理措施;分析两线盾构先后穿越钱塘江大堤时大堤沉降明显不同的原因,结合工程实践提出泥水盾构过堤控制沉降的措施;分析工程中盾尾密封失效的原因,并介绍在江底高承压水地层中采用液氮冻结封堵地下水和修复盾尾刷的方法。工程实践表明,良好的洞门密封可以避免洞门涌水和加固区土体坍塌;持续降雨和泥水压力的剧烈波动会加剧大堤的沉降,而通过优化盾构掘进参数,可以降低盾构施工对大堤的扰动;液氮冻结法可以安全地封堵地下水,更换第一道尾刷并且增设一道尾刷的方案可以成功地消除盾尾漏浆涌水的风险。     

Air quality in rooms conditioned by chilled ceiling and mixed displacement ventilation for energy saving

A transient-contaminant-transport model is developed for assessing IAQ in the breathing zone when introducing return air into rooms conditioned by CC/DV system to save energy. The steady state transport model of [1] is extended to transient conditions while accounting for significant wall plumes associated with external loads.Experiments are performed to validate the extended model predictions of IAQ expressed in the level of CO₂ concentration. Experiments are conducted in a chamber with two external walls in Kuwait Climate. Measurements are recorded in time of the air temperature and CO₂ concentration at selected locations in the room and compared with values predicted by the model. Experimental results agreed well with model predictions. The maximum errors in predicted CO₂ concentrations are less than ±25 ppm in presence of external load. 60% fresh air fraction resulted in 37% less energy consumption compared with 100% fresh air CC/DV system.The validated model is applied to a case study in Kuwait to evaluate energy saving over the cooling season for a typical office space while using mixed DV air. Energy savings of up to 20.6% can be realized using mixed supply air while maintaining IAQ compared with energy used for the 100% fresh air.     

冬季稳定人工环境实验室内温度的新方法

人工环境实验室对温度的控制精度低于工艺性环境要求,但冬季若采用分体式空调制热模式控制,实验室温度的波动范围过大,影响采集实验数据的准确性。提出冬季采用空调制冷模式联合电取暖器稳定人工环境实验室内温度的新方法,在背景实验中将新方法和传统空调制热温度控制方法进行对比,结果表明:采用新方法能大幅度提高人工环境实验房间温度的稳定性。为对新方法中空调的设定制冷温度与电取暖器功率匹配问题做进一步研究而进行探究试验,实验结果表明:空调制冷量Q_1、测试房间热负荷Q_2、电取暖器功率Q_3和测试房间其他设备功率Q_4存在匹配关系,当空调设定温度相同时,|Q_1+Q_2-Q_3-Q_4|值越小,人工环境实验室内温度波动频率越稳定,振幅越小。     

利用水源热泵全面回收矿井排风中的余热资源

提出了一种合理实用的矿井排风余热回收方式,即在回风扩散塔旁边新建一座横向通风面积较大、形似"空气喷淋室"的空气处理室,利用矿井原有的排风机将矿井排风全部导入空气处理室内,矿井排风以2.5～3 m/s的风速平稳地流过空气处理室内的气水换热空间,利用水源热泵机组的蒸发器所提供的低温水通过三级高密度水幕对矿井排风进行逆向喷淋,最大限度地全面回收矿井排风中的余热。     

Air infiltration induced inter-unit dispersion and infectious risk assessment in a high-rise residential building

Identifying possible airborne transmission routes and assessing the associated infectious risks are essential for implementing effective control measures. This study focuses on the infiltration-induced inter-unit pollutant dispersion in a high-rise residential (HRR) building. The outdoor wind pressure distribution on the building facades was obtained from the wind tunnel experiments. And the inter-household infiltration and tracer gas transmission were simulated using multi-zone model. The risk levels along building height and under different wind directions were examined, and influence of component leakage area was analysed. It is found that, the cross-infection risk can be over 20% because of the low air infiltration rate below 0.7 ACH, which is significantly higher than the risk of 9% obtained in our previous on-site measurement with air change rate over 3 ACH. As the air infiltration rate increases along building height, cross-infection risk is generally higher on the lower floors. The effect of wind direction on inter-unit dispersion level is significant, and the presence of a contaminant source in the windward side results in the highest cross-infection risks in other adjacent units on the same floor. Properly improving internal components tightness and increasing air change via external components are beneficial to the control of internal inter-unit transmission induced by infiltration. However, this approach may increase the cross-infection via the external transmission, and effective control measures should be further explored considering multiple transmission routes.     

夏热冬冷地区冬季供暖方式的选择

对夏热冬冷地区非供暖居住建筑冬季室内环境参数进行了实测，结果表明这类建筑冬季室内约80％的时间达不到人体健康要求的最低温度，明显具有不同于集中供暖地区建筑的室内热环境特征，且房间气密性和朝向对室内温度影响较小。分析了不同气密性房间供暖能耗的构成和不同供暖方式的节能效果，指出房间气密性是夏热冬冷地区选择供暖方式和设备的主要依据。     

被动房整体气密性测试方法及应用

阐述了被动房整体气密性测试的必要性，列举了房屋整体气密性的常见测试方法，并重点介绍了压差法测试建筑气密性的过程和要点。     

瞬态和稳态条件下G550冷弯型钢力学性能

冷弯型钢高温下的力学性能是防火安全设计和数值分析的重要因素。现多采用稳态试验方法研究高温下材料的力学性能。然而,瞬态试验方法能更好地反应火灾的真实情况。采用瞬态和稳态两种方法对厚度为1mm的G550钢材进行试验,并对两种方法的试验结果进行讨论。结果显示,G550钢材的稳态试验结果不同于瞬态试验结果。G550钢材的稳态试验结果高估了冷弯型钢结构的耐火性。此外,将试验结果与其他研究人员的研究结果以及现有设计规范的计算结果进行比较,结果显示,采用BS5950计算的G550钢材屈服强度与瞬态试验结果相一致,比稳态试验结果保守。然而,其他情况下BS5950,AS4100和EC3的计算结果并不保守。最后,采用拟合法给出高温下考虑G550钢材的屈服强度、弹性模量、极限强度等折减因素的统一方程。基于Ramberg-Osgood模型给出G550钢材的应力-应变方程。该方程的计算结果与试验结果相符,能够满足实际工程的需要。     

静压室原理用于多系统排风工程的实践

将静压室原理用于化纤厂多系统排风设计,静压室内最不利断面风速３￣４ｍ／ｓ。这种设计既简化了排风系统,又减少了机房面积和投资。２０多年的运行实践证明,该方法可行。     

盐岩地下储气库泄漏的喷射火事故后果定量分析

 为提高盐岩储气库营运的安全性,建立燃气从注采井套管破裂时的稳态泄漏率模型,提出将热辐射模型与伤害概率方程相结合的方法,对盐岩地下储库气体泄漏后可能发生的喷射火的热辐射后果进行研究,并与事故调查数据进行对比验证。研究结果表明,提出的喷射火热辐射危险距离的计算值与已发生的天然气输送管道喷射火事故现场观察的燃烧面积基本一致,计算值与实际观察值的误差都在20%以内。采用该方法对影响盐岩储气库喷射火事故后果的主要因素进行分析,得出喷射火的伤害半径随着注采井管径和运营压力(埋深)的增大而增大。提出的方法可为盐岩地下储库气体泄漏后的喷射火热辐射后果定量评价提供参考。     

The influence of the joint between the basement wall and the wood-frame wall on the airtightness of wood-frame houses

An airtight building envelope is crucial to achieve energy efficient buildings. The Norwegian airtightness requirements have become stricter, leading to an increased interest in methods for ensuring airtight building envelopes.The joint between the basement wall and the wood-frame wall is known to be a typical air leakage path. Using laboratory measurements and a statistical experimental design the influence of the 3 factors flatness of the basement wall, the sealing method used in the joint and the load between the wood-frame wall and the basement wall is investigated. The influence of this air leakage on real wood-frame houses is also estimated.The results show that the flatness of the basement wall top surface has a considerable influence on the air leakage, a flatter surface generally leading to less air leakage. The sealing materials have widely differing airtightness properties. The least airtight sealing materials, which also are the non-malleable ones, turn out to be sensitive to the flatness of the basement wall and the load on the wall. The estimates of the influence of the air leakage on real wood-frame houses show that the least flat surfaces should be avoided for the non-malleable sealing materials. It is also seen that if the least favourable sealing method is used, or if the sealing is forgotten, the influence on the total airtightness can be remarkable. However, the results also show that it is possible to make the influence of the joint on the total airtightness negligible.     

低矮房屋瞬态内压的风洞试验研究

设计一种新的试验方法模拟低矮房屋模型的门窗突然开启过程,在边界层风洞中采用高速同步压力扫描系统对模型开孔的瞬态内压响应进行了试验研究,发现了有别于已有试验研究结论的结果并由内压传播理论所定性验证。试验考虑了开孔率和背景孔隙率对风致瞬态峰值内压的影响,结果表明:门窗突然开启的过冲比(定义为瞬态峰值内压系数和稳态峰值内压系数之比)随开孔率的增大而增加,对于气密性较好的房屋由试验得到的过冲比在1.17～1.34之间,而理论计算的过冲比则更大,相应稳态峰值内压随开孔率的变化相对较小。过冲比随背景孔隙的增大而下降,当背景孔隙率达到0.2%时,瞬时过冲现象消失。