多孔围护结构热湿耦合传递过程研究及进展

相对于干热干冷气候区,湿热湿冷气候区的多孔围护结构热湿耦合作用引起的传热计算是一个复杂的过程,在建筑节能工程计算中依然采用的是经验方法.本文以多孔围护结构热湿耦合传递过程为研究对象,对业界在理论研究、计算方法及模拟工具等方面取得的进展进行了深入的研究分析,总结了国内外在多孔围护结构热湿耦合传递过程研究中所取得的主要成果.针对存在的问题,指出了其应用的局限性,同时展望了该领域的发展趋势.     

中庭火灾模型围护结构热模拟

阐述了对中庭围护结构进行热模拟的意义,同时提出了进行热模拟的思路。并针对圆柱形中庭建立起失火情况下围护结构一维传热方程组。利用数值解析的方法求解该方程组,并对计算结果加以分析、比较     

围护结构热湿耦合传递模型及简便求解方法

为了预测围护结构内的温度和湿度分布,以连续变量,相对湿度和温度为驱动势,考虑热传递与湿传递之间的耦合作用,建立了围护结构热湿耦合传递非稳态模型,并提出了基于多物理场耦合仿真模拟软件COMSOL的热湿耦合传递模型简便求解方法。通过对比新建模型模拟结果与HAMSTAD标准验证实例,验证了模型及求解方法的准确性。     

大连市冬季民用住宅室内热湿环境的实测调查研究--建筑围护结构与室内热湿环境的关系

通过主观调查和实测相结合的方法,研究了大连地区冬季多层民用住宅室内热湿环境状况,并从建筑围护结构与室内热湿环境关系的角度,分析了在散热器间歇供暖条件下,建筑围护结构的保温性、蓄热性、气密性、楼层位置和朝向等因素对室内温湿度、居住者热湿感觉以及居住行为的影响。     

竹炭湿物性测试及其对外墙热湿性能影响的模拟

为探索调湿性竹炭（BC）作为建筑填充材料对建筑构件和围护空间热湿性能的影响,测试了其平衡含水率(u)和蒸汽渗透系数(δ);在WUFI Plus软件中选择3组气候区的6个代表城市,对18组外墙进行了全年热湿性能模拟.湿物性测试结果表明：在测试范围内与3种竹板相比,BC调湿容量在相对湿度为334%～854%时得到扩大;BC蒸汽渗透系数为932×10-11kg/(m·s·Pa),是竹板的100～2132倍.建筑构造和围护空间热湿性能模拟结果显示：BC对构造填充层含湿量起显著稳定作用,并减小了外墙热湿流量和构件内表面温度振幅;BC有助于减小室内空气温湿度振幅,缩短暖通空调系统（HVAC）开启时间,降低围护空间供暖和制冷量,但对加湿和除湿量影响不明显.     

极端热湿气候区建筑湿负荷计算方法研究

针对极端热湿气候区建筑湿负荷计算值偏小的问题,本文对该气候条件下室内湿负荷的构成及计算方法进行了研究,在传统湿负荷计算方法的基础上,考虑了空气渗透及围护结构吸放湿引起的湿负荷。研究结果表明,极端热湿气候区建筑湿负荷占总负荷比例为58%左右。若采用附加百分数法计算建筑湿负荷,根据本文叠加法中湿负荷与显热负荷的比值得到附加百分数,其值宜取1.4。最后,根据本文湿负荷计算方法,本文列出了极端热湿气候区不同单位面积显热负荷对应的湿负荷,为空调装机容量的选择提供依据。     

有效湿渗透深度模型EMPD对建筑热湿耦合模拟的适用性研究

介绍了能耗模拟软件中使用最多的3种热湿耦合模型:有效湿渗透深度模型EMPD、热湿耦合传递模型HAMT以及有效湿容模型EC,分析了3种模型的公式基础及优劣。以南京地区办公室为例,使用能耗软件EnergyPlus作为计算平台,详细分析了EMPD模型对室内温湿度和全年能耗预测的准确度,比较了其与EC和HAMT的误差并分析了原因。研究结果表明,3种模型中EMPD在计算湿方面更接近作为参照标准的HAMT模型,尤其是在模拟夏季高温高湿情况下,误差小于5%,在计算能耗方面同样比EC模型更接近HAMT,误差小于8%,并且计算用时只有HAMT模型的几十至几百分之一,因此在需要兼顾计算精度和速度的情况下,可以选用EMPD模型进行建筑模拟。针对现有EMPD公式基础提出修改建议,以进一步提高计算精度。     

建筑围护结构中热桥稳态传热计算研究

在实验室进行了稳态传热条件下热桥表面温度和热流强度的测试实验,将实验结果分别与二维稳态传热模拟软件PTDA的模拟计算结果及我国现行标准中规定的一维简化方法的计算结果进行了对比。结果表明,PTDA的模拟结果较精确,而现行标准中的简化方法的误差较大,应及时修订。     

建筑围护结构热湿传递控制方程

介绍了多孔介质热湿迁移的机理,在此基础上提出了多孔材料热湿耦合传递理论,介绍了一定假设条件下建筑围护结构热湿传递控制方程及其边界条件,指出建筑围护结构热湿传递的研究,对节能和更好地改善热湿环境具有极其重要的作用。     

ECOTECT能耗模拟下既有住宅建筑围护结构节能改造的热环境分析研究

目前,既有住宅建筑节能改造主要有围护结构改造和供热计量改造两方面。围护结构节能改造主要包括:外墙节能改造、外窗节能改造、屋面节能改造等技术措施的研究;建筑物围护结构节能改造除了能够降低建筑能耗之外,对建筑物室内热环境也有很大影响。采用ECOTECT能耗模拟软件,对西安市某住宅建筑围护结构不同节能改造方案的热环境进行模拟,深入分析不同节能改造方案的能源消耗、不舒适度、围护结构得热、温度分布和热舒适度情况,以热舒适为前提、节能为目的选择最优的节能改造方案。为既有住宅建筑节能改造方案优选提供依据。     

Transient hygrothermal behaviour of a hemp concrete building envelope

The sustainable world's economic growth and people's life improvement greatly depend on the use of alternative products in the architecture and construction, such as industrial wastes conventionally called green materials. For this purpose, hemp concrete is more and more recommended by the eco-builders because hemp is a renewable plant, recyclable and does not degrade within time. It corresponds perfectly to the requirements of high environmental quality buildings. The objective of this article is to study transient hygrothermal behaviour of hemp concrete at whole building level. The physical model is one-dimensional and was implemented into the object-oriented simulation environment SPARK, using the finite difference technique with an implicit scheme. The numerical result showed that the use of hemp concrete wall in buildings can ensure good indoor air quality and energy savings in winter. Besides, the combined effect of moisture buffering with the adequate ventilation strategies increases hemp concrete building performance. Our results also suggest that taking into account the hygrothermal transfer at whole building level with heat and moisture production sources has significant effects on predictions.     

A new approach to compute heat transfer of ground-coupled envelope in building thermal simulation software

This study presents a new approach to compute the heat transfer of ground-coupled envelope quickly and correctly which is suitable for implementation into building thermal simulation software. The heat transfer process is decomposed into three processes which are controlled by ground-coupled envelope surface temperature, outdoor ground surface temperature and the temperature difference of ground-coupled envelope surfaces. The three processes are computed by computing one-dimensional Equivalent Slab, simplifying outdoor temperature as harmonic and computing one-dimensional Extra Partition Wall. Validation indicates that the heat flux of ground-coupled envelope surface computed by the new approach is very close to that computed by Finite Difference Method (FDM) under unsteady boundary conditions. The computing time is much less than that with FDM.     

Development of a radiant heating and cooling model for building energy simulation software

Efficient radiant heating and cooling systems are promising technologies in slashing energy bills and improving occupant thermal comfort in buildings with low-energy demands such as houses and residential buildings. However, the thermal performance of radiant systems in buildings has not been fully understood and accounted for in currently available building energy simulation software. The challenging tasks to improve the applicability of radiant systems are the development of an accurate prediction model and its integration in the energy simulation software. This paper addresses the development of a semi-analytical model for radiant heating and cooling systems for integration in energy simulation software that use the one-dimensional numerical modeling to calculate the heat transfer within the building construction assemblies. The model combines the one-dimensional numerical model of the energy simulation software with a two-dimensional analytical model. The advantage of this model over the one-dimensional one is that it accurately predict the contact surface temperature of the circuit-tubing and the adjacent medium, required to compute the boiler/chiller power, and the minimum and maximum ceiling/floor temperatures, required for moisture condensation (ceiling cooling systems), thermal comfort (heating floor systems) and controls. The model predictions for slab-on-grade heating systems compared very well with the results from a full two-dimensional numerical model.     

Development of HAM tool for building envelope analysis

Moisture-related building envelope failures have resulted in costly rehabilitation in various regions of North America. To advance building envelope design towards an engineering approach and reduce the occurrence of future failures, an advanced numerical tool was developed, in conjunction with an extensive full-scale experiment, to investigate hygrothermal performance of various wood-frame wall assemblies. Major features of the tool are multi-dimensional and transient coupling of heat and moisture transport; natural air convection integrated in hygrothermal simulation through Darcy–Boussinesq approximation; heat transfer by conduction and convection of sensible and latent heat; moisture transport by vapor diffusion, capillary suction and convection; material database of common building materials in North America; experimental settings or weather data as boundary conditions; and moisture added in the building envelope to simulate the wetting process. The numerical tool achieves good compliances to the benchmarking cases of the HAMSTAD project, and its predictions have shown good agreement with data from the full-scale wall experiment. The numerical tool employs the commercial finite-element software to solve the governing equations. This approach provides building science researchers the flexibility to modify, maintain and share their modeling work efficiently.     

楼宇式热电冷联产系统模拟软件开发及应用

提出了一种新的楼宇式热电冷联产系统模拟方法,并开发了模拟软件BCHPD.简要介绍了模拟软件的结构和功能.通过一个案例,将模拟结果与实测数据进行了对比,证明了模拟方法与软件的可靠性.     

闽南传统建筑外围护结构隔热性能研究

闽南地区属于夏热冬暖地区,夏季漫长,太阳高度角较大,辐射强烈。在漫长的历史中,闽南系传统民居对避风、防风的诸多考虑,反映在在房屋建造的各个方面。本文对此进行分析研究。     

Impact of combined moisture buffering capacity of a hemp concrete building envelope and interior objects on the hygrothermal performance in a room

In this article, a hygrothermal building model, taking into account the building envelope, indoor heat and moisture sources, indoor environment and moisture buffering capacity of interior objects, is presented and validated with the test cases found in the literature. The model is used to study the impact of hemp concrete and the moisture buffer capacity of the interior elements on the prediction of the hygrothermal comfort in the building. The numerical results show that the use of hemp concrete in buildings can ensure good hygrothermal comfort. Besides, taking into account the effect of moisture buffering of indoor objects increases the building performance. Our results also suggest that neglecting moisture transfer through the envelope increases significantly the predicted percentage of dissatisfied indices and reduces the acceptability of indoor air quality during the occupied period. This study also confirmed that the combined relative humidity-sensitive ventilation system and moisture buffering capacity of building envelope and of interior objects is a very efficient way to reduce the heating energy consumption.     

围护结构风致连续破坏数值模拟

基于CFX5.7软件平台,对一典型大跨度空间结构进行风荷载数值模拟,研究结构模型各墙面及屋盖等围护结构存在开孔时内外压联合作用的情况。并将模拟结果与依据《建筑结构荷载规范》（GB50009—2001）中关于内部压力修正的规定得出的结果进行对比,指出规范中存在的一些不足之处。归纳出建筑物围护结构风致连续破坏的一些规律。     

Development of regression equations for predicting energy and hygrothermal performance of buildings

Regression equations can be used for predicting indoor air temperature, relative humidity and energy consumption in an easier and more rapid way than building energy simulation tools. The independent variables, that is, the input data, are heating, ventilation and air conditioning (HVAC) power, outdoor temperature, relative humidity and total solar radiation. The present methodology for obtaining the regression equations is based on defining a couple of linear Multiple-Input/Single-Output (MISO) models, since two main outputs are involved, that is, indoor temperature and relative humidity. The methodology has been tested for the low- and high-thermal mass cases of the BESTest model (cases 600 and 900) and the output data is generated by using a building hygrothermal simulation tool. Validation procedures have shown very good agreement between the regression equations and the simulation tool for both winter and summer periods.     

Identification of the hygrothermal properties of a building envelope material by the covariance matrix adaptation evolution strategy

This paper proposes the application of the covariance matrix adaptation (CMA) evolution strategy for the identification of building envelope materials hygrothermal properties. All material properties are estimated on the basis of local temperature and relative humidity measurements, by solving the inverse heat and moisture transfer problem. The applicability of the identification procedure is demonstrated in two stages: first, a numerical benchmark is developed and used as to show the potential identification accuracy, justify the choice for a Tikhonov regularization term in the fitness evaluation, and propose a method for its appropriate tuning. Then, the procedure is applied on the basis of experimental measurements from an instrumented test cell, and compared to the experimental characterization of the observed material. Results show that an accurate estimation of all hygrothermal properties of a building material is feasible, if the objective function of the inverse problem is carefully defined.