Journal of Building Physics最新文献_第8页

Evaluation of methods for prediction of evaporation from water pools 水池蒸发预报方法的评价

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-07-26 DOI: 10.1177/17442591211034193

M. Shah

Calculation of evaporation is needed in many applications including swimming pools, water reservoirs, nuclear fuel pools, pools for rejection of heat from refrigeration systems, process tanks, etc. Hence accurate methods for prediction of evaporation are needed. Many prediction methods have been published including analytical models and empirical correlations. In the present study, 18 published prediction methods are compared to a very wide-ranging database which includes data from laboratory scale studies, swimming pools, and fuel pools in nuclear power plants. The data are from 25 sources. The range of data includes air temperatures from 6°C to 200°C, water temperatures from 7.1°C to 94.2°C, relative humidity from 0.21% to 98%, and air velocity from 0 to 8.5 m/s. The accuracy of prediction methods is examined for conditions in which natural convection dominates, that in which forced convection dominates, and that in which natural convection is absent. The results are reported and discussed. Recommendations are made for application.

在许多应用中都需要计算蒸发，包括游泳池、水库、核燃料池、制冷系统散热池、工艺罐等。因此，需要精确的蒸发量预测方法。许多预测方法已经发表，包括分析模型和经验相关性。在本研究中，将18种已发表的预测方法与一个非常广泛的数据库进行比较，该数据库包括来自实验室规模研究、游泳池和核电站燃料池的数据。这些数据来自25个来源。数据范围包括气温6℃~ 200℃，水温7.1℃~ 94.2℃，相对湿度0.21% ~ 98%，风速0 ~ 8.5 m/s。在自然对流占主导地位、强迫对流占主导地位和没有自然对流的情况下，对预测方法的准确性进行了检验。对结果进行了报告和讨论。提出了申请建议。

引用次数: 5

Smart wetting of permeable pavements as an evaporative-cooling measure for improving the urban climate during heat waves 可渗透路面的智能润湿作为一种蒸发冷却措施，在热浪期间改善城市气候

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-07-01 DOI: 10.1177/1744259120968586

A. Kubilay, A. Ferrari, D. Derome, J. Carmeliet

An urban microclimate model is used to design a smart wetting protocol for multilayer street pavements in order to maximize the evaporative cooling effect as a mitigation measure for thermal discomfort during heat waves. The microclimate model is built upon a computational fluid dynamics (CFD) model for solving the turbulent air, heat and moisture flow in the air domain of a street canyon. The CFD model is coupled to a model for heat and moisture transport in porous urban materials and to a radiative exchange model, determining the net solar and thermal radiation on each urban surface. A two-layer pavement system, previously optimized for maximal evaporative cooling applying the principles of capillary pumping and capillary break, is considered to design a smart wetting protocol answering the questions “when,” “how much,” and “how long” a pavement should be artificially wetted. It was found for the current optimized pavement solutions that a daily amount of 6 mm wetting over 10 min in the morning, preferentially between 8:00 and 10:00, guarantees a maximal evaporative cooling for 24 h during a heat wave.

利用城市微气候模型设计多层街道路面的智能润湿方案，以最大限度地提高蒸发冷却效果，作为热浪期间热不适的缓解措施。微气候模型建立在计算流体动力学(CFD)模型的基础上，用于求解街道峡谷空气域中的湍流空气、热量和水分流动。CFD模型与多孔城市材料中的热量和水分输运模型和辐射交换模型耦合，确定每个城市表面的净太阳辐射和热辐射。采用毛细管泵送和毛细管断裂原理优化了最大蒸发冷却的两层路面系统，考虑设计一种智能润湿方案，回答“何时”、“多少”和“多长时间”的问题。研究发现，对于目前优化的路面解决方案，每天在早上10分钟内，特别是在8点到10点之间，每天6毫米的润湿量，可以保证在热浪中24小时的最大蒸发冷却。

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引用次数: 19

Experiential learning in building physics: The icebox challenge 建筑物理中的体验式学习:冰箱挑战

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-05-26 DOI: 10.1177/17442591211017948

R. McLeod, C. Hopfe

This pedagogical note presents a novel learning activity (the icebox challenge) that was designed to facilitate deep learning of building physics energy transfer principles through a planning, prediction and analysis process following the Kolb learning cycle. The success of this strategy was evidenced by students relating and collating their knowledge and theoretical ideas and applying them to successfully solve a series of complex and inter-related practical building physics problems.

这篇教学笔记介绍了一种新的学习活动(冰箱挑战)，旨在通过遵循科尔布学习周期的规划、预测和分析过程，促进建筑物理能量传递原理的深度学习。这一策略的成功证明了学生们将自己的知识和理论思想联系起来并加以整理，并应用它们成功地解决了一系列复杂而相互关联的实际建筑物理问题。

引用次数: 2

Dependence of gas permeation and adsorption on temperature in vacuum insulation panels (VIPs) containing getter materials 含吸气剂真空绝热板中气体渗透和吸附对温度的依赖性

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-05-26 DOI: 10.1177/17442591211017154

Hideya Yamamoto, D. Ogura

Vacuum insulation panels (VIPs) with a glass-fiber core has been considered to be difficult to operate for a long period of time, such as for building applications, because the thermal conductivity rises rapidly as the pressure increases. However, glass-fiber-core VIPs contain a material called a getter that continuously adsorbs permeated gas, and a theoretical model that considers the properties of the getter has not yet been developed. In this paper, the gas-adsorption mechanism by getters was investigated and a long-term-performance prediction model that considers the temperature dependence was proposed. Some gases were not adsorbed by the getter in the VIPs; however, a model was proposed that takes into account the non-absorbed gases by applying partial pressure to the adsorption isotherm in advance. The long-term performance of VIPs with different areas and volumes was compared with the measured values, and the validity of the calculation results was confirmed. These results show that the long-term performance of VIPs of different sizes can be accurately predicted when the getter performance is well understood.

以玻璃纤维为核心的真空隔热板(vip)一直被认为难以长时间运行，例如用于建筑应用，因为热导率随着压力的增加而迅速上升。然而，玻璃纤维芯vip包含一种称为吸气剂的材料，它可以持续吸附渗透气体，并且考虑吸气剂特性的理论模型尚未开发。本文研究了吸附剂的气体吸附机理，提出了考虑温度依赖性的吸附剂长期性能预测模型。在vip中，有些气体没有被吸气器吸附;然而，通过对吸附等温线预先施加分压，提出了一个考虑未吸收气体的模型。将不同面积和体积的vip的长期性能与实测值进行比较，验证了计算结果的有效性。这些结果表明，在了解吸剂性能的前提下，可以准确预测不同尺寸的vip的长期性能。

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引用次数: 6

Effect of north wall internal surface structure on heat storage-release performance and thermal environment of Chinese solar greenhouse 北墙内表面结构对中国日光温室蓄热释放性能及热环境的影响

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-05-10 DOI: 10.1177/17442591211013449

Yiming Li, Xiang Yue, Lei Zhao, Huiyun Xu, Xingan Liu, T. Li

Chinese solar greenhouse (CSG) is an energy-saving agricultural building which is used to grow vegetables in winter. The north wall of CSG plays an crucial role in concerning the production yield and quality during the winter months. To improve the thermal performance of north wall, different internal surface structures (ISS) with same materials were compared. Based on the field experiment and the proposed valuation, the dynamic heat storage-release characteristics of the north walls have been analyzed and discussed. The results showed that compared with the flat wall and the striped wall, the alveolate wall has better properties of heat storage and thermal insulation. Moreover, relative humidity in this type of greenhouse is more suitable for growing crops. The alveolate wall can improve indoor thermal environment and reduce the sensitivity to external environment. The obtained results can provide a basis for the scientific construction of the CSG north wall. It has significant potential for the area in high latitude, high altitude and long winter.

中国日光温室(CSG)是一种用于冬季蔬菜种植的节能农业建筑。冬小麦北壁对冬小麦产量和品质起着至关重要的作用。为了提高北墙的热工性能，对相同材料的不同内表面结构进行了比较。在现场试验和评价的基础上，对北墙动态蓄热特性进行了分析和探讨。结果表明，与扁平壁面和条纹壁面相比，泡形壁面具有更好的储热和保温性能。而且，这种温室的相对湿度更适合种植作物。肺泡壁可以改善室内热环境，降低对外界环境的敏感性。所得结果可为CSG北墙的科学施工提供依据。在高纬度、高海拔、冬季较长的地区具有显著的发展潜力。

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引用次数: 4

Thermal resistance of masonry walls: a literature review on influence factors, evaluation, and improvement 砌体墙体的热阻:影响因素、评价及改进的文献综述

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-05-02 DOI: 10.1177/17442591211009549

M. Ismaiel, Yuxiang Chen, C. Cruz-Noguez, M. Hagel

Increasing the thermal resistance of masonry wall systems is one of the effective ways to reduce energy consumption in the operation of masonry buildings. This increase is also demanded by newer, more stringent energy codes. However, the effective thermal resistance (R-value) of masonry walls is affected by many factors, such as thermal bridging, which occurs in places where highly conductive structural components penetrate insulating materials. Thermal bridging is common when connecting masonry veneers to structural backup walls. Furthermore, quick and precise methods for estimating the R-value are needed for thermal design improvements and code-compliance calculations. This study presents a comprehensive literature review on key factors that influence the overall thermal performance of masonry walls, methods to effectively estimate and measure R-values, and improvements in thermal design. In addition to identifying the main technical and practical challenges and the corresponding progress made on each front, key design considerations, such as code compliance, material properties, insulation types, and location, as well as special ties and shelf angles types, are also discussed. This study summarizes critical information and recommendations that will help improve the thermal design of masonry walls, hence reducing the energy consumption of buildings.

提高砌体墙体系统的热阻是降低砌体建筑运行能耗的有效途径之一。更新、更严格的能源法规也要求这种增长。但砌体墙体的有效热阻(r值)受诸多因素的影响，如热桥接，发生在高导电性结构构件穿透保温材料的地方。当将砌体贴面连接到结构备份墙时，热桥接很常见。此外，在热设计改进和规范符合性计算中，需要快速精确地估计r值的方法。本研究对影响砌体墙体整体热工性能的关键因素、有效估算和测量r值的方法以及热工设计的改进进行了全面的文献综述。除了确定主要的技术和实践挑战以及在每个方面取得的相应进展外，还讨论了关键的设计考虑因素，例如符合规范，材料特性，绝缘类型和位置，以及特殊的领带和货架角度类型。本研究总结了关键信息和建议，将有助于改善砖石墙的热设计，从而减少建筑物的能源消耗。

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引用次数: 19

Sensitivity analysis of the hygrothermal behaviour of homogeneous masonry constructions: Interior insulation, rainwater infiltration and hydrophobic treatment 均质砌体结构湿热特性敏感性分析:内部保温、雨水渗透和疏水处理

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-05-01 DOI: 10.1177/17442591211009937

Klaas Calle, N. Van Den Bossche

Historical masonry constructions are difficult to mimic in hygrothermal models. The material properties of the walls are often highly uncertain due to the natural origin of the aggregates and the various, manual production processes used through time. Therefore, sensitivity analyses based on probabilistic simulations are powerful tools to indicate the risks on damage in masonry constructions. Damage criteria for relevant pathologies such as frost damage, potential decay of wooden beam heads and mould growth at the interior surface are used. The assessment methods (Scatter plots, Classification trees and Sobol indices) are based on 1D Heat, Air and Moisture simulations, including realistic variations on climate parameters and wall properties. These methodologies are applied to probabilistic simulations in which a potential damage risk is expected in historic masonries. The application of interior insulation, the use of hydrophobic treatments, and the impact of potential water infiltrations through cracks are discussed. In most of these situations a high dependency of each of the damage criteria on the rain intensity, the trend of the moisture retention/liquid conductivity curve and the absorption coefficient is evident, but also additional insights are found. For example, the thermal impact of interior insulation is negligible compared to its reduction of the first phase drying potential towards the interior. For hydrophobic treatments, the risk for damage typically decreases, but in combination with a rain water infiltration rate above approximately 5% of the wind driven rain the risk on mould growth at the interior surface significantly increases.

历史上的砖石建筑很难用湿热模型来模拟。由于骨料的天然来源和长期使用的各种手工生产过程，墙壁的材料特性通常高度不确定。因此，基于概率模拟的敏感性分析是预测砌体结构损伤风险的有力工具。使用了相关病理的损伤标准，如霜冻损伤、木梁头的潜在腐烂和内表面的霉菌生长。评估方法(散点图、分类树和Sobol指数)基于一维热、空气和湿度模拟，包括气候参数和墙壁特性的实际变化。这些方法被应用于概率模拟中，其中对历史砌体的潜在损害风险进行了预测。讨论了内部保温的应用，疏水处理的使用，以及潜在的水通过裂缝渗透的影响。在大多数情况下，每个损伤标准都高度依赖于雨强度，水分保持/液体电导率曲线的趋势和吸收系数，但也发现了额外的见解。例如，内部绝缘的热影响是可以忽略不计的，相比之下，它减少了对内部的第一阶段干燥潜力。对于疏水处理，损坏的风险通常会降低，但在雨水入渗率超过约5%的情况下，室内表面霉菌生长的风险会显著增加。

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引用次数: 11

Energy saving potential of phase change materials-enhanced building envelope considering the six Moroccan climate zones 考虑到摩洛哥六个气候区，相变材料增强建筑围护结构的节能潜力

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-04-22 DOI: 10.1177/17442591211006444

Amal Louanate, R. Otmani, K. Kandoussi, M. Boutaous, Daya Abdelmajid

Phase change materials (PCMs) show a good capability in absorbing massive heat when undergoing phase change, which have great potential to be incorporated into building envelopes to enhance indoor thermal comfort by preventing heat penetration into buildings and reducing energy requirements. In this work, a deep analysis of PCM enhanced-walls model has been conducted in six representative climate regions of Morocco: El Jadida, Fez, Marrakesh, Ifrane, and Errachidia. More in detail, numerical simulations were carried out to assess the thermal behavior and energy performance of a residential building integrated with four different PCMs. The results showed that the effectiveness and selection of PCMs strongly depend on local weather where they are applied, characteristics of HVAC systems, PCM layer thickness, and position. Furthermore, with reference to each climate zone, the appropriate PCM leading to the lowest annual energy consumption was identified. The findings show that PCMs are particularly suitable for Mediterranean climates, which a promising annual energy saving of about 41% was obtained. While, the lowest value was recorded in Errachidia city reveals that the integration of PCM has little effect in desert climate zone. As for the other climates considered, values of about 28% to 31% were achieved in the studied house model.

相变材料在相变过程中具有良好的吸热能力，在建筑围护结构中应用相变材料具有很大的潜力，可以防止热渗透到建筑内部，降低能耗，从而提高室内热舒适性。在本研究中，对摩洛哥六个具有代表性的气候区——贾迪达、非斯、马拉喀什、伊朗和埃拉奇迪亚进行了PCM增强墙模型的深入分析。更详细地说，进行了数值模拟，以评估与四种不同的pcm集成的住宅建筑的热行为和能源性能。结果表明，PCM的有效性和选择在很大程度上取决于应用地点的当地天气、暖通空调系统的特性、PCM层厚度和位置。此外，根据每个气候带，确定了导致最低年能耗的适当PCM。研究结果表明，pcm特别适合地中海气候，每年可节省约41%的能源。而埃拉奇迪亚城市的数值最低，说明在沙漠气候带，PCM的整合作用不大。至于考虑的其他气候，在研究的房屋模型中，价值约为28%至31%。

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引用次数: 17

Practical correlation for thermal resistance of 45° sloped-enclosed airspaces with upward heat flow for building applications 45°倾斜封闭空气空间的热阻与建筑应用中向上热流的实际相关性

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-04-22 DOI: 10.1177/17442591211009922

Hamed H Saber

Assessing the energy performance of building components with enclosed airspaces requires accurate determination of the thermal resistance (R-value) of the airspaces. The R-value of enclosed airspace depends on its size and orientation, direction of heat transfer through the airspace, and temperatures and emissivities of all surfaces that define the airspace. In previous studies, practical correlations were developed to determine the R-values for vertical enclosed airspaces, horizontal enclosed airspaces with upward heat flow and downward heat flow, and 30° and 45° sloped-enclosed airspaces with downward heat flow. However, to the authors’ best knowledge, there is no such practical correlations available to determine the R-values for wide ranges of dimensions and operating conditions for 30° and 45° sloped-enclosed airspaces with upward heat flow. This paper focused on the thermal performance of 45° sloped-enclosed airspaces with upward heat flow, and the predicted R-values were compared with the R-values provided in ASHRAE Handbook of Fundamentals at different conditions. The dependence of the R-value on the aspect ratio of the enclosed airspaces was also investigated. As well, considerations were given to quantify the potential increase in the R-value of enclosed airspace when a thin sheet having different values of emissivity on both sides was placed in the middle of the airspace. The results showed that depending on the value of the effective emittance and the thickness of the airspace, the R-value could be tripled by incorporating thin a sheet in the middle of the enclosed airspace. Finally, practical correlation were developed to determine the effective R-values of 45° sloped-enclosed airspaces with upward heat flow for wide ranges of aspect ratio, temperature difference across the airspace, mean temperature, and effective emittance. The results showed that the calculated R-values using this correlation were in good agreement with the predicted R-values.

评估具有封闭空气空间的建筑构件的能源性能需要精确确定空气空间的热阻(r值)。封闭空域的r值取决于其大小和方向、通过该空域的热传递方向以及定义该空域的所有表面的温度和发射率。在以往的研究中，建立了实用的相关性来确定垂直封闭空气空间、水平封闭空气空间(向上热流和向下热流)以及30°和45°倾斜封闭空气空间(向下热流)的r值。然而，据作者所知，对于30°和45°倾斜封闭的向上热流空气空间，没有这样的实际相关性可以确定大范围尺寸和操作条件下的r值。本文以热流向上的45°倾斜封闭空气空间为研究对象，将预测的r值与ASHRAE基础手册中提供的不同条件下的r值进行了比较。研究了r值与封闭空间宽高比的关系。此外，还考虑了在封闭空域中间放置两面发射率值不同的薄板时，如何量化封闭空域r值的潜在增加。结果表明，根据有效发射度的大小和密闭空间的厚度，在密闭空间中间加入薄板可以使r值增加三倍。最后，在宽宽比、空域温差、平均温度和有效发射度范围内，建立了实际关联，以确定热流向上的45°倾斜封闭空域的有效r值。结果表明，利用这种相关性计算的r值与预测的r值吻合较好。

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引用次数: 0

CLT construction without weather protection requires extensive moisture control 没有天气保护的CLT建筑需要广泛的湿度控制

IF 2 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of Building Physics

Pub Date : 2021-04-09 DOI: 10.1177/1744259121996388

L. Olsson

This study examines how cross-laminated timber (CLT) constructions, including joints, connections and attachment points, are affected by precipitation during construction. The case studies are based on moisture content measurements and material sampling as well as microbiological analysis during the structure’s construction stage. The study does not include remediation control. The field measurements show microbiological growth in all buildings and almost all floor structures that were investigated. Of a total of 200 measuring points analysed, half had mould growth and around a third had moderate or extensive growth. The moisture content measurements for one of the locations with the largest percentage of elevated or high moisture content was at the top of the floor structure in the bottom gap between timbers in the CLT top layer. This is one example of several materials or construction components where there is limited possibility of dry out. Based on the outcome, it would appear difficult, or impossible, to avoid the appearance of microbial growth during construction with CLT without weather protection. Previous studies indicate that microbiological analysis of CLT is extremely rare in both laboratory and field studies, which implies that there are obvious shortcomings in the scientific work. The fact that mould growth is often invisible needs to be disseminated, especially in practical studies. However, there seems to be a good level of awareness in the literature that theoretical studies often conduct mould growth risk evaluations. There do not appear to be any moisture safety assembly methods or solutions for CLT construction that do not have weather protection or a declaration of the critical moisture conditions for CLT products.

本研究考察了交叉层压木材(CLT)结构，包括接缝，连接和附着点，在施工过程中如何受到降水的影响。案例研究基于结构施工阶段的水分含量测量和材料取样以及微生物分析。该研究不包括补救控制。实地测量显示，在所调查的所有建筑物和几乎所有地板结构中都有微生物生长。在分析的总共200个测量点中，一半有霉菌生长，大约三分之一有中度或广泛的生长。含水率升高或高含水率百分比最大的位置之一是在CLT顶层木材之间底部间隙的地板结构顶部。这是几种材料或建筑部件干燥可能性有限的一个例子。根据结果，在没有天气保护的CLT施工期间避免微生物生长的出现似乎是困难的，或者是不可能的。以往的研究表明，CLT的微生物学分析在实验室和现场研究中都极为罕见，这意味着科学工作存在明显的不足。霉菌生长往往是看不见的，这一事实需要传播，特别是在实际研究中。然而，在文献中似乎有一个很好的认识，理论研究经常进行霉菌生长风险评估。似乎没有任何湿度安全组装方法或解决方案的CLT结构，没有天气保护或CLT产品的关键湿度条件的声明。

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引用次数: 5