Journal of Building Physics最新文献

{"title":"Thermal resistance of masonry walls: a literature review on influence factors, evaluation, and improvement","authors":"M. Ismaiel, Yuxiang Chen, C. Cruz-Noguez, M. Hagel","doi":"10.1177/17442591211009549","DOIUrl":"https://doi.org/10.1177/17442591211009549","url":null,"abstract":"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.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"22 1","pages":"528 - 567"},"PeriodicalIF":2.0,"publicationDate":"2021-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77881213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity analysis of the hygrothermal behaviour of homogeneous masonry constructions: Interior insulation, rainwater infiltration and hydrophobic treatment","authors":"Klaas Calle, N. Van Den Bossche","doi":"10.1177/17442591211009937","DOIUrl":"https://doi.org/10.1177/17442591211009937","url":null,"abstract":"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.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"9 1","pages":"510 - 538"},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88078587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy saving potential of phase change materials-enhanced building envelope considering the six Moroccan climate zones","authors":"Amal Louanate, R. Otmani, K. Kandoussi, M. Boutaous, Daya Abdelmajid","doi":"10.1177/17442591211006444","DOIUrl":"https://doi.org/10.1177/17442591211006444","url":null,"abstract":"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.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"15 1","pages":"482 - 506"},"PeriodicalIF":2.0,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87990816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Practical correlation for thermal resistance of 45° sloped-enclosed airspaces with upward heat flow for building applications","authors":"Hamed H Saber","doi":"10.1177/17442591211009922","DOIUrl":"https://doi.org/10.1177/17442591211009922","url":null,"abstract":"<p>Assessing the energy performance of building components with enclosed airspaces requires accurate determination of the thermal resistance (<i>R</i>-value) of the airspaces. The <i>R</i>-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 <i>R</i>-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 <i>R</i>-values were compared with the <i>R</i>-values provided in ASHRAE Handbook of Fundamentals at different conditions. The dependence of the <i>R</i>-value on the aspect ratio of the enclosed airspaces was also investigated. As well, considerations were given to quantify the potential increase in the <i>R</i>-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 <i>R</i>-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 <i>R</i>-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 <i>R</i>-values using this correlation were in good agreement with the predicted <i>R</i>-values.</p>","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"58 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138531400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CLT construction without weather protection requires extensive moisture control","authors":"L. Olsson","doi":"10.1177/1744259121996388","DOIUrl":"https://doi.org/10.1177/1744259121996388","url":null,"abstract":"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.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"121 1","pages":"5 - 35"},"PeriodicalIF":2.0,"publicationDate":"2021-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73465592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hygrothermal performance of cool roofs with reflective coating material subjected to hot, humid and dusty climate","authors":"H. Saber","doi":"10.1177/17442591211001408","DOIUrl":"https://doi.org/10.1177/17442591211001408","url":null,"abstract":"The measurements for the short-wave solar reflectivity of a Reflective Coating Material (RCM) with various cleaning operations that were obtained in a previous study were used in this study to conduct numerical simulations in order to assess the moisture and energy performance of cool and black roofs when they were subjected to the weather conditions of Saudi Eastern Province and Kuwait City. The results of the numerical simulations showed that black roofs always work with less moisture than cool roofs. Because the highest relative humidity in the different components of the black and cool roofs was well below 80%, there was no risk of condensation and mold growth in these roofs. For both weather conditions of Saudi Eastern Province and Kuwait City, the results showed that installing cool roofs have resulted in increasing the heating energy loads in relation to black roofs. Conversely, the results showed that the decrease in the cooling energy loads due to installing cool roofs were typically much greater than the increase in the heating energy loads. As such, cool roofs have resulted in net energy savings in relation to black roofs. Replacing black roof by cool roof in Saudi climate, the results showed that the annual energy savings in the total energy load was 25% and 34% as a result of installing cool roof with RCM at no cleaning and weekly homemade cleaning, respectively. Additionally, replacing black roof by cool roof in Kuwaiti climate, the results showed that the annual energy savings in the total energy load was 23% and 31% a result of installing cool roof with RCM at no cleaning and weekly homemade cleaning, respectively.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"288 1","pages":"457 - 481"},"PeriodicalIF":2.0,"publicationDate":"2021-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79410828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of wall composition on moisture related degradation of the wall surfaces in Hagia Sophia, Istanbul","authors":"Etsuko Mizutani, D. Ogura, T. Ishizaki, M. Abuku, Juni Sasaki","doi":"10.1177/1744259121996017","DOIUrl":"https://doi.org/10.1177/1744259121996017","url":null,"abstract":"Over the past 10 years, our research team has holistically studied the environmental aspects of the conservation and restoration of the Hagia Sophia, which is suffering from severe degradation of its wall paintings, including the exfoliation of wall paintings and inner finishing materials, mainly due to salt crystallisation. In the present study, we investigated the influence of environmental factors and wall composition on the hygrothermal behaviour in the structure, such as moisture accumulation and evaporation within the walls, which significantly affect salt crystallisation. The differences in distribution of high moisture content at second cornice are depending on the azimuth, and the high correlation between high moisture content and deterioration severity is significant. A two-dimensional numerical model of the simultaneous transfer of heat and moisture considering the measured material physical properties and wall composition of the exedra wall is developed to quantitatively investigate the influence of environmental factors on moisture accumulation. Numerical results show that infiltrated rainwater tends to accumulate because the original builders used connection mortar, which has a much larger moisture diffusivity than that of modern mortar, and the accumulated water at the bottom of the wall is difficult to drain owing to the shape of the wall. In the northwest exedra, the influence of wind-driven rain on water accumulation is similar to that of runoff rainwater from the upper roofs, which probably causes deterioration over a wide area. In addition, the effect of the deterioration suppression measure by the re-covering of the outer surfaces of the west wall in 2013 is verified, and an appropriate suppression measure against water permeation is examined using a numerical model.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"22 1","pages":"271 - 302"},"PeriodicalIF":2.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90450708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"WITHDRAWAL— Accidental Duplicate Publication – Editorial volume 41 no 1 (September)","authors":"","doi":"10.1177/1744259120964188","DOIUrl":"https://doi.org/10.1177/1744259120964188","url":null,"abstract":"","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"63 1","pages":"479 - 479"},"PeriodicalIF":2.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75631670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “The role of water in the behavior of wood”","authors":"","doi":"10.1177/1744259121989175","DOIUrl":"https://doi.org/10.1177/1744259121989175","url":null,"abstract":"","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"32 1","pages":"480 - 480"},"PeriodicalIF":2.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85387677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors affecting the performance of ventilation cavities in highly insulated assemblies","authors":"Klaus Viljanen, Xiaoshu Lü, J. Puttonen","doi":"10.1177/1744259121995221","DOIUrl":"https://doi.org/10.1177/1744259121995221","url":null,"abstract":"The article presents experimental studies of typical Finnish highly insulated (HI) envelopes with thermal resistance values (R value) for the wall and roof inside the ventilation cavity between 7.7 and 8.1 m2K/W and 13 m2K/W, respectively. The conditions in the ventilation cavities were studied by using typical and increased R values for the exterior part of the cavity, which were 0.18 m2K/W and 1.57 m2K/W in the walls, and 0.13 m2K/W and 2.13 m2K/W for the roof. With higher exterior R values of 1.57 m2K/W and 2.13 m2K/W, the cavity temperature increased only after closing the inlet gap of the cavities. If the cavity inlet was closed, the restriction of the outlet gap from 20–25 mm to 10 mm had no significant effect on the temperatures. A closed ventilation inlet resulted in increased absolute humidity in the cavity, which indicates that the restriction of cavity ventilation should be made with care to avoid impairing the drying-out ability. The computational analysis showed that the optimal air change rates in the wall and roof cavities of HI structures were 4–40 1/h and 20 1/h, respectively. The conventional 22-mm-thick wood cladding enables safe cavity conditions in HI walls if the vapor barrier is vapor tight and other moisture sources are low. A lower heat flux and additional heat loss caused by cloudless sky at night support the observation that HI roofs have a higher moisture risk. In HI roofs, a conventional exterior R value of 0.13 m2K/W should at least be increased to the range of 0.3–0.4 m2K/W, which is achieved, for example, by a 20-mm-thick mineral wool board under the roofing. The use of mold-resistant materials in the ventilation cavity is recommended to mitigate the possible ramifications of the moisture behavior of HI roofs.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"23 1","pages":"67 - 110"},"PeriodicalIF":2.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84670431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}