Journal of Building Physics最新文献_第10页

A methodology for hygrothermal modelling of imperfect masonry interfaces 不完善砌体界面的湿热建模方法

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-02-16 DOI: 10.1177/1744259121989388

M. Gutland, S. Bucking, M. S. Quintero

{"title":"A methodology for hygrothermal modelling of imperfect masonry interfaces","authors":"M. Gutland, S. Bucking, M. S. Quintero","doi":"10.1177/1744259121989388","DOIUrl":"https://doi.org/10.1177/1744259121989388","url":null,"abstract":"Hygrothermal models are important tools for assessing the risk of moisture-related decay mechanisms which can compromise structural integrity, loss of architectural features and material. There are several sources of uncertainty when modelling masonry, related to material properties, boundary conditions, quality of construction and two-dimensional interactions between mortar and unit. This paper examines the uncertainty at the mortar-unit interface with imperfections such as hairline cracks or imperfect contact conditions. These imperfections will alter the rate of liquid transport into and out of the wall and impede the liquid transport between mortar and masonry unit. This means that the effective liquid transport of the wall system will be different then if only properties of the bulk material were modelled. A detailed methodology for modelling this interface as a fracture is presented including definition of material properties for the fracture. The modelling methodology considers the combined effect of both the interface resistance across the mortar-unit interface and increase liquid transport in parallel to the interface, and is generalisable to various combinations of materials, geometries and fracture apertures. Two-dimensional DELPHIN models of a clay brick/cement-mortar masonry wall were created to simulate this interaction. The models were exposed to different boundary conditions to simulate wetting, drying and natural cyclic weather conditions. The results of these simulations were compared to a baseline model where the fracture model was not included. The presence of fractures increased the rate of absorption in the wetting phase and an increased rate of desorption in the drying phase. Under cyclic conditions, the result was higher peak moisture contents after rain events compared to baseline and lower moisture contents after long periods of drying. This demonstrated that detailed modelling of imperfections at the mortar-unit interface can have a definitive influence on results and conclusions from hygrothermal simulations.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"33 1","pages":"485 - 509"},"PeriodicalIF":2.0,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90506269","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}

引用次数: 4

Model of thermal buoyancy in cavity-ventilated roof constructions 空腔通风屋面结构热浮力模型

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-02-10 DOI: 10.1177/1744259120984189

T. Säwén, M. Stockhaus, C. Hagentoft, Nora Schjøth Bunkholt, P. Wahlgren

{"title":"Model of thermal buoyancy in cavity-ventilated roof constructions","authors":"T. Säwén, M. Stockhaus, C. Hagentoft, Nora Schjøth Bunkholt, P. Wahlgren","doi":"10.1177/1744259120984189","DOIUrl":"https://doi.org/10.1177/1744259120984189","url":null,"abstract":"Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"1 1","pages":"413 - 431"},"PeriodicalIF":2.0,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79214516","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}

引用次数: 5

Hygrothermal performance of six insulation systems for internal retrofitting solid masonry walls 砌体墙内加固用六种保温系统的湿热性能

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-02-10 DOI: 10.1177/1744259120988745

N. Jensen, S. Bjarløv, C. Rode, B. Andersen, E. Møller

{"title":"Hygrothermal performance of six insulation systems for internal retrofitting solid masonry walls","authors":"N. Jensen, S. Bjarløv, C. Rode, B. Andersen, E. Møller","doi":"10.1177/1744259120988745","DOIUrl":"https://doi.org/10.1177/1744259120988745","url":null,"abstract":"The study investigated the hygrothermal performance and risk of fungal growth in a phenolic foam system with a closed cell structure and a diffusion-open and capillary active lime-cork based insulating plaster, for internal retrofitting purposes. The setup comprised two 40-feet (12.2 m) insulated reefer container with controlled indoor climate, reconfigured with 24 holes (1 × 2 m each) containing solid masonry walls with embedded wooden elements on the interior side. Focus was on the conditions in the masonry/insulation interface and embedded wooden elements, and the performance of the two systems were compared to three diffusion-open insulation systems and one diffusion-tight. The effect of exterior hydrophobisation was also investigated. Relative humidity and temperature were measured in several locations in the test walls over 2½ years, and the risk of fungal growth was evaluated by on-site measurements and the VTT mould-growth model. The findings indicate that internally insulated walls with bare brick exterior surfaces performed poorly with high risk of fungal growth. The effect of exterior hydrophobisation was found to vary with the orientation and the installed insulation system, with a generally positive effect on walls facing south-west but limited effect for north-east. Furthermore, the more diffusion-tight insulation systems were found to perform better in combination with exterior hydrophobisation than the highly diffusion-open systems. The lime-cork insulating plaster showed high relative humidity and risk of moisture-induced problems. The on-site fungal tests showed no growth in the masonry/insulation interface inside the two insulation systems, probably due to high initial pH-value.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"18 1","pages":"539 - 573"},"PeriodicalIF":2.0,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81746773","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}

引用次数: 6

A comparison of hygrothermal simulation results derived from four simulation tools 四种模拟工具的热液模拟结果比较

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-02-09 DOI: 10.1177/1744259120988760

M. Defo, M. Lacasse, A. Laouadi

{"title":"A comparison of hygrothermal simulation results derived from four simulation tools","authors":"M. Defo, M. Lacasse, A. Laouadi","doi":"10.1177/1744259120988760","DOIUrl":"https://doi.org/10.1177/1744259120988760","url":null,"abstract":"The objective of this work was to compare the hygrothermal responses and the moisture performance of four wood-frame walls as predicted by four hygrothermal (HAM) simulation tools, namely: DELPHIN, WUFI, hygIRC and COMSOL. The four wall systems differ only in their cladding type; these were fibreboard, vinyl, stucco and brick. Three Canadian cities having different climates were selected for simulations: Ottawa, Ontario; Vancouver, British Columbia and Calgary, Alberta. In each city, simulations were run for 2 years. Temperature and relative humidity of the outer layer of OSB sheathing were compared amongst the four simulation tools. The mould growth index on the outer layer of the OSB sheathing was used to compare the moisture performance predicted by the respective hygrothermal simulation tools. Temperature profiles of the outer layer of the OSB sheathing were all in good agreement for the four HAM tools in the three locations. For relative humidity, the highest discrepancies amongst the four tools were found with stucco cladding where differences as high as 20% could be found from time to time. Mould growth indices predicted by the four HAM tools were similar in some cases but different in other cases. The discrepancies amongst the different HAM tools were likely related to: the material property processing, how the quantity of wind-driven rain absorbed at the cladding surface is computed and some implementation details. Despite these discrepancies, The tools generally yielded consistent results and could be used for comparing the impacts of different designs on the risk of premature deterioration, as well as for evaluating the relative effects of climate change on a given wall assembly design.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"23 1","pages":"432 - 456"},"PeriodicalIF":2.0,"publicationDate":"2021-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78127917","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}

引用次数: 11

Analysis of hygrothermal performance of low-energy house in Nordic climate 北欧气候条件下低能耗住宅的湿热性能分析

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-11 DOI: 10.1177/1744259120984187

F. Fedorik, S. Alitalo, J. Savolainen, Ilkka Räinä, Kimmo Illikainen

引用次数: 9

Illumination 照明

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-01 DOI: 10.1007/978-3-030-67372-7_8

M. Pinterić

引用次数: 0

Heat Transfer in Building Components 建筑构件的传热

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-01 DOI: 10.1007/978-3-319-57484-4_3

M. Pinterić

引用次数: 0

Basics of Waves 波浪基础

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-01 DOI: 10.1007/978-3-319-57484-4_5

M. Pinterić

引用次数: 0

Heat Transfer 传热

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-01 DOI: 10.1007/978-3-030-67372-7_2

M. Pinterić

引用次数: 0

Moisture in Building Components 建筑构件中的水分

IF 2 4区工程技术

Journal of Building Physics Pub Date : 2021-01-01 DOI: 10.1007/978-3-319-57484-4_4

M. Pinterić

引用次数: 0