Influence of Different Joints on Moisture Transport in Building Walls - A Brief Review

2019 ◽  
Vol 22 ◽  
pp. 19-23
Author(s):  
A.S. Guimarães ◽  
J.M.P.Q. Delgado ◽  
V.P. de Freitas ◽  
A.C. Azevedo
Keyword(s):  
Porous Media ◽  
Moisture Transport ◽  
Building Envelope ◽  
Petroleum Engineering ◽  
Soil Science ◽  
Building Ceramic ◽  
Science And Engineering ◽  
Building Envelopes ◽  
Building Walls ◽  
Building Engineering

The phenomena of transport in porous media arises in many diverse fields of science and engineering, ranging from agricultural, biomedical, building, ceramic, chemical, and petroleum engineering to food and soil science. Several authors provide an extensive description of the problems involving porous media. For building engineering, obtaining a good understanding of moisture transport in building envelopes is becoming one of the most important tasks. In the last few decades, many studies investigating moisture transport in building envelopes have been published, which have helped to improve overall building envelope design. This work presents a brief review of these studies.

LBE Flows in Disordered Media

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Porous Media ◽  
Fluid Mechanics ◽  
Condensed Matter ◽  
Disordered Media ◽  
Environmental Sciences ◽  
Science And Engineering ◽  
Particle Trajectories ◽  
Irregular Geometries ◽  
Numerical Tool ◽  
Bounce Back

The study of transport phenomena in disordered media is a subject of wide interdisciplinary concern, with many applications in fluid mechanics, condensed matter, life and environmental sciences as well. Flows through grossly irregular (porous) media is a specific fluid mechanical application of great practical value in applied science and engineering. It is arguably also one of the applications of choice of the LBE methods. The dual field–particle character of LBE shines brightly here: the particle-like nature of LBE (populations move along straight particle trajectories) permits a transparent treatment of grossly irregular geometries in terms of elementary mechanical events, such as mirror and bounce-back reflections. These assets were quickly recognized by researchers in the field, and still make of LBE (and eventually LGCA) an excellent numerical tool for flows in porous media, as it shall be discussed in this Chapter.

scholarly journals Upscaled phase-field models for interfacial dynamics in strongly heterogeneous domains

2012 ◽  
Vol 468 (2147) ◽  
pp. 3705-3724 ◽  
Author(s):  
Markus Schmuck ◽  
Marc Pradas ◽  
Grigorios A. Pavliotis ◽  
Serafim Kalliadasis
Keyword(s):  
Porous Media ◽  
Free Energy ◽  
Phase Field ◽  
Single Channel ◽  
Confined Geometries ◽  
Science And Engineering ◽  
Hilliard Equation ◽  
Phase Field Models ◽  
Cahn Hilliard Equation ◽  
Double Well Potential

We derive a new, effective macroscopic Cahn–Hilliard equation whose homogeneous free energy is represented by fourth-order polynomials, which form the frequently applied double-well potential. This upscaling is done for perforated/strongly heterogeneous domains. To the best knowledge of the authors, this seems to be the first attempt of upscaling the Cahn–Hilliard equation in such domains. The new homogenized equation should have a broad range of applicability owing to the well-known versatility of phase-field models. The additionally introduced feature of systematically and reliably accounting for confined geometries by homogenization allows for new modelling and numerical perspectives in both science and engineering. Our results are applied to wetting dynamics in porous media and to a single channel with strongly heterogeneous walls.

scholarly journals A Comparison Of Building Envelope Performance Levels Between Ontario, Denmark, Germany And The Passive House Standard, In The Low-Rise, Residential Context

2021 ◽  
Author(s):  
Blaine Attwood
Keyword(s):  
Energy Use ◽  
Building Envelope ◽  
Passive House ◽  
Building Envelopes ◽  
Residential Sector ◽  
Greater Toronto Area ◽  
Residential Context ◽  
Minimum Requirements ◽  
Other World ◽  
House Standard

This research compared and analyzed where the Ontario Building Code rates in the low-rise, residential sector in terms of its: in comparison to Denmark, Germany and the Passive House Standard. This was analyzed to see how Ontario compared against other world renowned energy efficient regulations and where or if there was room for improvement. For this, HOT2000 and THERM were utilized on all four of the reference standards, where both of these programs were managed in a way to compare the results of ‘typical’ building envelopes and the current regulation from each of the standards. These results were then able to provide a whole home’s heating and air conditioning energy use in the Greater Toronto Area climate. Overall, the results illustrated Ontario homes consume the most energy for both typically constructed homes and homes utilizing the minimum requirements. In addition to this, Ontario also had the least performing building envelope connection details. In total, the Passive House performed at the highest level followed by Germany, Denmark and then Ontario.

scholarly journals Influence of airtightness of steel sandwich panel joints on heat losses

2020 ◽  
Vol 172 ◽  
pp. 05008
Author(s):  
Markus Kuhnhenne ◽  
Vitali Reger ◽  
Dominik Pyschny ◽  
Bernd Döring
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Building Envelope ◽  
The Finite Element Method ◽  
Transmission Losses ◽  
Building Envelopes ◽  
Metal Building ◽  
Effective Heat Transfer Coefficient ◽  
The Heat Transfer Coefficient

Energy saving ordinances requires that buildings must be designed in such a way that the heat transfer surface including the joints is permanently air impermeable. The prefabricated roof and wall panels in lightweight steel constructions are airtight in the area of the steel covering layers. The sealing of the panel joints contributes to fulfil the comprehensive requirements for an airtight building envelope. To improve the airtightness of steel sandwich panels, additional sealing tapes can be installed in the panel joint. The influence of these sealing tapes was evaluated by measurements carried out by the RWTH Aachen University - Sustainable Metal Building Envelopes. Different installation situations were evaluated by carrying out airtightness tests for different joint distances. In addition, the influence on the heat transfer coefficient was also evaluated using the Finite Element Method (FEM). The combination of obtained air volume flow and transmission losses enables to create an "effective heat transfer coefficient" due to transmission and infiltration. This summarizes both effects in one value and is particularly helpful for approximate calculations on energy efficiency.

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