scholarly journals WIND PRESSURE EFFECTS ON TRANSFER OF HEAT AND MOISTURE ACROSS A BREATHING WALL : Study on properties of natural ventilation, thermal insulation and vapor transmission in a breathing wall Part 1

2000 ◽  
Vol 65 (531) ◽  
pp. 67-74 ◽  
Author(s):  
Seonghwan YOON YOON ◽  
Akira HOYANO ◽  
Kazumasa GONAIKAWA
Keyword(s):  
Thermal Insulation ◽  
Natural Ventilation ◽  
Pressure Effects ◽  
Wind Pressure ◽  
Heat And Moisture

CFD Modeling of Pressure Coefficients for a Natural Ventilation Study in an Experimental Low Rise Building

2013 ◽  
Author(s):  
Robel Kiflemariam ◽  
Cheng-Xian Lin
Keyword(s):  
Natural Ventilation ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Analytical Models ◽  
Cfd Modeling ◽  
Engineering Practice ◽  
Pressure Coefficients ◽  
Wind Pressure Coefficient ◽  
Detailed Assessment ◽  
Ventilation Rates

Mean wind pressure coefficient (Cp) is one of the major input data for natural ventilation study using building energy simulation approach. Due to their importance, they need to be accurately determined. In current engineering practice, tables and analytical Cp models only give mostly averaged results for simpler models and configurations. Considering the limitation of tables and analytical models, Computational Fluid Dynamics (CFD) could provide a means for an accurate and detailed assessment of Cp. In this paper, we make use of a relatively high resolution, detailed experiments done at Florida Intentional University to validate a CFD modeling of the pressure coefficients Cp. The results show that existing CFD model has a good agreement with experimental results and gives important information of distribution of Cp values over the surface. The local values of the Cp are investigated. In addition, the CFD derived Cp and discharge coefficient (Cd) values are utilized in semi-analytical ventilation models in order to get a more accurate value of ventilation rates.

scholarly journals Durability of Stone Cladding in Buildings: A Case Study of Marble Slabs Affected by Bowing

Buildings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 229 ◽  
Author(s):  
Sousa ◽  
Sousa
Keyword(s):  
Element Model ◽  
Pressure Effects ◽  
Wind Pressure ◽  
Stability Evaluation ◽  
Building Facade ◽  
Building Facades ◽  
Anchoring Strength ◽  
Wind Pressures ◽  
Loss Of Strength

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, the combination of bowing with wind pressure effects on the building façades can increase the risk of fracture and collapse of the stone slabs, especially if this combination is not properly evaluated during design. Motivated by a case study, this work describes a stability evaluation of a 15-year-old building façade coated with marble stone cladding affected by bowing and subjected to wind pressures. This evaluation was focused on the stone slabs, and was performed through finite element model (FEM) numerical simulations of these slabs submitted to wind pressures and through lab tests using samples of stone slabs removed from the building façade. The results obtained demonstrated stability problems on the stone slabs caused by wind pressure-induced stresses combined with the loss of strength due to aging and bowing effects, especially for slabs with larger dimensions.

Simulation and Measurement of Hygrothermal Behaviour of Newly Developed Plasters

2016 ◽  
Vol 824 ◽  
pp. 598-605
Author(s):  
Jitka Hroudova ◽  
Martin Sedlmajer ◽  
Vitezslav Novak ◽  
Jiri Zach
Keyword(s):  
Thermal Insulation ◽  
Lightweight Aggregate ◽  
Energy Performance ◽  
Existing Buildings ◽  
Insulation System ◽  
Architectural Features ◽  
Harmful Emissions ◽  
Heat And Moisture Transport ◽  
The Cost ◽  
Heat And Moisture

Recently, there has been increased interest in the rehabilitation of existing buildings especially in order to improve their energy performance. Thermal insulation brings not only savings in the cost of heating or cooling but also contributes to the reduction of harmful emissions such as carbon dioxide, sulphur dioxide or nitrogen dioxide. However, the thermal insulation of historical buildings or buildings listed as cultural heritage brings some problems due to architectural features. It is therefore necessary to choose an alternative whether it is the use of an internal thermal insulation system or to repair and rehabilitate the existing plaster with materials compatible with the original ones. The newly developed thermal insulation plasters based on silicate and using lightweight aggregate and natural fibres are optimum materials for the thermal insulation of both existing and newly constructed buildings. The paper describes the results of research focused on the examination of the behaviour of thermal insulation plaster mainly in terms of heat and moisture transport. Using a computational programme, this behaviour was simulated for a chosen detail of a real building in the vicinity of a window jamb.

Effects of Clothing Ventilative Designs on Thermal Insulation under Varying Wind Conditions

2011 ◽  
Vol 332-334 ◽  
pp. 1927-1930 ◽  
Author(s):  
Xiang Hui Zhang ◽  
Jun Li
Keyword(s):  
Experimental Investigation ◽  
Thermal Comfort ◽  
Thermal Insulation ◽  
The Body ◽  
Thermal Manikin ◽  
Clothing Insulation ◽  
Vertical Side ◽  
Wind Velocities ◽  
Heat And Moisture ◽  
Body Heat

This paper reports on an experimental investigation of the effects of clothing ventilative designs on thermal comfort measured in terms of thermal insulation. Eight T-shirts with varying areas and locations of mesh fabric were designed and produced for testing on a dry thermal manikin. Clothing thermal insulation of T-shirts was measured under three wind velocities: 0.5, 1 and 2m/s. The results showed that, the areas and locations of ventilation panels affect the total thermal insulation. The T-shirts with larger area of mesh fabric are preferable in terms of releasing more body heat. Among various designs tested, mesh fabrics applied at two vertical side seams can most effectively release heat and moisture from the body. Clothing insulation is also greatly affected by wind.

Effect of Different Initial Moisture Contents on the Characteristics of Coupled Heat and Moisture Transfer of a Reinforced Concrete-EPS Thermal Insulation Composite Wall in Harbin

2011 ◽  
Vol 250-253 ◽  
pp. 3044-3049
Author(s):  
Yu Gong Xu ◽  
Mei Lu ◽  
Zi Le Jia
Keyword(s):  
Reinforced Concrete ◽  
Thermal Insulation ◽  
Moisture Transfer ◽  
Heat And Moisture Transfer ◽  
Moisture Contents ◽  
Composite Wall ◽  
Condensed Water ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
The Heat Transfer Coefficient

This paper investigated the effect of different initial moisture contents on the characteristics of coupled heat and moisture transfer of a reinforced concrete-EPS thermal insulation composite wall in Harbin. The change of the moisture content with time and the change of the heat transfer coefficient with time of the reinforced concrete-EPS thermal insulation composite wall at different initial moisture contents in Harbin were numerically simulated. The relative humidity and the quantity of condensed water in the air layer of the reinforced concrete-EPS thermal insulation composite wall were also calculated. The paper provides a scientific proof for the influence of the process of construction of a reinforced concrete-EPS thermal insulation composite wall on the energy-saving of buildings.

Computational Simulation of Behaviour of Developed Thermal Insulation Plaster Based on Silicates with the Use of Program WUFI 2D

2017 ◽  
Vol 908 ◽  
pp. 111-117
Author(s):  
Jitka Peterková ◽  
Jiri Zach
Keyword(s):  
Thermal Insulation ◽  
Moisture Transport ◽  
Computational Simulation ◽  
Material Structure ◽  
Building Structures ◽  
Hygrothermal Behavior ◽  
Silica Materials ◽  
Heat And Moisture Transport ◽  
Increasing Demand ◽  
Heat And Moisture

The investigation of the hygrothermal behavior of advanced silica materials, which are today in ever increasing demand during the reconstruction of building envelopes, is an important point of research. For determining the moisture balance in building structures, the Glaser method is most frequently used to day which, however, considers during calculations water diffusion only in stationary state at simplified marginal conditions; it does not take into account the moisture transport in the capillary system of the material structure, nor the sorption properties of the material. The goal of the research is therefore to gain deeper knowledge of the way heat and moisture transport through the pore structure of these silica materials. The paper describes verification of efficacy of thermal insulation and rehabilitation silicate plastering. Based on experiences from previously research and their results were chosen 2 developed plasters for computational simulation of their behavior in the case of detail of window jamb. One type of developed plastering was placed from the site of interior and the second type of plastering was applied from the site of exterior.

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