The effect of flanking element length in thermal bridge calculation and possible simplifications to account for combined thermal bridges in well insulated building envelopes

2021 ◽  
Vol 252 ◽  
pp. 111397
Author(s):  
Jaanus Hallik ◽  
Targo Kalamees
Keyword(s):  
Building Envelopes ◽  
Thermal Bridge ◽  
Thermal Bridges

Comparison of Thermal Bridges Calculate Method through Window Jamb

2013 ◽  
Vol 855 ◽  
pp. 130-133
Author(s):  
Rastislav Ingeli
Keyword(s):  
Heat Conduction ◽  
Thermal Conductance ◽  
Theoretical Background ◽  
Building Envelope ◽  
Building Construction ◽  
Building Envelopes ◽  
Thermal Bridge ◽  
Detailed Specification ◽  
Flow Through ◽  
Thermal Bridges

This paper is focused on comparison of thermal bridges calculate method through window jamb in building envelopes. The present approach is based on an integrated 2D dynamic simulation. The theoretical background of the adopted approach is presented. The reliability of this approach in evaluating thermal bridges as well as its applicability to different geometric shapes is proved. Detailed specification and calculation of each thermal bridge in these buildings should be taken into account. the heat flow through a building construction is considered to be of the onedimensional (1D) type. This is because the thermal conductance and temperature differential in this direction are much greater than that in the lateral directions. The thermal bridge is the part of the building envelope through which heat conduction is multi-dimensional. Therefore, in recent studies, the problem of heat conduction in the building construction has been treated as a multi-dimensional.

Thermal Bridges Minimizing through Window Jamb in Low Energy Buildings

2014 ◽  
Vol 899 ◽  
pp. 66-69 ◽  
Author(s):  
Rastislav Ingeli ◽  
Boris Vavrovič ◽  
Miroslav Čekon ◽  
Lucia Paulovičová
Keyword(s):  
Thermal Protection ◽  
Low Energy ◽  
Building Envelopes ◽  
Thermal Bridge ◽  
Window Systems ◽  
Significant Difference ◽  
Low Energy Buildings ◽  
Window Position ◽  
High Thermal Resistance ◽  
Thermal Bridges

Building envelopes with high thermal resistance are typical for low-energy buildings. Detailed specification and calculation of each thermal bridge in these buildings should be taken into account. This paper is focused on thermal bridges minimizing through typical window systems in building envelopes. The aim of this article is to analyze the window position influence, as regards on thermal performance and to point out the installation modality in accordance with the characterization of the windows performance. This can be done by quantifying the percentage increment of the window jamb thermal transmittance. The calculated results also demonstrate that there is significant difference between results obtained by various available calculation approaches. This can be significant especially in buildings with high thermal protection.

scholarly journals Heat and moisture transfer in wall-to-floor thermal bridges and its influences on the insulation performance

2021 ◽  
Vol 2069 (1) ◽  
pp. 012216
Author(s):  
Yucong Xue ◽  
Jian Ge ◽  
Yifan Fan
Keyword(s):  
Water Vapour ◽  
Moisture Transfer ◽  
Structural Safety ◽  
Building Envelopes ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
Heat Transfers ◽  
Heat And Moisture ◽  
Insulation Performance ◽  
Transient Numerical Simulation

Abstract The moisture modifies the characteristics of heat transfer in building envelopes. Multiple factors, including the distinct hygric properties of various material, gravity, etc., affect the moisture content, resulting in a non-uniform distribution of water vapour in different parts of the envelope (e.g. column, beam, the main part of exterior walls). Usually, the more water vapour in a material, the higher the thermal conductivity, resulting in more heat transfers here. Moreover, condensation easily occurs where there is wet, marking such parts have risks both on structural safety and mould growth. The wall-to-floor thermal bridge (WFTB) occupies the largest area among all kinds of thermal bridges that formed by frame structures. In this study, we aimed to quantify the influence on heat loss through WFTB when the moisture transfer in envelopes is considered. The average apparent thermal resistance of WFTB (R TB, ave) was defined to access the insulation performance of WFTB in practical application. The results of transient numerical simulation indicated that when the moisture transfer is considered, the insulation performance of building envelopes decreases significantly, while the adverse effect of WFTB on heat insulation becomes less pronounced. The results indicated that the measures of insulation for WFTB should be reconsidered when the moisture transfer is considered.

scholarly journals Automatic Detection of Linear Thermal Bridges from Infrared Thermal Images Using Neural Network

2021 ◽  
Vol 11 (3) ◽  
pp. 931
Author(s):  
Changmin Kim ◽  
Jae-Sol Choi ◽  
Hyangin Jang ◽  
Eui-Jong Kim
Keyword(s):  
Neural Network ◽  
Detection Method ◽  
Early Stage ◽  
Thermal Anomaly ◽  
Building Envelopes ◽  
Subjective Judgment ◽  
Thermal Images ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
Infrared Thermal Images

Detecting thermal bridges in building envelopes should be a priority to improve the thermal performance of buildings. Recently, thermographic surveys are being used to detect thermal bridges. However, conventional methods of detecting thermal bridges from thermal images rely on the subjective judgment of audits. Research has been conducted to automatically detect thermal bridges from thermal images to improve problems caused by such subjective judgment, but most of these studies are still in the early stage. Therefore, this study proposes a linear thermal bridge detection method based on image processing and machine learning. The proposed method includes thermal anomaly area clustering, feature extraction, and an artificial-neural-network-based thermal bridge detection. The proposed method was validated by detecting the thermal bridges in actual buildings. As a result, the average precision, recall, and F-score were 89.29%, 87.29, and 87.63%, respectively.

scholarly journals The Influence of Different Facings of Polyisocyanurate Boards on Heat Transfer through the Wall Corners of Insulated Buildings

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1991 ◽  
Author(s):  
Tomas Makaveckas ◽  
Raimondas Bliūdžius ◽  
Arūnas Burlingis
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Thermal Insulation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
The Impact ◽  
Heat Flow Meter

Polyisocyanurate (PIR) thermal insulation boards faced with carboard, plastic, aluminum, or multilayer facings are used for thermal insulation of buildings. Facing materials are selected according to the conditions of use of PIR products. At the corners of the building where these products are joined, facings can be in the direction of the heat flux movement and significantly increase heat transfer through the linear thermal bridge formed in the connection of PIR boards with facing of both walls. Analyzing the installation of PIR thermal insulation products on the walls of a building, the structural schemes of linear thermal bridges were created, numerical calculations of the heat transfer coefficients of the linear thermal bridges were performed, and the influence of various facings on the heat transfer through the thermal bridge was evaluated. Furthermore, an experimental measurement using a heat flow meter apparatus was performed in order to confirm the results obtained by numerical calculation. This study provides more understanding concerning the necessity to evaluate the impact of different thermal conductivity facings on the heat transfer through corners of buildings insulated with PIR boards.

scholarly journals A new method to estimate point thermal transmittance based on combined two-dimensional heat flow calculation

2020 ◽  
Vol 172 ◽  
pp. 08005
Author(s):  
Jaanus Hallik ◽  
Targo Kalamees
Keyword(s):  
Heat Flow ◽  
Three Dimensional ◽  
Multiple Linear Regression Model ◽  
Building Envelope ◽  
New Method ◽  
Two Dimensional ◽  
Thermal Transmittance ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
Third Dimension

A well-insulated, airtight and thermal bridge free building envelope is a key factor for nearly zero energy buildings (nZEB). However, increased insulation thickness and minimized air leakages increase the effect of thermal bridges on overall energy efficiency of the nZEBs. Although several more prominent linear thermal bridges are accounted for in the practice the three-dimensional heat flow through vast array of fixation elements, mounting brackets and other point thermal bridges are usually neglected due to time-consuming model preparation routine, lack of input data as well as high number of different thermal bridges that have to be assessed for a single project. In this study a new method was proposed for predicting three-dimensional heat flow and the point thermal transmittance of thermal bridges caused by full or partial penetration of the building envelope with metal elements with uniform geometry in third dimension based on multiple two-dimensional numerical heat flow calculations. A new parameter (equivalent length of thermal bridge) was defined which incorporates the effect of additional thermal transmittance in third dimension when multiplied by the difference of two thermal coupling coefficients derived for two-dimensional cross section. Multiple linear regression model was fitted on database with 102 cases and verified with separate case of window to wall connection incorporating metal penetration at fixation points. The proposed methodology can be useful in general practice where the design team lacks the skills or software tools for conducting detailed numerical analysis in three dimensions.

scholarly journals Thermal Bridge Impact on the Heating Demand in a Low-Energy House

2010 ◽  
Vol 4 (-1) ◽  
pp. 76-81
Author(s):  
Martins Pelss ◽  
Andra Blumberga ◽  
Agris Kamenders
Keyword(s):  
Calculation Method ◽  
Software Tool ◽  
Low Energy ◽  
Thermal Bridge ◽  
Bridge Model ◽  
Building Components ◽  
Thermal Bridges ◽  
Thermal Bridging ◽  
Numerical Calculation Method ◽  
Simplified Calculation

Thermal Bridge Impact on the Heating Demand in a Low-Energy House Thermal bridges typically occur at the junction of different building components where it is difficult to achieve continuity in the thermal insulation layer. In this paper thermal bridges are investigated in the first one-family low-energy house in Latvia. The proportion of the overall heat loss due to thermal bridging is determined based on the results from a numerical calculation method described in the standard LVS EN ISO 10211 and from the simplified calculation method given in the standard LVS EN ISO 14683. In this paper the software tool THERM is used for two-dimensional thermal bridge model simulations. The results suggest that 7.7 % of the total heat transmission losses occur due to thermal bridges.

scholarly journals Assessment of the reliability of thermal protection of enclosing structures of buildings at the design and operation stages

2018 ◽  
Vol 251 ◽  
pp. 03057
Author(s):  
Galina Shibaeva ◽  
Ekaterina Ibe ◽  
Denis Portnyagin
Keyword(s):  
Thermal Imaging ◽  
Thermal Protection ◽  
Residential Buildings ◽  
Building Envelope ◽  
Design Solution ◽  
Construction Technology ◽  
The Finite Element Method ◽  
Building Envelopes ◽  
Thermal Bridge ◽  
Continental Climate

The article presents recommendations for assessing the heat and energy efficiency of a design solution for a building envelope based on the calculation of energy costs during typical periods of time. The recommendations are based on the analysis of defects in thermal protection of building envelopes during design and construction, by studying design documentation, thermal imaging, calculation and verification of building envelope components. Results of calculation of temperature in hazardous structural sites for the design winter conditions with the help of software that implements the finite element method are presented. In the present paper, the design solutions of the nodes of the walls of residential buildings are considered, where, during thermal imaging, thermal bridge are visible through the external walls. It is shown that the using of multilayer brick walls in the apartment houses in a sharply continental climate is irrational due to the rapid deterioration of the properties of the insulation layer. Also, the thermal protection of buildings is influenced by the design solution defects and violation of construction technology.

scholarly journals Experimental Assessment of Thermal Performance and Bridging Effects of Low-Cost Sandwich Panels under a High-Temperature Impinging Jet

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3620
Author(s):  
Wei Ye ◽  
Jian Cai ◽  
Yixiang Huang ◽  
Chengqiang Zhi ◽  
Xu Zhang
Keyword(s):  
Thermal Performance ◽  
Low Cost ◽  
Sandwich Panels ◽  
Impinging Jet ◽  
Maximum Temperature ◽  
Aluminum Silicate ◽  
The Core ◽  
Thermal Bridge ◽  
Angle Iron ◽  
Thermal Bridges

Sandwich panels are commonly used across industries for their ability to bear structural and thermal loads. In this paper, a panel chamber matching apparatus was designed to investigate the thermal performance of eight steel-based panels by exposing them to an impinging jet at approximately 550 °C for 30 min. Three types of low-cost materials (polycrystalline filaments, silica aerogel, and aluminum silicate) were used as the insulation core. The temperature of the panel surfaces was measured, as well as the metallic fasteners, including bolts, nails, battens, seams, and angle iron, to examine their thermal bridge effects. Major conclusions include the following: first, the maximum temperature on the impinged surface was consistent among all 20 cases, whereas that of the surface under free convection varied, ranging from 41 to 120 °C, depending on the core and thermal bridges. Second, most of the highest temperatures on opposite surfaces were caused by a section of bare angle iron, and this bridging effect could be significantly reduced by up to 50 °C using a few layers of cloth, although the improvement could be temporary. Bolts and nails were less effective as thermal bridges, while the battens could be more effective. Third, the estimated heat flux of all specimens ranged from 167 to 331 W·m−2.

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