scholarly journals Minimization of a point thermal bridge by a roof restraint system holder

2021 ◽  
Vol 1203 (2) ◽  
pp. 022001
Author(s):  
Roman Šubrt ◽  
Pavlína Charvátová
Keyword(s):  
Restraint System ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
Flat Roofs

Abstract Roof restraint systems are designed for flat roofs for safe maintenance and repairs. By anchoring them, considerable point thermal bridges are created, which can also lead to condensation in the roof cladding. We deal in this work with the design of minimization of these point thermal bridges.

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 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.

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 Instantaneous field measurements of thermal bridge parameters in ground floor residential room

2019 ◽  
Vol 112 ◽  
pp. 01016 ◽  
Author(s):  
Martin Ivanov
Keyword(s):  
Energy Demand ◽  
Field Measurements ◽  
Building Design ◽  
Building Envelope ◽  
Ground Floor ◽  
Thermal Bridge ◽  
Significant Temperature ◽  
Thermal Bridges ◽  
Infrared Thermal Images ◽  
Heating Energy Demand

The “thermal bridges” are defined as an isolated building’s areas, where the construction elements have higher thermal conductivity, compared with the rest of the building envelope. Thus, at cold winter conditions, a significant temperature difference may occur between neighbouring solid and air volumes within the construction. Moreover, it has been documented, that the heating energy demand of a building may be increased with more than 30%, due to the existence of thermal bridges and the increased heat losses from the indoors. Consequently, in the recent years, norms and standards have been developed, for avoiding thermal bridges during the building design process. But still, thermal bridges exist in the indoor environment, especially in older buildings, where no energy efficient measures have been applied. That is why, the presented study focuses on instantaneous field measurements of thermal bridge parameters in real existing ground floor residential room. The thermal bridge propagation is analysed relative to the indoor and outdoor air temperature and relative humidity, as well as with infrared thermal images of the affected external walls. The achieved results give valuable information about the generic conditions for thermal bridge existence, without considering the building envelope properties.

scholarly journals A Comparative Study between Jordanian Overall Heat Transfer Coefficient (U-Value) and International Building Codes, With Thermal Bridges Effect Investigation

2021 ◽  
Vol 3 (1) ◽  
pp. p10
Author(s):  
Ammar Alkhalidi ◽  
Suhil Kiwan ◽  
Haya Hamasha
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Energy Demand ◽  
Building Envelope ◽  
Overall Heat Transfer Coefficient ◽  
Thermal Bridge ◽  
U Value ◽  
Thermal Bridges ◽  
Heating Degree Days

Depletion of fossil fuel and the environmental effect associated with the use of it have made the topic of “thermal insulation regulations” a major concern in country Jordan and worldwide. This paper reviews the overall heat transfer coefficient U-value in Jordanian code for the building envelope, which represents how much the building envelope transfer heat to the outside environment. U-value was reviewed with respect to the following factors, heating degree days, the heating load required to achieve thermal comfort. Based on the review a new U-value of 0.65 W/m2.K was proposed and it was found that this value reduces the energy demand almost 50%. Moreover, the thermal bridge effect was investigated and it was found that an obvious increase in the U-value is present when having thermal bridges; this will affect the energy demand, almost 200%.

scholarly journals Impact of point thermal bridges on thermal properties of building envelopes

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 2181-2188 ◽  
Author(s):  
Jolanta Sadauskiene ◽  
Juozas Ramanauskas ◽  
Algimantas Vasylius
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Characteristics ◽  
Insulation Layer ◽  
Geometrical Properties ◽  
Thermal Transmittance ◽  
Energy Efficient Buildings ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
Bearing Layer

During the design of energy-efficient buildings with a ventilated fa?ade systems, the evaluation of point thermal transmittance is complicated. It requires additional theoretical knowledge, special software and skills to use it. Because of that, point thermal transmittance is often ignored in practice. The dependence of point thermal transmittance, which is appearing because of aluminum fixing elements used in the insulated wall with ventilated fa?ade system, from the thermal and geometrical properties of construction layers are analyzed in this paper. Research has shown, that thermal properties of the supporting wall, where fixing element is located, had the biggest influence on the point thermal transmittance. When thermal conductivity of the supporting wall was increasing, as well as a thickness of the insulation layer, a value of thermal bridge was increasing in a non-linear way. For this reason, the thermal transmittance coefficient of all construction could increase up to 35%. When the thickness of the supporting wall and thermal conductivity of the insulation layer was increased, the value of point thermal bridge was decreasing. The tests revealed strong dependency of the point thermal bridge on the thermal conductivity of bearing layer material and the thickness of the bearing layer of wall. For this reason, thermal bridges should receive greater consideration. It is not enough to use the diagrams of typical fasteners that very often do not take into account the exact thickness and thermal characteristics of materials

Behavior of Point Thermal Bridges from Mechanical Anchoring of Flat Roofs

2014 ◽  
Vol 1041 ◽  
pp. 117-120
Author(s):  
Markéta Bogárová
Keyword(s):  
Thermal Flux ◽  
Software Tool ◽  
Energy Performance ◽  
High Energy ◽  
Critical Value ◽  
Ansys Software ◽  
Mechanical Anchoring ◽  
Thermal Bridges ◽  
Flat Roof ◽  
Flat Roofs

Building of structures with high energy performance is topical. To achieve this, it is necessary to have processed besides other thing a detailed design. Thermal bridges have to be eliminated in the design period. Thermal bridges occur as point, linear and 3-dimmensional ones. Mechanical anchoring creates point thermal bridges too. In this paper will be described only the mechanical anchoring to stabilize a flat roof. In the space with anchoring elements there is increased the thermal flux. This flux depends on the composition of the flat roof and kind of anchoring elements. It could lead to the condensation of water vapour in these locations upon attainment of the critical value of surface temperature in the room. This issue has another not-less interesting side. It is behaviour in summer season, when the anchoring conducts heat to the interior of objects. These thermal bridges caused by the anchoring elements described in this article will be modelled with the Ansys software tool.

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