scholarly journals The The Occurrence of Thermal Bridges in Hemp-Lime Construction Junctions

2019 ◽  
Author(s):  
Magdalena Grudzińska ◽  
Przemysław Brzyski
Keyword(s):  
Energy Efficient ◽  
Composite Structures ◽  
Building Materials ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Energy Efficient Buildings ◽  
Moisture Condensation ◽  
Thermal Bridges ◽  
Frame Construction ◽  
Insulating Properties

Thermal bridges increase heat losses in buildings and reduce the temperature of the internal envelope surface, causing moisture condensation and mould growth. This is an important issue for building materials based on organic components such as a hemp-lime composite, as they are particularly susceptible to biological degradation.The hemp-lime composite is used as a filling in timber frame construction. The increased cross-section of wooden elements together with the geometry change in the construction joints can form thermal bridges. The paper presents numerical analyses of temperature distribution in the area of construction elements connections, taking into account several variants of junctions: external walls, corners, and window placement in a wall. The thermal parameters of hemp-lime composites used in the analyses were obtained from the authors’ own research.Despite relatively good insulating properties, timber elements have a noticeable influence on the local increase of the heat transfer in hemp-lime composite structures, forming thermal bridges in the partitions themselves and in the construction nodes. However, the linear thermal transmittance coefficients in the presented joints were not very significant (in the range of 0.026 ÷ 0.092 W/(m·K) depending on the type of connection), proving the usefulness of this type of construction in energy-efficient buildings.

scholarly journals Analysis of the Occurrence of Thermal Bridges in Several Variants of Connections of the Wall and the Ground Floor in Construction Technology with the Use of a Hemp–lime Composite

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2392 ◽  
Author(s):  
Brzyski ◽  
Grudzińska ◽  
Majerek
Keyword(s):  
Heat Transfer ◽  
Construction Technology ◽  
Floor Level ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Surface Condensation ◽  
Thermal Bridges ◽  
Almost All ◽  
Frame Construction ◽  
Temperature Factors

This article analyses the connection of the two types of floors on the ground (floors on joists and self-supporting floors), with the external wall made of a hemp–lime composite for the occurrence of thermal bridges. Several factors that may affect the heat transfer in the junction were taken into account: the level of the floor on the ground, the wall thickness, the thermal conductivity of the composite, and the location of the timber frame construction. The technology of using hemp and lime is relatively new, and there is a lack of such analyses in the literature. The two-dimensional (2D) heat-transfer in the described construction joints was analyzed based on the finite-element method with the use of the THERM 7.4 software. The results were presented as averaged and linear thermal transmittance coefficients dependent on the above mentioned factors. The possibility of surface condensation was also checked. The differences in the values of the thermal transmittance of the junction between the two variants of ground floors reached around 0.13%–1.67% and the values of linear thermal transmittance factor reached approximately 2.43%–10.13%. The junctions with the highest floor level showed a decrease in the thermal transmittance value by about 3.00%–5.77% and in the linear thermal transmittance, by about 21.98%–53.83%, compared to the junctions with the lowest floor level. Calculations showed that almost all analyzed junctions are free from surface condensation causing mould growth, because the minimum temperature factors f0.25 were higher than 0.78 (except for junctions with the lowered floor levels). The junction with a floor on the timber joists showed better thermal parameters than the junction with a self-supporting floor in each of the analyzed variants. By increasing the level of floor insulation, it is possible to limit the thermal bridges and improve the thermal properties of the junction.

Thermal Insulation Of The Foundation Walls Of Buildings And Calculation Of Its Thickness

2021 ◽  
Vol 03 (04) ◽  
pp. 70-78
Author(s):  
Tulakov Elmurad Salomovich ◽  
◽  
Matyokubov Bobur Pulatovich ◽  
Keyword(s):  
Surface Temperature ◽  
Thermal Insulation ◽  
Energy Efficient ◽  
Building Materials ◽  
The Body ◽  
Dew Point ◽  
Dew Point Temperature ◽  
Energy Efficient Buildings ◽  
Basement Walls ◽  
External Barrier

If the surface temperature of any building material drops sharply without changing the humidity and the surface temperature is lower than the dew point temperature, dew-like water droplets are formed on the surface of this material. This condition is called condensing humidity condition. Condensation moisture formed on the surfaces of building materials and external barriers is slowly absorbed into the body of building materials over time, increasing the relative humidity of this structure. Condensation moisture can be observed when the temperature of the surfaces of external barrier structures drops sharply. This condition can be observed everywhere where the basement is connected to the outer walls of the basement. The article deals with the issue of thermal insulation and calculation of basement walls of modern energy-efficient buildings, which are widely used in the country and abroad.

Sustainable “Low-Tech” Architecture–Take Traditional Residential Houses in West Hunan for Example

2011 ◽  
Vol 368-373 ◽  
pp. 3805-3808 ◽  
Author(s):  
Ming Fang Zhong
Keyword(s):  
Sustainable Development ◽  
Building Materials ◽  
Architectural History ◽  
High Tech ◽  
Timber Frame ◽  
Processing Cost ◽  
Renewable Natural Resources ◽  
Processing Procedure ◽  
Simple Processing ◽  
Frame Construction

The traditional residential houses in west Hunan, China were built on principle of be in harmony with the nature, with minimal alteration to the environment and with layouts that highlights natural environment. They are made of local building materials - renewable natural resources - with natural texture and simple processing procedure that takes the lowest transportation and processing cost. The structure system of the house is pre-cast timber frame construction highly developed during Chinese architectural history. It’s safe, steady, economic, and makes use of timber resource high efficiently. These original and “low-tech” – compared with the modern “high-tech” concept – but most operational ways are the advantages of the traditional buildings that modern buildings should learn from with regard to the environment and sustainable development.

scholarly journals Two-dimensional heat transfer analysis of timber structure walls filled with hemp-lime composite

2019 ◽  
Vol 252 ◽  
pp. 05015 ◽  
Author(s):  
Przemysław Brzyski ◽  
Sylwia Duda ◽  
Andrzej Raczkowski
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Timber Structure ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Thermal Insulating ◽  
Frame Construction ◽  
Industrial Hemp

Hemp-lime composite is a thermal insulating material used as a filling in timber frame construction walls. It is a material based on the wooden part of industrial hemp stalk (hemp shives) and lime binder. In practice, different wall thicknesses, composites with different thermal properties and various configurations of timber structure are used. These factors affect the temperature distribution in the wall. In the thermally weaker areas of walls, there is a greater risk of condensation and mould growth. This issue is important while designing walls based on organic materials. The paper presents the two-dimensional (2D) heat-transfer analysis based on the finite-element method, using THERM software. Several variants of external walls were adopted for the analysis. Thermal parameters of hemp-lime composites used in the analysis were obtained from our own research. The results of the analysis were presented as the values of the thermal transmittance coefficient and linear thermal transmittance equivalent to timber construction. The temperature distribution for an exemplary wall was also shown graphically in the form of isotherms and colour-flooded isotherms.

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

Influence of Thermal Break Element Applied in Balcony Slab on Internal Surface Temperature

2014 ◽  
Vol 1057 ◽  
pp. 79-86
Author(s):  
Peter Buday ◽  
Rastislav Ingeli ◽  
Miroslav Čekon
Keyword(s):  
Energy Efficient ◽  
Energy Use ◽  
Internal Surface ◽  
Building Envelope ◽  
Cold Climate ◽  
Energy Efficient Buildings ◽  
Thermal Bridge ◽  
Advanced Analysis ◽  
Thermal Bridges ◽  
Energy Efficient Building

Reduction of energy use in buildings is an important measure to achieve climate change mitigation. It is essential to minimize heat losses when designing and building energy efficient buildings. For an energy-efficient building in a cold climate, a large part of the space heating demand is caused by transmission losses through the building envelope. To achieve this, it is necessary to have processed a detailed design of buildings. Thermal bridges have to be eliminated in the design of buildings. Thermal bridges occur as point ones or linear. One of the specific details that create thermal leakage is located in balcony slabs. The balcony is one of the main reasons of the increased heat loss of buildings. The presence of thermal bridge in constructions of balcony envelopes influences the energy consumption, durability of the building envelopes, and also the thermal comfort of occupants. This paper is focused on advanced analysis of thermal performance of thermal break element applied in balcony slab with parametric correlation to the thermal properties of wall building envelope.

scholarly journals Towards Modern Technology and Traditional Form—Evolution of the Form of Energy-Efficient Houses in Poland over the Last Decades

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 30
Author(s):  
Jolanta Owerczuk
Keyword(s):  
Energy Saving ◽  
Energy Efficient ◽  
Building Materials ◽  
New Technologies ◽  
Modern Technology ◽  
Local Conditions ◽  
Traditional Form ◽  
Energy Efficient Buildings ◽  
Country Houses

The article is an attempt to capture the problem of changes occurring in the last dozen or so years in the architecture of energy-efficient houses in Europe, including Poland, in the light of economic and legal conditions. In the studies subordinated to the analysis of the literature, the focus was on those features of energy-efficient buildings that are derived from the logic of solutions of traditional country houses. The genesis of the form of the modern energy-saving house can be found in the principles of building and situating houses developed through the experience of previous generations. These principles took into account the specificity of the climate and existing local conditions. Modern energy-saving construction adds new technologies and new building materials to the traditional form.

scholarly journals An Analysis of Repeating Thermal Bridges from Timber Frame Fraction in Closed Panel Timber Frame Walls: A Case Study from Wales, UK

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1211
Author(s):  
Francesco Zaccaro ◽  
John Richard Littlewood ◽  
Carolyn Hayles
Keyword(s):  
Thermal Performance ◽  
Energy Use ◽  
Design Stage ◽  
Performance Gap ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Operational Energy ◽  
Thermal Bridges ◽  
Detrimental Impact

Calculating Repeating Thermal Bridges (RTBs) for Timber Frame (TF) closed panels that could occur in Offsite Manufactured (OSM) Modern Methods of Construction (MMC), such as exterior walls for nearly-to-zero operational energy dwellings to be constructed in Wales, United Kingdom (UK) is discussed in this paper. Detailed calculations for linear RTBs due to the TF components are often neglected when evaluating thermal transmittance (known as U-values hereafter). The use of standard TF fractions does not allow the designer to perceive their detrimental impact on RTBs and consequent U-values for exterior walls. With the increase of the thermal performance of exterior walls and as such lower U-values due to ever-tightening Building Regulations, specifically related to the energy use and carbon emissions from the space heating of dwellings, then the impacts of RTBs requires more investigation. By not calculating the potential of linear RTB at the design stage could lead to a performance gap where assumed U-values for exterior walls differ from manufacture to onsite. A TF detail from the Welsh manufacture has been chosen as a case study, to develop and apply a methodology using manufacturing drawings to evaluate TF fraction and their effect on the thermal performance.

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