scholarly journals Energy Performance Evaluation for Exterior Insulation System Consisting of Truss-Form Wire-Frame Mullion Filled with Glass Wool

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4486
Author(s):  
Jin-Hee Song ◽  
Cheol-Yong Park ◽  
Jae-Weon Jeong
Keyword(s):  
Energy Performance ◽  
Glass Wool ◽  
Steel Pipe ◽  
Rear Side ◽  
Ideal Condition ◽  
Insulation System ◽  
Thermal Transmittance ◽  
Thermal Bridge ◽  
Wire Frame ◽  
Major Factors

Heat loss and gain through opaque envelopes of buildings are major factors that affect the overall cooling and heating loads in buildings. The government has enforced regulations to strengthen the thermal transmittance requirement level as a major means of reducing greenhouse gas emissions in the building sector. In addition, the thermal bridge is considered to be one of the major factors in heating load of buildings. In this study, truss-form wire frame was developed in order to minimize thermal bridge of steel mullion in exterior insulation system. In the case of thermal transmittance test for specimen of 0.145 W/m2 K as design value, the value of the steel pipe was 0.190 W/m2 K and the value of the truss-form wire frame was 0.150 W/m2 K, respectively. This means the other is much smaller than the one in thermal bridge. For four cases, annual energy performance analysis was calculated using Passive House Planning Package (PHPP)—ideal condition without thermal bridge, steel pipe mullion without insulation in the rear side, steel pipe mullion with insulation in the rear side, and truss-form wire-frame mullion filled with glass wool. As results, the annual heating energy demands were 15.68 kWh/m2, 25.42 kWh/m2, 16.78 kWh/m2, and 16.09 kWh/m2, respectively.

Evaluation on the Energy Performance of PAS Wall Applying Vacuum Insulation

2013 ◽  
Vol 689 ◽  
pp. 237-240 ◽  
Author(s):  
Bo Hye Choi ◽  
Gyeong Seok Choi ◽  
Jae Sik Kang ◽  
Seung Eon Lee
Keyword(s):  
Heat Transfer ◽  
Outer Wall ◽  
Energy Performance ◽  
Heat Transfer Analysis ◽  
Insulation System ◽  
Thermal Transmittance ◽  
Thermal Bridge ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Insulation Performance

This study evaluates the insulation performance of the PAS so as to analyze the exterior insulation system, PAS(Panel Approach System), which is fixed to the structure by conducting a mock-up test and then calculates the linear thermal transmittance of the interior insulation and PAS-applied areas through a 3-dimensional steady state heat transfer analysis so as to conduct a comparison analysis of heat performance on the interior insulation system in thermal bridge areas. According to the results of the mock-up test conducted to evaluate the insulation performance of the PAS, the thermal transmittance value measured 0.15W/㎡K which shows outstanding insulation performance when compared to the Korean outer wall standard of apartment buildings that is 0.27~0.36W/㎡K. Moreover, as a result of calculating the linear thermal transmittance of the PAS in contrast to the interior insulation system through a heat transfer analysis of thermal bridge areas, the interior insulation measured 0.851W/mK, and 0.029W/mK when the PAS was applied. Thus, the insulation performance in thermal bridge areas was reduced by 96.6% in contrast to the interior insulation when the PAS was applied.

Heating Energy and Cost Evaluation of Sandwich Insulation Concrete System

2014 ◽  
Vol 525 ◽  
pp. 443-446 ◽  
Author(s):  
Yumin Kim ◽  
Ho Yeol Lee ◽  
Yong Jun Lee ◽  
Gyeong Seok Choi ◽  
Jae Sik Kang
Keyword(s):  
Energy Consumption ◽  
Economic Efficiency ◽  
Energy Performance ◽  
Significant Loss ◽  
Building Envelope ◽  
Cost Evaluation ◽  
Insulation System ◽  
Thermal Bridge ◽  
Insulation Systems ◽  
Heating Energy Consumption

It is essential to eliminate heat loss through the building envelope to reduce the energy consumption in buildings. However a significant loss of heating energy caused by thermal bridge between slab and external wall in internal insulation systems which were applied in the most apartments in Korea. To improve the performance of envelope, a sandwich insulation system was proposed. This paper evaluates the thermal performance, energy performance and economic efficiency of sandwich insulation system by comparing with internal insulation system. When the sandwich insulation system was applied, heating energy consumption was reduced by 17.8% compared with internal insulation system.

scholarly journals Thermal bridge effect of vertical diagonal tie connectors in precast concrete sandwich panels: an experimental and computational study

2020 ◽  
Vol 172 ◽  
pp. 08001
Author(s):  
Paul Klõšeiko ◽  
Reimo Piir ◽  
Marti Jeltsov ◽  
Targo Kalamees
Keyword(s):  
Computational Study ◽  
Precast Concrete ◽  
Sandwich Panels ◽  
Building Envelope ◽  
Heat Fluxes ◽  
Air Cavity ◽  
Thermal Transmittance ◽  
Thermal Bridge ◽  
Thermal Bridging ◽  
Air Cavities

The purpose of this work was to quantify the thermal bridge effect of vertical diagonal tie connectors in precast concrete sandwich panels (PCSPs). Special interest was in cases where the use of rigid insulation (e.g. PIR) would leave air gaps between insulation boards and diagonal ties, thus intensifying the thermal bridge. A climate chamber experiment using 5 different joint types was performed to gather reference data for CFD model validation. In the experiment, natural convection was observed in joints where no additional insulation was used, i.e. in air cavities. Significantly larger heat fluxes were measured in these cavities compared to insulated joints. The thermal bridging effect was evaluated for a typical PCSP (thermal transmittance without thermal bridges U = 0.11 W/(m²·K)) using CFD software taking into account 3D heat conduction and convection. Simulation results indicate that diagonal ties without adjacent air cavities increased the average thermal transmittance (U-value) of the envelope by 8%, diagonal ties with a 6 mm air cavity – 19...33% and diagonal ties with a 10 mm air cavity – 45...56%. In conclusion, it was found that the joints in insulation caused by diagonal ties affect the overall thermal performance of the building envelope significantly when efforts are not made to fill the air cavities around the connectors.

scholarly journals Factors affecting the deep renovation of a single-family building – a case study

2021 ◽  
Vol 246 ◽  
pp. 05004
Author(s):  
Triinu Bergmann ◽  
Aime Ruus ◽  
Kristo Kalbe ◽  
Mihkel Kiviste ◽  
Jiri Tintera
Keyword(s):  
Energy Efficiency ◽  
Performance Indicator ◽  
Energy Performance ◽  
Resource Efficiency ◽  
Final Decision ◽  
Air Leakage ◽  
Single Family ◽  
Building Stock ◽  
Thermal Transmittance ◽  
Family Building

The Energy Performance of Buildings Directive (EPBD) of the EU states that Each Member State shall establish a long-term renovation strategy to support the renovation of building stock into a highly energy efficient and decarbonised building stock by 2050. The motive for the study was the dissatisfaction of inhabitants of a single-family building about the heating costs and thermal discomfort. In this study both the emotional and resource efficiency aspects were considered. The structures and technical systems of the studied small dwelling are typical of representing single-family buildings of the Estonian building stock. The initial purpose was to improve the energy efficiency of a building while preserving the existing load bearing structures as much as possible. The research questions were: 1) what the situation before the renovation was, 2) what solutions can be used, 3) making decisions, whether to renovate or demolish. Calculations were carried out – the thermal transmittance of the envelope structures was calculated based on the construction information, and the linear thermal transmittance of geometrical thermal bridges was calculated by using the software Therm. Field tests performed - the thermography and the air leakage of the building was found by standard blower-door test. Specific air leakage rate qE50=11.1 m3/(hm2) was estimated. A renovation solution was offered considering the need for extra insulation and airtightness. The dwelling energy performance indicator was reduced from the existing 279 kWh/(m2y) to 136 kWh/(m2y). For significant energy efficiency improvement deep renovation measures must be used and the question was whether it is rational. Before making the final decision, several aspects have to be considered: 1) emotional – the demolition or renovation of somebody’s home, 2) environmental aspects and resource-efficiency – the possibilities of the reuse of materials.

scholarly journals Full-scale Studies of Improving Energy Performance by Renovating Historic Swedish Timber Buildings with Hemp-lime

2019 ◽  
Vol 9 (12) ◽  
pp. 2484 ◽  
Author(s):  
Paulien Strandberg-de Bruijn ◽  
Anna Donarelli ◽  
Kristin Balksten
Keyword(s):  
Energy Saving ◽  
Material Properties ◽  
Energy Use ◽  
Building Design ◽  
Energy Performance ◽  
Full Scale ◽  
Space Heating ◽  
Original Material ◽  
Insulation Material ◽  
Thermal Transmittance

With an increased focus on reducing greenhouse gas emissions, energy saving is of great importance in all sectors of society. EU directives set targets for member states to reduce energy use in buildings. Energy saving in historic buildings requires special measures, balancing energy-saving renovations against the preservation of heritage values. Traditional constructions are open to vapor diffusion and generally work differently from modern constructions. Modern materials in traditional constructions sometimes damages the original material as they are usually diffusion-tight. The aim of this study was to investigate whether hemp-lime could be used as an insulation material to improve the energy efficiency of historic timber building envelopes with a rendered façade in Sweden. The objective was to determine the actual energy savings for space heating. An additional objective was to determine the actual thermal transmittance and to study thermal buffering through in-situ measurements in a full-scale wall renovated with hemp-lime. Two full-scale wall sections were constructed at the Energy and Building Design laboratory at Lund University: A traditional post-and-plank wall with a lime render (80 mm), and a post-and-plank wall with a hemp-lime render (90 mm). Energy use for space heating was monitored continuously over a period of one year. The wall with a hemp-lime render required 33% less energy for space heating than the traditional post-and-plank wall with a lime render. This was accomplished without changing the framework, appearance or material in the render and without drastically changing the hygric properties of the façade. From the gathered data, the thermal transmittance (U-values) for both walls was calculated using two different methods, one based on material properties and the other based on energy use data. For both walls, thermal transmittance based on actual energy use data during the heating period was lower than what was expected from their material properties. This indicates that more material properties than thermal conductivity and material thickness need to be taken into account when performing energy use calculations. With hemp-lime, a renovation can be accomplished without damaging the timber structure and wooden slats, and it can be done with local traditional materials and building methods with no difference in appearance to a traditional lime render. This allows for heritage values to be preserved, while also allowing the building to comply with modern standards and with increased thermal comfort and reduced energy use.

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.

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 analysis and post construction verification

2019 ◽  
Vol 38 (1) ◽  
pp. 51-67
Author(s):  
Cormac Flood ◽  
Lloyd Scott
Keyword(s):  
Case Studies ◽  
Thermal Performance ◽  
Building Materials ◽  
Energy Performance ◽  
Research Project ◽  
Content Type ◽  
Thermal Transmittance ◽  
Standard Calculation

Purpose The residential sector in Ireland accounted for 25 per cent of energy related CO2 emissions in 2016 through burning fossil fuels, a major contributor to climate change. In support of Ireland’s CO2 reduction targets, the existing housing stock could contribute greatly to the reduction of space-heating energy demand through retrofit. Approximately 50 per cent of Ireland’s 2m dwellings pre-date building regulations and are predominantly of cavity and solid wall construction, the performance of which has not been extensively investigated at present. Although commitment to thermal upgrade/retrofit of existing buildings may increase under future government policies, the poor characterisation of actual thermal performance of external walls may hinder the realisation of these targets. Thermal transmittance (U-values) of exterior walls represents a source of uncertainty when estimating the energy performance of dwellings. It has been noted in research that the standard calculation methodology for thermal transmittance should be improved. Implementing current U-value calculation methods may result in misguided retrofit strategies due to the considerable discrepancies between in situ measurements and calculated wall U-values as documented in the case studies carried out in this research. If the method of hygrothermal analysis were to be employed as a replacement for the current standard calculation, it could have significant implications for policy and retrofit decision making. The paper aims to discuss this issue. Design/methodology/approach This research project analysed a case study situated in Dublin, Ireland. The case studies offer an account of the in situ thermal transmittance of exterior walls and link these to hygrothermally simulated comparisons along with more traditional design U-values. Findings The findings of this research identify discrepancies between in situ and design U-values, using measurement, hygrothermal simulation and standard method U-value calculations. The outcomes of the research serve as an introduction to issues emanating from a larger research project in order to encourage researchers to understand and further explore the topic. Originality/value It has previously been highlighted that moisture content is linked to the increase in thermal conductivity of building materials, thus reducing the thermal effectiveness and increasing the elemental U-value. Therefore, it is vital to implement reliable prediction tools to assess potential thermal performance values. This paper presents the findings of a critical instance case study in Dublin, Ireland in which an existing west facing external wall in a semi-detached dwelling was analysed, simulated and measured to verify the elemental wall assembly and quantify thermal transmittance (U-value) incorporating the major criteria required for building performance simulation.

Design and Numerical Modelling of Prefabricated Roller Blind Lintels

2016 ◽  
Vol 861 ◽  
pp. 56-63
Author(s):  
Miloš Lavický ◽  
Jan Pěnčík ◽  
Štěpán Karlík
Keyword(s):  
Numerical Modelling ◽  
Load Transfer ◽  
Winter Season ◽  
Masonry Structures ◽  
Heat Transmission ◽  
Insulation System ◽  
Common Solution ◽  
Single Leaf ◽  
Thermal Bridge ◽  
System Solution

The prefabricated roller blind lintels have become common solution, particularly for the single-leaf masonry structures without external thermal insulation system. These lintels, representing simple system solution, are designed to interrupt thermal bridges in a place of above the window lintel and simultaneously to provide sufficient reliability of load transfer. The actual outdoor blinds contribute to increase the thermal stability in the room in summer and winter season. They prevent overheating of the room in the summer months and reduce heat transmission through a window in the winter. This paper is focused on the design and numerical modelling of the prefabricated roller blind carrier lintels solutions. Methods of elimination of the thermal bridge are demonstrated on the example of a real produced prefabricated lintel. At the same time this paper deals with its structural analysis. Analyses were carried out using the method of numerical modelling, using finite element method and computing software ANSYS.

scholarly journals Circularity concepts for offsite prefabricated energy renovation of apartment buildings

2021 ◽  
Vol 2069 (1) ◽  
pp. 012074
Author(s):  
Kalle Kuusk ◽  
Kristel Kullerkupp ◽  
Peep Pihelo ◽  
Michiel Ritzen ◽  
Ana Tisov ◽  
...  
Keyword(s):  
Window Glass ◽  
Energy Performance ◽  
Building Envelope ◽  
Full Potential ◽  
Careful Selection ◽  
Thermal Transmittance ◽  
Building Component ◽  
Materials Used ◽  
Good Possibility ◽  
Selection Of

Abstract Deep energy renovation includes the realisation of the full potential of energy performance. A circular deep renovation, which contributes to a circular built environment, is based on 100% life cycle renewable energy, and all materials used within the system boundaries are part of infinite technical or biological cycles with the lowest quality loss as possible. In the current study, the circularity potential was assessed for deep energy renovation from different aspects: circularity of materials, building component and building structure. Careful selection of materials as well as connection, position and disassembly possibilities are needed to increase the degree of circularity. This shows a good possibility to increase energy performance by using circularity principles. The window glass circularity analyse showed that, at best, the thermal transmittance of a new circular product can be more than three times lower than the original. The circular use of materials, components, and structures pose new challenges for the building physic design of building envelope structures.

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