Building Envelope Construction Research Articles

Preparation of high-strength waste-derived eco-friendly ceramic foam as face brick and its estimation of building energy consumption for thermal insulation

Waste-derived ceramic foams as a logical solution for the reutilization of industrial solid wastes have been prepared using red mud and fly ash, eggshell as a foaming agent, and di-sodium tetraborate as a glass former. The effect of foaming (1–5 wt %) and glass-forming (20 wt %) agents on the microstructure, physico-mechanical properties, and chemical stability of foams are investigated. The optimized product (RFE3) with a total porosity (33%) and bulk density (2.14 g/cc) reveals high compressive strength (109.75 MPa) and low thermal conductivity (0.93 W/m•K) that is suitable as a load bearing outside building block face brick. The theoretical building energy simulation model using heat balance (HBM) and cooling load temperature difference (CLTD) method has revealed that the average annual energy conservation in India is 21816 MJ. Compared with the traditional face brick, our developed high strength ceramic foam face brick with low thermal conductivity saves satisfactory building energy consumption. The present work is relevant to international research regarding environment friendly building envelope construction.

Moisture Performance Requirements for Insulation in Exterior Wood-Frame Walls without a Vapour Barrier

An increased interest has been observed, especially among architects, in constructing the building envelope without using a vapour barrier membrane of polyethene (PE) foil. An increasing interest in biogenic building materials has also been expressed, as their use, besides storing embedded carbon, can reduce greenhouse gas emissions, replacing nonrenewable building components. Further, building envelope construction without a vapour barrier reduces expenses and the difficulty of the work process, especially around joints and penetrations. This study aims to determine the most important material properties of biogenic thermal insulation materials that influence the moisture-robustness of exterior wood-frame walls constructed without a vapour barrier. A literature study was performed to examine which material parameters have the most influence on the moisture conditions in an exterior wall without a vapour barrier. Hygrothermal simulations of lightweight exterior walls were performed to investigate the significance of variations in material properties (e.g., equilibrium moisture content and vapour diffusion resistance) and determine their necessary characteristics when used as thermal insulation material in an exterior wall without a vapour barrier in internal humidity class 3 (defined in EN ISO 13788). The moisture-robustness of the construction is assessed based on the risk of mould growth in the layer between the thermal insulation and wind barrier. The study suggests that the moisture capacity of the available common biogenic thermal insulation materials does not significantly affect the overall moisture performance of the wall. Simulations demonstrate that, for the thermal insulation layer in internal humidity class 3, at least one of the following requirements must be met to ensure moisture-robustness in exterior walls without a vapour barrier: (I) high diffusion resistance of the thermal insulation and (II) high moisture capacity of the thermal insulation material at relative humidity between 60% and 90%. Commercial biogenic thermal insulation materials on the market do not meet the latter requirement.

In-use conditions of air-tightening materials applied in the air gap of ventilated building envelope constructions: A parametric study for different European climates

Materials used in the building envelope have to withstand a wide range of varying and harsh conditions over their life cycle. Particular relevance falls upon the materials used for tightening buildings, such as wind barriers and tapes, as air infiltration was found to be responsible for between 10 and 30 % of heat losses of different national building stocks in Europe. However, there is large uncertainty about the conditions a material is exposed to over a building’s service life. A validated, hygrothermal model of a zero emission office building in Trondheim, Norway was simulated with 10-year climate files from different European locations: Bergen (NO), Berlin (DE), Oslo (NO), Paris (FR), Rome (IT), Tromsø (NO), and Trondheim (NO). This was done to investigate the temperature and humidity conditions in the ventilated air gap. The results show the total and median values for temperature in the ventilated air gaps of the simulated building’s walls and roof for the investigated locations. Moreover, the maximum change compared to the previous hour and the distribution of hours in 5 °C temperature and 10 % relative humidity intervals of the roofing underlay and wall to the west are reported.

Comprehensive analysis of structural and thermal performance for the concrete and steel joints used in the assembled building

The structure joints and connection type of buildings play a decisive role in their safety and reliability. Therefore, most studies have focused on the structural performance, ignoring their thermal performance. Three common assembled concrete joints and four steel joints usually used in the assembled building were selected to study their bearing capacity, seismic performance and stiffness degradation. In addition, the temperature and relative humidity distribution of six types of envelopes were evaluated within a year and the effect of different envelope options on the linear thermal transmittance of each joint was investigated. The results show that the best structural performance of concrete joints and steel joints are the grouting sleeve joint and the cantilever section bolt connection respectively. The seismic performance of steel joints is generally stronger. Furthermore, for every 25 mm increase in AAC thickness, the overall linear thermal transmittance of the component increases by 0.02–0.04 W·m−1·K−1. On balance, the grouting sleeve joint is the optimal concrete joint in terms of both structural and thermal performance, but better damp proofing measures are necessary outside of it. Moreover, the cantilever section bolt connection is the optimal steel joint and requires better insulation measures. Interestingly, the building envelope construction of “75 mm autoclaved aerated concrete + 90 mm mineral wool + 75 mm autoclaved aerated concrete” is the best choice for matching joints.

A Shingled Glass Envelope System Constructed from Reclaimed Insulated Glass

This paper presents a new approach to the design and construction of glazed building envelopes using salvaged insulated glazing units from demolition sites or surplus supply. Typically, Insulated Glazing Units (IGUs) are sent to landfill. Contemporary Architectural glazing is floated using virgin sand melted at 1700°C, a high energy extractive process. Obsolete architectural glass sent to recycling plants is not fed back into new float glass, rather it is downcycled to products such as glass bottles. This paper introduces a pathway for reusing obsolete and irregular Insulated Glazing Units into new curtainwalls; a pathway that currently does not exist. We demonstrate that the carbon footprint of glazed curtainwall could be halved by utilizing reclaimed IGUs. The system is a high-performance enclosure with weather tight compression gaskets and overlapping IGUs for thermal insulation and operational energy advantages over typical curtainwall systems. The system involves a computational configuration process for determining the best fit assembly of salvaged glass from a digitized inventory. The shingled glass façade system could be used in various applications, ranging from corporate offices to storefronts. This paper presents a one-to-one proof of concept, made from reclaimed IGUs of irregular size, collected in Lewes (UK).

Experimental determination of the resistance to heat transfer of various building envelope constructions

The aim of the current research is to examine instruments for measuring heat flow and temperature, and to present methods for calculating resistance to heat transfer in accordance with regulatory documents. Requirements for constructions chosen as samples, and the conditions for their testing under stationary, quasi-stationary, and non-stationary conditions, are discussed. The study investigates devices for measuring thermal characteristics based on the research conducted by Yaping Cui, Jingchao Xie, Jiaping Liu, Peng Xue. An experiment performed by Chinese scientists to determine heat transfer coefficients using a naphthalene sample is analyzed. The research also presents a field experiment conducted by E.A. Gnezdilova to calculate the design characteristics of heat loss through floor constructions and building envelope constructions in direct contact with the soil. The validity and reliability of applying various methodologies are justified.

A review of building envelope constructions designed for demanding operating and climatic conditions

Under the term demanding climatic conditions in connection with the topic, we can primarily imagine the excessive overheating of buildings in summer and on the other hand the exposure of the building to low temperatures in winter. Considering the extreme climatic conditions, the design of the building requires an individual approach. First of all, it is necessary to pay increased attention to the envelope structures such as roof and perimeter walls. The building can also be affected by other extreme conditions such as solar radiation and associated excessive lighting, i.e. glare in the work environment. This topic is increasingly coming to the fore due to climate change. Summer seasons are getting warmer and this problem is getting even worse. Even in locations where this issue has never been dealt with before. The article summarizes the conducted research related to the issue of overheating and excessive lighting of buildings. It also informs about how researchers in Slovakia and different locations around the world deal with this problem.

Recycling of Mining Waste in the Production of Masonry Units

Masonry units made of clay or Autoclaved Aerated Concrete (AAC) are widely used in constructions from Romania and other countries. Masonry units with superior mechanical and thermal characteristics can improve the energy efficiency of buildings, especially when they are used as the main solutions for building envelope construction. Their production in recent years has increased vertiginously to meet the increased demand. Manufactured with diversified geometries, different mechanical and/or thermal characteristics have a high volume in the mass of the building and a major influence in their carbon footprint. Starting from the current context regarding the target imposed by the long-term strategy of built environment decarbonization, the aim of the paper is to analyze the potential of reusing mining waste in the production of masonry units. Mining waste represents the highest share of waste generated at national level and may represent a valuable resource for the construction industry, facilitating the creation of new jobs and support for economic development. This review presents the interest in integrating mining wastes in masonry unit production and the technical characteristics of the masonry units in which they have been used as raw materials in different percentages. Critical assessment framework using SWOT analysis highlights the key sustainability aspects (technical, environmental, social, economic) providing a comprehensive and systematic analysis of the advantages and disadvantages regarding the integration of mining waste as secondary raw materials into masonry units production.

Assessment of the Thermal Performance of Vertical Green Walls Using Overall Thermal Transfer Value Based BIM Simulation Method: Case Study of Residential Buildings in Sub-Tropics

Construction of multifunctional building envelopes using vertical greenery walls (VGW) has emerged as a sustainable green technology to improving cooling efficiency. To attaining the desired level of building cooling performance, VGW and overall thermal transfer value (OTTV) of the walls are useful design factors. The study aims to revise the current VGW evaluation, considering the decreased heat flux due to thermal efficiency of wall construction based on OTTV values. To achieve this, OTTV based Building Information Modelling (BIM) simulation method was proposed using Autodesk-Revit and DesignBuilder simulation based on EnergyPlus. Six wall compositions with various OTTV values of south facade for residential buildings located in sub-tropical in cooling season, were evaluated. The findings demonstrate that in the presence of a green system, a good OTTV value of the exterior walls is required for optimal performance, to keep the space within set point of cooling for long time during the cooling season. The comparisons between the bare walls and the VGW have demonstrated a great variation due to the different OTTV reached up to 6.57% and 18.44% reduction in indoor air temperature. The best combination of VGW resulted a maximum of 1.2°C reduction in indoor air temperature, with number of hours (within 28°C or less) were higher by 2506h, representing 85.59% of the overall number of hours (2928h). Overall cooling energy saving is found as 103.3kwh, representing 13.63% of the total of energy saving, and decreased the heat gained by 38.82%, representing 61.51kwh reduction during cooling season compared to base wall.

IMPACT OF ENERGY EFFICIENCY OF MODERN RESIDENTIAL AREA ON THE ENVIRONMENT

Improving the energy efficiency of facilities should reduce greenhouse gas (GHG) emissions and independence from energy imports, increase jobs and energy security, as well as encourage researchers in further research to be creative, innovative and competitive. With about 40% of primary energy consumption accompanied by 36% of greenhouse gas emissions, the construction sector is one of the largest consumers in Europe. Energy consumption of the construction sector in Serbia has a significant share in total energy consumption of 48%, 65% of which refers to energy consumption in residential buildings. The legislation on Energy efficiency in Serbia implies a specific energy consumption of 65[kWh/m2] for one apartment buildings and 60[kh/m2] for multi-apartment buildings. In this paper, a settlement with 50 apartment buildings is analyzed, impact on building envelope construction and applied heating system type to carbon and primary energy footprint is estimated using the degree-day method. Although the mentioned specific energy consumption limit is determined by national legislation, this paper tackles the benefits and costs of reducing energy and carbon footprint by reducing carbon and primary energy footprint to a value lower than the mentioned limit.

Energy-Positive House: Performance Assessment through Simulation and Measurement

This paper presents the results for the operating energy performance of the smart operation for a low carbon energy region (SOLCER) house. The house design is based on a ‘systems’ approach, which integrates the building technologies for electrical and thermal energy systems, together with the architectural design. It is based on the concept of ‘energy positive’ buildings, utilising renewable energy systems which form part of the building envelope construction. The paper describes how the building energy model HTB2, with a range of additional ‘plugins’, has been used to simulate specific elements of the design and the overall energy performance of the house. Measurement data have been used in combination with the energy simulation results to evaluate the performance of the building together with its systems, and identifying the energy performance of individual components of the building. The study has indicated that an energy-positive performance can be achieved through an integrative systems approach. The analysis has indicated that the house, under normal occupancy, needs to import about 26% of its energy from the grid, but over the year its potential export to import ratio can reach 1.3:1. The paper discusses the performance gap between design and operation. It also considers the contribution of a transpired solar air collector (TSC) to space heating. The results have been used to gain a detailed understanding of energy-positive performance.

Life-Cycle Assessment of Alternative Envelope Construction for a New House in South-Western Europe: Embodied and Operational Magnitude

The building envelope is critical to reducing operational energy in residential buildings. Under moderate climates, as in South-Western Europe (Portugal), thermal operational energy may be substantially reduced with an adequate building envelope selection at the design stage; therefore, it is crucial to assess the trade-offs between operational and embodied impacts. In this work, the environmental influence of building envelope construction with varying thermal performance were assessed for a South-Western European house under two operational patterns using life-cycle assessment (LCA) methodology. Five insulation thickness levels (0–12 cm), four total ventilation levels (0.3–1.2 ac/h), three exterior wall alternatives (double brick, concrete, and wood walls), and six insulation materials were studied. Insulation thickness tipping-points were identified for alternative operational patterns and wall envelopes, considering six environmental impact categories. Life-cycle results show that, under a South-Western European climate, the embodied impacts represent twice the operational impact of a new Portuguese house. Insulation played an important role. However, increasing it beyond the tipping-point is counterproductive. Lowering ventilation levels and adopting wood walls reduced the house life-cycle impacts. Cork was the insulation material with the lowest impact. Thus, under a moderate climate, priority should be given to using LCA to select envelope solutions.

Fire induced pressure in airthigh houses: Experiments and FDS validation

The need for sustainability and smaller ecological footprint lead to the construction of more airtight building envelopes with better thermal insulation in order to increase the energy efficiency of houses, according to the Energy Performance of Buildings Directive. The specific fire hazards possibly associated with such structures raised questions amongst fire community in Belgium. A full-scale experimental facility was built in the region of Mons to study the effects of both the airtightness of the building envelope and the mechanical ventilation on fire hazards and especially on fire induced pressure.Two different ventilation duct configurations were tested: one with mechanical ventilation on, the other one with the ducts closed with an airtight metal cap, the mechanical ventilation being off. Measurements were made for gas pressure, mass loss rate, gas temperature, volumetric flow rate in the ducts and for some tests O2, CO2, CO and THC concentrations were also quantified.Pressure peaks from 870 to 2035 Pa were measured without mechanical ventilation (ducts closed), while values from 420 to 750 Pa were observed with the mechanical ventilation on. The mechanical ventilation network is not sufficient to prevent pressure inside the rooms. The occupants may not succeed in escaping during a period of several minutes due to the impossibility to open inward opening doors linked to this fire induced pressure.This experimental campaign was also used for validating the field model FDS version 6.5.0 predictive capability. The effective loss coefficients of the HVAC system were calculated from all the components of the ventilation network without the need of estimation from initial pressure data. Moreover, the variation of the effective leakages area of the setup as function of fire induced pressure has to be taken into account in the pressure zone modelling in order to obtain satisfactory simulation results compared to the experimental measurements. Consequently, in addition to classical blower door tests, pressurization tests up to 600 Pa were also carried out in order to measure the effective leakages area as function of pressure according to ASTM E779. This new capability was implemeted by the developers of FDS since the 6.5.0 version. The use of validated software could be helpful to take into account the fire-induced pressure in confined dwellings in fire safety design.

BUILDING MATERIALS FOR THERMAL PERFORMANCE RETROFITTING OF AN OFFICE BUILDING SKIN UNDER CONTINENTAL MEDITERRANEAN CLIMATE

In the context of optimizing the buildings energy consumption, the improvement of the parameters of nonperforming building skins may allow a greater energy efficiency and optimize indoor comfort conditions. This is greatly function of the building envelope construction materials characteristics. In effects, the building skin may contain weak points for heat exchange due to poor or missing insulation, provoking significant energy loss. To meet to such a problem, retrofitting strategy can be adopted for reducing energy loss in existing buildings through appropriate materials. For this study, the thermal behavior and envelop performance of an office building was investigated by means of infrared thermography. This provided clear evidence of thermal leaks. Subsequently, a numerical simulation was carried out using TRNSYS software in order compare the cooling and heating needs, first, at actual building, and then after applying a Rockwool external insulation together with energetic performant windows. The results show 28% of energy savings.

A Comparative Study of Traditional and Contemporary Building Envelope Construction Techniques in terms of Thermal Comfort and Energy Efficiency in Hot and Humid Climates

Expectations of traditional and contemporary buildings are different in terms of thermal comfort. Traditional buildings mostly achieve comfort through passive means, without HVAC support, but old levels of thermal satisfaction do not meet today’s expectations, although their passive thermal performances are notable for contemporary building designs. In this regard, the current study tries to investigate the possibility of comparing traditional and contemporary buildings’ construction techniques to achieve thermal comfort from an architectural point of view. In other words, is it possible to achieve passive building design by considering vernacular architecture principals as a reference? Likewise, how well can architects define insulation layers in contemporary construction surfaces in hot and humid climates? To this end, a dynamic, numerical, thermal calculation case study has been modeled in Famagusta, Northern Cyprus, to answer the above-mentioned questions. A mixed-use mode benefitting free-run periods is proposed and compared with a mode providing 24 hours of air-conditioning in different scenarios using the same initial settings. Thus, different floor-to-ceiling heights, insulation placements and indoor conditions have been tested separately in both winter and summer periods. The results show that thermal comfort can be achieved in free-run periods only during a limited percentage of the year. Furthermore, although increasing building heights may lead to a rise in the free-run periods, in contemporary buildings it increases the total energy usage of the buildings between 6% and 9% in the mixed mode. Therefore, vernacular architecture strategies are proper in their own context. However, this energy usage can still be controlled and optimized by such considerations as insulation material placement. In this regard, the best envelope properties for different building functions are proposed for application in hot and humid climates.

Enhancing Validity of Green Building Information Modeling with Artificial-neural-network-supervised Learning - Taking Construction of Adaptive Building Envelope Based on Daylight Simulation as an Example

Enhancing Validity of Green Building Information Modeling with Artificial-neural-network-supervised Learning - Taking Construction of Adaptive Building Envelope Based on Daylight Simulation as an Example

The Use of Products Recycled from Municipal Waste in Sustainable Architecture

Analysis of the use of products recycled from municipal and construction waste as a substitute of products from non-renewable sources. Current legislation on waste management in Slovakia. The process of manufacturing materials from recycled municipal waste and its environmental benefit to society. The products from recycled municipal and construction waste used in building constructions. Model verification of their application in building envelope construction. Their use as thermal, acoustic, and fire protection of wood-based buildings. Physical characteristics of model lightweight building envelopes assessed using mathematical and simulation solutions. Environmental comparison of a common solution for envelope construction with a solution using recycled waste products.

Critical Analysis of in situ Performance of Glass Fiber Core VIPs in Extreme Cold Climate

Glass fiber core vacuum insulation panels (VIPs) are becoming an increasingly attractive option for building envelope construction due to lower cost and availability around the world. Although fumed silica core VIPs have shown superior long-term performance under accelerated aging tests compared to glass fiber core VIPS, these laboratory test results have yet to be verified with long-term field performance data. In 2011, glass fiber core VIPs were installed in a commercial building retrofit project in Yukon, Canada (one of Canada’s most northern territories), and have been continuously monitored since. This paper summarizes the thermal performance of the glass fiber core VIPs over the period of 2011 – 2018 in an extreme cold climate. Findings from this study provided data to validate glass fiber core VIP accelerated aging test results and the aging rate of VIPs in a cold and dry climate was determined. These results will help developing a better understanding of the long-term performance of glass fiber core VIPs in a real-world context.

Mechanical Tests on Innovative BIPV Façade Components for Energy, Seismic, and Aesthetic Renovation of High-Rise Buildings

The paper shows the results of mechanical tests carried out on prototypes of a new Building Integrated Photovoltaic (BIPV) component developed by the author and SBskin Smart Building Skin s.r.l. This patented innovative component is able to merge structural function, insulation proprieties, and production of clean energy for retrofit actions and/or the construction of translucent façades in high-rise buildings located in different climatic contexts. Due to colored PV cells integrated into 3 Dimensional (3D) glass components and the dry-assembly system used for assembling them into precast and pre-stressed panels, an easy and creative customization of the product is allowed. Green energy production, safety, and energy efficiency of buildings can be assured in accordance with the environmental conditions and users’ needs. The pre-stressing force used to improve the mechanical resistance of the panel toward horizontal forces due to winds and earthquakes guarantees the construction of secure translucent and active building envelopes. The paper summarizes the features of this innovative and patented BIPV product by focusing on its mechanical behavior. Laboratory tests are described and commented for underlining the benefits derived from the use of the dry-assembly system and of the supporting structure made of plastic for the construction of the panels. Bending and breaking strength tests have been carried out on two sq.m of panel prototypes, which have been dry-assembled through a supporting structure made of Polypropylene (PP) in order to compare the results with the theoretical calculations derived from the Finite Element (FE) simulations. Cyclic mechanical testing of the panel has been also carried out to verify its behavior under cyclic loading and understanding its ability to counteract the actions of the wind and earthquake.

Overpressure induced by fires in airtight buildings

The need for sustainability and smaller ecological footprint leads to the construction of more airtight building envelopes with better thermal insulation in order to reduce the pollution and increase the energy efficiency, according to the Energy Performance of Buildings Directive (EPBD 2010/31/EU).The specific fire hazards possibly associated with such structures raised questions amongst fire community in Belgium. Consequently, in 2010 the Belgian Ministry of Interior funded a study about the fire hazards possibly associated with Passive Houses in comparison to traditional houses. The University of Mons and ISSeP used zone modelling for investigating how much the characteristics of a passive house such as airtightness, ventilation and thermal insulation could affect the fire development. A significant difference in pressure rise (due to thermal expansion of fumes) was observed because of the airtightness in the passive house. However, due to a lack of validation from experimental data at large scale, the scientific monitoring committee of the project decided to not mention the potential problem that the forces of pressure could block the occupants during a certain period due to inwards-opening doors.It was decided in 2015 to build a full-scale experimental facility in the region of Mons with the support of the KCC centrum and the Régie Provinciale du Hainaut. This facility was designed with the support of the Ghent University. The inner dimensions of the construction are the same as the inner dimensions of a 40-foot shipping container, but the outer shell consists of 20 cm concrete blocks and the inner shell is made of plaster board. The volume is divided into two rooms, which simulate two different rooms of a passive house. In one room air is extracted, while in the other one fresh air is supplied.In this study, we present the tests carried out in this facility by burning pallets stack and wood cribs. Two different ventilation duct configurations were tested: one with mechanical ventilation on, the other with the ducts closed with an airtight metal cap (the mechanical ventilation being off). Measurements were made for gas pressure, mass loss rate, gas temperature, volumetric flow rate in the ducts and for some tests O2, CO2, CO and THC concentrations were also quantified. Over pressure peaks from 850 to 2035 Pa were measured without mechanical ventilation (ducts closed), while values from 420 to 750 Pa were observed with the mechanical ventilation on. Both the reverse flow of the fan supplying fresh air and the extra flow rate of fumes in the extraction duct due to the overpressure inside the apartment were not sufficient to prevent overpressure inside the rooms. These tests confirm there may be problems of overpressure in very airtight houses such as passive houses in case of fire. Especially, the occupants may not succeed in escaping during a period of several minutes due to the impossibility to open inward opening doors. This experimental study confirms the observations carried out during the reconstruction of the fire which occurred during the night of the 5 February 2013 in an passive apartment in Cologne, the occupant being blocked for about 2 minutes.This experimental campaign was also used for validating the zone model CFAST predictive capability. The way to take into account the effective leakage which depends on the overpressure inside the building as well as the mechanical ventilation in CFAST for obtaining satisfactory simulation results are briefly presented in this paper. The use of validated software could be helpful to take into account the fire-induced overpressure in confined dwellings in fire safety design.