Building Envelope Structure Research Articles

Design and Evaluation of Building Structures Planned for Harsh Conditions

The paper describes a scientific project that is solved at the authors' workplace. The scope of the project is the analysis and experimental research of fragments and details of building envelope structures designed for demanding conditions. It will be a question of determining the physical properties (thermal, humidity, energy, aerodynamic, light and other) of building structures and the internal environment of buildings, for demanding conditions. In this case, it is the conditions in the design process - the assumption of environmental conditions (climatic conditions of the exterior, conditions of the interior, such as humidity), or the effect of other conditions in the implementation and use of the building. Measurements will be performed in buildings (in situ) and in experimental conditions in the laboratory. After verifying the boundary conditions, the tools leading to virtual reality will be used in the compilation of experimental models with the help of simulation programs for the effects of individual influences. The task of the project is to analyze these influences and solve them in mutual cooperation, i.e. in the interconnection and action of individual influences (heat, light, energy and others).

New test equipment for testing the watertightness of facade structures in-situ

With the current trend of construction of high-rise buildings in urban agglomerations, ensuring watertightness of their facade structures exposed to the effects of high-intensity wind-driven rain is coming to the fore. Laboratory experimental testing of water impermeability of elements of building envelope structures and their joints is performed in the process of preparation of the facade implementation in accordance with STN EN 1027: 2002 in rain chamber equipment. Due to the fact that the quality and functional properties of the finished facade are significantly influenced by the assembly technology and work discipline in its implementation, successful testing of the facade and its components in the rain chamber may not guarantee the watertightness of the finished facade. For this reason, the investor has the opportunity to check the finished facade in terms of its hydrodynamic safety and reliability by a functional test of its watertightness according to the standard regulation STN EN 13051 Curtain walling - Watertightness - Site test. The article describes in detail the new technological device for the implementation of the in-situ watertightness test of the facade, the measurement methodology, including its functional verification on the facade of the high-rise administrative building Nivy Tower in Bratislava.

Performance-Oriented Passive Design Strategies for Shape and Envelope Structure of Independent Residential Buildings in Yangtze River Delta Suburbs

The Yangtze River Delta is a relatively developed area with many detached houses in the suburbs. Such detached houses are usually 1–3 stories high, mostly self-built by local people. Due to the lack of passive design guidance in the design and construction process, these houses’ energy consumption is usually high. At present, residents in the area use air conditioners, fans, and other electrical equipment in their daily lives. This paper takes detached houses in the suburbs of Ningbo as the research objects, through performance simulation and big data mining of a large number of generated samples, and proposes a passive design strategy suitable for the local building form and envelope structure, which can guide local housing construction.

Laboratory Testing of Small Scale Solar Facade Module with Phase Change Material and Adjustable Insulation Layer

Active building envelopes that act as energy converters—gathering on-site available renewable energy and converting it to thermal energy or electricity—is a promising technological design niche to reduce energy consumption in the building sector, cut greenhouse gas emissions, and thus tackle climate change challenges. This research adds scientific knowledge in the field of composite building envelope structures containing phase-change materials for thermal energy storage. In this study, the focus lies on the cooling phase of the diurnal gain and release of solar energy. The experimental setup imitates day and night environment. Six alterations of small-scale solar facade modules are tested in two different configurations—with and without the adjustable insulation layer on their outer surface during the discharging phase. Modules explore combinations of aerogel, air gap, and Fresnel lenses for solar energy concentration. The results allow us to compare the impact of the application of an additional insulation layer at “night” for different designs of solar facade modules. The results show that modules with an air gap provide higher heat gains but do not take full advantage of the latent heat capacity of phase-change materials.

How to minimize the embodied environmental impact of green building envelope? An automatic optimization method

Building envelopes are a key element of green building design due to the immense amount of building energy and consumables. However, the quantitative evaluation of the embodied environmental impact of the envelope structure in green buildings is limited. This study aims to minimize the embodied environmental impact of the envelope structure. First, the types of embodied environmental impacts are classified into 12 categories (global warming, ozone depletion, eutrophication, smog, acidification, criteria air pollutants, indoor air quality, human health, ecotoxicity, habitat alteration, water intake, and fossil fuel combustion) using the causal network method and the equivalent factor method. Second, a quantitative model for evaluating the embodied environmental impact is developed based on the distance-to-target approach. Third, a green building in Jiangsu Province, China, is used as a case to form a green building envelope technology checklist by considering building envelope design principles. Building for Environment and Economic Sustainability (BEES) software is used to calculate the life cycle environmental impact inventory and embodied environmental impact. Furthermore, C# programming language is used to select 25 green building envelope packages with minimal environmental impact. This study offers an indepth understanding of the embodied environmental impact of green building envelope. The developed model not only calculates the accurate embodied environmental impact of green building but also provides an effective platform for identifying and determining the best building envelope structure to minimize the environmental impact of green buildings.

Preparation, Encapsulation, and Performance Evaluation of Ternary Phase Change Materials for Building Envelope

Background. In order to make up for the defect that a single phase change material cannot meet the phase change temperature in a specific application field, three kinds of materials with higher phase change temperature are selected in this paper. Through the phase change material composite method, it was adopted to carry out step cooling curve test and differential scanning calorimetry (DSC) test, based on the second law of thermodynamics and the theory of phase equilibrium. DSC thermal analysis and Fourier transform infrared spectroscopy (FT‐IR) characterization were carried out. The phase change diatomite was used for packaging materials and durability evaluation. The results show that when TD‐MA : LA = 6.2 : 3.8, the phase transition temperature of the experimental ternary composite phase change material is 20.1°C. The adsorption of diatomite to phase change material (PCM) is only physical adsorption, and the thermal stability is good after 100 phase change cycles. The maximum mass loss rate of phase change diatomite encapsulated by phenylpropene emulsion and cement powder is only 0.65%, at last, this phase change diatomite is suitable for building envelope structure.

Energy, Economic and Environmental Assessment of Thermal Barrier Application in Building Envelope Structures

Thermal engineering requirements for building structures are becoming more and more strict. Thermal barriers (TBs) are energy-active elements integrated into the building structure in which a heat transfer medium (water or air) flows. A survey of the scientific literature on the subject points to the fact that this is a very topical and promising area of research and, so far, most studies on TBs are based on calculations, computer simulations and experimental measurements. Few studies have focused on the economic and environmental aspects of TB use. Following the research results presented by authors from all over the world, as well as our contributions in this scientific field that are described in a European patent, three utility models and scientific articles, in this study we have focused on the evaluation of the TB in terms of energy performance, economic efficiency and environmental friendliness by comparing the use of a classical envelope wall with the required thickness of thermal insulation meeting the normative requirements for thermal resistance R ((m2K)/W) and a perimeter wall with an integrated TB significantly eliminating the thermal insulation thickness. We evaluate the use of the thermal barrier using: economic indicator one, where we compare the cost of heat delivered to the TB in a structure with significantly eliminated thermal insulation and the saved cost of thermal insulation at the standard thickness; economic indicator two, where we compare the cost of heat delivered to the TB in a structure with significantly eliminated thermal insulation with the potential gain from the sale of the useful area of the building gained compared to the area at the normative thickness of thermal insulation; and economic indicator three, where we compare the cost of heat delivered to the TB in a structure with significantly eliminated thermal insulation with the cost of grey energy at the normative thickness of thermal insulation. Based on a parametric study based on theoretical assumptions, it can be concluded that the thermal barrier shows a very promising and efficient solution in terms of the evaluation of economic indicators one to three, which are even more significant if we use heat for the TB from renewable energy sources (RES) or waste heat.

Analysis of wind-driven rain characteristics acting on building surfaces in Shanghai based on long-term measurements

Wind-driven rain (WDR) is a critical boundary condition for the thermal and moisture coupling calculations of buildings, and understanding its distribution patterns on facades helps to better design building envelope structures and reduce humidity-induced problems. Given that WDR research in China is limited to a small number of numerical simulations, with field measurement data especially lacking, long-term and high-time resolution WDR measurements on a building module were launched in Shanghai. This research aimed to explore the WDR characteristics of building facades under meteorological conditions in the Shanghai region and compare the accuracy of existing semi-empirical models of WDR through measurements. The results show that when the angle between the inflow wind direction and the vertical direction of the wall facade increased, the WDR capture ratio decreases, and the increases in rainfall amount and wind speed contributed to an increase in WDR amount. The measurement relative errors had a negative exponential relationship with the WDR amount in this research. Compared to non-rainy conditions, the temperature during rainfall was 4.0–5.6 °C lower, and relative humidity was 9.8–21.8% higher. WDR results were compared with two semi-empirical models, which indicated that the ISO model was 0.5–0.8 times that of the measured values, while the ASHRAE model was 1.3–2.4 times greater. The collected data can provide a valuable and unique reference for WDR semi-empirical models and computational fluid dynamics simulation validation in China.

Circularity concepts for offsite prefabricated energy renovation of apartment buildings

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.

Enhancing building energy efficiency using a random forest model: A hybrid prediction approach

The building envelope considerably influences building energy consumption. To enhance the energy efficiency of buildings, this paper proposes an approach to predict building energy consumption based on the design of the building envelope. The design parameters of the building envelope include the comprehensive heat transfer coefficient and solar radiation absorption coefficient of exterior walls, comprehensive heat transfer coefficient and solar radiation absorption coefficient of the roof, comprehensive heat transfer coefficient of outer windows, and window-wall ratio. The approach is applied to optimize the design parameters of the building envelope structure of a university teaching building in northern China. First, a building information model of a teaching building is established in Revit and imported into DesignBuilder energy consumption analysis software. Subsequently, a data set of the abovementioned 6 parameters is obtained by performing orthogonal testing and energy consumption simulations. On this basis, an RF model is used to predict building energy consumption and rank the importance of each parameter, and the Pearson function is used to evaluate the corresponding correlations. The results show that the most important parameters with the highest correlations to building energy consumption are the comprehensive heat transfer coefficients of the exterior walls and outer windows and the window-wall ratio. Finally, the RF prediction results are compared to the prediction results of a BP artificial neural network (BP-ANN) and support vector machine (SVM). The findings indicate that the RF model exhibits notable advantages in building energy consumption prediction and is the optimal prediction model among the compared models.

The Effect of Energy Saving and Emission Reduction of Semi-External Window Installation

As an important part of passive ultra-low energy building envelope structure, exterior windows play a very important role in lighting, heat gain, and thermal insulation. Passive doors and windows are currently mostly installed externally, and high installation costs, material costs, and safety have become obstacles in the promotion of energy-saving policies. We calculated and simulated the linear heat transfer coefficient of the window opening based on the software flixopro8, and obtained the window installation position with the smallest linear heat transfer coefficient between the door and window and different wall structures and the decisive factors affecting the linear heat transfer coefficient of the door and window opening.

SmartEnergyCoating-use experience in structure of exterior wall

A study of SmartEnergyCoating for building envelope structures in a harsh climate is presented. Installation of the layer with energy-absorbing elements in the composition of walls was researched. The feasibility of application of method for energy generation and support of a stable temperature regime for the building structures, pipelines and regulating elements has been proved temperature regime for the building structures, pipelines and regulating elements has been proved.

Experimental study of the coupled wall system of pipe-encapsulated PCM wall and nocturnal sky radiator for self-activated heat removal

The coupled pipe-encapsulated PCM wall system with a nocturnal sky radiator is a novel type of building envelope structure for low energy buildings. It absorbs outdoor heat and stored it by using the pipe-encapsulated PCM inside the wall in the daytime, and the stored heat is automatically discharged into space through the sky radiator by the effect of the gravity heat pipe at nighttime. It makes full use of the natural cooling source, which can effectively reduce indoor heat gain through the envelope and improve the utilization efficiency of PCM. In this paper, an experiment platform integrating the pipe-encapsulated PCM wall module, the nocturnal radiator module, the heat pipe circulation module and measurement system together is established. The heat transfer characteristics of the wall system in four cases under the dynamic boundaries are tested, and the performances are contrastively discussed. Comparing to the wall without nocturnal radiation, the coupled wall system can well reduce the indoor cooling load and the wall internal surface temperature. The wall internal surface average heat flux can reduce 10.2 W/m2, and the cumulative indoor heat gains can reduce 29.7%. The results show the good thermal performance and energy-saving potential of this coupled pipe-encapsulated PCM wall system with a nocturnal sky radiator. With the development of new materials for enhancing the capability of radiative cooling such as the glass-polymer hybrid metamaterial, the performance of the coupled wall system may be significantly improved when these materials are used in the sky radiators.

Energy efficiency of modernization of translucent building envelope structures

The article focuses on determining the energy efficiency of the translucent structures of building envelope (TSBE) use with different lighting and thermal parameters. The expediency of replacing TSBE with more modern ones with higher thermal resistance and lower solar radiations relative penetration coefficient (SRRPC) is considered. The comparison was made taking into account the influence of TSBE parameters on electricity consumption in the office premises on the compensation of heat energy losses, as well as its savings due to the receipt of solar radiation during the heating period, the removal of excess heat during the cooling period and energy savings through the use of daylight during a year. It was found that despite the smaller glazing area and light-transmitting characteristics of configuration No. 3 (profile Veka Softline 82 with triple-glazed window 4Solar-16Ar-4-12Ar-4і), electricity savings when changing the configuration of TSBE No. 1 to No. 3 leads to energy savings of 31.7 kWh/yr with the TSBE area of 0.5 m2 to 419.5 kWh/yr at 6 m2, and when replacing configuration No2 by No3 – from 24.7 (STSBE = 0.5 m2) up to 397.2 (STSBE = 6 m2). This makes it possible to determine the energy and economic feasibility of TSBE modernization by installing metal-plastic structures with different lighting and thermal parameters.

Theoretical-experimental analysis of selected passive timber house wall

The advancing times and legislation require constant research of new progressive building envelope structures. Walls based on wooden material are perspective in this regard. These are capable of elimination the wall thickness while providing the required thermal resistance. The pavilion research of KPSU UNIZA laboratory includes this kind of wall structures intended for passive wooden houses. This paper deals with one of the researched wall assemblies in the annual operation. The measurements show that such a construction is suitable for near to zero energy buildings. It also points out that the correct design can eliminate thermal bridges in the area of the load-bearing wooden studs.

Investigation of the humidity regime of multilayer enclosing structures of buildings and structures

The article describes an approximate analytical method for calculating the moisture regime of multilayer building envelope structures. The novelty of the proposed method lies in the use an analytical dependence for determination the position of the flatness possible condensation, obtained as a result of studying the function which is the difference between the partial pressures of water vapor in the considered section the enclosing structure and the partial pressure of saturated water vapor at the extremum. The article presents the results of calculating the moisture regime of the outer wall of a residential building under construction in Samara using monolithic sandless expanded clay blocks with a density equal to 600 kg/m3. The calculation showed that during the heating period the coordinate of flatness of possible condensation in sandless expanded clay concrete, measured from the inner surface of the wall moves from 0.444 m to 0.5 m. The made assessment of moisture accumulation in the considered outer wall, both for the annual period of operation of the building, and for the period of months with negative temperatures, showed compliance with the regulatory requirements for heated rooms.

Design optimization of office building envelope based on quantum genetic algorithm for energy conservation

Designing envelope configurations of building with the low construction cost and low energy consumption is of important significance to green building. At present, there are some mature professional software for building optimization design, however, these programs run for a long time and require detailed input of building parameters, which makes the design very inconvenient. It is relatively convenient to use some optimization algorithms to optimize the design of buildings. Genetic algorithm is a common algorithm for building design optimization. However, genetic algorithm has the disadvantage of being easy to be trapped into local optimization. Based on this, in this paper, we propose a design optimal method of office building envelope based on quantum genetic algorithm. We optimize the office building envelope structure, such as walls, windows, glass curtain wall, numbers of windows, etc. to minimize the construction cost at the required energy conservation. Compared with the traditional genetic algorithm, in this paper, when using the quantum genetic algorithm makes the design optimization of office building envelope configuration at the required ENVLOAD (energy load of building envelope) value, the total window area are increased by 13.8%, which means that the natural ventilation is better; glass curtain wall ratio is increased by 14%, which means that indoor lighting is better; the cost fall by 0.7%, which means the cost is lower; the generation number to achieve convergence is reduced by 50%, which means the convergence is faster. And compared with original design, the total cost reduces by 35.3%. Compared with other literatures, the construction cost per unit area of envelope in this paper is lower and the building energy load per unit area of envelope is smaller.

Dynamic parametric models for the holistic evaluation of semi-transparent photovoltaic/thermal façade with latent storage inserts

High energy efficiency, energy autonomy, and improved living conditions are basic requirements of sustainable buildings. Advanced building envelope structures can provide these requirements. In the present paper, multipurpose façade structure designed as semi-transparent modular building-integrated photovoltaic façade with a forced ventilated cavity and enhanced heat storage capacity, using encapsulated phase change inserts installed on inner glass pane of photovoltaic module and on building envelope, is evaluated. The design of the façade structure, including simultaneous optimization of photovoltaic cell-packing factor, phase change material inserts properties, and heat transfer by convection in air gap, was based on transient modeling. A 60% photovoltaic cell-packing factor enables the highest overall energy efficiency, while phase change material inserts on the inner glass pane of photovoltaic module have no impact on diurnal photovoltaic cell efficiency. However, a phase change material layer installed on the envelope decreases the diurnal heat losses by half at solar radiation of 2200 Wh/m2 day. The energy performance of an optimized modular structure was determined via in-situ experiments; the data were used for developing dynamic approximation models of energy efficiency indicators. It was found that multiple regression models with interactions and past values can predict dynamic responses with sufficient accuracy. Depending on the heating season’s climate conditions, the developed semi-transparent modular building-integrated photovoltaic façade decreases the energy needs 40% to 55% in comparison to the reference façade with solar energy utilization efficiency in the range between 44% and 63%. This proves that such structures can contribute to fulfilling of requirements of sustainable buildings.

Experimental and numerical study on the thermal performance of polycarbonate panels

Polycarbonate panels are a specific type of transparent insulation material that can be usefully integrated in building envelope structures. As the applications for such systems are increasing, it was necessary to analyse in detail data for materials which are already available to improve their thermal performance. In this paper the experimental campaign was based on the detailed characterization of the equivalent thermal conductivity parameters of several representative polycarbonate panels. The dependence of the equivalent thermal conductivity on the temperature and different angles of inclination are analyzed. Increasing the angle of the investigated polycarbonate panels changed the thermal conductivity parameters to a very minor degree. On the other hand, the effect of temperature on the thermal properties is proved to be significant and the conversion temperature coefficient is provided in this regard. The computational fluid dynamics (CFD) numerical analysis is employed to validate three-dimensional CFD models and simulate the thermal performance of low-e panels for it to theoretically improve their overall thermal parameters. When applying low-e functionality, depending on the type of polycarbonate panel, the equivalent thermal conductivity was found to range from 0.03750 W/(m·K) to 0.04172 W/(m·K), representing a reduction ranging from 43% to 24%.

Technology for repairing and improving energy efficiency of enclosing structures of large-panel buildings of the 1-335 series

The article deals with technological and design solutions for repairs with increasing the thermal properties of wall panels of large-panel buildings of the first series of mass developments. A technology for restoring wall panels using modified structural and heat-insulating concrete is proposed. The technology of repair of gas-concrete panels increases the thermal characteristics of building envelope structures to the level close to the standard, reduces their physical wear. Analysis of repair and restoration works of gas-concrete panels with modified material showed the rationality and financial attractiveness in comparison with the method of shotcrete and subsequent insulation and installation of a ventilated facade.