Double Skin Research Articles

Integration of Daylight Use and Analysis in Double Skin Facades: A Literature Review

Double skin facades (DSF) aim to save energy reducing the heat losses in buildings. They are visually appeal while allowing to use daylight efficiently. Such facade systems can reduce glare and distribute daylight evenly in the interior when compared to conventional facade systems. That is a result of cavities between two glass facades and locating sunshading elements in them, although this system provides a high level of transparency. As their primary purpose of application is to ensure thermal performance and ventilation, most studies in literature have focused on these. However, to construct and maintain a holistic point of view in building performance, researchers and professionals need to take into account the integration of daylight use and analysis in such facades. This study aims to analyse daylight performance implemented studies in relation to these systems and presents a comprehensive and recent review on integration of daylight use and analysis. Recent studies are shown in tabulated form and interpreted in detail with graphics. considering their methodologies, daylight parameters and findings. Results show that the daylight parameter is one of the most important issues that architects or designers should consider from the moment they start the design, and they should make their designs based on the optimum penetration of daylight into the building. This review can contribute to literature in calling attention to daylight studies in DSF. It provides feedback information on how recent researches and technological developments in DSF can let them benefit from daylight more efficiently. That makes more and further improvements in such facade system design. Thus, DSF helps to build an integrated building performance approach in achieving sustainability.

Experimental study on racking resistance of timber double-skin façade elements

The use of double-skin façade (DSF) is a quite new approach in building renovation process, complementing conventional renovation strategies. A double-skin facade is an envelope wall construction that consists of two transparent surfaces separated by a cavity and can essentially improve thermal and acoustic resistance of building envelope. Main double-skin wall components are usually composed of hardened external single glazing pane and internal three-layer insulation glass unit (IGU) which are rigidly bonded to the frame structure. Recently, many studies have analysed thermal and acoustic performance of DSF elements, but practically none in a sense of structural behaviour, especially in determination of racking resistance of such wall elements. Moreover, in terms of reduction of global warming potential, an eco-friendly timber frame instead of common used steel, aluminium or plastic frame is investigated in this analysis. The developed load-carrying real-size composite timber-glass DSF wall elements are subjected to experimental racking test using two different types of adhesives (polyurethane and epoxy) and consequent bonding type alternatives of connecting the internal three-layered thermal glazing to the timber frame. The obtained results for the maximal fracture force and racking stiffness are compared with previously tested prefabricated timber-glass wall elements using a single-skin three-layered thermal insulating glazing only. The results evidently demonstrate that this new approach of prefabricated load-bearing double-skin façade elements can essentially improve racking resistance and stiffness comparing with previously studied timber-glass wall elements and can thus be fully recommended especially in structural renovation process of old buildings. However, a lot of parameters still significantly effect racking resistance of such elements and thus have to be further numerically or parametrically investigated.

Applying Natural Ventilation for Commercial Buildings With Atrium: Indoor Environment Prediction and Outdoor Pollutant Impact

Abstract The use of natural ventilation for commercial buildings becomes ever attractive due to the potential for economic savings and increased occupant satisfaction. However, it has proven to be particularly challenging to predict the indoor air temperature and airflow distribution from natural ventilation in more complex building geometries such as those with an atrium. This study used the energy-simulation-coupled computational fluid dynamics (CFD) method to predict the indoor temperatures of a typical multi-story, open-floorplan office building with a central atrium. The prediction accuracy using CFD was slightly improved for the periods with extreme outdoor conditions, where large temperature disparities often occur between simulation and experiment. For the tested cases, adjustment of window opening sizes seems to have marginal impacts on the simulation results. This paper further explores the impacts of outdoor gas-phase pollutants on indoor air quality of such a naturally ventilated commercial building with an atrium. A few architectural features such as window blockers and double skin façade (DSF) designs were numerically investigated for their performance to lower the indoor pollution levels while still maintaining adequate building ventilation rates. The results reveal that the features affecting the wind patterns around and above the building have a strong influence on the contamination rates on each floor of the building. DSF can not only reduce indoor pollution levels but also reduce the ventilation rate. When a pollutant source is not close to the building, a conventional central atrium design is preferred for better ventilation rates.

Testing, numerical analysis and design of CFDST cross-sections with square stainless steel outer tubes in bending

The structural performance and design of concrete-filled double skin tubular (CFDST) cross-sections with square stainless steel outer tubes are studied herein. A total of 17 four-point bending tests on CFDST cross-sections with varying concrete grades, together with accompanying material tests, were first conducted. The details of the test rig and procedures, as well as the key experimental results are reported. Following the physical testing, a numerical modelling campaign was carried out. A finite element (FE) model was initially validated against the tests, and then adopted to conduct a parametric study to acquire further FE data, covering a broader spectrum of material strengths and cross-section slendernesses. The obtained test and FE results were used to evaluate the applicability of the general design provisions for concrete-filled carbon steel members in the current European and American design codes. Overall, the examined design codes are shown to provide unduly conservative (less so for the higher concrete grades) and rather scattered moment resistance predictions, though some moment resistances predicted using the European code were on the unsafe side. Modifications to the European design treatment in relation to the assumed stress distribution, to take due account of the partial spread of plasticity in the outer tube, and the effective compressive strength of the concrete infill, to reflect the reduced relative effectiveness of using higher concrete grades, are proposed and shown to improve the consistency of the resistance predictions.

Performance analysis of transparent BIPV/T double skin façades integrated with the decision-making algorithm for mixed-mode building ventilation

ABSTRACT This study addresses building performance profiles of building-integrated photovoltaic/thermal double-skin façades (BIPV/T-DSF) integrated with the decision-making for the opening control algorithm in the mixed-mode building ventilation system. Three cases were generated and simulated in this study. The integrated case (a focused case) indicated its potential in comparison with two other fixed single-mode ventilated BIPV/T-DSF cases (non-ventilated cavity and cavity ventilated BIPV/T-DSF cases). The mixed-mode building ventilation algorithm was logically generated and implemented in the integrated case to maximize passive heating and cooling while reducing energy consumption, increasing the indoor thermal comfort level, and preventing the overheating of BIPV. The temperatures of spaces used as major criteria in the developed algorithm were identified through optimization analysis. Three cities were chosen to represent three different climates: hot summer continental and cold winter climate (Daejeon, South Korea), tropical savanna (Bangkok, Thailand), and continental subarctic (Tayshet, Russia). Multi-criteria simulation results showed that implementing the logically created mixed-mode building ventilation algorithm in a transparent BIPV/T-DSF has outstanding potential to improve thermal comfort, especially during moderate weather, and somewhat reduces energy consumption compared to the two other studied cases.

Double-skin façade simulation with computational fluid dynamics: A review of simulation trends, validation methods and research gaps

Dynamic simulation of a double-skin façade (DSF) with computational fluid dynamics (CFD) can be challenging due to the lack of validated models and benchmarking datasets. Furthermore, there is a lack of consensus in the scientific community on what constitutes a successfully validated DSF model. The present review study identifies simulation trends and research gaps for DSFs simulated with CFD. Additionally, this article presents a series of CFD simulations in which key aspects of the DSF modelling are varied: 2D or 3D modelling approaches, turbulence viscosity models (TVMs), radiation models, and wall function. These simulation results are compared to the empirical data (both temperature and velocity fields) of a benchmark test with laboratory-controlled boundary conditions. This analysis shows that using the k-ε RNG model with enhanced wall treatment and surface-to-surface (S2S) radiation model yields the best results for the 2D case of natural convection flow. Moreover, it is shown that accounting for the velocity field in the validation process is essential to ensure the suitability of a model. Finally, the authors advocate for the use of selected dimensionless numbers to improve the comparability of the different DSF scientific studies. This would also help to identify relevant experimental datasets for validation and suitable CFD simulation settings for specific DSF cases.

Assessing the impact of double-skin façades on social activities of people in urban spaces using empirical and syntactical analysis

ABSTRACT Despite the fact that previous literature has validated the significant role of urban facades in the initiation of social behaviors, there is still an existing scientific gap regarding the impact of double-skin facades on the establishment of social activities within an urban context. The main objective of the present study is to scrutinize the impact of double-skin facades on the establishment of social activities. A quantitative and qualitative research method was applied using Space Syntax and empirical observations methods. A t-test was also used to compare the independent groups using the SPSS software. The results indicated that the establishment of social and behavioral activities in front of double-skin facades were found to be significantly higher than single-skin facades. Meanwhile, the types of observed behaviors in front of double-skin facades were found to be more social and optional compared to those observed in front of single-skin facades. The implication of this study may contribute to urban and landscape designers, planners, and architects, and assist them in creating a more socially sustainable and walkable built environment.

Energy Efficiency in Building Based on the BIPV Panels System Used as a Double Skin Envelop in a Hot Arid Region

This paper aims to solve one of the energy issues using specific new building designs using the building-integrated photovoltaic (BIPV) panels as a double skin envelope. The BIPV system can be an innovative material for the building envelope during the design process as a: frame component, curtain wall or shading device. In addition to its power generation, the use of the BIPV can be an integrated part of the design of future envelopes and in the energy renovation of old buildings; these systems can producerenewable energy, minimize energy consumption, provide adequate indoor comfort and have less impact on the environment. As an external envelope of the buildings and a source of energy, the BIPV systems can represent the architectural appearance and aesthetic arrangements of the future building. Our investigation is based on an Energy report in many existing office buildings in a hot arid region of Algeria in order to assess their energy consumption, thereafter; calculate the energy yield after the BIPV hypothetical use in building architecture. The important result shows that the BIPV system enhances energy consumption with different percentages of the total energy consumption per year (Building sample 1: 50%, Building sample 2: 30% and Building sample 3: 65%) this is due to many architectural elements; such as: envelop form, shading devices, opening ratio, and environment masks. The major conclusion of the research reveals that The BIPV systems can preserve the architectural aesthetic appearance as well as enhancement of energy consumption.

Double Skin Façade Adoption Influencing Ventilation Performance in Educational Buildings

Double skin façades are adaptive envelopes that aim to improve building energy consumption and comfort performance. Their adaptive principle relies on the dynamic management of the cavity's ventilation flow and the shading devices, which can integrate with the environmental systems. This research demonstrates the possibility of modifying existing buildings to study unconventional building envelope solutions. Scenarios A and B show insignificantly decreasing measures in air velocity, relative humidity, and air temperature; however, Scenario C shows the most significant changes, the average air velocity increases by 45%, the air temperature drops between 5 to 8%, and the relative humidity drops between 5 to 8%. The utilization of DSF can be used to reduce solar heat gain, enhance natural ventilation, and mitigate the inefficiencies of mechanical ventilation in educational buildings. The Double Skin Façade is effective in improving parameters that are in accordance with thermal comfort.

Seismic behaviour of connections between replaceable coupling beam and double skin composite shear wall

In order to optimize the performance of hybrid coupled wall system, a novel of connections between replaceable coupling beam (RCB) and double skin composite shear walls (DSCSWs) are proposed. The seismic design of RCB-to-DSCSW connection is very important for structural safety. This study investigates the seismic behaviour of RCB-to-DSCSW connections. Two specimens with different layout schemes of embedded rebars and one with embedded steel I-beam were subjected to reversed cyclic loading. The failure process of all the specimens was basically the same, mainly by steel faceplate local buckling, weld tensile fracturing and the concrete crushing at both ends of the joint. The strength and ductility of connections were highly affected by the weld tensile fracturing and concrete crushing. At the current loading level or the next loading level of weld tensile fractured, the connection specimens reached its peak loading capacity, and then the concrete rapidly crushed. The ductility coefficients of all the specimens were smaller than those of RC structures. In addition, the mechanical properties of these two kinds of embedded rebar connections were similar. The steel I-beam connection exhibited higher initial stiffness. Under the same rotation of loading, the cumulative energy consumption of the steel beam was higher. Finally, according to the stress pattern of each component, the simplified mechanical model and calculation formulae of the connection bearing capacity were developed.

Analytical behavior and bearing capacity research on out-of-code tapered CFDST members under pure torsion and compression-torsion combination

Facing the apparent enhancement of rated power of offshore wind turbines, the increasing rotor diameter and blade length gradually pose severe challenges to its support structure for resisting extreme loads. Due to the remarkable composite effect, the recently developed tapered concrete-filled double skin steel tubular (CFDST) members can provide a high-performance structural type and competitive application prospect compared to traditional steel tower barrels. Therefore, this paper conducted the numerical and theoretical research on out-of-code tapered CFDST members under pure torsion and compression-torsion combination. The finite element (FE) model was established to examine the full-range mechanism including torque versus deformation response (T-θ curve), interaction behavior and component contribution, indicating that four characteristic points can distinguish the T-θ curve under pure torsion, and slight contact pressure between the inner tube and sandwich concrete exists along the height direction. The parametric study was performed to investigate the influences of geometric-physical parameters, e.g., by increasing tapered angle (ψ) 0.2°, the torsional capacity obtains a reduction of 5%; hollow ratios (χ), axial compression ratios, and diameter-to-thickness (D/t) ratios of double-skin tubes obviously affect the torsion resistance; altering steel yield grade influences torsional capacity than concrete grade. Subsequently, a theoretical multilayered cylinder model as the simplified design tool was proposed to simulate full-range T-θ curves of tapered CFDST members. Moreover, a modified design method for calculating N-T correlation curve was developed and validated by introducing the refined equations of pure torsion resistance (Tu), where the design methods in current codes displayed a quite conservative prediction for tapered CFDST members with out-of-code parameters (e.g., hollow ratios or D/t ratios). The above research on out-of-code tapered CFDST members can offer valuable design guidelines for its engineering applications.

Endurance Strength and Residual Life Assessment of T23 Steel after 96000 Hours of High Temperature and High Pressure Service

The macroscopic morphology, oxide layer characteristics, rupture strength and residual life of T23 steel after 96000 hours of service at high temperature and high pressure were analyzed. The results show that T23 steel pipe has good macroscopic appearance, without obvious abnormal features such as cracks, folds, rolling breaks, double skin, scabs, delaminations and sharp scratches. The chemical composition of different pipe sections conforms to the standard, and the structure is mainly bainite, with uniform distribution and no obvious coarse phase. There is an obvious interface between the metal substrate and the internal oxide layer, and there is an obvious wavy line at the interface. The oxide layer is relatively dense and continuous. The tensile properties at room temperature and high temperature are good. At room temperature, the yield strength exceeds 420MPa, the tensile strength exceeds 540MPa, and the elongation exceeds 19%. After 96000 hours of use, the remaining creep life of T23 split platen superheater submitted for inspection is 84000 hours, and the remaining creep life of T23 rear platen superheater submitted for inspection is 40000 hours.

Study on axial behaviour of concrete filled steel tubular columns

Concrete-filled steel tube (CFST) columns have gained wide acceptance in the construction of high-rise buildings due to their exceptional ability to withstand axial load. They are commonly employed as columns in large-span high-rise buildings, bridges, and piers. This research aims to investigate the performance of concrete-filled steel tube (CFST) columns when subjected to axial load. One key advantage is that the steel tube serves as a permanent confinement for the concrete. The concrete filling inside the tube prevents local buckling and enhances the lateral stability of the member. Moreover, the external steel tube acts as a formwork. Eight composite columns were constructed, comprising four CFST columns and four CFDST (Concrete-filled Double Skin Tubular) columns, and were subjected to axial loading for evaluation. The experimental study was conducted to determine the relationship between load, axial displacement, and lateral displacement, as well as the ultimate load-carrying capacity. Furthermore, finite element analysis using Abaqus was performed to investigate the composite columns analytically. A parametric study was also carried out, considering the diameter-to-thickness ratio and grade of concrete. Confinement significantly enhances the load-carrying capacity, and the presence of concrete infill reduces the lateral deflection of long columns.

Double-Skin Façades for Building Retrofitting and Climate Change: A Case Study in Central Italy

In recent years, the need to make the built environment more resilient and adaptable to climate change has become essential. In Europe, this aspect concerns most existing buildings with several deficiencies from the energy efficiency point of view, considering they were designed before the introduction of modern codes. Among the various strategies for building energy retrofitting, Double-Skin Façades (DSFs) have gained attention due to their potential to improve the building performance and inhabitants’ comfort. This research aims to evaluate the use of adequately designed DSFs for the energy restoration of buildings. In detail, various DSF configurations are applied to a residential building located in Central Italy and investigated under present and future climate conditions, estimated through regional climate models. The installation of multi-layered façades, particularly the Multi-Storey typology, greatly reduces energy consumption and increases the expected comfort rates. When the selected configuration was considered, the results underline a decrease in the annual building energy requirement of about 37–56% up to 42–59%, respectively, for 2030 and 2070. Moreover, using multi-layer façades can increase indoor minimum operative temperatures up to 3.8% during the coldest months and reduce the maximum summer ones by 1.9–3.8%, raising comfort levels.

Hybrid simulation test and seismic assessment of CFDST moment resisting frame

Concrete filled double skin steel tubular (CFDST) moment resisting frame is an effective structural system owing to the higher strength to weight ratio and better fire performance compared with traditional concrete filled steel tubular (CFST) structures. This paper aims to analyze the seismic response of assembled CFDST moment resisting frame with blind bolted joints by the hybrid simulation test and numerical approaches. A prototype CFDST moment resisting frame was designed and its numerical model was established by Opensees software. After the validation of the numerical model, typical failure modes and dynamic response of the CFDST moment resisting frame observed from the hybrid simulation test were detected and discussed under maximum-considered earthquake (MCE) and 2MCE levels (2 times MCE level), respectively. Detailed behavior of the columns and joints were analyzed for the prototype building. It verified that a large portion of energy was dissipated by the joints under seismic loads. Subsequently, parametric analyses were performed to study the influence of joint stiffness on the global behavior of CFDST moment resisting frames by the endurance time method. The energy dissipated by the columns and joints were investigated in detail, indicating that the energy dissipated by the joints was more than 70% of the total hysteretic energy of the frame under earthquakes. It indicated that decreasing the joint stiffness was beneficial for the joint to dissipate more energy and for protecting the column from being damaged. It also generalized that decreasing the joint stiffness had a positive contribution to the uniform story drift distribution and would not always increase the maximum story drift. The analysis results verified that the CFDST moment resisting frame exhibited excellent seismic behavior and activated the application of CFDST moment resisting in engineering practice.

Axial-flexural strength of steel-concrete composite shear walls

A predictive equation is proposed for the axial-flexural strength of rectangular and flanged Composite Plate Shear Walls-Concrete Filled (C-PSW/CF), with and without endplates and boundary elements. The proposed equation is based on plastic stress distribution, adjusted by coefficients to account for influential design parameters. The adjustment coefficients are established by a regression analysis performed on the data developed using an extensive numerical parametric study. The continuum-based finite element model used for the simulations is first validated using the available test data. The effects of various design variables, including the aspect ratio, slenderness ratio, reinforcement ratio, axial load ratio, infill concrete compressive strength, and yielding strength of the steel faceplates on axial-moment are then numerically examined. Four cross-sections, including double skin plate, double skin plate with endplates, double skin plate with boundary elements, and double skin plate with flanges, are considered. The results are used to develop a new predictive equation to obtain the flexural strength of C-PSW/CFs in presence of axial loading. The proposed equation is finally validated using the experimental test data and its accuracy is evaluated by comparing it to available predictive equations and the method proposed by the 2016 AISC Seismic Provisions. The results show that the proposed design equation can well predict the flexural moment capacity of C-PSW/CFs with various cross-sections in presence of axial loading.

REVIEW PENERAPAN SHADING DEVICE PADA DOUBLE SKIN FAÇADE UNTUK KENYAMANAN TERMAL DAN EFFISIENSI ENERGI BANGUNAN

The application of Double Skin Façade on the building envelope as an effort to save energy and increase thermal comfort, has been carried out for several decades. The application of DSF design parameters needs to be considered to achieve maximum energy savings and thermal comfort. A shading device as one of the parameters in the DSF not only functions as a shade but can also reduce heat entering the room. This study focuses on the effectiveness of applying a shading device in the DSF cavity for thermal comfort and energy efficiency of buildings. The literature review method was used to review previous studies that had been carried out, by examining the shading parameters to see their effect on comfort and energy savings. The results show that the positioning of the shading device can reduce energy use and increase thermal comfort significantly.

Axial compression performance of square concrete filled double skin SHS steel tubular columns confined by CFRP

This paper focuses on the axial compression performance of 15 concrete-filled double skinned tubes CFDST columns with different CFRP reinforcement schemes. The design of this test used an outer square steel tube with a square steel tube inside, with concrete poured at the sandwich and the inner steel tube kept hollow. The structure is both cost effective and allows the hollow to be used for utility access. However, in recent years damage to CFDST has occurred due to fire, earthquakes, corrosion etc. Therefore, research into the reinforcement and repair of this structure is crucial. Compared to other reinforcement methods, FRP has the advantage of being lighter and more robust and does not significantly alter the original structure. In this study, the mechanical properties of the specimens were further analyzed from the data of load displacement, peak load and ultimate displacement by mainly observing and analyzing the damage mechanism of the specimens through the strengthening effect of different strengthening schemes for different hollow ratios. The results show that when the hollow ratio is not bigger than 0.33, the CFRP reinforcement effect is relatively obvious, especially the three-layer CFRP wrapped CFDST specimens have a substantial increase in bearing capacity and stiffness. Finally, an analytical study was carried out based on previous research and the experimental results agreed well with the calculated results.

Experimental and numerical investigation on hysteretic behavior of posttensioned precast segmental Concrete-filled double skin steel tubular piers

The posttensioned precast segmental concrete-filled double skin steel tubular (CFDST) piers proposed in this study combines the advantages of posttensioned precast segmental piers and composite CFDST piers, in such way to reduce on-site construction burdens, increase section modulus, and reduce self-weight. To investigate the hysteretic behavior of this new type of bridge pier, one posttensioned precast segmental CFDST pier was designed and tested under cyclic lateral loading, with one cast-in-place CFDST pier as reference. Test results show that the proposed posttensioned precast segmental pier performs well with good ductility, satisfactory energy dissipation, and small residual displacement. The damage to precast segments is effectively avoided by using CFDST members. Moreover, a numerical study was also conducted to investigate the influences of different design parameters on the hysteretic behavior of posttensioned precast segmental CFDST piers. The design parameters studied in this paper included the pier aspect ratio, amount of energy-dissipating (ED) bars, axial load ratio due to gravity, axial load ratio due to prestressing force, initial stress level in prestressing strands and CFDST cross-sectional parameters. It has been found that the amount of ED bars, axial load ratio due to gravity and axial load ratio due to prestressing force are the more important factors on energy dissipation and self-centering capacities. The pier aspect ratio being greater than 7 has a negative effect on residual drift ratio of posttensioned precast segmental CFDST piers due to P-Δ effect. The initial stress level in prestressing strands has little effect on energy dissipation and self-centering capacity, but influences the failure mode and deformation capacity.

Slenderness limit for inner tubes with internal stiffeners in DSSTCC columns

In recent years, composite columns have gained much attention in offshore and marine engineering. This paper, with the motivation of a better design for circular straight double skin steel tubes confined concrete (DSSTCC) columns, theoretically explores the local buckling of the internally stiffened inner skin in this column. Firstly, the force analysis of a DSSTCC stub column was conducted, and its common failure modes were outlined. Based on the similar structural performance of the inner tube and the fixed circular arch, a concise buckling analysis model was built up. Then different buckling modes of clamped circular arches under the uniform radial load were presented. The ultimate load-carrying capacity of internally stiffened inner tubes under different buckling modes was also discussed, which shows relatively high dependence on the structural stability. Next, the calculation method of the expected ultimate hoop compressive stress was given, and the main computational procedure of the cross-sectional slenderness limit for internally stiffened inner skins was illustrated. In addition, a very simple prescriptive equation that considers the elastic modulus, the yield stress, and the formed arch's central angle value was fitted to estimate the cross-sectional slenderness limit for inner tubes with internal stiffeners, with which a slender cross-section can be delineated from an effective one. Meanwhile, the elastic buckling stress of the inner tube was also given. Finally, the applicability of the proposed methodology to materials with the bilinear model, the bilinear plus nonlinear hardening model, the idealized multilinear model, or the Ramberg-Osgood model was investigated, thereby demonstrating its good adaptability to these four common nonlinear constitutive models.