Window Wall Research Articles

Cycle Performance of Aerated Lightweight Concrete Windowed and Windowless Wall Panel from the Perspective of Lightweight Deep Learning.

This paper aims to explore the seismic mechanical properties of newly developed fabricated aerated lightweight concrete (ALC) wall panels to clarify the interaction mechanism between wall panels and structures. It first introduces the lightweight deep learning object detection algorithm and constructs a network model with faster operation speed based on the convolutional neural network. Secondly, combined with the deep learning object detection algorithm, the quasi-static loading system is adopted to conduct the repeated loading test on two fabricated ALC wall panels. Finally, the hysteresis load-displacement curve of each test is recorded. The experimental results show that the proposed deep learning algorithm greatly improves the operation speed and compresses the model size without reducing the accuracy. The lightweight deep learning algorithm is applied to the study of the slip performance of the wall plate. The pretightening force of the connecting screw characterizes the slip performance between the wall plate and the structural beam, thereby affecting the deformation response of the wall plate when the interstory displacement increases. The hysteresis curve of the ALC wall panel has obvious squeezing effect, indicating that the slip of the connector can unload part of the external load and delay the damage of the wall panel. The skeleton curve suggests that the fabricated windowless ALC wall panel has higher positive and negative initial stiffness and bearing capacity than the fabricated windowed wall panel. However, the degradation analysis of the stiffness curve reveals that the lateral stiffness deviation of the fabricated windowless ALC wall panel is more obvious. It confirms that the proposed connection method based on the lightweight deep learning model can improve the seismic performance of ALC wall panels and provide reference for the structural analysis of embedding fabricated ALC wall panels. This work shows the important practical value for exploring the application effect of embedded ALC wall panels.

Selection of Energy Improvement Factors and Economic Analysis of Standard MDU Complexes in Korean Metropolitan Regions

In Korea, energy consumption within apartments in metropolitan areas accounted for more than 33% of the total energy consumption by buildings in 2020. In this study, in order to increase the energy efficiency of MDU (multi-dwelling unit) complexes in metropolitan areas, improvement factors and economic effects were analyzed using ECO2, a building energy efficiency evaluation program. Optimal improvement measures are proposed, to reduce the economic burden on users by applying energy saving technologies. This study was conducted in four stages; in the first stage, using ECO2 software, five types of apartments were selected as standards among 46 complexes. Standard MDUs were selected if more than two factors were satisfied from among the following: (1) household type, (2) average exterior wall insulation and window performance, (3) average energy consumption and demand per unit area per year, (4) average applied facility system, and (5) average monthly energy demand per unit area. In the second stage, improvement factors were derived by analyzing the 10 most recent energy efficient MDU complexes. The third stage involved analysis of the energy saving effect generated by the improvement of windows and total heat exchangers in five selected complexes. Primary energy consumption per unit area per year improved from 158.8 to 132. kWh/m2y in complex E, which had been upgraded from ‘floor heating system’ to ‘total heat exchanger’. Finally, in the fourth stage, optimal improvement factors were selected for economic analysis. By simultaneously applying the optimal improvement factors, such as windows and total heat exchanger, to the M complex, primary energy consumption per unit area per year was improved from 147.6 to 111.4 kWh/m2 y. When optimal improvement factors were applied to 59 m2, 74 m2, 84 m2 types in complex M, life cycle cost savings of energy consumption for 30 years became $1384~1970.

Airtightness of Nepalese Residential Buildings

Experimental field measurements regarding airtightness following the fan pressurisation method were done on 25 typical residential buildings at different locations in Nepal. The field measurement data were classified according to building type and building age. The mean air permeability (Q50 ) for the studied buildings was 6.9 l/s·m2 and the mean air change rate was 55.5 air changes per hour at 50 Pa. The maximum air leakage rate (Q50 ) was 28.4 l/s·m2 for brick masonry in mud mortar type and the minimum recorded was 1.7 l/s·m2 for brick masonry in cement mortar type building. Brick masonry in mud mortar-type buildings was found to be leakier regardless of the building age, and brick masonry in cement mortar-type buildings was comparatively more airtight. Leakage locations identified through visual inspection included the spacing between the door frame and operable door area, horizontal window slider, joint areas of window frame and wall, wood plank-based wall structure, roof joint areas and holes in the wall. This research is the first of its kind in Nepal to assess the airtightness of buildings, and the outcome of this research is one of the key parameters to evaluate the thermal performance of Nepalese buildings scientifically.

기후대별 솔라사이니지 반투명 태양전지 창호 적용 사무용 건물의 에너지 성능분석

Purpose: This study analyzed building heating, cooling, and lighting energy performance and power generation performance under various climate zones in accordance with Solar Signage Semi-transparent window application. Method: American climate areas, them being tropical, desert, maritime, and microthermal, have been selected and 40%~80% window wall ratio (WWR) has been established in relation to five Solar Signage Semi-transparent windows. Designbuilder, building energy analyzation software, was used to model office building and simulate. Result: Total energy consumption presented Phoenix was highest, followed by Miami, Ann Arbor, with San Francisco being the lowest. The smaller the WWR the higher the heating energy consumption at San Francisco and Ann Arbor appeared with G1 window confirmed to be the highest. Cooling energy consumption in all four climate zones increased as WWR increased due to increase in amount of solar gain. Lighting energy consumption in all four climate zones decreased as WWR increased, with G5 showing smaller consumption than G1 due to VLT’s influence. Climate zone with the amount of energy savings on account of power generation being largest turned out to be San Francisco. Especially, possibility of zero energy building achievement in case of G1, G2 window being applied when WWR was 80% was confirmed. With the result of this particular research, to expand applicability as building exterior materials, products improved upon traits such as colour, insulation, and strength should be under continuous performance evaluation study across various foreign and domestic climate zones.

Research on Visual Preference of Chinese Courthouse Architecture Appearance

Whether courthouse architecture should be solemn or friendly is a topic worth exploring. Currently, a large quantity of courthouse buildings have been constructed in China, but the architectural style differs greatly. This situation provides a good foundation for the study on visual preference appraisal of the external form of courthouse buildings. This research selected 50 representative courthouse buildings as the research object and set architectural style, height–width ratio, window–wall ratio, and open ground in front of the buildings as the physical properties under study. Participants of different demographic characteristics were chosen to conduct a photo stimulation experiment. The results obtained were analyzed by SPSS. According to the research results, the neoclassical courthouse building with a large window–wall ratio, small height–width ratio, and large open ground is the most favorite among the participants; participants of different demographic characteristics render different visual preference appraisals of the external form of Chinese courthouse buildings. Contemporary Chinese court building should have a new image. This research can be taken as a reference for the external design of Chinese courthouse buildings.

LIGHT IN THE SACRED SPACE OF THE MODERN GREEK CATHOLIC CHURCHS

Based on domestic and foreign experience, an analysis of the natural light filling of the sacred space of Modern Greek Catholic churches in Ukraine and abroad. Similarities and differences in the formation of the light environment of the modern church, compared with the traditional one, have been establish. The architecture of Modern Greek Catholic churches in Ukraine significantly influenced by the traditions of architectural formation of other branches of Christianity. This influence manifested primarily in the organization of their lighting environment. In Modern Greek Catholic churches, there is a top light from the domes in the cover, but its share in the total flow of daylight significantly reduced. Due to the large stained glass windows in the walls significantly increases the overall illumination of the interior of the temple. Uniform arrangement of windows in the outer walls equalizes the light on the inner surfaces. Contribute to the creation of uniform illumination of surfaces used in the decoration of walls of light colors with the same brightness in the field of view. These factors indicate the convergence of the light composition of the interior of Greek Catholic churches with the interiors of Protestant churches. At the same time, partial (horizontal or vertical) or complete glazing of the walls in the altar, installation of large stained glass windows at full height in the side walls, installation of light lanterns, mostly in the roof over the altar space, bring together modern Greek Catholic churches their space with modern Catholic churches. Modern Greek Catholic churches contain many techniques of light-spatial composition that not related to the tradition already developed by the system of Ukrainian national attributes, and rather reflect the authorial style of an architect.

Using Noninvasive Depth–Sensors to Quantify Human Productivity Levels in Desk–Related Workspaces

Numerous neuroscientific studies demonstrate the interaction between movement, memory, and environmental conditions. We present a new in–the–field tool that can be used by interior designers, environmental psychologists, and architects to understand and quantify human productivity in desk–related work and study spaces. In this investigation, an interior space, equipped with a new generation of nonintrusive sensors and analytical algorithms synchronously measured multiple individuals and working groups. We tested the hypothesis that a positive correlation exists between stillness and cognitive function associated with self–reported productivity. We explored, which design attributes, Seat Orientation, Zones, Table Crowdedness, and Table Types were associated with statistically significant changes in users’ self–reported productivity and micro–movements. A mathematical model was developed to map a “stillness value” for each person across time, deriving a measurable productivity factor (PF) that could be used to synchronously assess the impact of design features in multiple users. Experiments were conducted over 12 days involving 640 academic students in a semi–enclosed reading/study room within a recently built city public library with extensive views of the waterfront, harbor, and bay. Three–dimensional depth–cameras anonymously measured head and body movement while subjects worked and completed productivity surveys. Methods were validated using video recordings, sensor data, questionnaires, and observations. The results showed the PF was significantly correlated to the time spent in different Zones and was greatest at Seat Orientations furthest away from walk–through traffic and in Zones with the highest exposure to the window wall and views. Users in these settings experienced a higher and longer–lasting PF during the high–performance phase of their stay.

A Novel Method of BP Neural Network Based Green Building Design—The Case of Hotel Buildings in Hot Summer and Cold Winter Region of China

With the advent of the big data era, architectural design gradually tends to become more quantified and intelligent. This study proposes a novel green design method for energy-saving buildings based on a BP neural network. This study changed the traditional trial–error mode by evaluating energy consumption based on design performance parameters such as building shape, space, and interface. Instead, energy consumption quota values obtained from statistical data, as well as thermal parameters and energy system parameters in energy-saving standards, were taken as input parameters, and then the design scheme of building shape can be obtained through BP neural network technology. Based on data of 61 hotel buildings in a representative city among a hot summer and cold winter climate zone, the BP neural network model is established to control the building design variables, with 41 kgce/m2·a as its energy-saving design target. Through the energy consumption quota, the trained BP network is applied to predict the optimal architectural design parameters, including the building orientation angle, shape coefficient, window–wall ratio, etc., for twelve building typologies in an area range of 5000~60,000 m2. With recommended control thresholds of quantifiable architectural design elements obtained, this research can provide effective design decision-making suggestions for architects.

Impacts of Courtyard Envelope Design on Energy Performance in the Hot Summer–Cold Winter Region of China

This paper aims to investigate the effects of courtyard envelope design on the energy performance of office buildings in the hot summer–cold winter region of China. Two types of courtyard buildings were simulated with 200 energy models by changing the following variables: window–wall ratio (south, north, east, and west walls), window U-value, wall U-value, solar heat gain coefficient, and orientation. The treed Gaussian process (TGP) sensitivity analysis method was employed to quantify the contributions of parameters related to courtyard design that result in the changes of annual cooling, heating, lighting, and total energy consumption. The results show that the courtyard envelope design has a significant effect on the energy consumption in this case study. The most influential factor affecting annual cooling energy consumption and the annual total energy consumption is the orientation, which is responsible for 37% and 81%, respectively, in two layouts to annual cooling energy use. The corresponding proportion increased to 45% and 86% in terms of the total energy consumption. The most influential factor influencing annual heating energy use is the window U-value, which explained nearly 60% of the changes to the heating energy use. The effect of the solar heat gain coefficient in two kinds of layouts is as high as 82% and 79% for lighting energy use in this case study. Due to the different courtyard forms, the magnitude of the effect of the parameters on energy consumption and the main trend of the effect is slightly different.

소형 주택의 창면적비에 따른 냉방 및 난방 에너지 소요량과 시공비용 연구

As the global warming problem becomes more serious, the Korean government is putting considerable effort to reduce primary energy consumption and carbon generation by implementing relevant policies. In this study, a small-scale house with a floor area of 114.51 m2 located in Yangpyeong, Gyeonggido, Korea was selected to study the effect of window wall ratio on cooling and heating energy consumption, energy cost, and construction cost. Cooling and heating loads and energy consumption in consideration of the window design were analyzed using PHPP, an energy balance, and a passive house planning tool. The height of the east side window was fixed at 3.89 m, while the width was changed to the present Base and two alternative designs. The window areas were 18, 12, and 6 m2 for Base, ALT-1, and ALT-2, respectively. Temperature, humidity, and infiltration were measured for PHPP input values. When the window areas were reduced by 33% and 67% relative to the Base, cooling and heating energy per unit floor area were reduced by only a small amount. Similar results were obtained for heating and cooling energy costs. Our findings indicated that adopting ALT-2, the design with the least window area can reduce the construction cost by 8.5% or 7.764 million won. Therefore, unlike for the energy consumption, much higher construction cost reduction can be achieved with a small window area. This is expected to have a significant impact on the facade design according to the client

Developing climate-responsive passive strategies for residential envelopes in the warm humid climate of South India

PurposeEnergy codes for residential buildings in India prescribe design guidelines for each climate zone. However, these guidelines are broad and similar for different cities under the same zone overlooking climatic variations due to altitude, location and other geographical factors.Design/methodology/approachTo develop strategies addressing the city-specific requirements, a stepwise simulation approach was used. Integrated Environmental Solutions–Virtual Environment (IES-VE) was used to create a prototype of a singly detached residence. The applicability of strategies is studied during the day and night times. Optimum orientation, the thickness of insulation, Window–Wall Ratio, the impact of cross-ventilation and shading depth are determined for two cities – Tiruchirappalli and Coimbatore under the warm-humid climate zone of India.FindingsResults indicate that optimum insulation thickness and WWR vary between both cities during daytime and night time. In Tiruchirappalli, roof and wall insulation using polyurethane board (100 mm) and foam concrete (25 mm) offers a maximum reduction of 2.2°C indoors. Foam concrete (25 mm) insulation for roof and expanded polystyrene (25 mm) for walls reduce a maximum of 2.6°C during daytime in Coimbatore. Further, night ventilation with 20% WWR allows an average decrease of 0.5–0.6°C in triply exposed spaces facing the South. The use of a 2'0" depth shading device shows a maximum reduction of 0.1–0.3°C.Originality/valueThe contribution of this work lies in developing city-specific inputs presenting the advantage of easy replicability for other cities in the Indian context.

Daylighting Performance Design for Art Studios of Old Factory Renovation Buildings in Subtropical Regions

In the subtropical zone of China, a large number of old factory buildings rich in industrial historical and cultural value have been transformed into art studios. In the existing research on building renovation, there are still problems such as insufficient lighting, low uniformity, and ignoring the effect of glare in the lighting environment of buildings after transformation. To fill this research gap, this paper provides a daylighting design strategy for these factory buildings in subtropical zones to ensure that the transformed art studios can offer an excellent indoor daylighting environment. Through the control variable method, the window-to-wall ratio, the form of external windows, and the visible light transmittance of glass are set with quantitative and variable values, and a design strategy that meets the requirements of international general daylighting standards is obtained step by step through the simulation. The daylight factor, uniformity, daylight autonomy, and dynamic glare probability are used in this research process to measure whether the daylighting strategy meets the daylighting requirements of the CIBSE Lighting Guide for art studios. The results show that the average indoor lighting coefficient can be increased from 1.29 to 6.18, and the minimum value of the lighting coefficient can be increased from 0.4 to 4.4 by enlarging the windowed wall ratio from 1:30 to 1:3, using the combination method of the horizontal window, skylight and skylight recommended by the analysis results, and selecting veneer glass with 88% transmittance. This allows for better uniform lighting inside the building and reduces glare. This conclusion can support the lighting performance design of industrial buildings in the future.

Multi-factor optimization of energy performance in naturally ventilated building: a case study of office building in hot summer and cold winter climate

Nowadays, building energy consumption is responsible for 30% to 40% of total energy usage in many countries. The energy performance of each building is related to many factors. Most of them are determined in design stage. Meanwhile, natural ventilation is one of the most potential passive energy conservation, especially in hot summer and cold winter climate zone. This study aims to figure out how to make the most of natural ventilation in building energy conservation in hot summer and cold winter climate zone. By comparing different building design plans, this study try to provide a method to help find the best-optimized building parameters design solutions. Six main factors are selected, including: building orientation, exterior wall masonry, window wall ratio, shading overhang depth, binds slat angel(include the situation when there is no blinds at all), exterior window structure. A seven-layer office building in hot summer and cold winter zone is modelled and simulated in Energyplus. Two building running plans are compared: (a) the air conditioning system is always on during office occupancy time; (b) the air conditioning system is off when natural ventilation can guarantee thermal comfort inside the building. The results shows, plan (b) saves more than 40% energy on different building parameters designs comparing to plan (a).

Numerical study on the bearing behaviour and design of aluminium sub-heads with removable beads in façade systems

A window wall is a lightweight external wall composed of glass and aluminium, which does not carry any gravity loads from the building except for its own weight. Wind load is transferred to the main structural system through the connections of sub-frames (consisting of sub-heads and sub-sills) with slabs. An aluminium sub-head with a removable bead (ASHWRB) is a common type of sub-head consisting of two parts: a base and a bead. Under wind load, the bead flange is directly loaded by the mullion and undergoes bearing failure due to its long length. This paper presents a detailed numerical study on the bearing capacities of the ASHWRB sections subject to wind loading. For this purpose, finite element models were simulated using ABAQUS/CAE and validated with our previously conducted experimental work in terms of ultimate loads, load-displacement curves, and failure modes. Validated finite element models of the ASHWRB sections were then used for an extensive parametric study covering a wide range of thicknesses, flange widths , bearing widths, and engagement lengths. Notably, the ultimate loads obtained from the parametric study are not product nor manufacturer specific, whereas, the data obtained from experimental study is specific to the manufacturer products. The acquired bearing database was used for a detailed assessment of the consistency and reliability of the previously proposed design rules by the authors (DRA) based on the experimental tests as well as currently available cold-formed steel design rules (DRSs). It was found that the bearing capacities determined by both DRA and DRSS are unreliable for predicting the bearing capacities of the ASHWRB sections in the window wall. Thus, modifications were made to DRA and DRSS. Consequently, new design rules were proposed in this paper (DRA P ), which accurately predicted the bearing capacities and correlated very well with the numerical results. • Numerically investigated the bearing behaviour of aluminium sub-heads with removable beads in façade systems. • Considered various section geometries, bearing widths and, loading and boundary conditions. • The finite element models were validated against the previous test results and extensive parametric study were performed. • Current cold-formed steel design equations were not suitable for aluminium sub-heads with removable beads in window walls. • New design rules were proposed for aluminum sub-heads with removable beads based on the numerical results.

The effect of external airflows on ventilation with a rooftop windcatcher

This study aims to investigate how a modern style windcatcher, which is much shorter than the traditional ones, is more sensitive to the exterior flows interacting with the associated building itself. This interaction between the onset flows and building façades can influence the ventilation behaviour inside the building. Therefore, full simultaneous exterior and interior measurements are conducted in the wind tunnel around the envelope of a 1:12 generic building model with a two-sided rooftop windcatcher and a wall window. Wind tunnel flow visualisations are carried out to gain insights into the effect of the exterior building topology on ventilation. It was found that rooftop windcatchers performance is strongly influenced by the flows surrounding the building's façades, especially at the building roof with dominating flow separation, and near the room window. Hence, the windcatcher was most effective at oblique wind directions and with an opened room window. On the other hand, the performance response of two Reynolds-averaged Navier-Stokes (RANS) based turbulence models was presented throughout the results.

Passive Energy-Saving Optimal Design for Rural Residences of Hanzhong Region in Northwest China Based on Performance Simulation and Optimization Algorithm

The rural residences of Northwest China are characterized by a state of high energy consumption and low comfort due to the limited economic level and awareness of energy-saving compared with the urban residences. To remedy this, appropriate passive design strategies should be adopted first, in order to provide a design mode with low energy consumption and low cost for rural residences under the premise of thermal comfort. In this paper, taking Hanzhong region (Shaanxi Province, China) as an example, we establish a benchmark model based on a field survey and develop an optimization process by combining EnergyPlus simulation software, the MOBO optimization engine, and weighted sum method. The action mechanisms of passive design parameters, including the building orientation, length–width ratio, building envelope parameters, external shading system, and window–wall ratio, on heating, cooling, and total energy consumption are analyzed, and the quantitative relationships between single-parameter and energy consumption are established. Then, the mutually restricted indices of total energy consumption and initial investment cost are taken as optimization objectives, and 17 design parameters are selected as the optimization variables. The NSGA-II algorithm is adopted to conduct the multi-parameter, multi-objective optimization design for rural houses in Hanzhong area, through coupling of the EnergyPlus and MOBO software. In this way, Pareto solutions are obtained and the value distributions of the multi-objectives and design parameters are analyzed. Based on the actual requirements of decision-makers and using the weight method, three design schemes focusing on different performance tendencies are proposed. The results indicate that by using the proposed optimization process, the building energy consumption can be significantly reduced while taking initial investment costs into account, where the energy-saving rate is in the range of 31.9–61.5%. When the EC/IC ratio is 1:1, 2:1, and 1:2, the energy-saving rate can reach 51.5%, 57.8%, and 43.5%, respectively. It can provide a beneficial pattern for the energy-saving design and renovation of rural residences in Hanzhong area of China.

Numerical study on bearing behaviour and design of aluminium sub-heads in façade systems

A sub-head refers to the horizontal member at the top of an aluminium window wall system. Under wind load, bearing failure of the aluminium sub-head (ASH) flange due to its long length is a common failure mode, being subjected to high concentrated load transferred from the vertical members (mullions). The bearing behaviour of ASH sections was previously investigated experimentally by the authors and suitable equations (DRAI) were proposed to predict the bearing capacities. These design rules were manufacturer and product specific and only applicable for sections considered in the test plan. To address these limitations, the present study further investigates the behaviour and design of ASH sections through non-linear static analyses using ABAQUS, based on implicit integration schemes. The effects of mesh size, element type, and loading plates on the bearing behaviour of ASH section under different loading and boundary conditions was addressed. The finite element models were validated against the test results in terms of ultimate loads, load–displacement curves and failure modes, and the validated model was then used to perform an extensive parametric study. A broad range of ASH sections covering flange widths ranging from 40 to 100 mm, thicknesses varying between 2 and 4 mm, bearing widths ranging from 50 to 150 mm, and six engagement lengths (5 to 30 mm) was considered in the parametric study. It should be noted that the ultimate loads obtained from the parametric study are not product nor manufacturer specific. Since no aluminium design rules exist to predict the bearing capacities of ASH sections, the accuracy of the current cold-formed steel design rules (DRSs) and that of DRAI were assessed. Both DRSs and DRAI were found not to be suitable for ASH sections in window walls, hence appropriate modifications were made in this study and the proposed design rules (DRAP) predicted accurate bearing capacities which agreed well with the numerical results.

Investigation of thermal adiabatic boundary condition on semitransparent wall in combined radiation and natural convection

Two thermal adiabatic boundary conditions arise on the semitransparent window (wall made of glass material) owing to the fact that whether semitransparent window allows the energy to leave the system by radiation mode of heat transfer or not. It is assumed that the energy does not leave by the conduction mode of heat transfer, due to the low thermal conductivity of semitransparent material. This does mean that the semitransparent window may behave as only conductive adiabatic or combined conductive and radiative adiabatic In the present work, the above two thermal adiabatic boundary conditions have been investigated for natural convection in a cavity, whose left vertical wall has been divided into upper and lower parts in the ratio 4:6. The upper section is a semitransparent window, while the lower section is an isothermal wall at a temperature of 296 K. A collimated beam is irradiated on the semitransparent window with values 0, 100, 500, and 1,000 at an azimuthal angle 135°. The cavity is heated from the bottom by convective heating with free stream temperature 305 K and heat transfer coefficient 50 While the right wall is also isothermal at the same temperature as of lower left wall and the upper wall is adiabatic. All walls are opaque for radiation except the semitransparent window. The results reveal that the dynamics of both the vortices inside the cavity change drastically with irradiation values and also with the boundary conditions on the semitransparent window. The temperature and Nusselt numbers increase many folds inside the cavity for combined conductive and radiative adiabatic condition than only conductive adiabatic condition on the semitransparent window.

Bearing behaviour of aluminium sub-heads with removable beads in façade systems

Occupying a substantial proportion of the overall building expense, building envelopes are the subject of ongoing research and improvement in both aesthetic and structural aspects. The aluminium window wall frame, consisting of vertical members (mullions) and horizontal members (head and sill transoms), is placed between sub-heads at the top and sub-sills at the bottom of the wall. These window walls are designed to carry lateral wind loads. Of particular importance to design stability is the bearing behaviour of aluminium sub-heads. The bearing behaviour and capacities of C-shaped sub-heads were recently investigated through a detailed experimental study at Griffith University for the development of strength prediction equations. To allow for easier assembly of façade panels, a kind of sub-head section known as sub-head with removable bead is used in aluminium window wall system. Two parts of this sub-head are connected together without any external mechanisms. The present research places emphasis on assessing the bearing behaviour of aluminium sub-heads with removable beads through comprehensive experimental testing. A total of 36 tests were conducted using six section geometries, two engagement lengths, and three bearing widths. The bearing strengths obtained from tests of aluminium sub-heads with removable beads were compared with the bearing capacities predicted using the design rules developed by the authors for conventional C-shaped aluminium sub-heads and available cold-formed steel design provisions (AISI S240 2015, TI 809-07, and SSMA 2000 specifications). As a result of the investigation, the current design equations were found to be unreliable for estimating the bearing capacity of aluminium sub-head sections with removable beads. Hence, new design expressions have been developed which accurately predict the strengths of aluminium sub-heads with removable beads under out-of-plane loads. Furthermore, the influence of the removable beads on the bearing behaviour and capacity is discussed in detail.

Current status and perspective of colored photovoltaic modules

AbstractPhotovoltaic (PV) systems, which directly convert solar light into electricity, are one of the most attractive renewable energy sources to fulfill the increased demand for clean energy. The accumulated installation of PV systems has expanded rapidly, reaching over 700 GW in 2020. Although black colored PVs maximize energy generation by harvesting a broad range of solar light, their monotonous color limits their installation in urban areas and portable devices where the harmonization of color with neighboring exterior elements is a high priority. Moreover, it is not suitable for covering transparent area of buildings, such as window and curtain wall. Hence, the demand for aesthetic PV systems is increasing significantly. In this review, we focus on the current status of colored PV systems and their prospects for aesthetic energy harvesting system. This work reviews possible approaches to realize colored PV systems by implementing semitransparent cells, selective reflective films, and luminophores. Additionally, the research progress to minimize light sacrifice for color production has been investigated. Moreover, the technical limitations of each technology for colored PV systems are presented in terms of color purity and efficiency. Finally, obstacles to commercialization and their solutions are discussed. Therefore, this study provides a crucial review of the latest developments and current status in the field of colored PV systems.This article is categorized under: Photovoltaics > Science and Materials