Window Assembly Research Articles

Beyond the Building Code: A Forensic Approach to Construction Defect Evaluation Utilizing the Construction Variance Evaluation Methodology

The applicable building code provides prescriptive specifications that allow construction of the built environment without the need for design professionals to dictate every aspect of every project; however, the building code does not consider all available materials, designs, and/or methods of construction — nor does it consider possible alternatives or construction variances. Since there is more than one way to accomplish a goal, a forensic investigation should consider the intent and purpose of a prescriptive specification (i.e., the desired performance) in order to determine whether an as-built construction variance is capable of accomplishing the same without adversely affecting a structure. This paper will explore the installation of cement plaster veneer and manufactured window assemblies to demonstrate how construction variances can still meet the intent and purpose of applicable prescriptive specifications. As a result, a true forensic approach to construction defect evaluation should not blindly follow prescriptive specifications. Instead, it should employ engineering analysis and a practical method such as the construction variance evaluation methodology (CVEM) to consider the performance aspects of construction variances before concluding that such variances are construction defects.

Futures for electrochromic windows on high performance houses in arid, cold climates

This study investigates high performance electrochromic windows used on a passive house and residential dwelling to IECC 2021 (i.e., IECC dwelling). In the lab, the electrochromic film switches transmitted solar heat gain coefficient (SHGC) from 0.09 to 0.7 and visible transmittance from 0.15 to 0.82 with power consumption of 1.23 W/m2 during switching times less than 3 minutes. We extrapolate these results to a window assembly. Building energy models of the houses were evaluated in Santa Fe, New Mexico. A Monte Carlo analysis for 2020, 2040, 2060, and 2080 was conducted for Shared Socioeconomic Pathways 2-4.5, 3-7.0, and 5-8.5. Cases with and without the electrochromic windows and with and without electricity were used to determine energy use intensity and hours beyond thermal safety thresholds.The passive house showed 1.3-3.1% mean energy savings and the IECC dwelling 4.4-5.1% with electrochromic efficiency benefits growing into the future for both cases. Even so, overall savings decrease into the future for the passive house, due to growth in cooling load being dominant, conversely overall energy savings increase into the future for the IECC dwelling due to heating loads being dominant. For thermal resilience, the passive house exhibited a mean percent decrease of 0.02-0.31% hours in the extreme caution (i.e., > 32.2∘C, ≤ 39.4∘C) range while the IECC dwelling exhibited 0.38-4.38%. The study therefore shows that electrochromic windows will have smaller benefits for the passive house in comparison to the IECC dwelling. The relationship between electrochromic windows is shown to have a complex relationship between house efficiency and climate change by these results.

NUMERICAL MODELLING OF WIND LOADS ON WINDOWS. VALIDATION FOR A HIGH-RISE SQUARE PLAN BUILDING

This paper presents the results of numerical and experimental modelling of mean and peak pressure coefficients for window assemblies on a rectangular building. The applicability of the SST and GEKO k-ω turbulence models implemented in ANSYS Fluent is investigated. A simple steady-state method for determining the peak wind pressures, which utilizes the turbulence kinetic energy calculation, is shown to be sufficient for practical purposes. A comparative analysis with the values of pressure coefficients given in the Russian building code is carried out. The obtained results can be used in the design of window assemblies of typical buildings.

Stress-strain curve mapping by nanoindentation – a technique to qualify diffusion-bonded window assemblies for ITER

The International Thermonuclear Experimental Reactor (ITER) is an international nuclear fusion research and engineering project with the aim to prove the feasibility of nuclear fusion as a large-scale carbon-free source of energy. The reactor vessel contains several diagnostic windows that provide a line of sight to the plasma. Design and qualification of such windows is challenging due to severe in-service conditions and the necessity to combine glasses with metals. One specific window is composed of fused silica glass that is connected to an Inconel ferrule via an aluminium bonding layer, where the joint is consolidated through a diffusion bonding process. The optimization of design and production process parameters of the windows is object of continuous improvements via dedicated three-dimensional finite element model (FEM) simulations. Importantly, these FEM simulations necessarily require stress-strain curves as input parameters. Such curves are difficult to obtain, especially from complex systems with dissimilar joints. In the present paper a methodology based on dynamic spherical nanoindentation has been developed and applied to map the stress-strain characteristics across the diffusion bonded joints. The methodology takes inspiration from the well-known theory to extract stress-strain curves from spherical nanoindentation. Here, it is applied to automated large indentation mapping with more than 1000 indentations including fully automated post-processing. The results provide bulk equivalent mechanical properties including yield stress, yield strain, work hardening parameters and elastic modulus at a micrometre resolution. Results show outstanding correlation with microstructural changes across the bonded cross-section, including grain refinement and twinning at the Inconel/aluminium interface.

Enhancing the performance of anti-blast windows through the use of carbon nanotube reinforced polymer gaskets

Anti-blast windows are critical in ensuring the safety of structures exposed to explosive threats, such as terrorist attacks or accidental explosions. These windows consist of blast-resistant glass and a structural framing system that must be able to withstand the high-pressure shock of an explosion. The present study presents a novel structural framing system for anti-explosion windows that adheres to the standards set forth by the American Institute of Steel Construction (AISC) 360-16 Specifications and the Aluminum Design Manual (ADM) 2020. The system encompasses a distinct combination of aluminum 6063-T6 angles and ASTM A36 steel embed plates that are connected by spaced bolts and augmented by the addition of a carbon nanotube-reinforced polymer CNT/polymer gasket. A numerical investigation utilizing ABAQUS software was performed to evaluate the mechanical behavior of the window assembly under intense blast loads, taking into account the effect of incorporating the CNT/polymer gasket and the impact of the gasket weight fraction on the performance of the structure. The results of the study demonstrate that the use of the CNT/polymer gasket and increasing the wight fraction ratio resulted in improvement of the blast performance of the window frame structure in terms of the significant reduction in stress, deformation and rotation, as well as the increasing of the energy dissipation during the blast event compared to when the gasket was not utilized. These findings offer crucial benchmarks for the proposed structure and offer recommendations for its implementation in industry practice, with the ultimate goal of developing more efficient and effective designs for anti-explosion windows that meet industry standards.

Design of multispectral optical window assembly for high and low temperature test device

箱外光电系统综合检测仪是光电成像系统高低温性能检测装置的重要组成部分，多光谱光学窗口是高低温箱和外置目标模拟器的接口。论文根据应用需求及材料分析结果，选取多光谱ZnS作为光学窗口材料，通过热传导理论对光学窗口组件低温使用状态进行分析，重点分析窗口组件在低温条件下加热对窗口组件面型的影响，并提出了实现微应力装配的结构形式及解决窗口组件在低温条件下结霜结雾的设计方案；通过sigfit对有限元计算结果进行提取、处理以及数据拟合，并通过CODE V分析口径为<i>Φ</i>310 mm窗口组件在使用温度范围内的波像差RMS，分析结果显示优于<i>λ</i>/15，满足窗口组件的光学性能要求，最后通过实物样机进行了验证。实验结果表明：该多光谱光学窗口组件的结构设计方案既满足多波段使用要求，又满足低温除霜除雾要求，同时保证了高低温条件下的光学性能要求。

Measurement of laser absorption in underdense plasmas using near-field imaging of the incident and transmitted beams.

Measurements of laser absorption in high-temperature, underdense plasmas produced at the Omega Laser Facility are made using two near-field imaging detectors that diagnose the spatial profile and energy of the port P9 beam before and after it transmits through the plasma. The incident beam is sampled using a partial reflection from a full-aperture, (30 cm-diam) uncoated wedge pickoff located before the target chamber vacuum window and final focus lens assembly. A concave mirror reduces the reflected beam size, allowing it to be recorded directly using a charged-coupled device (CCD) camera. The P9 transmitted beam diagnostic (P9TBD) characterizes the transmitted light by terminating the expanded beam on a semi-transparent diffuser and imaging the illuminated surface using a lens and CCD camera. The P9TBD samples a numerical aperture twice as large as the input beam, allowing the energy of transmitted beams with moderate levels of beam spray to be measured accurately. Calibration shots with no plasma provide a path to infer absorption without absolute photometric calibration of either detector. The cross-calibration between the two detectors was measured to remain stable at ±200 ppm, enabling measurements of total beam absorption below 1% with ±0.07% error.

Proposal of a testing procedure to qualify ITER window assemblies and absorbing coatings exposed to high microwave stray radiation

In any large device for research on magnetic confinement thermonuclear fusion, the window assemblies are essential to preserve the conditions for successful experiments and to guarantee adequate access for inspection and measurement. In ITER, the materials traditionally used for the windows will be exposed to an exceptionally harsh environment. Moreover, the systematic use of tritium as fuel would make any failure of the primary vacuum containment a particularly dangerous accident. It is therefore essential to understand the potential threats to the integrity of the windows assemblies and define a series of tests to ensure their properties and quality before installation. One specific hazard to the windows is the microwave radiation due to either heating schemes or specific diagnostics. A fraction of the stray radiation incident on the window leads to dielectric heating, which causes a thermal load. The potentially harmful consequences of such a thermal load on the window assemblies are: (i) excessively high temperature (risk of bonding melting) and (ii) excessive, heating rate (risk of cracking due to a high temperature gradient at the location of the bonding). In this paper the main causes of degradation, which could lead to failures under microwave loads, have been identified. A series of laboratory tests have been defined, to assess the quality of the materials and the assemblies, including the coatings for the absorption of the microwave radiation in the ducts leading to the windows. Complete testing procedures and an overview of the main facilities, where the assemblies and materials could be qualified, are also provided.

Thermal Analysis and Verification Test of the Entrance Window Assembly for Space Solar Observatory

Thermal Analysis and Verification Test of the Entrance Window Assembly for Space Solar Observatory

Proposal of a Testing Procedure to Qualify Iter Window Assemblies Exposed to High Microwave Stray Radiation

Proposal of a Testing Procedure to Qualify Iter Window Assemblies Exposed to High Microwave Stray Radiation

Design and Integrated Analysis of a Flexible Support Microstructure with a Honeycomb Sandwich for the Optical Window of a Hypersonic Remote Sensor.

In order to reduce the influence of the optical window on the image quality of a hypersonic visible light optical remote sensor, we propose a method of adding a double-layer semicircular honeycomb core microstructure with flexible support of a high temperature elastic alloy between a window glass and a frame to reduce the influence of complex thermal stress on the surface accuracy of the optical window. An equivalent model of a semicircular honeycomb structure was established, the elastic parameters of the semicircular honeycomb sandwich microstructure were derived by an analytical method, and a numerical verification and finite element simulation were carried out. The results show that the equivalent model is in good agreement with the detailed model. The optical-mechanical-thermal integrated simulation analysis of the optical window assembly with flexible supporting microstructure proves that the semicircular honeycomb sandwich flexible supporting structure has a positive effect on stress attenuation of the window glass and ensures the wave aberration accuracy of the transmitted optical path difference of the optical window (PV < 0.665 λ, RMS < 0.156 λ, λ = 632.8 nm). Combined with the actual optical system, the optical performance of the window assembly under the flexible support structure is verified. The simulation results show that the spatial frequency of the modulation transfer function (MTF) of the optical system after focusing is not less than 0.58 in the range of 0–63 cycle/mm and the relative decline of MTF is not more than 0.01, which meet the imaging requirements of a remote sensor. The study results show that the proposed metal-based double-layer semicircular honeycomb sandwich flexible support microstructure ensures the imaging quality of the optical window under ultra-high temperature conditions.

Implications of passive energy efficiency measures on life cycle greenhouse gas emissions of high-rise residential building envelopes

The building industry has been developing measures for reducing operational emissions in the fight against climate change. Some of these well-intentioned measures may result in higher embodied emissions, potentially more than offsetting reductions achieved during operation. This research evaluates the effectiveness of different levels of application of five passive energy efficiency measures to reduce life cycle greenhouse gas (GHG) emissions in high-rise residential buildings in Toronto, Canada, while considering projected future climate and GHG intensity of energy sources. Through combining and automating life cycle assessment and energy simulation on a visual programing interface, the study evaluates 16,128 envelope variants, examining 56 wall, 12 roof, 6 window assemblies and 4 window-to-wall ratios (WWRs). Decreasing the WWR is found to be the most effective measure to reduce total envelope related GHG emissions (by about 28%). Increasing wall and roof insulation with GHG intensive materials (e.g., extruded polystyrene [XPS]), and increasing spandrel wall insulation potentially augment total emissions, depending on the scenario. Higher trade-offs between embodied and operational emissions are found when highly efficient electric HVAC systems are implemented (e.g., heat pumps). Results demonstrate it is imperative to assess both embodied and operational emissions during the design process of building envelopes to effectively reduce GHG emissions.

Experimental mechanical analysis of traditional in-service glass windows subjected to dynamic tests and hard body impact

The large use of glass in buildings, and especially the presence of fenestrations and facade systems, represents a potential critical issue for people safety. The brittle nature of glass (with limited elastic deformation and resistance) is often enforced by its use in combination of several secondary components, whose reciprocal interaction and potential damage should be properly assessed. In the case of windows, accordingly, a special care should be spent for glass members but also for the framing system and possible adhesive or mechanical connections. This study aims at exploring the dynamic response and damage sensitivity of traditional glass window systems, based on the experimental derivation of few key material properties and mechanical parameters. To this aim the attention is focused on traditional, in-service windows that belongs to existing residential buildings and are typically sustained by timber frames, through a linear flexible connection. In doing so, major advantage is taken from experimental analysis, both in the static and dynamic field, for whole window assemblies of single components. For comparative purposes, selected window specimens including plastic (PVC) frame members and Insulated Glass Units (IGUs) are also taken into account in the paper. The static characteristics of the windows components are first preliminary derived. The dynamic performance of such a kind of systems is then experimentally explored with the support of modal analysis techniques and hard body impact procedures, including the experimental derivation of stiffness parameters for the frame members and the glass panels. Further assessment of experimental outcomes is finally achieved with the support of Finite Element numerical analyses.

FEM analyses of the ITER EC H&amp;CD torus diamond window unit towards the prototyping activity

The chemical vapour deposition (CVD) diamond torus window unit is a sub-component of the ITER Electron Cyclotron Heating and Current Drive (EC H&CD) system used for a diverse range of applications including plasma heating and control of plasma magneto-hydrodynamic (MHD) instabilities. It consists of an ultra-low loss polycrystalline diamond disk brazed to copper cuffs and then enclosed by a metallic structure. The diamond disk with 1.11 mm thickness already passed successfully the ITER final design review (FDR) in 2018. In view of the complete window assembly FDR, prototyping activities of the window are essential and, therefore, they shall start soon in order to check the feasibility of the proposed manufacturing and assembling sequence of the component. In this perspective, as the design of the systems surrounding the window is currently in development phase, the paper describes the finite element method (FEM) analyses of the window to carry out with the aim to prove the soundness of the design used for the prototyping and also to define requirements for the surrounding systems. Specific methodologies are adopted such as the limit analysis approach for the external loads acting on the window unit. Several combinations of forces and moments are applied to the window unit to find the maximum loads, i.e. the limits loads, which generate stresses in the unit equal to the allowable ones, according to the selected design criteria.

User Experience Sensor for Man-Machine Interaction Modeled as an Analogy to the Tower of Hanoi.

This paper presents a novel user experience optimization concept and method, named User Experience Sensor, applied within the Hybrid Intelligence System (HINT). The HINT system, defined as a combination of an extensive AI system and the possibility of attaching a human expert, is designed to be used by relational agents, which may have a physical form, such as a robot, a kiosk, be embodied in an avatar, or may also exist as only software. The proposed method focuses on automatic process evaluation as a common sensor for optimization of the user experience for every process stage and the indicator for human-expert automatic session activation. This functionality is realized by the User Experience Sensor, which constitutes one of main elements of the self-optimizing interaction system. The authors present the optimization mechanism of the HINT system as an analogy to the process of building a Tower of Hanoi. The proposed sensor evaluates the user experience and measures the user/employee efficiency at every stage of a given process, offering the user to choose other forms of information, interaction, or expert support. The designed HINT system is able to learn and self-optimize, making the entire process more intuitive and easy for each and every user individually. The HINT system with the proposed sensor, implemented in a window assembly facility, successfully reduced assembly time, increased employees’ satisfaction, and assembly quality. The proposed approach can be implemented in numerous man–machine interaction applications.

Computational investigation of the impact of glass flexure on thermal efficiency of double-pane windows

Windows contribute significantly to the energy efficiency of a building because a considerable amount of energy can potentially be lost through windows. Double-pane windows are particularly efficient at reducing heat loss, primarily via the thermal insulation afforded by the insulating gas filled inside the gap between two panes of glass. However, glass flexure and deformation during window assembly and cold weather can substantially alter the effective thermal resistance of double-pane windows. We systematically consider this (inward and outward) flexure effect on thermal performance in the current work. A validated finite volume method with k-$$\omega $$ SST turbulence model is utilized to perform 3D simulations of a commercially available double-pane window. High-performance computing-based simulations are performed to unravel the impact of different amounts of flexure on effective heat loss. We find that the total heat loss increases as the degree of inward flexure increases, with the case of maximum inward flexure resulting in $$\sim 15\%$$ more heat loss compared to the baseline no-flexure case. On the other hand, outward flexure of the glass does not result in any appreciable variation in heat loss. This suggests pre-flexure as a viable means of ensuring consistent performance under wide weather conditions. Finally, we develop a quasi-2D approach that approximates the very expensive 3D simulations presented here. The quasi-2D method essentially integrates a series of 2D slices in a 3D case to estimate the total heat loss across that 3D case. This decomposition of a 3D window simulation into several 2D simulations substantially reduces total computation efforts and produces reliable results for the very large aspect ratio exhibited by the double-pane window geometry.

Moisture accumulation analyses over windowpane, based on onsite measurements in sleeping room

The current paper presents moisture accumulation analyses over windowpane, based on onsite measurements in genuine sleeping room. During the measurements, the room was occupied with two adults and a baby, and the occupant’s behaviour was not additionally modified. The examination of the results represented the generic conditions for the windowpane condensation appearance, without taking into account the window assembly properties or the building construction. The studied windowpane has visually confirmed condensation in the lower left corner. This moisture accumulation is confirmed by the obtained measurement results near the windowpane, which clearly showed lower air temperature and higher relative humidity, compared with the rest of the occupied space. Thermal images also confirm this effect, and give better interpretation of the time periods, at which the surface temperature of the windowpane is lower than the dew point temperature in the affected zone. The analysed results offer important understanding of the interference of the different indoor parameters, related to the generic conditions for windowpane condensation appearance. These results may contribute the development of numerical model, capable to predict the heat losses and the moisture accumulation processes, in such affected areas from the building envelope.

Novel design and diagnostics improvements for increased production capacity and improved reliability at the Los Alamos Isotope Production Facility

The Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL) is used to produce an array of isotopes for medical, global security, and research applications with an intense beam of protons supplied by the linear accelerator at the Los Alamos Neutron Science Center (LANSCE). An Accelerator Improvement Project (AIP) was recently conducted at IPF to improve facility reliability and reduce programmatic risk while increasing general isotope production capacity and flexibility. This was accomplished through the installation of an improved beam window assembly, more robust beam diagnostics, an active and adjustable collimator, and a new beam rastering system. This paper will highlight the four exciting innovations and how they were designed, validated, and installed in parallel as well as the significant operational advantages they provide to IPF. Key experiments and the increased currents achieved in routine production runs demonstrating the enhanced capability from the AIP will be presented. The most notable capability enhancements include irradiations with beam currents ranging from 100 nA experimental runs up to 300 μA on routine production targets and utilization of a range of cylindrical target diameters.

An empirical study on life cycle assessment of double-glazed aluminium-clad timber windows

PurposeLife cycle assessment (LCA) is a useful tool to determine the environmental performance of materials and products. The purpose of this paper is to undertake the LCA of double-glazed aluminium-clad timber windows in order to determine their environmental performance.Design/methodology/approachThe scope of the LCA study covers the production and the use of windows over a 30-year life span. The LCA exercise has been carried out by auditing the materials and processes involved in the making of the windows. Windows production facilities were visited to investigate the respective quantities and embodied energy of the major constituting materials, i.e. timber, aluminium, glass, infill gases and auxiliary components. The main processes involved, i.e. powder coating of aluminium cladding profiles, glazing unit production and window assembly, were also examined. SimaPro software was used to calculate the environmental impacts associated with the windows for three types of glazing infills: Argon (Ar), Krypton (Kr) and Xenon (Xe).FindingsEmbodied energy of a standard sized (1.2 m×1.2 m) double-glazed aluminium-clad timber window is found to be 899, 1,402 and 5,400 MJ for Argon (Ar), Krypton (Kr) and Xenon (Xe) infill gases, respectively. It is also found that an Argon-filled window can lose 95,130 kWh of energy resulting into over 37,000 kg of CO2 emissions.Originality/valueBesides carrying value for research community, the findings of this study can help the building and construction industry adopt windows that are energy-efficient and environmentally less burdensome. It can also help the concerned legislative bodied.

An experimental analysis of the optical, thermal and power to weight performance of plastic and glass optics with AR coatings for embedded CPV windows

A low concentrator photovoltaic is presented and the optical losses within a double glazed window assembly are described. The use of plastic instead of glass is analyzed for its reduced weight and hence greater power to weight ratios. Although the transmittance of glass is higher, the power to weight ratio of the plastic devices was almost double that of the glass counterparts and even higher than the original non concentrating silicon cell. The plastic Topas material was found to be the best performing material overall. Crystal Clear, a plastic resin, had a higher average transmittance but had a lower optical efficiency due to the cold cast manufacturing process in comparison to injection moulding of the other materials. This proves the importance of considering both the materials and their associated manufacturing quality.External quantum efficiencies, optical properties, silicon cell temperatures and performance is analyzed for concentrating photovoltaic devices made of varying optical materials. The measurement methods for optical analysis are given in an attempt to separate the optical losses experimentally. The Silicon cells were found to gain higher temperatures due to the insulating plastic optics in comparison to glass but these effects are eliminated during vertical window orientation where instead the encapsulate dominates the insulation of the cell. The results presented here prove plastic optics to be a worthwhile alternative to glass for use in low concentration photovoltaic systems and have the significant effect of reversing the weight disadvantage concentrator photovoltaic technology has compared to standard flat plate solar panels.