Glazing Systems Research Articles

Energy Efficiency Evaluation of Different Glazing and Shading Systems in a School Building

The energy conversations methods and techniques take a significant role in the energy performance of the buildings. Façade and shading systems are in continuous development, and recent studies are showing the importance of implementation of such systems to reduce energy consumption and enhance the effectiveness of the building performance. School buildings are mostly being used during daytime, hence, require active use of sunlight. A measure that is taken on a school building envelope can prevent overheating and overcooling and reduce the heating and cooling energy consumption but at the same time can increase the lighting energy consumption vice versa. Thus, it is necessary to optimise the energy required for climatisation of a building with lighting energy demand. The main aim of the paper is to provide analysis for façade and shading systems applied to a school building and study the effectiveness of it on energy consumption and conservation. The case study for this paper is a typical building project designed to be located in Istanbul, Turkey and has a traditional façade system which is clear double layer windows without any shading devices. The analyses of the energy efficiency of these systems will be presented. The different glazing types and shading systems alternatives will show the most efficient one to be used as some optimised alternatives for the systems. Findings indicate that proper glazing and shading systems can reduce the needed energy for heating and lightening and thus total energy consumption of a school building significantly.

Evaluation of Indoor Daylight Focused on the Human Circadian System

The circadian phototransduction issue caused strong interest at the beginning of the new millennium, while the research of non-visual influence of light is predominantly developing in medicine field of science. The outputs confirmed hypothesis that human habits are strongly related with ambient light conditions and disruption of natural light conditions may result in complex of health diseases with negative consequences. Actual effort for minimizing energy demands of buildings is very important for sustainable architecture, but the aspect of “circadian-friendly” design should not be neglected, even though it is not entirely investigated yet. The growth of building envelope´s thickness, as an example, causes noticeable drop of amount of penetrating daylight with the same dimensions of fenestrations. The paper presents an overview of evaluation methods of circadian effect of light on human including available actual calculation equations and standards, providing certain principles to design indoor spaces intended for long term occupation. The aim is to extend the knowledge focused on suggestion of internal surfaces, glazing and active shading systems into building physics and architectural design with a possibility to achieve a control by system of intelligent building

An Experimental Study on Energy and Exergy for Glazed and Unglazed Solar System with Perforated Absorber Plate and Wire Mesh Layers

The purpose of this experimental study is to construct and evaluation three solar heaters (glassed heater 90 o bed angle, unglazed heaters 90 o bed angle and glassed heater 47 o bed angle), these heaters device 50 mm height of the bed with a perforated absorber plate and wire mesh layers. The perforated plate and six steel wire mesh layers were painted black then placed parallel to each other in heater bed; the mesh layers had a cross-sectional area of 2.2 mmA— 2.2 mm and an internal diameter of 4.11 mm, perforated plate had an internal hole diameter of 2 mm, pitch 4 mm. In this search, the outlet temperature and thermal efficiency were studied in a geographical zone, located in the Baghdad city, Iraq. The experimental results showed that the thermal efficiency increases as the air velocity increases in the range of 2 m/Sec to 7.5 m/Sec. The maximum efficiency obtained using the glazed solar heater 90 o bed slope was I·= 63%, but for unglazed solar heater same bed slops the maximum thermal efficiency decreased to I·= 43.3%. The maximum thermal efficiency increased to I·= 65.6% as decrease the bed slop to the 47 o for the glazed heater at a flowing air velocity of 7.5 m/Sec. Additionally, the temperature differences, ∆T , (T out – T in ) and exergy efficiency for three beds of solar heater indicated an inverse association with flowing air velocity: Temperature differences, ∆T, and exergy efficiency, I· Ex , increased as the air velocity decreased. The maximum temperature differences and exergy efficiency for glazed solar heater bed slope 90 o are ∆T = 37.9 °C and I· EX = 4.8 %, for unglazed solar heater bed slope 90 o , ∆T =16.8 o C and I· EX =2.23 %, for glazed solar heater bed slope 47 o are ∆T = 48 C o and I· EX = 5.24 %, which were recorded for the duration 12:00 am at maximum solar intensity, I. The results validated an improvement in the outlet air temperature T out , thermal efficiency, I· and exergy efficiency, I· EX . Â

Annual performance of photovoltaic-thermal system under actual operating condition of Dire Dawa in Ethiopia

As cooling of Photovoltaic panel by water improves the electrical conversion efficiency and produces warm water as a by-product, photovoltaic thermal system is being used for cogeneration of electrical energy and hot water. In this study, the annual performance of a glazed photovoltaic thermal system (combination of PV module and solar flat plate collector) with storage tank was investigated by the dynamic computational model. The model was developed using MATLAB under actual hot water demand condition for co-generation electrical energy at Dire Dawa in Ethiopia. The computational model determines the electrical energy production and temperature of water at different points and other components of the PV-T system within a given time interval. In addition summaries of monthly and annual incident solar irradiance, electrical energy generation, thermal energy transported to storage and thermal energy supplied as hot water to end users are computed, considering the hourly hot water consumption pattern and storage size effect. The simulation, which is conducted for 20 m2 PV-T system, consists of 12 panels with each 1.64 m2 module areas resulted in generation 803 kWh/year thermal energy and 310 kWh/year electrical energy. The annual average electrical efficiency, thermal efficiency, hot water end use overall efficiency and co-generation (PV-T) efficiency of the system were 15.4%, 50.4%, 38%, and 65.8% respectively. The fraction of solar energy in meeting the heating load for hot water generation was 44.5% for 60℃ hot water supply temperature. Hence, that PV-T system can only be used for water preheating meeting at maximum half of the heating load in tropical area.

An ICT-enabled Product Service System for Reuse of Building Components

Abstract The paper outlines the development of a prototype cyber-physical data exchange system that connects RFID, BIM and the Cloud-based data platform by which reusable building components may be identified, tracked and managed. The digital platform is then adapted to support an ongoing Product-Service System (PSS) relationship between suppliers/providers and users/clients. This enables advanced services for reuse of building components at the highest value and with mutual benefits. Via an integration of the ICT-based data management and PSS, the types of life cycle, performance, cost and other data required for service relationships can be identified so that suppliers may manage building components over their extended life, retain their optimum value and find new profit centres. Clients can be assured that the quality and performance of reused components meet required service expectations, coupled with savings in cost and carbon. An example of internal glazed system is presented to demonstrate the application of the proposed method.

Energy and thermal analysis of insulating window systems

The advanced requirements of the transparent building envelopes include safety, durability, high thermal and sound resistance, possibilities for controlled transmittance in the solar spectrum, low embodied energy, carbon footprint and cost. The simultaneous achievement of these desirable features is difficult - the design of facades and the choice of the glazing systems are implemented at reasonable compromises. This paper details a case study of the performance of insulating window systems in reha- bilitated residential building in Bulgaria, taking into account the reduction of the energy demands for the heating, the energy payback time and the thermal loads at the facades with different orientations.

Formation mechanism of titania based opacified glaze with novel core-shell nanostructure

The formation mechanism of titania based opacified glaze is discussed in this paper. The glaze system composed of albite, kaolin, talc, calcite, quartz, titanium dioxide and zinc oxide is used to adjust the glaze formula and to obtain the glaze samples with better opacifying effect. The whiteness and glossiness of glaze products formed with different TiO2 contents are characterized by whiteness meter and gloss meter respectively. The structure of glaze layer is analyzed by means of SEM, TEM and EDS. The results show that the introducing of TiO2 can promote the phase separation and forms the special Si-rich/Ti-rich core-shell nanostructure. During the cooling process of the glaze, the liquid-liquid phase separation occurs and results in the formation of uniform Si-rich nanoparticles. While the Ti-containing components are enriched at the interface between the different phases and a special spherical core-shell structure is obtained around the Si-rich nanoparticles. The glaze layer is filled with the core-shell nanospheres and shows a network structure like opal. However, due to the decrease of cationic content (Ti, Zn, Ca, and Mg) in the interface between glaze and body, the network nanostructure like reverse opal would be formed. In the interaction of special opal and reverse opal structure, the opacifying effect is enhanced obviously.

Thermal performances of glazed energy storage systems with various storage materials: An experimental study

In the literature, two materials (such as water and phase change materials) have been studied frequently as potential heat energy storage medium in building applications. Many perspectives have been mentioned by researchers but there is too little information about significance of its application. In this experimental study, water and PCM glazing systems were tested simultaneously in natural environment using test chambers. Temperature histories were recorded in the corresponding chambers at interior glass surface for each sample. Time lag, temperature damping and average temperature for each glazing system were comparatively analyzed. It was observed that temperature variation at interior glass surface over a period of 48 h changes differently for each material. Compared to the traditional air filled glazing system, it was found that water glazing system has most promising temperature damping properties, but significantly unfavorable average temperature, while PCM glazing system has significantly promising average temperature and temperature dumping properties.

Evaluation of solar factor using spectral analysis for CdTe photovoltaic glazing

Solar and luminous light transmission control using Cadmium Telluride (CdTe) based PV glazing systems (15 cm × 15 cm × 0.6 cm) were evaluated in this work. Indoor spectral characterisation showed that average solar transmission for investigated three different CdTe glazing systems were 5.77% (CdTe1), 9.54% (CdTe2) and 12.34% (CdTe3). Spectral behaviour of reflections in the range of solar and visible wavelengths was similar for these three different transparent CdTe glazing. Near infrared (NIR) reflection was higher compared to luminous reflection after 1500 nm for all three glazing systems. Solar factor (SF) for CdTe1, CdTe2 and CdTe3 glazing were 0.23, 0.28, 0.26. CdTe3 is the best candidate for glazing application as it has 113% higher luminous transmission while SF only increases by 21% compared to CdTe1.

Numerical investigation on the seismic dissipation of glazed curtain wall equipped on high-rise buildings

The dynamic interaction between glazed curtain wall stick systems and modern high-rise mega-frame buildings is investigated. In the present paper, four moment resisting frames (MRFs), consisting of thirty- and sixty-storey steel-based prototypes, are designed according to European standards: internal concentrically braced frame (CBF) core, outriggers and belt trusses are adopted to limit inter-storey drift and second order effects. Force-displacement relationships are derived from available full-scale test data performed on non-structural aluminium façade units. Therefore, 3D finite element (FE) models are developed to interpret the physical phenomena involved in façade dynamics: as a result, equivalent 1D nonlinear links are calibrated to simulate these phenomena independently. Nonlinear time history analyses (NLTHAs) are executed to investigate the potential combination of stiffness and strength of such hybrid systems, i.e. achieved through the integration of glazed curtain walls on the MRF lateral force resisting system (LFRs). Local and global performance will be shown in terms of inter-storey drifts and displacement peak profiles, forces and percentage peak variations, highlighting static-to-seismic load ratios in critical members and the sensitivity to the structural height. Conclusions point out that, even if accurately designed according to current standards, the façade omission from the seismic analyses of high-rise structures may lead to a crucial underestimation in the dissipation capacity of the building.

Vacuum enclosures for solar thermal panels Part 1: Fabrication and hot-box testing

Non-concentrating solar thermal collectors are generally available in two forms, flat plate or evacuated tube. Recently a third configuration, the evacuated flat plate, has attracted interest due to enhanced performance and aesthetic characteristics. By isolating a solar absorber in a vacuum space (<1 Pa) heat loss from the absorber can be minimized resulting in improved efficiency. In addition the improved thermal insulation performance of evacuated panels over conventional glazing systems makes them attractive solutions for integration into energy efficient building facades.This two part paper describes the design, construction techniques and thermal performance of two vacuum enclosures, fabricated at Ulster University, as prototype components for evacuated flat solar collectors. The first enclosure consists of two glass panes sealed to an edge spacer and separated by an array of support pillars on a regular square grid to form a narrow evacuated space. The second enclosure incorporates an uncooled copper sheet to represent a solar thermal absorber. The enclosures were tested at three conditions i.e. with an internal pressure of high vacuum (0.0021 Pa), low vacuum (8.4 Pa) and no vacuum (atmospheric pressure).Part 1 of this paper describes the fabrication process for the vacuum enclosures and the measurement of their thermal insulation properties using a hot box calorimeter. The theory of heat transfer through an enclosure with support pillars is discussed; experimental results are compared with mathematical models predictions. A fabrication methodology has been successfully established and a U-value of 1.35 W/m2 K for an enclosure with an internal pressure of 0.0021 Pa has been demonstrated. The experimental results are in good agreement with the predictions.Part 2 of this paper describes solar simulator testing of the enclosure containing a copper plate. The highest stagnation temperature (121.8 °C) was reached under steady-state conditions in the high vacuum test and was in good agreement with predictions. The transient plate and glass surface temperatures were measured and found to be consistent with the predicted curves.

Shear behaviour of structural silicone adhesively bonded steel-glass orthogonal lap joints

This paper outlines an experimental study on the shear behaviour of structural silicone adhesively bonded steel-glass orthogonal lap joints. In the combination of steel plate and glass panel to form a hybrid structural glazing system, bonded joints with structural silicones can provide certain flexibility which relieves stress peaks at critical points of glass panel. The cohesive failure and its related fracture pattern of test joints with varied geometries of adhesives are examined experimentally. It is shown that the presence of two failure modes as discrete voids and macro cracks is closely related to the adhesive thickness. The effects of geometric parameters of adhesives on the joint shear strength are examined. It is demonstrated that the joint shear strengths are increased with increased individual overlap length, reduced adhesive thickness or increased adhesive width while the shear deformation corresponding to maximum shear force is mostly influenced by adhesive thickness. Mechanical contributions for those effects are analyzed accordingly. Finally, an analytical formula allowing for the equilibrium of strain and force on the adhesive and adherend is proposed for the analysis of shear strength. It is demonstrated that calculated normalized shear force ratios predicted by proposed formula agree well with those from experimental results.

Subdivided switchable sun protection glazing

The facade, as an interface between the interior and the exterior environment, performs multiple tasks. On one hand it has to ensure the highest possible comfort for building occupants, on the other hand it should contribute to minimizing the energy demand of the building. The detailed requirements on a facade depend on its orientation, local climatic conditions and the building use. Since surrounding conditions vary, an invariant facade system cannot react properly to this variability. In order to overcome this limitation, the authors are developing a switchable glazing unit with adjustable light and energy transmission properties. The functional principle is based on the use of liquid crystal materials. The main component of the switchable glazing is a thin switchable cell which is embedded in an insulating glazing unit. The cell area can be substructured into independently tintable pixels. This ensures maximum utility of the glazing. Currently, a prototype glazing is investigated under real conditions. A floor-to-ceiling glazing is assembled using small sized cells (310 mm $$\times $$ 286 mm) arranged in nine rows and six columns. The cell size is currently limited by the restrictions of the available production capabilities. However, cell integration in other insulating glazing units is possible as well. An effective daylight and shading control can be provided within these glazing units. In order to enhance the effectiveness of the system, the authors are developing different control strategies. The switchable glazing system and its simulation-based performance analysis will be presented in the paper.

Addendum

This article refers to:Comfort and energy performance analysis of different glazing systems coupled with three shading control strategies

Sustainable facade design for glazed buildings in a blast resilient urban environment

In facade construction the glazed elements have always been considered the most critical components for the minimization of hazards during a blast event. In today’s blast events, terrorists have changed their mode of action and targets where the glass performance is weak have become even more of a concern. Therefore counter-terrorism offices (such as in the UK) have been introducing design guidelines for crowded places, making a compromise between safety and sustainability. This paper describes how it is possible to achieve a resilient urban environment, where glass is still the dominant element of the architectural scope making use of glazed facade systems with excellent blast protection performances. Novel facade systems have recently been developed by means of effective simulation techniques. The numerical tools recognize, enhance and balance the already existing facade capacity to resist the blast loads and take into account the fundamental dynamic interactions between all facade elements. In this way, innovative facade components (such as curtain walling brackets) have been developed which have the ability to upgrade conventional or lightly enhanced glass facade systems to higher blast protection levels.

Mistral Tower: Value of System Design, Manufacturing and Installation in Cold Bent SSG Units

ABSTRACTIn cold‐bent Structural Sealant Glazing (SSG) systems, back‐flipping retention forces and differential displacements imposed to SG joints play a major role in the system design and need to be properly controlled. During last years, investigation on simplified equations to calculate cold bending stress into SG joints and tests to evaluate creeping and relaxation behaviour of Sikasil® structural silicones has allowed to identify where opportunities for systems optimizations are and to clarify that effective cold‐bending solutions cannot be uncoupled from new principles of system design, pre‐manufacturing and installation. The development of Mistral Tower in Izmir offers the chance to evaluate in detail the impact of different design solutions in combination with different production and installation methods and is used to present valuable options for approaching design of cold‐bent units effectively. The use of slim adapter frame bonded to glass units and free to slide into load‐bearing frame represents the basic requirement to limit cold bending effects on SSG joints, while minimizing production efforts. Valuable optimization results can be further achieved if bonding on either pre‐shaped frame or pre‐shaped frame/glass assembly is possible or if cold‐bending stress can be limited in time by a clever production method in controlled conditions. Advanced FE analysis simulating SSG joints by hyperelastic law confirms the influence that cross sectional depth of bonded profile has on stress introduced into SG joints due to cold‐bending.

Technological Advances to Maximize Solar Collector Energy Output: A Review

Since it is highly correlated with quality of life, the demand for energy continues to increase as the global population grows and modernizes. Although there has been significant impetus to move away from reliance on fossil fuels for decades (e.g., localized pollution and climate change), solar energy has only recently taken on a non-negligible role in the global production of energy. The photovoltaics (PV) industry has many of the same electronics packaging challenges as the semiconductor industry, because in both cases, high temperatures lead to lowering of the system performance. Also, there are several technologies, which can harvest solar energy solely as heat. Advances in these technologies (e.g., solar selective coatings, design optimizations, and improvement in materials) have also kept the solar thermal market growing in recent years (albeit not nearly as rapidly as PV). This paper presents a review on how heat is managed in solar thermal and PV systems, with a focus on the recent developments for technologies, which can harvest heat to meet global energy demands. It also briefs about possible ways to resolve the challenges or difficulties existing in solar collectors like solar selectivity, thermal stability, etc. As a key enabling technology for reducing radiation heat losses in these devices, the focus of this paper is to discuss the ongoing advances in solar selective coatings and working fluids, which could potentially be used in tandem to filter out or recover the heat that is wasted from PVs. Among the reviewed solar selective coatings, recent advances in selective coating categories like dielectric-metal-dielectric (DMD), multilayered, and cermet-based coatings are considered. In addition, the effects of characteristic changes in glazing, absorber geometry, and solar tracking systems on the performance of solar collectors are also reviewed. A discussion of how these fundamental technological advances could be incorporated with PVs is included as well.

Development of experimental methods for quantifying the human response to chromatic glazing

Thermochromic (TC) windows have the ability to regulate daylight and control the solar heat gains that shape a building's internal environment. They therefore offer the potential to improve indoor comfort and reduce building energy demand when used in place of traditional clear glazing systems. However, the quality of the luminous environment is affected due to their chromatic appearance (e.g. common TC coatings impart a bronze or blue hue), resulting in changes to correlated colour temperatures (CCT). Previous studies show that experiments performed under daylight conditions are difficult to be control, while those conducted under artificial lighting conditions cannot faithfully reproduce window properties. In order to investigate the influence of TC windows on visual performance and comfort of subjects in an efficient and economical way, an innovative test room cubicle was designed. It is a mock-up office lit by an artificial window, simulating luminous conditions filtered through two types of TC window (one blue tinted and one bronze tinted). Clear glazing was used as a reference. Objective visual tasks involving Landolt charts and subjective assessments made using questionnaires were used to determine subjects' response to the three different luminous conditions. Results show that the experimental method is effective at determining human response to chromatic glazing. Additionally, the method is flexible due to its small scale and its ability to artificially represent different window types.

Efficiency Enhancement of a Dual-axis Solar PV Panel Tracker Using Water-Flow Double Glazing Technique

إنّ زاويةَ سقوط أشعةِ الشمس على سطحِ اللوح الشمسي ودرجة حرارته يُؤثّرانِ سلبياً على الطاقة الكهربائية للوح وكفاءته. أن مشكلة زاويةِ السقوط عادةً ما يتم حلها بإستخدام منظومة التتبع (المقتفي) الشمسي ذات المحورِين والذي يُبقي اللوح بشكل مستمر متعامد مع أشعةِ الشمس طِوال اليوم. هذا يُؤدّي إلى أقصى إمتصاصِ للإشعاعِ الشمسيِ والضروريِ لإنتاج الكميةِ القصوى مِن الطاقةِ وعند مستوىات عالية مِن الكفاءة الكهربائية. لحَلّ مشكلةَ الحرارة فقد تمّ استخدام تقنية الغرفة الزجاجية (المزججة) والتي يتدفقِ خلالها الماء بوصفها طريقة تبريد جديدةِ لتخفيض درجة حرارة اللوح. في هذه البحث، تمّ تصميم منظومِة التزجيج المقترحة بالتكامل مَع منظومة التتبع ثنائية المحاور واجريت التجارب المختبرية عليها لغرض تحسين كفاءةَ اللوح الشمسي، لاسيما في المناخِ الحارِ. نظام التزجيج المُقتَرَحِ يُمْكِنُ أَنْ يُؤدّي وظيفتين بشكل آني، أولاً، يعَمَل أداة تبريد لتقليل الحرارةِ المَخْزُونة في داخل اللوح أثناء عَملها وثانياً مرشِحا بصريا للطيفِ الضوئي. تمّ حساب معاملات التصميمُ الأمثل وبمستويات مختلفة لقيم نظامِ التزجيج وفقاّ لطريقةِ تاكوتشي. تمّ تنفيذ تجارب الإختبارِ في مدينةِ بغداد في العشرين والحادي والعشرين مِنْ يوليو/تموز 2016 على منظومة التتبع في حالتين مع إستعمال مقترح منظومة التزجيج وبدونها. تبُين النتائِج المستحصلة بأنّ، درجةَ الحرارة اللوح الشمسي بإستعمال منظومة التزجيج هَبطت بشكل ملحوظ بمقدار 44% وزادت كفاءتها الكهربائية بحاولي36.6 % عند بالمقارنة مع المنظومة التقليدية عند قيمة اشعاع شمسي 1213 W/m2.

Acoustic measurements on monolithic aerogel samples and application of the selected solutions to standard window systems

Silica aerogels are thermally and acoustically insulating and can offer advantages in building thermal applications. They come in granular (multiple small pieces) and monolithic (single piece) form. Granular aerogels are relatively easy to produce and can be incorporated into large window systems. Large monolithic aerogels are more difficult to produce, but they offer superior optical and thermal performance. The aim of this paper is to experimentally investigate the acoustic properties of monolithic aerogel samples fabricated using a rapid supercritical extraction method. The acoustic absorption coefficient (α) and the transmission loss (TL) were measured at normal incidence in a traditional impedance tube in the 100–5000 Hz frequency range, for three thicknesses, from 12.7 to 25.4 mm. Good acoustic performance was achieved: 12.7-mm-thick cylindrical monoliths have a peak acoustic absorption coefficient of 0.88 at ∼1500 Hz. When the thickness increases, α decreases (to 0.78 and 0.54 for 19-mm and 25.4-mm thick samples, respectively), with peaks at lower frequencies (1300 and 1100 Hz). The transmission loss increases with aerogel thickness with values as high as 10–15 dB in the 100- to 1600-Hz range. When compared to granular aerogels, the monoliths have TLs that are 5–7 dB larger in the 100- to 1600-Hz range. To further compare performance, small glazing packages were fabricated from glass panels with air, granular, or monolithic aerogel in the interspace. The TL was evaluated and found to be in the 35- to 45-dB range for all samples. The monolithic aerogel glazing had the highest TL, particularly in the 200- to 1000-Hz range. Based on these results, we estimated a 3-dB increase in the sound insulation index for the glazing system with a monolith when compared to the glazing system with air, and a 1- to 2-dB increase when compared to the granular aerogel glazing. This study demonstrates that the use of transparent monolithic silica aerogel in the interspace of conventional glazing systems would result in significant improvement in noise insulation.