Solar Control Glass Research Articles

Thermal performance of a novel double-glazed window combining PCM and solar control glass in summer

The integration of PCM into glazed envelope to enhance its thermal inertia has shown great energy-saving potential. However, this could bring indoor overheating in summer due to the insufficient heat insulation for solar radiation in pure PCM glazed units. This work proposed a composite double-glazed window incorporating PCM and solar control glass, and numerically investigated its thermal behaviors under sunny and cloudy conditions in summer of northern China. The effects of glass optical properties, involving absorption coefficient and refractive index, on the phase change cycling, indoor thermal comfort and building energy efficiency were analyzed. The results show that the increase of glass absorption coefficient facilitates the melting of PCM, but degrades the thermal comfort, even resulting in overheating risk on the sunny day. Moreover, as the absorption coefficient and refractive index of glass increase, the energy efficiency of PCM window equipped with solar control glass instead of general glass can be improved remarkably, and the influence of refractive index is more drastic than that of absorption coefficient. On the sunny day, the energy saving rate is 14.25% for the glass absorption coefficient of 160 m−1, which is 41.53% for the glass refractive index of 3.

Adjustment Of Light Distribution In Auditorium Of Universitas Negeri Manado

This paper provides an overview about the visibility condition in an auditorium of Universitas Negeri Manado. As a place used for holding official meetings and numerous formal activities, it requires proportional light distribution. An experimental simulation about lighting system in auditorium is carried out based on data analysis using AutoCAD and Dialux. The simulation resulted paucity of light intensity and bleak radiance distribution which, based on Indonesian national standards, is noncompliance. Several methods of lighting adjustment are proposed: enlargement of exposure by replacing and setting glass material proportional to the incoming sunlight, adjustment of reflectance equipment in the vicinity, applying lightselves and setting light spots. Enlarging exposure and adjusting reflectance equipment permits 15% larger comfort area for user, based on DIALux simulation. Adjusting the use of solar control glass and lightselves at the aperture will reduce ablaze of light by up to 20%. Using LED reliably light offers magnificent brightness and providential low voltage.

Energy Saving Building Strategies through The Application of Solar Control Glass

ABSTRAKSesuai dengan konsep Green Building, desain bangunan harus memperhatikan penghematan energi operasional bangunan. Semakin besar beban termal, maka semakin boros konsumsi energi listrik. Salah satu cara untuk menurunkan energi listrik adalah dengan mengurangi beban termal eksternal, sehingga pemilihan jenis solar control glass merupakan aspek yang sangat penting. Metoda analisis dilakukan secara kuantitatif. Sebagai kasus studi yaitu Gedung Kantor Pengelola Bendungan Sei Gong di Batam, dan berdasarkan perhitungan Calculator OTTV akan ditentukan alternatif solar control glass yang tepat agar memenuhi syarat dengan batas maksimal OTTV di Indonesia (45 Watt per meter persegi). Manfaat penelitian ini adalah memperoleh masukan pemilihan tipe kaca yang tepat berdasarkan SHGC, pada kasus bangunan kantor.Kata kunci: Hemat energi operasional bangunan, Overall Thermal Transfer Value, Solar Control Glass, Solar Heat Gain Coefficient ABSTRACTIn accordance with the Green Building concept, building designs must pay attention to building operational energy savings. The greater the thermal load, the more wasteful the electricity consumption of the AC system. One way to reduce AC loads is to reduce external thermal loads, then choosing the type of solar control glass is a very important aspect. The method of analysis is done quantitatively. As a case study is Sei Gong Dam Management Office Building in Batam, and based on OTTV Calculator calculation an appropriate solar control glass alternative will be determined to meet the requirements with the maximum OTTV limit in Indonesia (45 Watt per square meter). The benefit of this research is to get input on selection of the right type of glass based on SHGC, in the case of office buildings.Keywords: Energy saving on building operation, Overall Thermal Transfer Value, solar control glass, Solar Heat Gain Coefficient

First-Principles Calculations of x-Dependent Ground Structures and Optical Properties of Ca x La1-x B6.

High transparency in the visible region is desired to manufacture solar control films and glasses for various applications. To improve the visible light transparency of LaB6 nanoparticles which exhibit strong absorption in the near-infrared region, the substitution of La with Ca is investigated using first-principles calculations. Among the numerous atomic replacement configurations in CaxLa1–xB6, all 762 structures existing in the supercells that are up to 8 times the primitive cell are comprehensively evaluated, and the most stable ground structures in CaxLa1–xB6 are deduced. The optical properties of the ground structures are derived by performing high-precision calculations using the HSE06 functional, which reveal that CaxLa1–xB6 with 0 < x < 1/4 is preferred as a solar shielding material with improved visible transparency. This method is effective for the investigation of the effect of substitutional elements in composite compounds on their physical properties.

Bioclimatic greenhouses for energy efficiency in buildings

The research aims to verify the contribution to microclimatic comfort offered by the bioclimatic solar greenhouse at the ENEA Casaccia, F92 building. The analysis was carried out using the opensource software, EnergyPlus, for thermal simulation and dynamic energy diagnosis of buildings, based on the 3D geometric model built using the Google SketchUp software. The simulation led to evaluate the gained energy from solar radiation through the glazed surfaces due to the bioclimatic greenhouse and the consequent increase in the operating temperature of the internal environment during the winter season. The research moves from the most recent regulatory developments in terms of energy saving and more modern technology developments related to the design and construction of high energy performance solar control glass elements to demonstrate the effectiveness of bioclimatic greenhouse systems in improving internal comfort levels reducing non-renewable energy consumption for indoor air conditioning. The Temperature hourly trends showed an average increase in the operating T°, during the winter season of about 0.59°C.

Evaluation of Building Energy and Daylight Performance of Electrochromic Glazing for Optimal Control in Three Different Climate Zones

The objective of this paper is to analyze the control conditions of the transmittance rate, and determine the conditions that are most optimal with respect to building energy and daylight performance in three climate conditions: Riyadh, Saudi Arabia (hot climate); Inchon, South Korea (hot and cold climate); and Moscow, Russia (cold climate). The analysis was based on the electrochromic glass developed by a research team. Electrochromic glass is a next generation solar control glass that can control the transmittance of the glass itself. Therefore, proper control methods are essential for rational use of this electrochromic glass. To properly control electrochromic glass, daylight performance must be considered, along with building energy (heating, cooling, and lighting). If only building energy is considered, transmittance needs to be lowered during the summer season and increased during the winter season. Controlling electrochromic glass transmittance with such a method would not improve the satisfaction of users and occupants of a building due to the resulting glare. In addition to energy reduction, the basic function of solar control glass is to prevent glare. Therefore, in this study, we develop the Energy and Daylight Performance Index (EDPI) using, to evaluate the combined building energy and daylight performance and deduce the optimal control method for electrochromic glass. In addition, optimal control conditions for the three different climatic regions were obtained. Limitations of this study were that the scope was restricted to the eastern climate region, and that the building analysis model was limited to one climate region. It is expected that the optimal control method could be used as an initial database in the development of a electrochromic glass control system.

Deducing the Optimal Control Method for Electrochromic Triple Glazing through an Integrated Evaluation of Building Energy and Daylight Performance

Electrochromic glass is anticipated as the next generation of solar control glass for construction because it can control the transmittance of the glass itself. This study analyzed building energy and light environment performance by applying electrochromic glass in triple glazing in order to verify both the solar control characteristics of electrochromic glass and its high insulation performance. This paper evaluates the performance of the electrochromic glass developed by our research team in Korea in five control conditions of varying temperatures and solar radiation levels. By analyzing the cooling and heating load, lighting energy, Daylight Glare Index (DGI), and interior illuminance when applying the selected conditions to office buildings, this paper discerns the optimal control conditions for electrochromic glass. To do so, the optical characteristic data of the electrochromic glass was analyzed via an experiment, and the creation of triple glazing for construction was conducted. The performance of electrochromic glass was evaluated by analyzing hourly and yearly data for cooling, heating load, and lighting energy during a typical day in summer and winter. From this analysis, the control condition with an outstanding performance from an energy perspective was identified. The performance of the light environment was assessed, and the EDPI overall evaluation index was used to find the electrochromic glass’ optimum control conditions for integrating energy and light environment.

Smart windows for carbon neutral buildings: A life cycle approach

This study assesses the influence of photovoltachromic windows (PVCCs) on the Life Cycle Impact and Life Cycle Total Energy of office buildings. To this aim, two commercial buildings, having the same size and typology, only differing on glazing's technologies—PVCCs and commercial solar control glass panes integrated with photovoltaic (PV) panels—were compared. A full analysis was performed in three locations representative of as many climatic conditions (Aswan, Brindisi and London). The results obtained showed that the overall impact due to the production of a PVCC cell is considerably lower than the one of traditional technologies offering the same performances. Reductions of impacts spanning between 41% and 44% were obtained. Moreover, all impact categories benefited from smart windows' building integration in the operational phase, especially in the Mediterranean climate. If in Aswan the reduction of impact is mainly ascribable to energy demand for cooling, in cold climates savings in lighting energy dominate.

Energetic and visual comfort implications of using perovskite-based building-integrated photovoltaic glazings

Building integration of photovoltaics (BIPVs) has been recognized worldwide as a pivotal technology enabling the exploitation of innovative renewable energy sources in buildings, acting as electric power generators within the new framework of smart cities. Photovoltaic (PV) modules can be designed as relevant components of building envelopes, energy-producing units, fulfilling the multiple requirements of construction elements. Their integration in architectural glazings is still impeded by the inherent optical features of commercial solar cells, but also aesthetic, economic and social constraints, still acting as relevant barriers. In this roadmap, novel PV technologies could be effective drivers of a real change of paradigm. We have recently demonstrated that a coherent and exhaustive study of BIPV for semitransparent cells requires a “holistic approach”, taking into account the complex fallouts of semitransparent modules on the energy balance, but also the full assessment of visual comfort benefits deriving from their integration in glazings. We have demonstrated that BIPV could offer manifold advantages: visual comfort effects comparable to commercially available solar control glasses and fair energy yield. Moreover, we found that in several cases the annual energy production overcomes the amount of electric energy used for artificial lighting.

Building integration of semitransparent perovskite-based solar cells: Energy performance and visual comfort assessment

This study presents a prediction of the yearly energy production and visual comfort benefits deriving from the adoption of building integrated semitransparent photovoltaic windows. Measured electrical and optical properties of neutral-colored solid-state planar heterojunction perovskite cells, characterized by promising transparency and photovoltaic conversion efficiency, were applied to a hypothetic photovoltaic glazing. Such experimental data were used as input to estimate annual energy production and visual comfort effects. The effect of different climate conditions was also investigated. A south-oriented test-room was modelled, assuming two window-to-wall ratios (WWRs) for office buildings, 19% and 32%, respectively. Energy yield was calculated at different locations showing figures between 20 and 30kWh/m2 per year, with negligible reduction (not exceeding 3% in the hottest climates) when cell temperature was taken into account. Visual comfort assessment was carried out using two typical metrics: Useful Daylight Illuminance (UDI) and Daylight Glare Probability (DGP), comparing the performances of a photovoltaic glass with those of a commercial solar control glass and of a clear glass, acting as a reference. We found that the use of photovoltaic glass, independent of the location latitude, showed a significant increase in UDI values respect to clear glasses and performances comparable to solar control glasses. With reference to DGP, the use of photovoltaic glass allowed the reduction of occurrence of high DGP values (>0.45) of about 12–23%, depending on the location. Finally, we compared the annual energy production of building integrated photovoltaic cells to the annual use of electric energy for artificial lighting, finding that in most of the cases the annual energy production overcomes the amount of electric energy used for artificial lighting.

The Thermal and Optical Behavior of Multilayer Low-E Solar Control Glass Surfaces

Glass is one of the most popular and versatile building materials used today. One reason is because of its constantly improving solar and thermal performance. And one way this performance is achieved is through the use of passive and solar control low-e coatings. In architecture, the proper use of natural light can help reduce the energy consumption of a building (by reducing the heat load for heating - based on the superior of solar contributions, with an appropriate glass type and daylighting). This paper aims to present the thermal behavior of multilayer glass surfaces, low-e solar control and highlight differences to ordinary glass.

FB720 project: development of new solar control glazing with passive seasonal discrimination of solar radiation incomes

Currently, the most balanced technical solution for sun protection of glazed areas is the Venetian blind, because it prevents the entry of direct solar radiation, but at the same time provides a view of the outside and allows light to diffuse into the building. The current challenge is to find an improved, integrated technical solution at an af- fordable cost that requires low maintenance, is suitable for every geographical situation (latitude) and adaptable to each orientation of building facades. The solar control glass facade FB720 presented here integrates into a single structural element the advantages of protective glass and Venetian blinds.

Environmental monitoring and microclimatic control strategies in “La Specola” museum of Florence

This work presents the results of the environmental monitoring of some rooms of the “La Specola” Museum in Florence, affected by significant overheating problem in summer mainly due to the absence of efficient solar shadings. The elaboration and analysis of the microclimatic data have been carried out according to the Italian Standard UNI 10829 and the Performance Index of the most important thermo hygrometric parameters has been calculated and assessed. This analysis shows that temperature and RH conditions were not reasonably acceptable for the preservation of the kind of objects exhibited. In order to reduce this problem, solar gain control solutions (shadings and solar control glasses) has been analyzed with a dynamic thermal simulation tool for two sample rooms, as a possible solution to improve architectural integration with the historical context. In order to reduce the risk of damage, the evaluation of different strategies has been expressed in terms of the reduction of energy need for space cooling and in terms of the ability to control dry bulb temperature values. The results can be extended to several historical buildings, where large windows and skylights imply high energy consumption and poor indoor environmental conditions that can cause damage to the artefacts.

Energy saving potential of semi-transparent photovoltaic elements for building integration

Within the building energy saving strategies, BIPV (building integrated photovoltaic systems) present a promising potential based on the close relationship existing between these multifunctional systems and the overall building energy balance. Building integration of STPV (semi-transparent photovoltaic) elements affects deeply the building energy demand since it influences the heating, cooling and lighting loads as well as the local electricity generation. This work analyses over different window-to-wall ratios the overall energy performance of five STPV elements, each element having a specific degree of transparency, in order to assess the energy saving potential compared to a conventional solar control glass compliant with the local technical standard. The prior optical characterization, focused to measure the spectral properties of the elements, was experimentally undertaken. The obtained data were used to perform simulations based on a reference office building using a package of specific software tools (DesignBuilder, EnergyPlus, PVsyst, and COMFEN) to take proper account of the STPV peculiarities. To evaluate the global energy performance of the STPV elements a new Energy Balance Index was formulated. The results show that for intermediate and large façade openings the energy saving potential provided by the STPV solutions ranges between 18% and 59% compared to the reference glass.

The Energy Upgrading of Existing Buildings: Window and Shading Device Typologies for Energy Efficiency Refurbishment

Residential buildings built after the Second World War have high energy consumption and inadequate thermal comfort, especially in summer conditions, largely attributable to the high transmittance of windows and lack of effective shading devices. Performance improvement of these components is essential for energy upgrading of existing buildings. This paper shows the results of the research, which aims to evaluate effects on energy consumption and environmental comfort of combined solutions of windows and shading devices applied to a case study representing a typical post World War II Italian building. In this paper, the main typologies of solar control systems are described and evaluated on the basis of a case study in different climatic locations (Berlin, Milan, Florence and Athens). Thermal behavior has been assessed through the EnergyPlus dynamic calculation code, by using appropriate performance indicators for energy and thermal sensation. Starting from performance evaluation of the existing building, different strategies have been assessed: replacement of existing windows with high-energy performance ones and introduction of shading devices and solar control glasses. Finally, a global comparative analysis has been carried out based on energy, acoustic and lighting performances, technical feasibility and management problems. Results of the different solar shading devices assessment are reported in the form of a data sheet.

Thermo-fluid dynamic modeling and simulation of a bioclimatic solar greenhouse with self-cleaning and photovoltaic glasses

This paper describes the multifunctional complex “Solaria”: a development project of an unused industrial area, located in a urban district in the immediate outskirts of Perugia (Italy), conceived and designed according to principles of sustainable buildings. Energy efficiency solutions and innovative experimental components are synergically integrated in a single project, enabling to reach important results, as demonstrated by the assessment of environmental achievements and the calculation of avoided CO2 emissions. Since a quantitative evaluation of the energy savings, that can be achieved with the use of bioclimatic greenhouses, is very complex, due to the large number of parameters,which are necessary to describe their operation, the research work focused on the thermo-fluid dynamic modeling of these systems, with the use of a specific CFD-FEM software, COMSOL Multiphysics™.In particular a model was created, initially conceived in 2D and currently developed in 3D, which reproduces the thermo-fluid dynamic behavior of an experimental greenhouse in the Solaria complex. The possibility of changing parameters characterizing materials and climatic conditions allowed to appreciate the influence on energy performance of special reinforced thermal insulation, solar control glasses and external sliding sunshades. A further added value is the possibility to simulate an organic thin-film photovoltaic device of nanometric thickness.

Glass Coating Removal by Atmospheric Oxygen Plasma

Coatings such as Cr, Ni, Ti, and SiO2/SnO2 on solar-control and low-emissivity (low-E) glasses are commonly used in the energy efficient glass windows. However, coloring in the re-manufactured glass panels using recycled window glasses resulting from the coatings reduces the glass transparency significantly. Traditional ways to remove coatings by manual wheels and pneumatic removal machines are labor intense and slow processes. In this study a new way to remove the coatings on recycled coated glasses was investigated. The Ultra Violet/Visible/Infrared (UV/VIS/IR) spectra and Secondary Electron Microscope (SEM) pictures were taken before and after 30s. atmospheric pressure oxygen plasma treatments. It was confirmed that the atmospheric oxygen plasma treatment is a fast, efficient, and low pollution way to remove the coatings before the remanufacture of recycled glasses. Other than the physical sputtering off the coatings from the plasma, there are many excited oxygen species in the plasma which effectively react to the coating and the products are then removed.

Sol–gel derived photonic bandgap coatings for solar control

Sol–gel derived photonic bandgap films have been investigated as possible multilayer coatings for solar control glass applications. Multilayer Bragg mirrors, in particular, have been modelled by the Transfer Matrix method, designed to have either near-UV or near-IR reflectivity, but visible transparency, based on alternating aluminosilicate glass/titania quarter-wave stacks. Such composite multilayer structures have been deposited by sol–gel processing on selected glasses and other types of substrates and their optical characteristics have been measured by optical absorption and reflection spectroscopies, as well as spectroscopic ellipsometry to determine the single layer refractive index and thickness. The UV–visible-IR absorption and reflection characteristics of these multilayer coatings revealed solar control properties, due to the presence of peaks near ∼350–400 nm and ∼900–1000 nm, with reflectivities of the order of 70%, which appear promising for solar control application.

Solar Control Glass

Solar control glass has applications for windows and glazed facades in order to modify indoor visual and thermal comfort in buildings. The article presents the results of evaluation study of optical properties of selected types of solar control glasses and foils. The spectral transmittance measurements were used as input data for daylight comparative studies, and the consideration of convenience of selected solar control glasses and foils for windows are summarised on the basis of analysis of optical properties.

Optical properties of CeO 2/Fe 3O 4 solar control glass coating

A cerium-iron oxide solar control coating on glass was prepared by citric acid sol-gel method, dip-coating techniques and proper heat treatment process. Results show that the cerium-iron glass coating is composed of nanocrystalline CeO 2, Fe 2O 3, and nano holes. The cerium-iron glass coating has high transmit-tance in visible light, low UV and near IR transmittance. The wavelength of absorption edge for most glass coating has an obvious redshift to about 375 nm. There exist a wide absorption band at the range of 800 – 1600 nm and high transmittance at the wavelength from 400 nm to 800 nm, and the solar energy and visible transmittances are 50% and 65%, respectively. It ascribes to the high content of trivalence cerium and bivalence iron ions in the cerium/iron coating. It is indicated that this kind of glass coating has very good UV-sheering and heat-insulating property, can be used as an effective solar control glass in automobile and architecture.