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Simulation study on the influence of thermal performance of energy-saving doors and windows on building energy consumption
Published in Mohd Johari Mohd Yusof, Junwen Zhang, Advances in Civil Engineering: Structural Seismic Resistance, Monitoring and Detection, 2023
Ming Cao, Shanshan Xu, Yunli Zhang, Leixin Yu, Bingxiang Zhao
Among many performance indexes of architectural glass, heat transfer coefficient and solar thermal coefficient can be used to judge its energy-saving characteristics. Heat transfer coefficient (U or K, hereinafter referred to as K value) refers to the amount of heat transfer through 1m2 glass per unit time with the air temperature difference on both sides of the window of 1°C under the condition of stable heat transfer, expressed in W/(m2·K). Heat transfer coefficient is a general parameter of enclosure structure. Generally speaking, the lower its value, the better its thermal insulation performance. The thermal coefficient of the sun (SHGC) refers to the ratio of the amount of solar radiation energy entering the room through the window glass and the amount of solar heat entering the room through the same size but no glass opening under the same conditions. For K value and SHGC value, the former mainly measures the heat transfer caused by temperature difference, while the latter mainly measures the heat transfer ratio caused by solar radiation, and the two kinds of influences exist at the same time in real life environment. However, for different climatic zones in China, K and SHGC values have different influences on energy saving effect. In this paper, we use DeST software to simulate and calculate the energy consumption of buildings located in different climatic zones, and discuss the influence of K and SHGC values of door and window glass on building energy consumption in different climatic zones.
Perspective on Materials, Design, and Manufacturing of Electrochromic Devices
Published in Avinash Balakrishnan, Praveen Pattathil, Nanostructured Electrochromic Materials for Smart Switchable Windows, 2018
Avinash Balakrishnan, Praveen Pattathil
The electrolyte, which is ionically conducting but electronically insulating, separates the electrodes. The electrolyte can be made up of either a polymer (gels) or a thin film. Polymer electrolytes lead to laminated sandwich EC structures while thin film electrolytes are the basis of all-thin film EC coatings. The thin film coatings are manufactured by deposition processes common to the architectural glass coating industry, e.g., sputtering, evaporation, and chemical vapor deposition (CVD). The battery-like EC windows have extended open circuit memory where continuous current is supplied to maintain the device in the colored state. Here the depth of coloration is proportional to the current density. Solution and hybrid EC windows fall into the self-erasing category, in which one or both of the color-changing EC materials is dissolved in a liquid or gel electrolyte, where it can easily diffuse. These approaches have been implemented in commercially successful EC mirrors [21,22].
Applications
Published in Pramod K. Naik, Vacuum, 2018
Thin films deposited in vacuum have several applications in the fields including optics, electronics, metallurgy, magnetics, mechanics and photovoltaics. Chemical vapour deposition 21 and plasma chemical vapour deposition 22 (which also needs vacuum for producing plasma) are potentially promising techniques for thin film coatings. Excluding the coatings on architectural glass, most films are presently deposited in vacuum. Antireflection coatings 23 on lenses are used in a number of optical objects such as eyeglasses, cameras and in optical equipment including telescopes, microscopes. Such coatings generally consist of layers of contrasting refractive indexes. The thicknesses of the alternate layers are selected to produce destructive interference in the reflected beams from the interfaces, and constructive interference in the transmitted beams. High-reflection (HR) coatings are based on the periodic layer system with two materials, one with a high index, and the other with low index material. Such a system enhances the reflectivity of the surface in a certain wavelength range known as band-stop. The width of the band stop is decided by the ratio of the two indices for quarter-wave system. The maximum reflectivity increases up to about 100% with a number of layers stacked. The reflected beams interfere constructively with one another to maximize reflection and minimize transmission. Common HR coatings can achieve 99.9% reflectivity over a broad wavelength range.
Heliotropic Shading: Daylighting a Rare Books Reading Room with Electrochromic Glass and Parametric Analysis
Published in LEUKOS, 2023
One of the key benefits of EC glazing is the minimal impact on views, which has been shown to be one of the key factors in occupant well-being within buildings (Heschong 2021; Ko et al. 2022a, 2022b). Manufacturers of EC glazing products tout the ability to reduce visual light transmission without obscuring views to the exterior. Additionally, containing daylight control within the IGU reduces issues with maintenance, cleaning, and silent control with no noise from motors compared to roller shades. EC glass can also block ultraviolet (UV) light, which can be harmful to both people and materials, where prolonged exposure can cause skin damage, fade upholstery and carpets, and degrade materials like plastics, wood, or paper. Electrochromic glass can block a significant amount of UV radiation (Tuv) in the 300–380 nm range, while still allowing visible light to pass through by adding UV-absorbing compounds to the electrochromic material or to one or both of the glass panes (Mortimer et al. 2015). An additional metric, “Damage Weighted Transmittance” (Tdw) “assigns a specific damage weight factor to each wavelength of UV or visible light based on its contribution to fading,” and that includes a larger swath of wavelengths from 300–600 nm (Vitro Architectural Glass n.d., 2). The application of electrochromic interlayers severely limits the Tdw percentage when the tint is applied.
The impact of Jin Mao Tower on life-cycle civil engineering of tall buildings
Published in Structure and Infrastructure Engineering, 2022
The moment frames on the north and west sides of the building form an exposed concrete ‘stiffened frame’ outside the architectural glass enclosure of the building. The ‘stiffened frame’ consists of primary frame columns spaced at 9 m on center, connected together with primary frame beams connecting the columns together at every 3 stories. Each 9 m wide x 12.3 m tall bay is further stiffened with the addition of secondary frame columns and beams that infill the primary bay in the form of an architectural pattern. Delayed pour joints are provided where stiffening element connected to the primary frame to minimize gravity loads transmitted into the stiffening elements. Floor slabs are held back from the screen frames to create slots, with the only engagement of the floor structure and screen frames occurring at the connecting floor girders that frame into the columns. The ‘necks’ of the girders at the slots are specially designed for seismic and gravity loads (Figure 38).
Self-diffusion method for broadband reflection in polymer-stabilized cholesteric liquid crystal films
Published in Liquid Crystals, 2022
Xuetao Zhang, Weiting Shi, Rui Han, Hui Li, Hui Cao, Yinjie Chen, Zhou Yang, Dong Wang, Wanli He
In this paper, a simple and efficient method for preparing broadband reflective LC films is proposed by using a polymer network in the PSCLCs itself as a diffusion channel in combination with the technique of sticky and anti-stick glass surface treatment. This has been confirmed by SEM and contact angle tester, respectively. The results show that by controlling the content of R5011 and UV-327, the diffusion time and the thickness of the nematic liquid crystal, the λm and the Δλ are adjusted. After curing, the Δλ is widened again. The widest reflection bandwidth of the film prepared by this method almost covers the whole near-infrared region. This simple method of preparing reflected bandwidth films is expected to have great potential for applications such as energy-efficient architectural glass, laser protection, and infrared shielding.