Specification of Glazings for Façades Based on Spectrophotometric Characterization of Transmittance

Abstract

The correct specification of glazings for façades can reduce the energy consumption in buildings. The heat exchange occurs through transparent surfaces and radiation reaches the building as light and heat. Therefore, glazings significantly contribute to the heat transfer between outdoor and indoor spaces and act directly on daylighting and thermal comfort. This paper reports on the spectrophotometric characterization of glazings transmittance for the study of components of a modular façade system and its suitability for the climate of Portugal (temperate climate). The study focused on results of spectrophotometric measurements of optical properties, specifically the transmittance of some types of glazings (solar control, self-cleaning, low-e, float, and extra-clear) and two types of double glazings. The results show the percentage of transmission to ultraviolet, visible, and near-infrared regions and its importance, which enabled the analysis of the glazing efficiency regarding daylighting and the correlation to thermal performance. Subsidies and indications for the specification and adequate uses of transparent surfaces have been presented and complemented the datasheets available from the manufactures.

Ultraviolet Radiation Transmission in Buildings’ Fenestration: Part I, Detection Methods and Approaches Using Spectrophotometer and Radiometer

“…Information concerning mechanical resistance, acoustic insulation, and thermal transmittance are usually provided by glass manufacturers for their products. However, such information tends to lack specificity and omit specific data pertaining to the material's behavior within the ultraviolet radiation spectrum [40]. Ultraviolet transmission serves as an indicator of the degree of protection or potential harm that a substance or material can offer or inflict when subjected to UV radiation.…”

“…Thus, recommending either laminate glass or a pair of clear and UV protection glass sheets treated with a UV protection film is appropriate. These configurations attain 100% and 96.7% UV protection efficacy from natural light, respectively [40]. As detailed in Figure 10, laminate glass provides a significantly higher level of protection against UV radiation compared to float glass.…”

“…[ 48,49] These devices do not have portability or mobility due to their large size and require careful handling because they are made of sensitive materials, which makes them unsuitable for everyday use. [40,60] Possible interference from external factors such as light, noise, temperature, vibrations, dust, etc. may affect the accuracy and precision of the measurements.…”

Zastosowanie szkła konstrukcyjnego w kształtowaniu przeszklonych elewacji

“…The glass used in facades is manufactured and modified for specific uses and technical requirements in building envelopes. First of all, the spectrophotometric properties of glass are applied to obtain products characterized by specific features, including visible light transmission, protection against sunlight, reflectivity or anti-reflectivity (Sacht et al, 2021;Kosmala, Kuśnierz and Kozłowski, 2022, p. 28). Insulating glass units (IGUs) with low-emissivity glass that ensure thermal insulation are also produced (Aguilar-Santana et al, 2020).…”

Influência da absorção de vidros de controle solar no consumo de energia para climatização de um edifício de escritórios

“…Ainda assim, poucos autores exploram a influência que outras propriedades ópticas dos vidros podem ter na eficiência energética da edificação. Sacht et al [9], avaliou as características espectrofotométricas dos vidros, correlacionando com a performance térmica, a partir do percentual de radiação UV, visível e infravermelho transmitido por ENTAC2022 -Ambiente Construído: Resiliente e Sustentável 3 cada amostra. Mas, também limitou-se as características de catálogo (FS e U-value).…”