Definition of the CIE standard skies and application of high dynamic range imaging technique to characterize the spatial distribution of daylight in Chile

Abstract

Manuscript Code: 0446 Date of reception/acceptation: 01sep2014/01dec2014Resumen La efectividad y precisión de un estudio de iluminación natural depende de conocer las condiciones de clima y la luz disponibles en un lugar, para así evaluar la iluminancia obtenida durante el proceso proyectual. Se presentan las metodologías aplicadas de una investigación realizada cuyo objetivo fue conocer y entregar datos realistas de la distribución espacial de los cielos, para así construir las bases para futuros estudios de iluminación en Chile. Se inicia con una revisión de las métricas para cuantificar la luz natural; posteriormente se presenta la metodología utilizada para levantar la información de frecuencias mes a mes en cuatro tipos de cielos CIE estándar a partir de archivos meteorológicos. Finalmente, se expone el método de fotografías de alto rango dinámico (High Dynamic Range-HDR) aplicado para conocer la distribución espacial de los cielos de seis ciudades de Chile. Se concluye que conocer los cielos CIE estándar posibilita focalizar los estudios de iluminación natural para cielos predeterminados, realizando un diseño y análisis para los cielos más frecuentes. Así mismo, el método aplicado para caracterizar la distribución espacial de los cielos debe ser calibrado para cada localidad de estudio.Palabras claves: Luz Natural, modelos de cielo CIE, distribución de iluminancia del cielo, fotografía de alto rango dinámico, captura del cielo AbstractThe effectiveness and accuracy of a daylighting study relies on knowing the climate and light conditions available at a given place, to then evaluate the illuminance obtained during the project development process. This paper presents the methodologies of a research process, whose objective is providing realistic data to establish the foundations for future lighting studies in Chile. It starts with the revision of the metrics used to quantify daylight; later, the methodology used to collate the monthly frequencies on four types of standard CIE skies, starting from climate files, is presented. Finally, both the methodology and the results obtained are presented to measure and characterize the real skies, as well as the High Dynamic Range photographs (HDR) and, as complement of this information, the illuminances measurements of the sky dome to define the types of skies of six Chilean cities. From the study applied, it is possible to conclude that knowing the standard CIE skies of a place allows us to adjust and focus the daylighting study for predetermined and predominant skies. It is just as important to mention that the measuring techniques for the skies must be adjusted and calibrated for each studied location.

Daylight Glare Probability Prediction for an Office Room

“…The Perez sky is based on a weather file and uses a time-related sky distribution (Alshaibani et al, 2020). The latter is preferred in daylighting studies (Piderit et al, 2014) The setup (Figure 1) consists of an office room with dimensions (H x L x W) 2.40 m x 3.00 m x 2.40 m, which is similar to the setup used in (Goovaerts et al, 2017). The window is south-east oriented.…”

An experiment of double dynamic lighting in an office responding to sky and daylight: Perceived effects on comfort, atmosphere and work engagement

“…Sky- and daylight sensorsA short study was designed to determine how the illuminance values received by the sky scanner change regarding the sky condition. 49–52 Over two weeks in May 2019, sky photographs were taken every fifth minute, resulting in 2000 pictures, accompanied by timestamps. Two research assistants manually labelled each of the pictures taken, and for each labelled instance, the latest sky scanner reading was matched.…”

Passive system optimization in office buildings using a reference testbed building

“…The number of hours was calculated with help of a climate database (Meteonorm 7) [14]. The overcast hours were identified by calculating sky clearness («) based on the following equation, [15,16]:…”