Sky model blends for predicting internal illuminance: a comparison founded on the BRE-IDMP dataset

Mardaljevic, John

doi:10.1080/19401490802419836

Cited by 17 publications

(14 citation statements)

References 12 publications

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“…The luminous output of the sun is based directly on the value for direct normal illuminance, and the sun position is determined from the time-stamp. The sky luminance distribution is either inferred from the illuminance data in the climate file using a sky model blending function [63], or generated automatically using, say, the Perez All-Weather model [64]. Some CBDM software can output, for example, total illuminance as four illuminance components, i.e.…”

Section: Summary and Future Prospectsmentioning

confidence: 99%

Daylight metrics and energy savings

Mardaljevic

Heschong²,

Lee

2009

Lighting Research & Technology

281

120

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The drive towards sustainable, low-energy buildings has increased the need for simple, yet accurate methods to evaluate whether a "daylit" building meets minimum standards for energy and human comfort performance. Current metrics do not account for the temporal and spatial aspects of daylight, nor of occupants comfort or interventions. This paper reviews the historical basis of current compliance methods for achieving daylit buildings, proposes a technical basis for development of better metrics, and provides two case study examples to stimulate dialogue on how metrics can be applied in a practical, real-world context.

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Section: Summary and Future Prospectsmentioning

confidence: 99%

Daylight metrics and energy savings

Mardaljevic

Heschong²,

Lee

2009

Lighting Research & Technology

281

120

View full text Add to dashboard Cite

show abstract

“…This convenience has resulted in the Perez All-Weather model being favoured for some studies, and also inclusion in some end-user daylight modelling tools. However, the Perez All-weather model has been shown to perform less reliably than a blend formulation which 'mixes' CIE overcast and clear sky patterns based on a simple rule [31]. This may be because the Perez All-weather model was founded on data collected only at one site, i.e.…”

Section: Deriving Sun and Sky Conditions From The Climate Datamentioning

confidence: 88%

“…Additionally, the model can occasionally produce distorted luminance patterns that contain spurious 'cusps' of negative luminance. For these reasons, the sky luminance patterns used for this study were derived from blends of CIE skies [31].…”

Section: Deriving Sun and Sky Conditions From The Climate Datamentioning

confidence: 99%

A framework for predicting the non-visual effects of daylight – Part II: The simulation model

Mardaljevic

Andersen

Roy³

et al. 2013

Lighting Research & Technology

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This paper describes a climate-based simulation framework devised to investigate the potential for the non-visual effects of daylight in buildings. It is part 2 of a study where the first paper focused on the formulation of the photobiological underpinnings of a thresholdbased model configured for lighting simulation from the perspective of the human nonvisual system (e.g. circadian response). This threshold-based model employs a static dose-response curve and instantaneous exposure of daylight at the eye to estimate the magnitude of the non-visual effect as a first step towards a simulation framework that would establish a link between light exposure at the eye in an architectural context and expected effects on the non-visual system. In addition to being highly sensitive to the timing and duration of light exposure, the non-visual system differs fundamentally from the visual system in its action spectrum. The photosensitivity of the retinal ganglion cells that communicate light exposure to the brain is known to be shifted to the blue with respect to the photopic sensitivity curve. Thus the spectral character of daylight also becomes a sensitive factor in the magnitude of the predicted non-visual effect. This is accounted for in the model by approximating 'yellow' sunlight, 'grey' skylight and 'blue' skylight to three distinct CIE illuminant types, and then tracking their 'circadianlux' weighted contributions in the summation of daylight received at the eye. A means to 'condense' non-visual effects into a synthesised graphical format for the year, split by periods of the day, is described in terms of how such a format could inform design decisions. The sensitivity of the simulation model's predictions to prevailing climate and building orientation is demonstrated by comparing results from eight European locations.

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“…One can note that, in building applications, alternative approaches of sky model blends were also developed in order to extend the capabilities of existing 'narrow-range' models. For instance, it has been shown that simple blends of the CIE overcast, CIE clear and intermediate models may be adequate to improve prediction of time-varying sky luminance patterns (Mardaljevic, 2008).…”

Section: Empirical Modelsmentioning

confidence: 99%

Modelling the clear-sky intensity distribution using a sky imager

et al. 2015

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International audienceThis paper introduces a new empirical formulation of the clear-sky intensity distribution based on images acquired with a sky imager developed at the PROMES-CNRS laboratory (Perpignan, France). Both the formulation and image processing methodology are detailed and stand for key steps in the development of a high quality cloud detection algorithm. The work presented in this paper is a part of a research project which aims at improving solar plant control procedures using direct normal irradiance forecasts under various sky conditions at short-term horizon (5-30 min) and high spatial resolution (∼1 km 2). Modeling the clear-sky intensity distribution in real time allows clear-sky images to be generated. These clear-sky images can then be used to remove the clear-sky background anisotropy on images and so improve cloud detection algorithms significantly. Cloud detection is essential in short-term solar resource forecasting. The new formulation is especially designed for improving performance of the existing models in the circumsolar area. When tested over more than 2200 clear-sky images, corresponding to a solar zenith angle spanning from 24 • to 85 • , the new formulation outperforms a standard approach based on the All-Weather model (Perez et al., 1993) by 15% on the whole sky and more than 20% in the circumsolar area. Application of the methodology for the real-time cloud detection purpose is discussed at the end of the paper

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Sky model blends for predicting internal illuminance: a comparison founded on the BRE-IDMP dataset

Cited by 17 publications

References 12 publications

Daylight metrics and energy savings

Daylight metrics and energy savings

A framework for predicting the non-visual effects of daylight – Part II: The simulation model

Modelling the clear-sky intensity distribution using a sky imager

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