Comparison of radiosity and ray-tracing techniques with a practical design procedure for the prediction of daylight levels in atria

Tsangrassoulis, Aris; Bourdakis, Vassilis

doi:10.1016/s0960-1481(03)00078-8

Cited by 30 publications

(13 citation statements)

References 4 publications

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“…Since interior illuminance analysis has a great effect on the control of artificial lightings, it may be viewed to be related with the energy consumption of an entire building. Tsangrassoulis et al [8] performed the comparative study between radiosity and ray-tracing methods in terms of the daylight levels in atria under a variety of conditions. Hviid [9] suggested the combined approach between radiosity and ray-tracing techniques to develop a simple but accurate tool for the proper prediction of indoor daylight level.…”

Section: Open Accessmentioning

confidence: 99%

Window Material Daylighting Performance Assessment Algorithm: Comparing Radiosity and Split-Flux Methods

Yoon

Jeong

2014

Energies

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Abstract:Windows are the primary aperture to introduce solar radiation to the interior space of a building. This experiment explores the use of EnergyPlus software for analyzing the illuminance level on the floor of a room with reference to its distance from the window. For this experiment, a double clear glass window has been used. The preliminary modelling in EnergyPlus showed a consistent result with the experimentally monitored data in real time. EnergyPlus has two mainly used daylighting algorithms: DElight method employing radiosity technique and Detailed method employing split-flux technique. Further analysis for illuminance using DElight and Detailed methods showed significant difference in the results. Finally, we compared the algorithms of the two analysis methods in EnergyPlus.

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Section: Open Accessmentioning

confidence: 99%

Window Material Daylighting Performance Assessment Algorithm: Comparing Radiosity and Split-Flux Methods

Yoon

Jeong

2014

Energies

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“…Although a good agreement between the measured and simulated LID was found, the luminance distributions only corresponded when the most accurate BRDF model was applied, indicating that more complex models are needed for evaluation of luminance distributions [5]. Tsangrassoulis et al [6] performed the comparative study between Radiosity and Ray-tracing methods to analyse the daylight levels in atria under a variety of conditions. Hviid [7] suggested the combined approach between Radiosity and Ray-tracing techniques to develop a simple but accurate tool for the proper prediction of indoor daylight level.…”

Section: Background and Purposementioning

confidence: 99%

“…where, (6) where, / / = interpolated daylight factors for sun and skies k and k′; / = exterior horizontal illuminance from sun and sky; / = fraction of horizontal illuminance from sky due to sky type k and k′; and, (7) (8) where, = Direct normal solar irradiance; = Exterior direct horizontal solar irradiance; Z = solar zenith angle; = luminous efficacy of direct radiation from sun; = luminous efficacy of diffuse solar radiation from sky.…”

Section: Analysis Of Algorithmmentioning

confidence: 99%

Comparative Study of Two Daylighting Analysis Methods with Regard to Window Orientation and Interior Wall Reflectance

Yoon

Manandhar

2014

Energies

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Abstract:The accuracy and speed of the daylighting analysis developed for use in EnergyPlus is better than its predecessors. In EnergyPlus, the detailed method uses the Split-flux algorithm whereas the DElight method uses the Radiosity algorithm. Many existing studies have addressed the two methods, either individually or compared with other daylight analysis methods like Ray tracing but still there is lack of detailed comparative study of these two methods. Our previous studies show that the Split-flux method overestimates the illuminance, especially for the areas away from the window. The Radiosity method has the advantage of accurately predicting this illuminance because of how it deals with the diffuse light. For this study, the EnergyPlus model, which has been calibrated using data measured in a real building in previous studies, has also been used. The calibrated model has a south oriented window only. This model is then used to analyze the interior illuminance inside the room for north, west and east orientation of the window by rotating the model and by changing the wall reflectance of the model with south oriented window. Direct and diffuse component of the illuminance as well as the algorithms have been compared for a detailed analysis.

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“…those that interact with the view will be considered in the calculation. In contrast, in following the light rays from the source, most of the calculation would be useless, as the majority do not contribute to the required image [20][21][22].…”

Section: Radiance Simulation Setupmentioning

confidence: 99%

Interactions between louvers and ceiling geometry for maximum daylighting performance

2009

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a b s t r a c tThe impact of ceiling geometries on the performance of louvers was investigated using physical model experiments and Radiance simulations. Two performance indicators, the illuminance level and its distribution uniformity, were used to assess daylighting performance in a room located in a subtropical climate region. It was found that the performance of the louvers can be improved by changing the ceiling geometry. The illuminance level increased in the rear of the room, and decreased in the frontdnear the windowdcompared to rooms having horizontal ceilings. Radiance results were found to be in good agreement with physical model data obtained under a clear sky and high solar radiation. Louvers' daylighting performance was reduced by tilting the louvers downward. The best ceiling shape was found to be one that is chamfered in the front and rear of the room.

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Comparison of radiosity and ray-tracing techniques with a practical design procedure for the prediction of daylight levels in atria

Cited by 30 publications

References 4 publications

Window Material Daylighting Performance Assessment Algorithm: Comparing Radiosity and Split-Flux Methods

Window Material Daylighting Performance Assessment Algorithm: Comparing Radiosity and Split-Flux Methods

Comparative Study of Two Daylighting Analysis Methods with Regard to Window Orientation and Interior Wall Reflectance

Interactions between louvers and ceiling geometry for maximum daylighting performance

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