Study of tubular daylight guide systems in buildings: Experimentation, modelling and validation

Malet-Damour, Bruno; Guichard, Stéphane; Bigot, Dimitri; Boyer, Harry

doi:10.1016/j.enbuild.2016.08.019

Cited by 36 publications

(37 citation statements)

References 25 publications

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“…The first are based on geometrical optics analysis, while the second is based on a combination of theoretical and experimental analysis. The study [30] provides support to a problem discussed in the literature concerning the accuracy of semi-empirical models in the reproduction of the performance of light tubes, proposing the use of a model generator called HEMERA. The approach was based on a Galilean sequence; after the observation of the experimental case, they better understand the phenomena and validate the developed method.…”

Section: An Overview On Light Pipesmentioning

confidence: 84%

Modeling of Light Pipes for the Optimal Disposition in Buildings

2019

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A light pipe is an excellent solution to transport and distribute daylight into environments without or with little lighting, guaranteeing comfort inside the rooms. As stated in the literature, the evaluation of the performances of light pipes presents numerous complexities, making the work very difficult for technicians and designers. This study is aimed to present a methodology that is able to identify the potential of light pipes using indices such as daylight autonomy (DA), continuous daylight autonomy (DAc), and useful daylight illuminance (UDI). This paper presents an analysis of daylight obtained by several configurations of simple models of light pipes installed into a 5 × 5 m plant area room. All simulations are carried out in a DAYSIM environment, which allows calculating the annual availability of daylight based on a RADIANCE raytracer backward. Several daylight conditions were analyzed for different light pipe configurations, considering different pipe lengths and a variable number of light pipes. The light pipes are tested also in the horizontal position, for different orientations. The results of all the combinations were compared with the performances of a window with dimensions equal to 1/8 of the internal surface, which was in accordance with the minimum value to be guaranteed by the Italian Regulation (D.M. 5 July 1975 n. 190) for different orientations. The results indicated a difference in daylight distribution, showing a strong correlation between the percentage levels of DA and DAc with the length and number of pipes, during different periods of the year. The simulated model is strongly influenced by the aspect ratio (R = diameter/length). The results show that the illuminance levels decrease drastically, increasing the length.

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Section: An Overview On Light Pipesmentioning

confidence: 84%

Modeling of Light Pipes for the Optimal Disposition in Buildings

2019

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“…Although empirical validation procedures, based on real metering and auditing data, are considered as very reliable procedures [47], they are often used for the validation of tools and mathematical models developed for simulating specific phenomena. In this regard, the literature shows several examples of such a procedure applied to the validation of models relative to thermally activated building systems [48][49][50], daylighting or HVAC interactions with respect to window or solar gain [51,52], double skin facades or ventilated cavity [53][54][55][56], activities of occupants and their interaction with the building loads [57], etc. It is worth noting that though experimental validations of single mathematical models for the simulation of the energy performance of a specific new building's technology, component or material, can be often easily carried out, the experimental validation of whole BEPS tools is mostly unfeasible.…”

Section: Literature Reviewmentioning

confidence: 99%

Building Energy Performance Analysis: An Experimental Validation of an In-House Dynamic Simulation Tool through a Real Test Room

et al. 2019

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This paper focuses on the experimental validation of a building energy performance simulation tool by means of a comparative analysis between numerical results and measurements obtained on a real test room. The empirical tests were carried out for several months under variable weather conditions and in free-floating indoor temperature regime (switched off HVAC system). Measurements were exploited for validating an in-house simulation tool, implemented in MatLab and called DETECt, developed for dynamically assessing the energy performance of buildings. Results show that simulated indoor air and surface room temperatures resulted in very good agreement with the corresponding experimental data; the detected differences were often lower than 0.5 °C and almost always lower than 1 °C. Very low mean absolute and percentage errors were always achieved. In order to show the capabilities of the developed simulation tool, a suitable case study focused on innovative solar radiation high-reflective coatings, and infrared low-emissivity materials is also presented. The performance of these coatings and materials was investigated through a comparative analysis conducted to evaluate their heating and cooling energy saving potentials. Simulation results, obtained for the real test cell considered as equipped with such innovative coatings and material, show that for the weather zone of Naples a 5% saving is obtained both in summer and in winter by simultaneously adopting a high-reflectance coating and a low- emissivity plaster for roof/external walls and interior walls, respectively.

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“…The performance of such a passive system depends mainly on the transmission properties of the light-guide body, but also on the instantaneous meteorological conditions [9][10][11][12]. The optical parameters of straight pipes have been intensively studied by many authors [13][14][15][16][17], while some have demonstrated that clear skies more than overcast ones produce complex illuminance patterns in the interior spaces. Illuminance levels, the angular distribution of light and also its dynamics altogether affect both the visual comfort and working conditions in a room.…”

Section: Introductionmentioning

confidence: 99%

An Accurate Prediction of Daylight Pipe Harvesting of Interior Space

Kómar

Kocifaj

2019

Applied Sciences

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Featured Application: The results of this research are useful in correct assessment of daylighting quality in the interiors respecting the typical instability of sky states. The computations we have performed allow for designing the optimum energy-saving solutions for light-pipe systems. Abstract:The performance of a light guide under arbitrary meteorological conditions is difficult to predict numerically because none of the present methods can account for the random configuration of clouds. Although, partly cloudy skies typically occur very frequently in many regions over the globe, the effects of cloud sizes, distributions, or altitudes on the luminous effectiveness of a light guide remain virtually unknown. The physical installation of light guides does not allow for a controlled experiment in which a single parameter can be varied within a defined range, while holding all other parameters constant. Numerical modeling is the only practical way to provide deep insights on the role of a specific property, such as cloud coverage, and its importance relative to all others (e.g., atmospheric turbidity). We have developed a unique solution through linking the UniSky simulator and HOLIGILM (hollow light guide interior illumination method) tool, while providing for the first time a powerful method that can provide accurate predictions and understanding of the fundamental differences of light guide behaviors under homogeneous and inhomogeneous sky states. The use of homogeneous skies in low-accuracy empirical models often results in overestimated/underestimated effectiveness of some light-guide systems. The model we have developed can predict complex optical signatures that are normally impossible to reproduce using up-to date empirical models (e.g., the illuminance patterns due to isolated clouds or clouds traversing across the sky). The optical efficiency, average cosine and working-place illuminance are analyzed and compared in order to demonstrate the model capabilities.

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Study of tubular daylight guide systems in buildings: Experimentation, modelling and validation

Cited by 36 publications

References 25 publications

Modeling of Light Pipes for the Optimal Disposition in Buildings

Modeling of Light Pipes for the Optimal Disposition in Buildings

Building Energy Performance Analysis: An Experimental Validation of an In-House Dynamic Simulation Tool through a Real Test Room

An Accurate Prediction of Daylight Pipe Harvesting of Interior Space

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