A Large Scale Daylighting System Based on a Stepped Thickness Waveguide

Vu, Ngoc Hai; Shin, Seoyong

doi:10.3390/en9020071

Cited by 30 publications

(22 citation statements)

References 25 publications

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“…Optical fibres also can be combined with solar concentrators for a building daylighting system (waveguides). They can deliver sunlight deep into the interior rooms of a building [19,20]. This technology allows to supply rooms without outside connection with natural daylight.…”

Section: Methodsmentioning

confidence: 99%

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

Gürlich¹,

Reber²,

Biesinger³

et al. 2018

Preprint

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Daylight usage in buildings improves visual comfort and lowers the final energy demand for artificial lighting. The question that always occurs is how much conservation can be achieved? New or rare materials and constructions have a lack of information about their application. Therefore, the current investigation quantifies the daylight and energy performance of a rare multilayer textile membrane roof. A translucent, thermal insulation with a glass fibre fleece between the two roof membranes combines daylight usage and heating demand reduction. A sports hall built in 2017 is used as a case study building with 2300 m 2 membrane roof surface. The optical properties of the roof construction are measured with a total visual light transmittance τv of 0.72 % for a clean surface. A climate-based annual daylight modelling delivers daylight indicators for different construction scenarios. The results show that in comparison to only one glass facade, the additional translucent and thermally insulated membrane roof construction increases the annual daylight autonomy (DA700) from 0 % to 1.5 % and the continuous DA700 from 15% to 38 %. In the roof-covered areas of the sport field, this results in a 30 % reduction of the electricity demand for artificial lighting from 19.7 to 13.8 kWhel/m²/a, when a dimming control is used. The study also found out, that the influence of the soiling of one layer decreases its light transmittance by a factor 0.81. Two soiled layers lower τv by a factor 0.66 to 0.47 %. This increases the electricity demand for lighting by only 12 %. The results should be very valuable as a comparison and benchmark for planners and future buildings of a similar type.

show abstract

Section: Methodsmentioning

confidence: 99%

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

Gürlich¹,

Reber²,

Biesinger³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…They can deliver sunlight deep into the interior rooms of a building [22,23]. This technology allows supplying rooms without outside connection with natural daylight.…”

Section: Methodsmentioning

confidence: 99%

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

et al. 2018

View full text Add to dashboard Cite

Daylight usage in buildings improves visual comfort and lowers the final energy demand for artificial lighting. The question that always occurs is how much conservation can be achieved? New or rare materials and constructions have a lack of information about their application. Therefore, the current investigation quantifies the daylight and energy performance of a rare multi-layer textile membrane roof. A translucent, thermal insulation with a glass fibre fleece between the two roof membranes combines daylight usage and heating demand reduction. A sports hall built in 2017 is used as a case study building with 2300 m 2 membrane roof surface. The optical properties of the roof construction were measured with a total visual light transmittance τ v of 0.72% for a clean surface. A climate-based annual daylight modelling delivers daylight indicators for different construction scenarios. The results show that, in comparison to only one glass façade, the additional translucent and thermally insulated membrane roof construction increases the annual daylight autonomy (DA 700 ) from 0% to 1.5% and the continuous DA 700 from 15% to 38%. In the roof-covered areas of the sport field, this results in a 30% reduction of the electricity demand for artificial lighting from 19.7 kWh el /m 2 /a to 13.8 kWh el /m 2 /a, when a dimming control is used. The study also found that the influence of the soiling of one layer decreases its light transmittance by a factor 0.81. Two soiled layers lower τ v by a factor of 0.66 to 0.47%. This increases the electricity demand for lighting by only 12%. The results should be very valuable as a comparison and benchmark for planners and future buildings of a similar type.

show abstract

Section: Introductionmentioning

confidence: 99%

“…The original concept of utilizing a kind of planar solar concentrator of "stepped-shape" to collect and redirect sunlight from multi Fresnel lenses was proposed in [13]. The system in [13] used linear Fresnel lenses and a larger slab STW. Sunlight was focused from a large area to a line by linear Fresnel lenses so that the system can use only a single sun-tracking system instead of the usual dual sun tracking system.…”

Section: Introductionmentioning

confidence: 99%

Optical Fiber Daylighting System Combined with LED Lighting and CPV based on Stepped Thickness Waveguide for Indoor Lighting

Shin

2016

Journal of the Optical Society of Korea

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We present a design and optical simulation of a cost-effective hybrid daylighting/LED system composed of mixing sunlight and light-emitting diode (LED) illumination powered by renewable solar energy for indoor lighting. In this approach, the sunlight collected by the concentrator is split into visible and non-visible rays by a beam splitter. The proposed sunlight collector consists of a Fresnel lens array. The non-visible rays are absorbed by the solar photovoltaic devices to provide electrical power for the LEDs. The visible rays passing through the beam splitters are coupled to a stepped thickness waveguide (STW) by tilted mirrors and confined by total internal reflection (TIR). LEDs are integrated at the end of the STW to improve the lighting quality. LEDs' light and sunlight are mixed in the waveguide and they are coupled into an optical fiber bundle for indoor illumination. An optical sensor and lighting control system are used to control the LED light flow to ensure that the total output flux for indoor lighting is a fixed value when the sunlight is inadequate. The daylighting capacity was modeled and simulated with a commercial ray tracing software (Lighttools TM ). Results show that the system can achieve 63.8% optical efficiency at geometrical concentration ratio of 630. A required accuracy of sun tracking system achieved more than ±0.5 o . Therefore, our results provide an important breakthrough for the commercialization of large scale optical fiber daylighting systems that are faced with challenges related to high costs.

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A Large Scale Daylighting System Based on a Stepped Thickness Waveguide

Cited by 30 publications

References 25 publications

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

Daylight Performance of a Translucent Textile Membrane Roof with Thermal Insulation

Optical Fiber Daylighting System Combined with LED Lighting and CPV based on Stepped Thickness Waveguide for Indoor Lighting

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