Laser Cut Panel Research Articles

On the combined use of laser-cut panel light redirecting systems and horizontal blinds for daylighting and solar heat control, a focus on visual comfort objectives

Aiming to explore its performance as energy efficient system, in this study, the window is subdivided according to functions, in which the upper part would act as a daylight optimization unit. Two variant positions of lasercut panel, known as ‘louvre-style’ and ‘venetian-style’ are placed in the upper window unit, in order to take advantage of their angle selective redirecting capabilities. Their effectiveness to provide a satisfactory visual comfort is evaluated by assessing their potential for solar control and daylight redirection indoors. The first results indicate that the use of lasercut panel as a sole system, its insufficient to provide an adequate visual environment, with a reduced risk of glare for the occupants. Aiming to improve its performance, horizontal blinds are added as supplementary element to the interior-upper part of the window, blended in an arrangement called ‘secondary system’. As a result of a comprehensive evaluation, in which, the upper and middle window units are considered, two lasercut panel styles are identified as those providing sufficient daylight provision indoors, and a reduced risk of discomfort glare. The properties of the fenestration systems tested here, were described using their corresponding BSDF data, while the evaluation was performed using the RADIANCE matrix multiplication methods.

A novel method for making laser cut panel based daylight collector coupled to a tubular light guide

The work in this paper focuses on the development of a daylighting device which can increase the light output for longer lengths of hollow mirrored light pipe. The device proposed is passive, easy to build, and inexpensive. It uses the concept of total internal reflection in acrylic laser cut panels (LCPs) and extends the idea into a complete collector based on mathematical modelling. The novel method of fabricating laser cut panels with steep cutting angles and partial depth cuts has been discussed in this paper. This method has been combined with weight optimisation to make a lightweight yet efficient collector with no laser cuts exposed to the atmosphere. The simulation results of this collector have been compared with a flat acrylic plate coupled to a light pipe and experimental validation of simulation has been performed using a prototype. The simulation results for collector coupled to 80% reflective light pipe have shown up to 4.3 times the illuminance on model room floor as compared to light pipe with a flat plate on 21 December- the low solar altitude season for which the collector was primarily designed. Another simulation of a real dimension office space with multiple collectors shows that at least 175 lx of average illuminance is available on the work surface with 227 cm2 cross-section light pipes.

A customised method for estimating light transmission efficiency of the horizontal light pipe via a temporal parameter with an example application using laser-cut panels as a collector

The purpose of the study presented in this paper was to develop a customized method for estimating the transmission efficiency of a horizontal light pipe (HLP). The proposal is based on the established method and customized to encompass real incident daylight that horizontal light pipes could collect. Natural incident light is introduced using both direct and diffuse light sources through the temporal parameter of their altitude and azimuth. The temporal parameter is presented as a matrix model consisting of solar altitude and azimuth used in measurement and analysis. Because each location on Earth is characterized by a unique solar altitude and azimuth during the year, the proposed method establishes the measuring template, based on a specific location on Earth and applicable for the HLP. The methodology is supplemented with a theoretical model of an indoor space equipped with an HLP that can be used to analyse data and validate necessary threshold illuminance under real physical conditions. An example of an application of the customized method is demonstrated using a case of light collectors for the HLP light-deflecting panels, the laser-cut panel (LCP).•A method for predicting the transmission efficiency of the HLP for any location and any orientation on a building's façade.•Estimation of transmission efficiency for the HLP implementing a temporal parameter through solar altitude and azimuth.•Resulting data for transmission efficiency for the HLP using a template that is easily applicable for decision-making during a specific period of the year, season or the entire year.

Designing a laser-cut panel for light collection for daylighting using a generalised mathematical model

The current daylighting requirements require a system that can maintain a uniform light output throughout the day while enabling deep and controlled penetration of sunlight. If such a system is simple to manufacture, inexpensive and incorporates no moving parts and maintenance, it can easily fulfil all the daylighting needs. This paper focuses on the development of such a system using laser-cut panels. Mathematical models for determining the dimensions of a laser-cut panel and its efficiency were developed. A laser-cut panel collector was designed based on these models and simulated. The results showed enhanced light output at light pipe end by up to 47 times and 32 times as compared to a flat plate collector in the month of June and December, respectively and up to nine times for a dome collector for the designed range of sun altitudes. For this range, the ratio of pipe output to input was up to 4.5 times higher than the other collectors. The light at diffuser side was more distributed for the laser-cut panel collector. The current design, however, did not provide appropriate reduction in illuminance at peak hours in June. This approach can easily be used for light collection without involving any complex mechanisms.

Photon mapping in image-based visual comfort assessments with BSDF models of high resolution

Data-driven models replicate the irregular Bidirectional Scattering Distribution Functions (BSDFs) of optically Complex Fenestration Systems in daylight simulation. RADIANCE employs the tensor tree to store the BSDF at high directional resolution. Its application in backward ray-tracing is however challenging, since the density of stochastic samples must match the model resolution. BSDF proxy and peak extraction address this problem, but are limited to cases when either the fenestration geometry, or the shape and direction of the transmission peak are known. Photon Mapping is proposed to efficiently sample arbitrary BSDFs from the known sun direction. The existing implementation in RADIANCE is extended to account for light sources and their reflections in the field of view, that are of particular importance for visual comfort assessments. The method achieves a high degree of accordance with ray-tracing, and reduces simulation times by ≈95% with data-driven models of high resolution.Abbreviations: BRT: Backward Ray-Tracing; BSDF: Bidirectional Scattering Distribution Function; CBDM: Climate-Based Daylight Modelling; CFS: Complex Fenestration System; DGI: Daylight Glare Index; DGP: Daylight Glare Probability; FPM: Five Phase Method; GPGPU: General Purpose Graphics Processing Unit; LCP: Laser Cut Panel; OoC: Out-of-Core; PM: Photon Mapping; RMSE: Root Mean Squared Error

Improving the Performance of Light Pipe System Using Laser Cut Panel

Light pipe systems (LPS) are simple devices that allow the transmission of daylight into interiors of buildings. It is a convenient concept for illumination of windowless parts of buildings. The light performance of this is highly dependent on the solar altitude due to the small inlet aperture. Placing the laser-cut panel (LCP) at the entrance aperture in light pipe system, will increase the light performance during low solar angle. This paper presents the results of light performance a 400mm diameter light pipe integrated with a laser-cut panel at entrance aperture as collector. For that reason, this research adopted an experimental approach to compare the light pipe performance via 1:10 scale model. Two scale models were built. LCP in the form of pyramids was fitted at the entrance aperture of light pipe in different tilted angle 40° and 47.5°. The system has been monitored 30 minutes interval with lux meter to evaluate the improvement light performance on a working plane for 6 days under good sky condition. The results of this experiment shows that LCP with 40° tilted angle performed better than 47.5° tilted angle. The light pipe with LCP as collector the minimum recommended illuminance by Malaysian Standard (MS) 1525:2007 can be achieved as early at 8am.

Maximizing the Performance of Laser Cut Panel by Interaction of Ceiling Geometries and Different Aspect Ratio

The interaction between different ceiling geometries with laser cut panels (LCPs) is investigated using real experiments and computer simulations to maximize the daylight performance of the LCP. In addition, LCP with different aspect ratios (width to depth ratio) is studied using simulation with clear sky conditions in hot climate region. Two main performance parameters are investigated: illuminance level and distribution uniformity in a large space located in a sub-tropical climate region like Jordan. It was found that curved and chamfered ceilings increased the daylight level in the rear part of the studied room by 20% compared to a horizontal flat ceiling and reduce it by 30% in front part that improve the quality of daylight by improving the uniformity. LCP with high aspect ratio of 5:6 performed well in climate with clear sky and high solar angles than LCP with ratio of 4:6. © 2014 The Author(s). Published by solarlits.com. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

Daylight enhancement using laser cut panels integrated with a profiled Fresnel collector

Performance of conventional vertical light pipes with acrylic domes is highly dependent on the solar altitude since for lower solar elevation the acceptance angle is limited due to the small inlet aperture. A profiled Fresnel collector with a multi-lens system is useful in enhancing light in a light pipe at low solar altitudes but suffers losses due to multiple reflections during transmission. In this paper we show that further enhancement of light during the morning and evening hours is possible by using a profiled Fresnel collector integrated with graded laser cut panels, i.e. laser cut panels with bands of varying depth to width ratio that can redirect low altitude sun rays axially down the light pipe. The effect of various depths to width ratios of the laser cut panel with respect to variation in incident light on the performance of a light pipe is also presented in this paper. The graded laser cut panel performed better than other laser cut panels. Optimum tilts of the laser cut panel at which maximum light is deflected for various incident angles of the source were identified. Maximum light output for the graded laser cut panel was for lower incidence of solar altitude angle. The graded/profiled laser cut panel was integrated with Fresnel north and south facing collectors and the performance was assessed in daylight. Good redirection of light was observed for the Fresnel collector in the morning and evening hours when compared to a light pipe with an acrylic dome or a Fresnel collector without a laser cut panel. The light is redirected more parallel to the axis of the pipe thus minimizing the reflections on the internal lining and thereby increasing the performance of the light pipe.

Optical scatter measurement and analysis of innovative daylight scattering materials

Bidirectional reflection and transmission distribution (BRTD) measurements are an important tool in understanding the transmission of light across complex fenestration systems. Facade designers usually control the daylighting, glare, shading and to some extent heating or cooling with the choice of glazing used in fenestration systems. Light redirection and diffusion is of immense interest because of the potential to save operation costs with daylight use in office buildings and other commercial buildings while providing a comfortable working environment. In this paper, we have presented the detailed BRTD measurements for five different light scattering samples, which are developed for integration into building facades. The samples scatter a large portion of the incident light into non-specular directions. The samples vary from a double glazing unit with embedded diffusing structure, redirecting films, a laser cut panel and a semitransparent photovoltaic panel. The properties of these samples were studied with a goniophotometer to observe the angular resolved reflection and transmission. The percentage of light contributing to the non-regular transmission is also estimated. The results emphasize that reflection and transmission of such complex fenestration samples should be assessed at various angles of incidence or sun position in order to assess the potential of these systems reliably.

Computer simulation study of a horizontal light pipe integrated with laser cut panels in a dense urban environment

A computer simulation study on the daylighting performance of a horizontal light pipe system integrated with laser cut panels at the entrance and output apertures was performed for two identical test rooms with different degree of obstructions in a dense urban environment under the CIE clear sky condition. It is observed that by properly varying the separation-to-thickness ratio and the aperture tilt angle of the laser cut panel at the entrance aperture, the illumination beneath the pipe emitter can be enhanced. It is concluded that due to the obstructed environment, the horizontal light pipe should aim at capturing light from high altitude sky and sun. An optimal set of STR and ATA values for the LCP at the entrance aperture of 0.5 and 35° respectively is found to be effective for both high and low floors in buildings within a dense urban context.

Experimental validation of simulation methods for bi-directional transmission properties at the daylighting performance level

The objective of this paper is to assess the capability of existing lighting simulation methods to predict the performance of Complex Fenestration Systems (CFS), whose potential in daylight and sunlight control make them an increasingly popular alternative to conventional glazing. The research was conducted in two phases. First, collect reliable reference data by taking illuminance measurements inside a black-box under a measured and controlled external luminance distribution, the black-box's only aperture being covered with a complex glazing sample. Two types of materials were used: a Serraglaze™ element and a Laser Cut Panel (LCP). Several simulation methods were then investigated and validated against this reference case. For the first method, measured BTDF for both material samples were integrated into different simulation tools to determine the resulting indoor lighting conditions under the external luminance distribution chosen for the reference case. The same method was then applied with calculated BTDF data, based on ray-tracing calculations. Finally, one of the CFS (the LCP) was modeled using the backward ray-tracer RADIANCE so that the inside illuminance distribution could be deduced without requiring BTDF data. The comparison between the experimental reference data and the simulation results showed that the effect of the CFS on the room's illumination could be predicted with acceptable accuracy for most of the tested methods (generally within 10–20%). The simplicity of the testing scenarios allowed error sources related to simulation to be highlighted and helped determine the extent to which an accurate physical description of the samples could influence the results. Based on this study, recommendations were made for a better use of existing simulation methods.

RADIANCE algorithm to simulate laser-cut panel light-redirecting elements

The computer lighting simulation tool RADIANCE has been used to simulate the laser-cut panel (LCP), a novel daylighting technology used to redirect sunlight and skylight for more effective natural illumination in buildings and improved solar thermal control. The algorithm used to model the LCP material in RADIANCE is described, and simulations of the material are presented. The results of these simulations demonstrate the easy application of the developed algorithm, and the effect of installing the LCP material.

Enhancement of crop illuminance in high latitude greenhouses with laser-cut panel glazing

This paper presents theoretical predictions and experimental measurements of the enhanced illuminance available in high latitude greenhouses in winter by use of double-glazing comprising laser-cut panels and glass to deflect low elevation sunlight onto the crop. Provided the structure of the greenhouse is optimised for light enhancement, i.e, single slope south-facing roof with vertical north wall, the predicted daily time averaged enhancement, the ratio of horizontal illuminance with laser-cut panel double-glazing to that obtained with a single clear glazing, approaches 100% for most of winter in greenhouses at latitudes >50°; much greater than the enhancement that can be achieved with other passive optical systems investigated. The predicted enhancements, which take account of diffuse sky and direct sunlight components, are strongly dependent on latitude and atmospheric turbidity and agree with experimental enhancements measured in scale model greenhouses.

Transmission of light through right-angle corners in hollow light guides

Transmission of light through the corners in hollow light guides is compared for a new type of corner that is based on a laser-cut light-deflecting panel and for a flat, 45°, mirror-type corner. Corner efficiency is defined, and an experimental method for the measurement of the corner efficiency versus the angular width of the input light is described. Measured corner efficiencies were found to be nearly independent of the angular width of the incident light for metallic hollow light guides, with the average efficiency of the laser-cut-panel corner (65%) lower than that of the mirror corner (80%).