Mathematical Model Applied To Improve The Natural Lighting Design

Daylighting must be considered as the greenest way to illuminate any space and one of the most important architectural design challenges and opportunities. Human life is strongly influenced by natural lighting, and nowadays we have to add to this factor the importance of energy conservation and pollution reduction objectives. The development of hollow light guides offers people the advantages of natural lighting and the benefits of reduced energy consumption systems, providing changes in architectural form of spaces where sunlight does not have direct access. Hollow Cylindrical Prismatic Light Guides (CPLGs) are transparent optical components able to transmit high diameter light beams in daylight buildings applications without relevant losses. The goal of this paper is to show a novel lighting design based on hollow prismatic light pipes, which let daylight to be introduced inside of buildings. An improved mathematical modelling to predict light transmission efficiency based on realistic software simulations and experimental models is presented

Application of dynamic merit function to nonimaging systems optimization

Automatic optimization algorithms have been recently introduced as nonimaging optics design techniques. Unlike optimization of imaging systems, nonsequential ray tracing simulations and complex noncentered systems design must be considered, adding complexity to the problem. The merit function is a key element in the automatic optimization algorithm; nevertheless, the selection of each objective’s weight, {wi}{wi}, inside the merit function needs a prior trial and error process for each optimization. The problem then is to determine appropriate weights’ values for each objective. We propose a new dynamic merit function with variable weight factors {wi(n)}{wi(n)}. The proposed algorithm automatically adapts weight factors during the evolution of the optimization process. This dynamic merit function avoids the previous trial and error procedure by selecting the right merit function and provides better results than conventional merit functions

Spectral damage model for lighted museum paintings: Oil, acrylic and gouache

A spectral aging test was developed to estimate the photochemical damage of oil, acrylic and gouache paints exposed to permanent lighting. The paints were irradiated at seven different wavelengths in the optical range to control and evaluate their spectral behaviour. To reach this objective, boxes with isolated aging cells were made. In each of box, one LED of a different wavelength and one photodiode were installed. Inside the boxes, the temperature of an exhibit area was recreated through a thermocouple sensor that controlled the temperature using a fan. The heat produced by the LED was dissipated by a thermal radiator. Moreover, to evaluate the exposure time dependence of the irradiation level, the test was performed using two different irradiation levels in ten exposure series. After each series, the spectral reflectance was measured, and the data collected for each paint and wavelength were used to develop a model of damage produced by the interaction between the spectral radiant exposure and the paint

Advances on geometric flux optical design method

Nonimaging optics is focused on the study of methods to design concentrators or illuminators systems. It can be included in the area of photometry and radiometry and it is governed by the laws of geometrical optics. The field vector method, which starts with the definition of the irradiance vector E, is one of the techniques used in nonimaging optics. Called “Geometrical flux vector” it has provide ideal designs. The main property of this model is, its ability to estimate how radiant energy is transferred by the optical system, from the concepts of field line, flux tube and pseudopotential surface, overcoming traditional raytrace methods. Nevertheless this model has been developed only at an academic level, where characteristic optical parameters are ideal not real and the studied geometries are simple. The main objective of the present paper is the application of the vector field method to the analysis and design of real concentration and illumination systems. We propose the development of a calculation tool for optical simulations by vector field, using algorithms based on Fermat`s principle, as an alternative to traditional tools for optical simulations by raytrace, based on reflection and refraction law. This new tool provides, first, traditional simulations results: efficiency, illuminance/irradiance calculations, angular distribution of light- with lower computation time, photometrical information needs about a few tens of field lines, in comparison with million rays needed nowadays. On the other hand the tool will provides new information as vector field maps produced by the system, composed by field lines and quasipotential surfaces. We show our first results with the vector field simulation tool

Advanced daylighting evaluation applied to cultural heritage buildings and museums: Application to the cloister of Santa Maria El Paular

A method to evaluate the risk of using daylight in museums and cultural heritage exhibitions is presented along this study. Although daylight is an ecological and sustainable source of energy and sometimes also an intrinsic part of the artwork, the use of Natural lighting may cause damages in them due to the difficulty of controlling its variability. The developed method quantifies the damage produced to the artworks by daylight compared to artificial light taking into account the level of radiation and its spectral distribution in space and time by comparison with the damage caused by an Illuminant A (Global Risk Factor). The method, applied to the permanent paintings exhibition in the cloister of the fifteenth century of the Monastery of Santa Maria de El Paular, certifies that the control and exploitation of Natural Light should consider an optimal balance between exposure and damage

Evolutionary optimization algorithms for nonimaging optical design

Evolutionary optimization algorithms have been recently introduced as nonimaging optics design techniques. Unlike optimization of imaging systems, non sequential ray tracing simulations and complex non centred systems design must be considered, adding complexity to the problem. The Merit Function (MF) is a key element in the automatic optimization algorithm, nevertheless the selection of each objective's weight, {wi}, inside merit function needs a previous trial and error process for each optimization. The problem then is to determine appropriate weights value for each objective. In this paper we propose a new Dynamic Merit Function, DMF, with variable weight factors {wi(n)}. The proposed algorithm, automatically adapts weight factors, during the evolution of the optimization process. This dynamic merit function avoids the previous trial and error procedure selecting the right merit function and provides better results than conventional merit functions (CMF). Also we analyse the Multistart optimization algorithm applied in the flowline nonimaging design technique

Colorimetry to assess the visual impact of dust deposition on mosaics at sheltered archaeological sites

One of the most important alteration factors for archaeological sites is the deposition of dust, primarily onto horizontal surfaces, because it affects both the conservation state of the remains and their appearance. The deposition is responsible for visual changes that prevent proper appreciation of the site, and this is especially negative for the decorative elements such as mosaics. Dust deposition has been seen as a significant problem in sheltered sites as opposed to those located in the open air, where deposits are regularly washed away. However, there is a lack of knowledge on the visual effects of dust on sheltered archaeological remains despite the fact that this information could help to determine cleaning regimes. This research has been undertaken at the House of Hippolytus, a Roman villa located on the outskirts of Complutum, situated where the city of Alcalá de Henares (Spain) stands today. The site was covered with a partially enclosed shelter in 1999 and it contains a magnificent mosaic in the central area. This ornamental floor is the center of attention for visitors and has often been used as a promotional image because of its high artistic value. This study has objectively evaluated the visual changes (color and spectral characteristics) of the mosaic at the House of Hippolytus before and after being cleaned with dry and wet systems using a novel approach based not only on a spectrophotometer (CM-2600d Konica Minolta®) but also on a LumiCam® 1300 camera (Instrument Systems GmbH). Although wet cleaning implies the use of water, which is a decay factor, it has been found to be the best option for recovering the original aspect of the mosaic

History of optics: a modern teaching tool

The history of optics is a very rich field of science and it is possible to find many simple and significant examples of the application and success of the experimental method and therefore is a very good tool to transmit to the student the way science proceeds and to introduce the right spirit of critical analysis, building and testing of models, etc. Optical phenomena are specially well suited for this because in fact optical observations and experiments have made science advance in a crucial way in many different periods of history, because they are in many cases quite visual, quite simple in concept and it is very easy to produce experimental setups in classrooms. Also, the intrinsic multidisciplinary character of Optics, which is a subject that has historically influenced in a notorious way fields as art, philosophy, religion and cultural and social studies in general, provide a very wide frame that permits to apply these examples to many different auditories. We present here some reflections about the role that history of optics can play in teaching and show some real examples of its application during the many years that we have been employing it in the context of the Optics School of the Complutense University of Madrid, Spain

Efficient and sustainable energy lighting solutions

The electric lighting is responsible for 15% of the electricity consumption, the efficiency in this sector has a good progress in recent years, it can still improve more. Conventional energy sources are polluting and limited, so it is essential to use less aggressive energies with the environment. In lighting, this premise is being implemented in a cross-cutting manner, but in response to varied and sometimes contradictory interests. The development of lighting devices based on solar radiation is an inalienable objective, as is the use of artificial lighting sources that are clean with the environment. To achieve these two objectives, it is essential to know and study the design techniques of non-image optics. In the present work we present new systems design techniques and lighting elements: ray tracing optimization technique, light vector field technique. As well as its implementation and application in various areas of lighting: lighting in office buildings, libraries museums. We show that renewable energy strategy in the field of lighting not only produce energy save, also produce good effects in other aspects of human life like well-being, productivity and heritage conservation