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Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This document is a summary of a special issue on lighting in buildings. The issue covers various research papers on topics such as integrative lighting, indoor lighting, and daylighting. The papers explore the impact of lighting on occupant well-being, performance, and comfort, as well as the effects of lighting color on emotions. The research also investigates the use of sensors and advanced controls to optimize energy efficiency while meeting occupants' needs. The document concludes with a call for papers for a follow-up special issue on lighting in buildings. [Extracted from the article]

Designing the floodlighting of objects in the context of improving the night image of the city is a very complex task, requiring not only a time commitment but also precise analysis and innovative solutions. In particular, designers must consider the principles of aesthetics and adapt the lighting to the architectural style and details of the facilities while ensuring energy efficiency and minimising the impact on the natural environment. For single objects, the task is relatively simple. The problem arises when the task is to develop a lighting concept for a large ensemble. Computer applications strictly dedicated to lighting analysis cannot capture a 3D model rich in architectural detail. The article presents a case study that focuses on a comprehensive approach to designing the floodlighting of a complex of architectural objects. The steps for designing the floodlighting of objects are presented. Based on a computer simulation, a visual lighting concept and a detailed analysis of the luminance distribution and floodlighting efficiency were presented. The obtained average luminance levels are consistent with recommendations and standards, and the project is characterised by a high lighting efficiency of 56%. This approach enables an understanding of how light affects architectural structures and the surroundings, which is crucial to achieving harmony between the technical side of the project and its aesthetics. The project presented in the article is an inspiring example of how a comprehensive approach to illumination can contribute to creating an attractive night landscape of the city, taking into account the aspects of sustainable development. This is very important nowadays, when the floodlighting of architectural objects is often considered an element of the landscape that can be omitted. [ABSTRACT FROM AUTHOR]

The creation of lightscapes in colleges and universities are of great significance in enhancing the perception of the campus environment, improving physical and mental health, and shaping humanistic connotations. This research aims to examine lightscape perceptions and impacts of different campuses. At Chongqing University A and B Campuses, lightscape walking experiments, subjective questionnaires, objective luminance measurements, and HDR picture processing were used to examine lightscape perception and factors. The relevance and differences in the perception of circadian lightscapes in the two campuses were analyzed using SPSS software. The study found: (1) natural lightscapes such as sky light, cloud shadow, and lake water reflection were the most popular during the daytime, while artificial lightscapes, such as decorative lighting of buildings, were positively evaluated at night; (2) the frequency of visits by a crowd directly impacts the ambiance of the environmental area; (3) males showed strong emotional awareness and social interaction skills in daytime, leading to increased social activity and stronger emotional responses, but no differences in nighttime; (4) optimal nighttime luminance enhances the overall perception satisfaction of the illumination; (5) the amount and arrangement of outdoor space, vegetation, minor landscape design, and service facilities all affect the perception of circadian lightscapes. In conclusion, design concepts and proposals of landscapes were suggested to optimize college and university lightscapes. [ABSTRACT FROM AUTHOR]

Curved displays can adjust their shape to accommodate different objects and are used in electronics and decorative lighting. Due to the immutable pixel spacing, existing commercial curved displays are flexible but not compatible with undevelopable surfaces. Inspired by kirigami and auxetic structures, we propose an approach that combines luminescent elements and rotating square tessellations to create a stretchable, arbitrary curve adaptive display. We connect square islands by vertical interconnects to relieve the stress concentration and provide extra deformation patterns. The vertical interconnects are patterned on a flexible printed circuit board (FPCB) using laser cutting and folded up via specially designed molds. Further, the freed-up space by folded interconnects allows the structure to be compressed. A prototype stretchable display is demonstrated that it can maintain electrical performance under biaxial strain and adapt to different Gaussian curvature surfaces, including cylindrical, spherical, saddle and arbitrary surfaces. Theoretical models and finite element calculations are established to describe the tensile behavior of the structures under different boundary conditions and agree with the experimental results. This proposed technology paves a feasible solution of mass production of adaptive curved displays and sets the trend for the next-generation display. [ABSTRACT FROM AUTHOR]

Visual information acquisition is essential for our daily lives, with vision relying on the presence of light. Lighting systems serve the fundamental purpose of enabling vision. This study aims to contribute to sustainable architectural design by emphasizing the efficient utilization of natural daylight. Specifically, the design of skylights or light wells in low–lateral-area, deep-depth structures is of significant importance. While current design criteria consider skylight dimensions and the skylight-to-building height ratio, these factors alone may not suffice for optimal skylight design. To achieve an appropriate lighting and architectural design for such structures, it is essential to evaluate the factors influencing the required amount of daylight on different floors. This study aims to investigate the impact of skylights and light wells on the energy consumption and CO2 emissions of a four-storey building located in Hail, Kingdom of Saudi Arabia. The physical parameters of skylights and light wells were analyzed, taking into account various aspects that affect the amount of light reaching different levels. The findings highlight the significant influence of skylight size on the light reaching the building's floors. For square skylights, reducing the well index (increasing skylight size) exponentially increases the daylight factor. Furthermore, this study evaluates the annual energy consumption and carbon dioxide emissions of the building, considering the daylighting factor. The results demonstrate that skylights contribute to increased solar heat gain, thermal conductance, and artificial lighting efficiency. Notably, as the lighting factor of the building increases from 3% to 6%, there is an annual decrease of 3% in CO2 emissions. [ABSTRACT FROM AUTHOR]

The development of computer technology, the computing power of graphics cards and processors, and the use of appropriate software allows us to create extremely realistic three-dimensional images. The effects of the generated visualisations can be difficult to distinguish from real photos of objects. Architects often verify the fulfilment of design goals based on a rendered digital image. Unfortunately, designers are often not fully aware of the limitations and simplifications of the tools used to create these visualisations. An uncritical approach to the presented results may lead to various design errors. This article presents the possibilities of visualisation in selected computer programs used by architects, and cases in which correct visualisation is possible only through the use of specialised software. The article also pays special attention to the possibility of errors in the visualisation of architectural lighting. [ABSTRACT FROM AUTHOR]

There are many possible LED lighting applications where separate regulation of the LED current (luminous flux) of individual LED strings would be desirable—specialized variable correlated color temperature lights for ambient lighting, decorative lighting, surgical lights, horticultural lights, etc. Separate regulation of the current or light flux of individual LED strings is associated with a known problem: the necessity of using a controllable LED driver for each string, which increases the total component count, overall system complexity and costs. One of the possible solutions—a current source mode single-inductor multiple-output LED driver—was discussed in previous different papers. However, the practical implementation of this solution was not discussed in detail. This article aims to correct this omission. [ABSTRACT FROM AUTHOR]

Green areas and parks are places where people's quality of life improves, places of recreation and relaxation, in which to carry out various social activities. Among these, the historic gardens represent the union between green areas and historic architecture. Light is considered one of the main factors influencing the perception of such spaces at night; therefore, lighting solutions should be properly balanced. Immersive virtual reality is a tool that allows for lighting design management from different viewpoints. This study investigates how the lighting of a monumental garden affects people's perception of its architecture at night. With this aim, a detailed 3D model of the western part of Escorial's monumental complex in Spain was built in DIALux evo 11 and Unreal Engine 4.27 and used to propose six different lighting scenarios. Participants viewed the scenarios through a head-mounted display and provided subjective feedback on the perceived light strength of the environment and architecture. Results highlight that illuminating surrounding areas affects the environment and building perception, as well as the order in which elements capture observer attention. In particular, lit elements between the observer and the façade can reduce façade importance. [ABSTRACT FROM AUTHOR]

Daylight dynamic metrics are useful tools for quantifying the switch-on time or the dimming of electric lighting according to the architectural scenario. A variant of these metrics can also be used to define strategies to control the lighting fixtures, dimming the luminous flux with no need for external input and reducing therefore the energy consumption of the lighting systems. Given this context, a new approach is proposed, Continuous Overcast Daylight Autonomy (DAo.con), defined as the percentage of occupied time when an illuminance threshold is met by daylight alone under continuous overcast sky conditions, considering a partial credit linearly to values below the threshold defined. This concept acts as an algorithm which adjusts the luminous flux of the luminaires according to the Daylight Factors measured or simulated, considering user requirements and ignoring any internal device for actively measuring the lighting conditions. The Daylight Factors can be modified according to the use of shading devices that affect to the indoor natural light. Accordingly, this algorithm can significantly reduce the embodied cost of the lighting smart controls, promoting their spread and its implementation in building refurbishment, while the energy consumption in electric lighting is reduced by up to 76% for large windows and by up to 65% for medium-sized openings. The results show that the use of this algorithm in office environments with LED fixtures can promote energy savings of up to 7.8 W/m2 for locations with predominantly clear skies and up to 5.7 W/m2 for northern latitudes with mainly overcast skies. [ABSTRACT FROM AUTHOR]

Copyright of Revista CPC is the property of Revista CPC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Changing the spatial luminance distribution patterns has the potential to improve the restorative potential of indoor environments through spatial visual perception intervention, which is helpful to meet our growing need for psychological restoration and well-being. However, the efficiency, progress, and principles for improving the spatial luminance distribution of indoor environments have not been verified, and the reusable and restorative spatial luminance distribution patterns that can be applied to the restorative reserve levels created by the architectural configurations and dispositions of the different spaces have yet to be established. Using a living room environment as the typical space and a hotel room as the research subject, we conducted this study by setting up a control group for the assessment experiment, combining three subjective and objective measures: the Perceived Restorativeness Scale (PRS), the eye-movement test, and the case interview. The results showed the following. (1) The spatial luminance distribution of artificial lighting can improve the PRS score by 30.9%. (2) The spatial luminance distribution of artificial lighting improves the restorative perception potential, which negatively correlates with the restorative reserve level of the environment (the correlation coefficient values were −0.405, p < 0.01). (3) The spatial luminance distribution elicited two visual cognitive responses: visual attraction and visual load, with the former being positively correlated with restorative perception (the correlation coefficient values were 0.288, p < 0.01), while the latter was negatively correlated (the correlation coefficient values were −0.264, p < 0.01). (4) The visual cognitive conclusions of spatial luminance distribution including the six dimensions present the visual characteristics of the status quo in the restorative spatial luminance distribution of artificial lighting. Based on the findings, this study starts from the optimization of visual attraction and visual load by improving both the restorative level and the degree of restorative perception, proposing a restorative spatial luminance distribution pattern of artificial lighting applicable to environments with different restorative reserve levels. [ABSTRACT FROM AUTHOR]

The subject of the research is to reduce light pollution produced by architectural lighting, by decreasing the luminous flux reflected to the sky, but without diminishing the visibility of façades at night. The article is a continuation of the authors' previous article, which showed that a façade with asymmetric reflection can be obtained when using only ordinary materials with diffuse reflection. The method consists of the use of horizontal decorative microprofiles (fins), with dimensions that are easy to achieve technologically. The optimization of the geometry of these profiles is the objective of this article. For optimization, generalized modeling of light reflection in MATLAB is used, through original scripts. These scripts also automatically generate the mesh necessary for the discretization of the façade, for profiles whose angle is modified for the whole range of technologically feasible values. Based on numerical simulations, an optimal domain is identified, based on which the experimental program of effective measurements of the luminance of the façade is optimized, by using imaging. [ABSTRACT FROM AUTHOR]

LED lighting still suffers from its thermal problem linked mainly to the increase in junction temperature. The situation becomes more and more aggravated when it comes to decorative lighting. Indeed, this type of lighting application sometimes requires that the heat sink of the LED lamp be integrated into a narrow space, such as false or sloped ceilings, which limits the transfer of heat to the outside. In this article, the current study reports a numerical analysis of natural convection heat transfer around rectangular heat sink for LEDs lighting applications. The radiator is put in an inclined cavity with an orientation angle varying from 0° to 60°. The effects of the enclosure inclination and its length on thermal behavior, flow structure in the cavity as well as on optical properties of the light source were highlighted. The CFD simulation showed a significant effect on the heat transfer rate when varying the cavity length (presented as an aspect ratio A) and its orientation. A = 4 was determined as an optimal cavity aspect ratio, and it was found that higher orientations are more sensitive to the increase of the length of the cavity. For θ = 60°, the luminous efficiency is ameliorated by about 10% when increasing the cavity length from one to four. Accordingly, we proposed correlations in simple form to predict the heat transfer rate for different configurations studied. [ABSTRACT FROM AUTHOR]

Copyright of Técnica Industrial: Revista Cuatrimestral de Ingeniería, Industria e Innovación is the property of Fundacion Tecnica Industrial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)