Simple Nomographs for Assessing Lighting in Urban Environments

Daylight standards contribute significantly to the form of buildings and the urban environment. Direct solar access of existing and new buildings can be considered through the use of solar envelope and solar collection isosurface methods. The first determines the maximum volume and shape that new buildings cannot exceed to guarantee the required solar rights on existing surrounding facades. The latter predicts the portion of facades of new buildings that will receive the required direct sunlight hours in urban environments. Nowadays, environmental design software based on the existing methods permits the generation of solar envelopes and solar collection isosurfaces to use in the schematic design phase. Nevertheless, the existing methods and software present significant limitations when used to design buildings that must fulfil the Estonian daylight standard. Recent research has successfully developed computational workflows based on the existing methods and available tools to tackle such shortcomings. The present work uses the findings to propose a novel computational method to generate solar envelopes and integrate solar collection analysis. It is a subtractive form-finding method that is more efficient than the existing additive methods and other recent workflows when it is applied to high-rise buildings in fragmented urban environments. The tests performed show that the new method permits the realisation of compliant and larger solar envelopes, which furthermore embed formal properties. The objective of the research is to contribute to the development of computational methods and tools to integrate direct solar access performance efficiently into the design process.

This paper concentrates on the propagation loss of the rooftops of buildings in urban environment by using parabolic equation. The radio communication is direct to each subscriber, the prediction of signal strength is most important in urban environments where subscriber density is high, and the buildings have a profound influence on the propagation. Because of complexity of radio propagation theoretical prediction in built-up areas, and propagation must take place through the buildings or over the rooftops with the field diffracted at the roofs down to street level, what's more, the primary propagation path lies over the tops of the buildings. Therefore, we have mainly taken into account the propagation-loss of the building rooftops. In the paper, the rows of buildings in urban areas are modeled as a series of perfectly conducting rectangular plateau with the purpose of simplifying the model to facilitate the solution. In addition, we proposed four kinds of typical urban models. As we all know, a highly attractive and effective model for the prediction of electromagnetic-wave propagation effects above the Earth's surface is the split-step parabolic-equation (SSPE) method, which it requires less computing effort than full elliptic methods. In this paper, we applied it to predicate the propagation-loss of the rooftops of buildings in urban environments. The comparison between the parabolic equation prediction and experimental data of the various models are presented, and the results are very promising. It is proved that the parabolic equation is a powerful and accurate method to calculate the electromagnetic wave propagation.

The new version of the European Standard of Interior Lighting (EN 12464-1) considers LED technology for energy saving and minimizing environmental impact by giving new criteria for quantitative and qualitative lighting, including those that concern the “non-image-forming effects” (NIF) of light. In addition, it takes into account normal aging as an assumption for proposing increased light levels in indoor workplaces. In real applications, this seems to create lighting conditions that do not fully support human well-being based on the criterion of WELL Building Standard v2 (2021) for Circadian Lighting Design. Therefore, in offices, it is proposed to increase the light levels by at least one step from the minimum provided by the EN Standard. In order to examine this hypothesis, a typical office space is examined. In addition to the main requirements, the Mean Ambient Illuminance (Ēamb) and the Mean Room Surface Luminous Exitance (Mrs) are calculated according to the EN Standard but also the Equivalent Melanopic Lux (EML) and the Melanopic Equivalent Daylight Illuminance (M-EDI) as proposed by the WELL Standard. The comparison between EN 12464-1 and Well Standard has shown that the qualitative lighting design criteria are stricter in WELL than in EN Standard.

The modern use of ancient theatres related to acoustic and lighting requirements: Stage design guidelines for the Greek theatre of Syracuse

This article deals with the state-of-the-art of experimental and numerical studies carried out regarding air pollutant dispersion in urban environments. Since the simulation of the dispersion field around buildings depends strongly on the correct simulation of the wind-flow structure, the studies performed during the past years on the wind-flow field around buildings are reviewed. This work also identifies errors that can produce poor results when numerically modelling wind flow and dispersion fields around buildings in urban environments. Finally, particular attention is paid to the practical guidelines developed by researchers to establish a common methodology for verification and validation of numerical simulations and/or to assist and support the users for a better implementation of the computational fluid dynamics (CFD) approach.

Smart lighting of public open spaces plays a crucial role in creating sustainable cities. Investing in optimal methods for improving the energy efficiency of urban lighting systems has become strategic for the economic, technological, and social development of cities. In addition to technical considerations such as energy efficiency and photometric measurements, lighting design should also take into account the subjective aspect of visual safety. However, measuring lighting efficiency in terms of human perception can be challenging because people’s perceptions vary and depend on the urban and architectural context. To address this issue, a sustainability coefficient of outdoor lighting ambiences (Sn) is presented to quantify the compliance of urban open spaces with sustainable lighting design. This coefficient combines two subjective factors: illumination likability and perceived illuminance intensity. The study uses the SEC methodology (suitable for everyone, environmentally accepted, cost-effective), which provides insight into the factors that influence the Sn value. The results showed significant correlations between psychological and aesthetic-functional factors and the Sn, while sociological factors had little influence. The validity of the Sn in a realistic environment can be confirmed. The main reasons for certain Sn levels were identified and possible solutions were proposed, ranging from changes in lighting intensity to architectural redesigns, to improve environmental comfort in urban environments. This study paves the way for a deeper understanding of the role of urban lighting in shaping environmental comfort and human behavior.

In this contribution, possibility of using the backward ray tracing (RT) coupled with the finite-difference timedomain (FDTD) method for two-dimensional (2-D) simulations of the wave propagation in urban environments is demonstrated. For increased accuracy of exposure-assessment simulations, the FDTD method is used in small domains including inhomogeneous scatterers, whereas RT is used to simulate the wave propagation between these domains and buildings in urban environment. In this approach, contrary to the forward RT, many rays are generated for each diffracted ray and contributions from each receiver-transmitter path finally provide an excitation for the FDTD domains. A heuristic model of diffraction based on the uniform theory of diffraction has been used in the developed code. For the sake of simplicity, the method is presented in 2-D.

Lighting design in indoor environments is of primary importance for at least two reasons: 1) people should perceive an adequate light; 2) an effective lighting design means consistent energy saving. We present the Invisible Light Switch (ILS) to address both aspects. ILS dynamically adjusts the room illumination level to save energy while maintaining constant the light level perception of the users. So the energy saving is invisible to them. Our proposed ILS leverages a radiosity model to estimate the light level which is perceived by a person within an indoor environment, taking into account the person position and her/his viewing frustum (head pose). ILS may therefore dim those luminaires, which are not seen by the user, resulting in an effective energy saving, especially in large open offices (where light may otherwise be ON everywhere for a single person). To quantify the system performance, we have collected a new dataset where people wear luxmeter devices while working in office rooms. The luxmeters measure the amount of light (in Lux) reaching the people gaze, which we consider a proxy to their illumination level perception. Our initial results are promising: in a room with 8 LED luminaires, the energy consumption in a day may be reduced from 18585 to 6206 watts with ILS (currently needing 1560 watts for operations). While doing so, the drop in perceived lighting decreases by just 200 lux, a value considered negligible when the original illumination level is above 1200 lux, as is normally the case in offices.

Sensors are an important part of intelligent lighting. They can sense the sound and brightness of the environment, the movement and presence of the human body, and sense the temperature, humidity and air quality of the environment. After sensor detection, it can further control the movement of lighting products, switch light and shade, color temperature, switch and scene changes, achieve the lighting effects of functional lighting, scene lighting, and environmental protection requirements for energy saving and emission reduction. The application of sensors and light sensors in intelligent lighting control has increased the level of intelligence in lighting control and saved a lot of energy.

Reliability analysis and design of randomly imperfect thin cylindrical shells against post-critical drops

4. Lighting design considerations

From an ecological perspective, sustainable lighting in urban marine areas requires striking a balance between meeting human needs and protecting marine ecosystems from the harmful effects of disrupting natural light regimes. While managing artificial lighting is crucial, we argue that preventing obstructions to light penetration into the water is as important, as many marine organisms depend on the euphotic zone. This study intends to review the key factors for the implementation of wildlife-friendly lighting design in the urban marine environment, as the subject is explored in ecological studies but scarcely discussed in urban studies. An integrative literature review and cases are employed to synthesise evidence about changes to the light regime in urban marine areas from four perspectives: light reach, intensity, spectrum, and duration. The cases present measures implemented to benefit marine species affected by alterations to the light regime following urbanisation in a way that they could still thrive in a modified built environment. In discussion, it is acknowledged that achieving sustainable lighting in urban marine areas is a multifaceted challenge involving concurrent influencing factors, including a shared agency between humans and non-humans, which may require comprehensive lighting designs that are tailored to specific goals and target species.

The main control-room is the most important monitoring and control center of nuclear power plant, and is also the most complex place in the man-machine interface of the plant. It has been thought the most frequently place where the accidents due to human factors happened. In order to avoid the possibility of error operation of operators caused by the improper lighting design, the human factors consideration for the lighting design is described in this paper according to the characteristics of digital control-room of nuclear power plant nowadays.

The impact of artificial light at night on ecology is an urgent and continuous consideration in lighting design. People’s needs and wishes for light in urban areas often conflict with demands for minimising ecological impact. For example, in city parks people may desire light that offers a pleasant experience of nature and the feeling of safety, while the fauna may thrive best with no light at all. How to overcome this seemingly unresolvable conflict, especially in hybrid environments like city parks? This paper presents Light Sketching for Ecology, a cooperative lighting design tool to help balance lighting demands from the human experience side with demands for minimising ecological impact. Results from a pilot study show the potential of Light Sketching for Ecology to create a win-win situation in which park users are more positive about the park lighting while the lighting’s ecological impact is significantly lowered.

A dual-sided coded-aperture radiation detection system