Search results for "daylight."
showing 10 items of 44 documents
Empirical BAC factors method application to two real case studies in South Italy
2021
Abstract The application of Building Automation and Control (BAC) systems has many advantages. One of these is the reduction of the end-user electricity consumption and, if applied to lighting systems, the achievement of well-acknowledged benefits from daylight, such as productivity, health, visual comfort and well-being. Concerning the first aspect, the international Standard EN 15232 proposes the so-called BAC Factors (BF) method to assess the impact of BAC systems on the final energy consumption. The method provides a simplified estimation of the energy savings due to automation in buildings and questions arise on its applicability in some situations. For this reason, the authors have ca…
Performance Analysis of a Prototype High‐Concentration Photovoltaic System Coupled to Silica Optical Fibers
2021
High-concentration photovoltaic (HCPV) systems are one of the most promising technologies for the generation of renewable energy with high-conversion efficiency. Their development is still at an early stage, but the possibility of integrating high-concentration systems into buildings offers new opportunities to achieve the net-zero-energy building goal. Herein, the optical and energetic performance of a hybrid daylighting−HCPV prototype based on pure- or doped-silica optical fibers (OFs) to guide 2000× concentrated sunlight inside the buildings is evaluated. There, the light can either be used to illuminate interior spaces or projected on solar cells to generate electricity. The system equi…
Ultraviolet-visible light-induced solarisation in silica-based optical fibres for indoor solar applications
2021
Abstract The transmission performances of pure- and doped-silica (a-SiO2) optical fibres are compared during the exposure to a high-power broadband light source approximating the solar spectrum. From the Gaussian decomposition of the attenuation spectra, we found that Al- and P-doped fibres show a fast solarisation effect which leads to transmission degradation in the ultraviolet-visible range. Similarly, Ge-doped fibres undergo photoinduced colour-centre formation which, however, does not prevent visible-light propagation. One of the two tested pure-silica fibres results completely unaffected by light exposure whereas the other shows an absorption band probably due to the presence of chlor…
Modeling of light pipes for the optimal disposition in buildings
2019
A light pipe is an excellent solution to transport and distribute daylight into environments without or with little lighting, guaranteeing comfort inside the rooms. As stated in the literature, the evaluation of the performances of light pipes presents numerous complexities, making the work very difficult for technicians and designers. This study is aimed to present a methodology that is able to identify the potential of light pipes using indices such as daylight autonomy (DA), continuous daylight autonomy (DAc), and useful daylight illuminance (UDI). This paper presents an analysis of daylight obtained by several configurations of simple models of light pipes installed into a 5 ×
Towards a More Sustainable City: The Role of the Daylight Factor in Evaluating the Energy Requirements of Buildings
2018
The Daylight factor is the reference parameter used in Energy Standard EN15193:2008 to assess daylight contribution in the energy performance of buildings. But its efficacy in putting in relation buildings energy performance, daylight availability and visual tasks is now a subject of discussion in literature. In fact, the daylight factor is a static indicator independent from building geometry and environmental parameters. From the energy point of view, it has still to be assessed if it can ensure when the switch of artificial light is needed, representing therefore the most disadvantageous outdoor illuminance conditions. The goal of this study is demonstrating if the daylight factor calcul…
Within and between population variations of incubation rhythm of great tits Parus major
2014
Uniparental incubation frequently means that eggs remain unattended for periods where the incubating bird is foraging out of the nest. The determination of incubation rhythms (i.e., the length and temporal pattern of incubation sessions) and the factors which affect them are therefore important to understand life-history trade-offs. We described the incubation rhythm and its temporal variation of a southern European great tit Parus major population, and review previous studies to check for latitudinal trends. In the studied population, females were active (from first exit in the morning to last entrance in the evening) 12.5 h per day, performing incubation sessions (on-bouts) of 26 min and …
Aspects and issues of daylighting assessment: A review study
2016
Abstract Proper assessment of indoor daylighting conditions can significantly reduce energy consumption due to artificial lighting and can improve indoor visual comfort. This paper gives a critical review of the fundamental aspects of daylighting indices with the aim to provide a broad overview of methods and indices available to assess daylighting from varying points of view. Assessments cover distribution, availability over time and in specific climatic contexts, uniformity in the space, visual comfort issues and the relations between each of these aspects and a proper building and lighting design. A special focus on the assessment of indoor spatial and temporal uniformity is given. An an…
Technical‐economic evaluation of the effectiveness of measures applied to the artificial lighting system of a school
2021
Ensuring optimum interior lighting is a topic of great importance, as this influences not only the well-being of users but also the optimal performance of visual tasks. Lighting can be natural, but if not sufficient, it can be compensated with artificial lighting. This study highlights a methodology for designing a new lighting system that takes into account both technical and economic aspects. The method was applied to an existing school located in southern Italy, in which the electricity consumption is related to the current lighting system. The school is chosen as being representative of the construction type and layout of many local schools. In addition, the coexistence of several visua…
Assessment of indoor illuminance and study on best photosensors' position for design and commissioning of Daylight Linked Control Systems. A new meth…
2018
Abstract Artificial lighting systems have to ensure appropriate illuminance with high energy efficiency according to best design practice and technical standards. These aims can be tackled, by incorporating a Daylight linked control system. However, the system behaviour is strongly influenced by several factors and, in particular, by the sensors' position. Indeed, very often the illuminance on work-plane is not fully correlated with illuminance measured by the photo-sensor used to control the luminaires. This fact leads to wrong information for the Daylight linked control systems affecting its efficacy. The artificial intelligence of Neural Networks can be exploited to provide a method for …
Assessing the lighting systems flexibility for reducing and managing the power peaks in smart grids
2020
Abstract The application of “shiftable” or “modulable” load (i.e. washing machine, dishwasher, etc.) in a Smart Grid, can provide energy saving or modify the power flows in the grid, allowing a reduction of the electrical power peak. This paper explores the possibility to modulate the indoor artificial lighting to support this reduction. The study examines the impact of two different measures of power shaving. On the one hand, the change of Correlated Colour Temperature of the light source, and, on the other hand, the dimming of its luminous flux. The possibility to merge the above-mentioned technical solutions is also analyzed. Based on these strategies, several daily schedules of lighting…