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Complex fenestration systems (CFS) include windows featuring complex glazing such as translucent and transparent insulation, solar control films, patterned or decorative glass, in-between pane shades, etc. CFS are believed to exhibit superior energy performance, but may have adverse effects on environmental features important for building-occupant satisfaction requirements such as the outdoor view (connection to outside), indoor view (feeling of privacy), luminance (major factor for discomfort glare), and light diffusion quality (relates to uniformity of illuminance on work plane). This article is part of a larger effort to rate complex fenestration systems for energy performance and indoor environment quality (IEQ). In the end, IEQ ratings must be derived from direct studies of how building occupants perceive the indoor environment conditions created by the installed fenestration product. As a first step, this work tackles the theoretical development of new metrics to rate CFS with regards to IEQ, namely the view impairment index, luminance index, and light diffusion quality index. The new indices are applied to some typical CFS, namely a diffuse window, and a clear window combined with an interior shading screen, and integrated perforated Venetian blinds. The results show that the diffuse window may increase the luminance by more than 100% under clear sky conditions when compared with a clear window with a similar light transmittance. White colored Venetian blinds may increase the window luminance by up to 50% and reduce the outdoor view by up to 66% as compared with a clear window with a similar light transmittance.

New and more advanced guidance systems are nowadays available, allowing bringing natural light into buildings and offering potentials for energy savings associated to well-being for occupants. From a design point of view, the key factor is the knowledge of their photometric performances in terms of global light transmission efficiency, so as to predict the daylight availability in an interior space due to an array of guidance systems (or, the other way around, to predict the number of pipes needed to produce a minimum natural light illuminance according to standard requirement) through known analytical methods such as the lumen method. In spite of this, determining the global light transmission efficiency of advanced guidance systems is a quite complicate matter because of the redirecting optical properties these elements rely on even in the case of simple typologies (for instance, passive domes with micro-prismatic profiles and micro-prismatic or holographic films used as pipe’s coating). This paper presents an approach to characterize photometric performances of tubular daylight guidance systems in terms of light transmission efficiency: the global system efficiency is the result of the product of the efficiencies of the three individual components (collector, pipe and diffuser) and each efficiency is determined as the ratio of the flux emitted through the output window to the flux hitting the input window, accounting for both the beam and the diffuse efficiency. The approach, based on both measurements on physical models and simulations, was applied to different typologies of pipes and passive collectors and the obtained data were used to eventually calculate the global efficiency for the analyzed system.

U ovom završnom radu se projektiralo upravljanje osvjetljenjem za prostoriju s krovnim prozorom. Prvi korak je identificiranje i validiranje modela doprinosa vanjskog i unutarnjeg osvjetljenja ukupnom osvjetljenju na površini od interesa. Alat kojim se koristi za ostvarenje tog koraka su neuronske mreže te njihovo ostvarenje pomoću Neural Network Toolbox-a u sklopu programskog alata MATLAB. Drugi korak je izrada algoritma upravljanja kako bi se održavali željeni uvjeti osvjetljenja na navedenoj površini od interesa, odnosno radnom stolu, uz minimalnu potrošnju električne energije. Algoritam je provjeren programski također u sklopu programskog alata MATLAB, te simulacijski u Simulink okruženju istog programskog alata. U konačnici je izrađeno nekoliko scenarija za doprinose vanjskog osvjetljenja te se kroz usporedbu potrošnje bez sustava upravljanja i uz sustav upravljanja došlo do određenih zaključaka vezanih za vrijednost implementiranja takvih sustava u zgradarstvu.

This paper describes a methodology for calculating the daylight coefficient for complex fenestration systems whose optical behavior (transmission, reflection and scattering) may change during simulation. The methodology splits the daylight coefficient into two components: one corresponding to the unscattered transmitted light and the second to the scattered transmitted light. Both components are calculated based on the daylight coefficients of a reference fenestration, and the opticaltransmission characteristic and scattering effect of the actual fenestration. The resulting daylight coefficients for a given complex fenestration system need only be calculated only once prior to simulation and the methodology has been incorporated into Daylight 1-2-3, a new integrated energy and daylighting analysis tool for offices and classrooms., 10th IBPSA Building Simulation Conference: 3 September 2007, Beijin, China

This paper presents a comparison study between the simulations of SkyVision and measurements made in a scale model. SkyVision is a computer tool to calculate the overall optical characteristics, indoor daylight availability and energy saving potential of projecting and tubular skylights. The measurements included the overall visible transmittance and indoor daylight illuminance of the skylight. A rectangular wooden box was used as a scale model of a simple commercial building. The top surface of the box was fitted with a curbed opening to accommodate the skylights to be tested. Seven skylight shapes were tested: two circular dome models, one with clear and one with white acrylic glazing; two rectangular bubble dome models, one with clear and one with white acrylic glazing; a clear acrylic hexagonal pyramid model; a clear polycarbonate barrel vault model; and a tubular skylight model. The measurements were conducted for a whole day period, thereby covering different sky conditions: overcast, partly cloudy and clear sunny skies. SkyVision's simulations for the skylight transmittance compared reasonably well with the actual measurements, except for the hexagonal pyramidal skylight. The hexagonal pyramid surface exhibited some lens effects around the surface vertices, which were not possible to model in SkyVision. As for the skylight indoor illuminance comparison, the SkyVision's simulations were in good agreement with the actual measurements for all occurrences of sky conditions., Also presented at the ASHRAE Summer Meeting, June 24-28, 2006, Quebec City

The need for energy conservation in buildings has spurred innovations in window technologies. These products include windows combined with shading devices, and windows featuring complex glazings such as smart glazings, translucent and transparent insulation, patterned or decorative glass. Unfortunately, little is known about their impact on the quality of the indoor environment. This paper addresses the development of new lighting quality indices for the outdoor view (which gives a feeling of connection to the outside), indoor view (which may affect feelings of privacy), and window luminance (which indicates the potential risk of discomfort glare). The new indices were applied to a typical fenestration system, consisting of a clear window equiped with an interior perforated shading screen with opaque and translucent materials. The simulation results indicate that the the light-coloured screen has a significant impact on the outdoor view and window's luminance, depending greatly on the sky conditions. Under clear sky conditions, the window's luminance may be increased by up to 80% compared with overcast sky conditions, particularly for a window with a translucent screen., IBPSA - Canada Esim Conference: 02 May 2006, Toronto, Ontario

Aussi disponible en français: Un nouveau modèle calcule les indices d'éclairage et de visibilité des systèmes de fenêtrage complexes

A Canadian researcher has found a way to calculate the energy savings from tubular skylights, and a way to work out the optimum distance they should be spaced apart. Using Sydney weather data imported into SkyVision, a free software design tool, Canadian researcher Dr Aziz Laouadi found the combined system would use from 10% (in June) to 45% (in January) less electrical energy than an electric-only system. The average monthly saving would be 29%.

IRC has released the final version of its SkyVision software for predicting skylight performance afterextensive validation testing on the beta version released last year. Skylight designers, skylightmanufacturers, building designers, fenestration rating councils, architects and educators can use the toolto predict the daylighting performance and energy saving potential of conventional and tubular skylights.This report outlines the test methodology to measure the skylight performance, and presents thecomparison study between the software's predictions and the actual measurements. This report alsoincludes a comparison with the results of the California PIER (Public Interest Energy Research) programfor the effective transmittance of skylight and well combinations. The results of the PIER programcovered additional skylight settings, and provided valuable benchmarks not only for the effectivetransmittance, but also for the thermal transmittance (U-value) and the solar heat gain coefficient ofprojecting skylights., L'IRC a publié la version définitive de son logiciel SkyVision de prédiction des performances des lanterneaux après avoir soumis la version bêta parue l'an dernier à des excès de validation exhaustifs. Les concepteurs et les fabricants de lanterneaux, les concepteurs de bâtiments, les conseils d'évaluation de fenestrages, les architectes et les éducateurs peuvent utiliser l'outil pour prédire les performances en matière d'éclairage naturel et le potentiel de conservation d'énergie des lanterneaux de forme classique ou tubulaire. Le rapport donne les grandes lignes de la méthode d'essai utilisée pour mesurer les performances des lanterneaux et présente l'étude de comparaison entre les prédictions du logiciel et les mesures réelles. Il inclut également la comparaison avec les résultats du programme PIER (Public Interest Energy Research) de la Californie relatif à la transmittance effective de combinaisons de lanterneaux et de puits de lumière. Les résultats du programme PIER couvraient des environnements de lanterneaux supplémentaires et offraient des repères précieux non seulement pour la transmittance effective, mais aussi pour la transmittance thermique (valeur U) et le coefficient d'apport par rayonnement solaire des lanterneaux en saillie.

Daylighting by means of skylights has significant potential for reducing lighting energy in commercial building space, but efficient design is required. SkyVision is a design tool for assisting skylight manufacturers and building designers in developing appropriate skylight designs for given building types and daylighting applications. This paper uses SkyVision to investigate some of the design elements of skylights such as: the proper selection of skylights and wells, skylight spacing, and potential energy and cost savings., CIB World Building Conference: 02 May 2004, Toronto, Ontario

Software

Skylights can offer useful benefits in reducing building energy consumption and improving building occupants satisfaction. Skylights may also offer interesting features which increase a building's market value by conveying an aesthetic look to buildings, admitting natural light indoors and connecting building occupants to the outside world. While skylight features are fully exploited, their benefits are still not fully understood and accounted for in currently available computer tools. In fact, research has shown that skylights may result in high-energy consumption if not properly designed. The SkyVision software aims to assist skylight manufacturers and building designers in developing appropriate skylight designs for given buildings and daylighting applications. The software analyses the optical characteristics of various types and shapes of skylights, and calculates their daylighting and energy performance. This paper presents a description of the software and its capabilities along with some preliminary software comparison studies. SkyVision predictions of indoor illuminance compared very well with the ADELINE 3 suite of programs (RADIANCE and SUPERLITE)., Building Simulation, 8th IBPSA Conference: 11 August 2003, Eindhoven, Netherlands