/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCFor the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1016/S0360-1323(01) Building and Environment, 37, 4, pp. 363-377, 1998-11-01 Applicability of daylighting computer modeling in real case studies: comparison between measured and simulated daylight availability and lighting consumption Galasiu, A. D.; Atif, M. R. Application of Daylighting Computer Modeling in Real Case List of Tables SummaryThis official IEA report is a deliverable of the IEA SHC Task 21 / IEA ECBCS Annex 29: Daylight in Buildings. The task focuses on daylighting systems and strategies which can be applied in new and existing buildings with high electricity saving potential such as offices, schools, commercial and institutional buildings. The daylighting performance of these strategies is tested in laboratory facilities, through modeling, and in real case study buildings. This report is a deliverable of the Subtask C research projects. The main objective of Subtask C, as stated in the Implementing Agreement of IEA SHC Task 21 / IEA ECBCS Annex 29 is "to improve the capability, accuracy and ease-of-use of daylighting design and analysis tools for building design practitioners. The practitioners will be able to predict the performance of different daylighting systems and control strategies and to evaluate the impact of the integration of daylighting in the overall building energy concept by using these design tools". Subtask C work included the development of the Adeline lighting software, along with the assessment of its capabilities and accuracy.This report investigates the accuracy and limitations of the Adeline 1.0 lighting software in simulating the illuminance distribution from daylighting and the electrical lighting energy savings of an existing atrium building. The purpose of the study was to compare the Superlite, Superlink and Radiance computed outputs against data collected in a real building.The case study is an enclosed atrium space located in Ottawa, Canada. The atrium is a threestorey octagonal construction roofed by a pyramidal skylight made of several glazing systems. The space is equipped with an automatic on/off lighting control system operated by a daylight photosensor located in another atrium space part of the same facility. Field work was conducted for both summer and winter conditions and included measurements of horizontal indoor and outdoor illuminance, solar radiation and electrical lighting system time-of-use. The computer simulation phase consisted in the creation of two computer models, a Superlite/Superlink simple model and a Radiance model used to simulate the daylighting performance of the atrium...
/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1016/j.solener.2003.12.007 Society, 76, 5, pp. 523-544, 2004-05-01 Impact of window blinds on daylight-linked dimming and automatic on/off lighting controls Galasiu, A. D.; Atif, M. R.; MacDonald, R. A. reduced the lighting energy consumption on average by 50 to 60% when compared to lights fully on from 6 AM to 6 PM. These savings, however, dropped by 5 to 45% for the dimming system, and by 5 to 80% for the automatic on/off system with the introduction of various static window blind configurations. The savings in lighting energy were more significant when the lighting control systems were used with photocontrolled blinds. This was due to the capability of the blinds to adjust their position automatically in direct response to the variable daylight levels. Solar Energy -Journal of the International Solar Energy
This paper presents the field-measured energy performance of two common types of daylight-linked lighting control systems, continuous dimming and automatic on/off installed in two existing large atrium spaces located in Canada. The daylighting performance was evaluated based on the daylight contribution to the indoor illuminance and the amount of electrical lighting displaced by daylighting via the daylight-linked lighting control systems. Measured daylighting contribution to the space indicates that significant lighting energy savings can be achieved in atrium spaces if the daylight-linked lighting control system is appropriately selected, installed and commissioned throughout its existence. Results extrapolated from measurements collected during summer and winter indicate that as installed, the continuous dimming lighting control system provides 46% annual savings in electrical lighting consumption, while the automatic on/off saves between 11-17% in lighting energy. These savings account for 68% of the lighting energy consumed during main occupancy for the continuous dimming system, and 31.5% for the automatic on/off. Operation irregularities such as a reduced dimming linearity and an incorrect adjustment of the phases of the dimming control system, as well as the inadequate location of the photocell controlling the automatic on/off lighting system, the improper maintenance of the skylight during winter and the oversizing of the lighting system reduced the energy efficiency of the lighting control systems by 30-65%.
/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1016/S0017-9310(00)00195-2International Journal of Heat and Mass Transfer, 44, 10, pp. 1973-1981, 2001 Natural convection heat transfer within multi-layer domes Laouadi, A.; Atif, M. R. Natural convection heat transfer within multilayer domes Laouadi, A.; Atif, M. R.A version of this paper is published in / Une version de ce document se trouve dans : International Journal of Heat and Mass Transfer, v. 44, no. 10, May 2001, pp. 1973-1981 www.nrc.ca/irc/ircpubs on natural convection heat transfer within these layers. This information is required for the evaluation of the dome thermal performance (e.g., the U-factor). NRCC-43954 Natural Convection Heat Transfer within Multi-layer DomesThis paper presents a numerical study on heat transfer by laminar natural convection within multi-layer domes with uniform spacing heated from the outside. The flow and temperature fields within the domed enclosure were obtained using the control volume approach combined with the fully implicit scheme. Correlations for the heat transfer as a function of the dome shape and the gap spacing between the layers were developed under steady state conditions. The results showed that the convection heat transfer for fully hemispheric domes (half of spheres) may reach more than 13% higher than that for low profile domes (hemispherical caps) for small gap spacings (gap spacingto-radius ratio δ < 0.1) and more than 100% for large gap spacings (δ > 0.3). The critical gap spacing that yields the maximum heat transfer was quantified for each dome shape.2
/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. Research and Technology, 30, 3, pp. 111-118, 1998 Transparent domed skylights: optical model for predicting transmittance, absorptance and reflectance Laouadi, A.; Atif, M. R. International Journal of Lighting Transparent domed skylights: optical model for predicting transmittance, absorptance and reflectance Laouadi, A.; Atif, M.R.A version of this paper is published in / Une version de ce document se trouve dans : International Journal of Lighting Research and Technology, v. 30, no. 3, 1998, pp. ABSTRACTDaylighting and thermal loads are very important design issues for skylight design, especially in large spaces such as atria. However, the trade-off between daylighting and thermal performance of skylights has been difficult to solve, due to a lack of daylighting and thermal design tools. A mathematical model was developed to predict the visible/solar transmittance, absorptance and reflectance of multi-glazed domed skylights for both direct and diffuse radiation. The model is based on tracking the beam and diffuse radiation transmission through the dome surface. Since all building-energy simulation and fenestration-rating tools are limited to planar skylights, the model was translated into a simple method where domed skylights were substituted by optically equivalent planar skylights. The results showed that domed skylights yield slightly lower visible/solar transmittance at low sun zenith angles and substantially higher visible/solar transmittance at high sun zenith angles, or near the horizon than planar skylights having the same aperture. Absorptance of domed skylights is higher than that of planar skylights, particularly at high sun zenith angles, or near the horizon. The model was also compared to the IESNA transmittance calculation procedure for domed skylights and to the Wilkinson model.
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