The Experts below are selected from a list of 9864 Experts worldwide ranked by ideXlab platform
Jeanlouis Scartezzini - One of the best experts on this subject based on the ideXlab platform.
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design and validation of a compact embedded photometric device for real time Daylighting computing in office buildings
Building and Environment, 2019Co-Authors: Jerome Henri Kampf, Jeanlouis ScartezziniAbstract:Abstract Studies have shown that the exposure to daylight can have substantial visual/non-visual benefits for building occupants. To optimise Daylighting provision while maintaining a comfortable visual environment, Daylighting control systems have been investigated by architectural design and academic research for a number of years. However, real-time regulation of Daylighting in buildings requires transient Daylighting simulation with high accuracy and, Daylighting simulation, as performed to date, is significantly impacted by the employed sky luminance distribution models which only crudely reproduce the real sky characteristics due to oversimplification and limited luminance sampling inputs. In this paper, an embedded photometric device is proposed to combine high dynamic range (HDR) imaging based high-resolution sky luminance monitoring with quasi real-time on-board Daylighting computing, composed of a low-cost image sensor and a field programmable gate array (FPGA) micro-processor. A deliberate calibration procedure of the whole imaging system, regarding its spectral response (spectral correction error f’1 = 8.89%), vignetting effect and signal response, was formulated and validated experimentally. The device was made to measure a wide luminance range (150 dB) including that of the direct solar disk, sky vault, and landscape simultaneously. Finally, experiments during predominant clear and overcast sky conditions were conducted respectively to assess its performance in Daylighting simulation, both qualitatively and quantitatively. The experimental results demonstrated its quality in solar tracking as well as its capability to reduce Daylighting simulation error to 1 7 ∼ 1 3 of that of a common practice using the conventional Perez all-weather sky model for workplane illuminance calculation in office buildings.
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modelling complex fenestration systems using physical and virtual models
Solar Energy, 2010Co-Authors: Anothai Thanachareonkit, Jeanlouis ScartezziniAbstract:Abstract Physical or virtual models are commonly used to visualize the conceptual ideas of architects, lighting designers and researchers; they are also employed to assess the Daylighting performance of buildings, particularly in cases where Complex Fenestration Systems (CFS) are considered. Recent studies have however revealed a general tendency of physical models to over-estimate this performance, compared to those of real buildings; these discrepancies can be attributed to several reasons. In order to identify the main error sources, a series of comparisons in-between a real building (a single office room within a test module) and the corresponding physical and virtual models was undertaken. The physical model was placed in outdoor conditions, which were strictly identical to those of the real building, as well as underneath a scanning sky simulator. The virtual model simulations were carried out by way of the Radiance program using the GenSky function; an alternative evaluation method, named Partial Daylight Factor method (PDF method), was also employed with the physical model together with sky luminance distributions acquired by a digital sky scanner during the monitoring of the real building. The overall Daylighting performance of physical and virtual models were assessed and compared. The causes of discrepancies between the Daylighting performance of the real building and the models were analysed. The main identified sources of errors are the reproduction of building details, the CFS modelling and the mocking-up of the geometrical and photometrical properties. To study the impact of these errors on Daylighting performance assessment, computer simulation models created using the Radiance program were also used to carry out a sensitivity analysis of modelling errors. The study of the models showed that large discrepancies can occur in Daylighting performance assessment. In case of improper mocking-up of the glazing for instance, relative divergences of 25–40% can be found in different room locations, suggesting that more light is entering than actually monitored in the real building. All these discrepancies can however be reduced by making an effort to carefully mock up the geometry and photometry of the real building. A synthesis is presented in this article which can be used as guidelines for Daylighting designers to avoid or estimate errors during CFS Daylighting performance assessment.
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minimizing lighting power density in office rooms equipped with anidolic Daylighting systems
Solar Energy, 2010Co-Authors: Friedrich Linhart, Jeanlouis ScartezziniAbstract:Physical or virtual models are commonly used to visualize the conceptual ideas of architects, lighting designers and researchers; they are also employed to assess the Daylighting performance of buildings, particularly in cases where Complex Fenestration Systems (CFS) are considered. Recent studies have however revealed a general tendency of physical models to over-estimate this performance, compared to those of real buildings; these discrepancies can be attributed to several reasons. In order to identify the main error sources, a series of comparisons in-between a real building (a single office room within a test module) and the corresponding physical and virtual models was undertaken. The physical model was placed in outdoor conditions, which were strictly identical to those of the real building, as well as underneath a scanning sky simulator. The virtual model simulations were carried out by way of the Radiance program using the GenSky function; an alternative evaluation method, named Partial Daylight Factor method (PDF method), was also employed with the physical model together with sky luminance distributions acquired by a digital sky scanner during the monitoring of the real building. The overall Daylighting performance of physical and virtual models were assessed and compared. The causes of discrepancies between the Daylighting performance of the real building and the models were analysed. The main identified sources of errors are the reproduction of building details, the CFS modelling and the mocking-up of the geometrical and photometrical properties. To study the impact of these errors on Daylighting performance assessment, computer simulation models created using the Radiance program were also used to carry out a sensitivity analysis of modelling errors. The study of the models showed that large discrepancies can occur in Daylighting performance assessment. In case of improper mocking- up of the glazing for instance, relative divergences of 25–40% can be found in different room locations, suggesting that more light is entering than actually monitored in the real building. All these discrepancies can however be reduced by making an effort to carefully mock up the geometry and photometry of the real building. A synthesis is presented in this article which can be used as guidelines for Daylighting designers to avoid or estimate errors during CFS Daylighting performance assessment.
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comparing the accuracy of Daylighting physical and virtual models for complex fenestration systems
PLEA 2006 - The 23rnd Conference on Passive and Low Energy Architecture, 2006Co-Authors: Anothai Thanachareonkit, Jeanlouis Scartezzini, Darren RobinsonAbstract:Nowadays, many new window components known as complex fenestration systems (CFS), such as laser-cut panels and prismatic films, are considered in order to improve the overall luminous properties of building spaces : detailed studies of CFS remain necessary however to validate their Daylighting performance. Physical and virtual models are commonly used to assess the Daylighting performance of more conventional Daylighting strategies within buildings. Several recent studies have reported significant errors for both physical and virtual modelling procedures, 10% modelling errors leading in both cases to 15% up to 170 % inaccuracy in modelled daylight factors assessment: no similar error analysis was carried out in a systematic way for Daylighting strategies involving CFS use. A side lit office room equipped with double glazing and a CFS (laser-cut panel and prismatic film) was mocked-up for that purpose in a Daylighting test module. The office room was reproduced by way of a 1:10 scale physical model placed under a scanning sky simulator, as well as a virtual model built-up by the way of Radiance lighting program. Several model parameters were varied, leading to the evaluation of model inaccuracies through a sensitivity analysis. The most significant factor (internal surface reflectance) is considered in this paper, leading to a first set of modeling guidelines.
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comparing Daylighting performance assessment of buildings in scale models and test modules
Solar Energy, 2005Co-Authors: Anothai Thanachareonkit, Jeanlouis Scartezzini, Marilyne AndersenAbstract:Physical models are commonly used to assess Daylighting performance of buildings using sky simulators for purpose of research as well as practice. Recent studies have pointed out the general tendency of scale model assessments to overestimate the performance, usually expressed through work plane illuminance and daylight factor profiles, when compared to the real buildings. The cause of the discrepancy between buildings and scale models is due to several sources of experimental errors, such as modelling of building details, mocking-up of surface reflectances and glazing transmittance, as well as photometer features. To analyse the main sources of errors, a comparison of a full scale test module designed for experimentation of Daylighting systems and its 1:10 scale model, placed within identical outdoor Daylighting conditions, was undertaken. Several physical parameters were studied in order to determine their impact on the Daylighting performance assessment. These include the accurate mocking-up of surface reflectances, the scale model location, as well as the photometric sensor properties. The experimental study shows that large discrepancies can occur between the performance figures. They lead, on average, to a relative divergence of +60% to +105% in favor of the scale model for different points located in the side lit room. Some of these discrepancies were caused by slight differences in surface reflectances and photometer cosine responses. These discrepancies were reduced to a +30% to +35% relative divergence, by putting in the effort to carefully mock up the geometrical and photometrical features of the test module. This included a sound calibration of photometric sensors, whose cosine-response appeared at the end to be responsible for the remaining relative divergence observed between the Daylighting performance figures.
Seoyong Shin - One of the best experts on this subject based on the ideXlab platform.
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a large scale Daylighting system based on a stepped thickness waveguide
Energies, 2016Co-Authors: Seoyong ShinAbstract:This paper presents a study on the use of optical fiber and a solar concentrator for a building Daylighting system. Daylighting is essential for improving indoor environments and reducing electric lighting power consumption in office buildings. Traditionally, optical fiber Daylighting systems were implemented only on a small scale. More complicated technologies are required for more amounts of daylight over further distance via a smaller light guider. The proposed solar lighting system with optical fiber is composed of an array of linear Fresnel lenses and a stepped thickness waveguide. The linear Fresnel lenses collect light into the stepped thickness waveguide. The stepped-thickness waveguide is an optical component which redirects focused sunlight from the vertical direction to the horizontal direction, and it guides light to the attached optical fiber. Simulation models were developed using commercial optical simulation tools (LightTools™). The optical efficiency and angular tolerance of the system are analyzed. The overall system cost is also estimated. Some considerations on the economic expansion of the system in terms of efficiency and estimated annual average energy saving are discussed. The results show that the presented optical fiber Daylighting system is a strong candidate for low-price and highly efficient solution for solar energy application to building energy savings.
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highly concentrated optical fiber based Daylighting systems for multi floor office buildings
Energy and Buildings, 2014Co-Authors: Irfan Ullah, Seoyong ShinAbstract:Abstract Daylighting is essential for improving indoor environments and reducing electric lighting power consumption in office buildings. Traditional, fiber-based Daylighting systems were implemented only on a small scale. To this end, two efficient approaches are presented. The first approach consists of a parabolic trough and the second approach contains a linear Fresnel lens. Sunlight is captured through the concentrator and distributed through the optical fibers. Since it is difficult to achieve a high concentration, a trough compound parabolic concentrator (CPC) is used to pass the maximum captured collimated sunlight into the optical fibers in both approaches. Optical-simulation results have shown that the efficiency achieved in the implemented Daylighting systems—which is estimated based on the average illuminance in the interior and on the illumination quality of the system through combining daylight and light-emitting diode (LED) light—is better than that of traditional lighting systems.
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development of optical fiber based Daylighting system with uniform illumination
Journal of The Optical Society of Korea, 2012Co-Authors: Irfan Ullah, Seoyong ShinAbstract:Daylighting has a very effective role in reducing power consumption and improving indoor environments in office buildings. Previously, it was not under consideration as a major source of renewable energy due to poor reliability in the design. Optical fiber as a transmission medium in the Daylighting system demands uniform distribution of light to solve cost, heat, and efficiency issues. Therefore, this study focuses on the uniform distribution of sunlight through the fiber bundle and to the interior of the building. To this end, two efficient approaches for the fiber-based Daylighting system are presented. The first approach consists of a parabolic mirror, and the second approach contains a Fresnel lens. Sunlight is captured, guided, and distributed through the concentrator, optical fibers, and lenses, respectively. At the capturing stage, uniform illumination solves the heat problem, which has critical importance in making the system cost-effective by introducing plastic optical fibers. The efficiency of the system is increased by collimated light, which helps to insert maximum light into the optical fibers. Furthermore, we find that the hybrid system of combining sunlight and light emitting diode light gives better illumination levels than that of traditional lighting systems. Simulation and experimental results have shown that the efficiency of the system is better than previous fiber-based Daylighting systems.
Marilyne Andersen - One of the best experts on this subject based on the ideXlab platform.
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unweaving the human response in Daylighting design
Building and Environment, 2015Co-Authors: Marilyne AndersenAbstract:Abstract Daylighting as a research topic situates itself at the interface between psycho-physiological and environmental factors, bringing together questions relevant to architectural design and building engineering, but also to human physiology and behavior. While Daylighting has a strong impact on human health and well-being, and an undeniable association with (subjective) emotional delight and perceived quality of a space, it is also highly dynamic and variable in nature, based on a combination of predictable (sun course) and stochastic (weather) patterns. This makes it both a challenging and essential aspect of how “performative” a space can be considered. This paper aims to discuss selected research developments regarding how architectural engineering and other domains of science could be more strongly bridged to address the need for meaningful decision support in Daylighting design: how can we better integrate the complexity of human needs in buildings into effective design strategies for daylit spaces? As a basis for discussion and to illustrate this overview, it describes a unified goal-based approach in an attempt to address the multiplicity of perspectives from which Daylighting performance can – and should – be evaluated in building design. Through five very different perspectives ranging from task-driven illumination or comfort to human-driven health and perception, it proposes a simulation and visualization framework in which one can start approaching these from an integrated approach.
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An interactive expert system for Daylighting design exploration
Building and Environment, 2011Co-Authors: Jaime M.l. Gagne, Marilyne Andersen, Leslie K NorfordAbstract:Architects increasingly use digital tools during the design process, particularly as they approach such complex problems as designing for successful Daylighting performance. However, while simulation tools may provide the designer with valuable information, they do not necessarily guide the user toward design changes which will improve performance. This paper proposes an interactive, goal-based expert system for Daylighting design, intended for use during the early design phases. The expert system consists of two major components: a Daylighting knowledge-base which contains information regarding the effects of a variety of design conditions on resultant Daylighting performance, and a fuzzy rule-based decision-making logic which is used to determine those design changes most likely to improve performance for a given design. The system gives the user the ability to input an initial model and a set of Daylighting performance goals in the form of illuminance and Daylighting-specific glare metrics. The system acts as a "virtual Daylighting consultant," guiding the user toward improved performance while maintaining the integrity of the original design and of the design process itself. Two sets of case studies are presented: first, a comparison of the expert system results to high performing benchmark designs generated with a genetic algorithm; and second, an evaluation of the expert system performance based on varying levels of esthetic constraints. The results of these case studies indicate that the expert system is successful at finding designs with improved performance for a variety of initial geometries and Daylighting performance goals. © 2011.
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Daylighting metrics for residential buildings
Proceedings of the 27th Session of the CIE, 2011Co-Authors: John Mardaljevic, Marilyne Andersen, Nicolas Roy, Jens ChristoffersenAbstract:It is now widely accepted that the standard method for Daylighting evaluation - the daylight factor – is due for replacement with metrics founded on absolute values for luminous quantities predicted over the course of a full year using sun and sky conditions derived from standardised climate files. The move to more realistic measures of Daylighting introduces significant levels of additional complexity in both the simulation of the luminous quantities and the reduction of the simulation data to readily intelligible metrics. The simulation component, at least for buildings with standard glazing materials, is reasonably well understood. There is no consensus however on the composition of the metrics, and their formulation is an ongoing area of active research. Additionally, non-domestic and residential buildings present very different evaluation scenarios and it is not yet clear if a single metric would be applicable to both. This study uses a domestic dwelling as the setting to investigate and explore the applicability of Daylighting metrics for residential buildings. In addition to Daylighting provision for task and disclosing the potential for reducing electric lighting usage, we also investigate the formulation of metrics for non-visual effects such as entrainment of the circadian system.
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comparing Daylighting performance assessment of buildings in scale models and test modules
Solar Energy, 2005Co-Authors: Anothai Thanachareonkit, Jeanlouis Scartezzini, Marilyne AndersenAbstract:Physical models are commonly used to assess Daylighting performance of buildings using sky simulators for purpose of research as well as practice. Recent studies have pointed out the general tendency of scale model assessments to overestimate the performance, usually expressed through work plane illuminance and daylight factor profiles, when compared to the real buildings. The cause of the discrepancy between buildings and scale models is due to several sources of experimental errors, such as modelling of building details, mocking-up of surface reflectances and glazing transmittance, as well as photometer features. To analyse the main sources of errors, a comparison of a full scale test module designed for experimentation of Daylighting systems and its 1:10 scale model, placed within identical outdoor Daylighting conditions, was undertaken. Several physical parameters were studied in order to determine their impact on the Daylighting performance assessment. These include the accurate mocking-up of surface reflectances, the scale model location, as well as the photometric sensor properties. The experimental study shows that large discrepancies can occur between the performance figures. They lead, on average, to a relative divergence of +60% to +105% in favor of the scale model for different points located in the side lit room. Some of these discrepancies were caused by slight differences in surface reflectances and photometer cosine responses. These discrepancies were reduced to a +30% to +35% relative divergence, by putting in the effort to carefully mock up the geometrical and photometrical features of the test module. This included a sound calibration of photometric sensors, whose cosine-response appeared at the end to be responsible for the remaining relative divergence observed between the Daylighting performance figures.
Irfan Ullah - One of the best experts on this subject based on the ideXlab platform.
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highly concentrated optical fiber based Daylighting systems for multi floor office buildings
Energy and Buildings, 2014Co-Authors: Irfan Ullah, Seoyong ShinAbstract:Abstract Daylighting is essential for improving indoor environments and reducing electric lighting power consumption in office buildings. Traditional, fiber-based Daylighting systems were implemented only on a small scale. To this end, two efficient approaches are presented. The first approach consists of a parabolic trough and the second approach contains a linear Fresnel lens. Sunlight is captured through the concentrator and distributed through the optical fibers. Since it is difficult to achieve a high concentration, a trough compound parabolic concentrator (CPC) is used to pass the maximum captured collimated sunlight into the optical fibers in both approaches. Optical-simulation results have shown that the efficiency achieved in the implemented Daylighting systems—which is estimated based on the average illuminance in the interior and on the illumination quality of the system through combining daylight and light-emitting diode (LED) light—is better than that of traditional lighting systems.
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development of optical fiber based Daylighting system with uniform illumination
Journal of The Optical Society of Korea, 2012Co-Authors: Irfan Ullah, Seoyong ShinAbstract:Daylighting has a very effective role in reducing power consumption and improving indoor environments in office buildings. Previously, it was not under consideration as a major source of renewable energy due to poor reliability in the design. Optical fiber as a transmission medium in the Daylighting system demands uniform distribution of light to solve cost, heat, and efficiency issues. Therefore, this study focuses on the uniform distribution of sunlight through the fiber bundle and to the interior of the building. To this end, two efficient approaches for the fiber-based Daylighting system are presented. The first approach consists of a parabolic mirror, and the second approach contains a Fresnel lens. Sunlight is captured, guided, and distributed through the concentrator, optical fibers, and lenses, respectively. At the capturing stage, uniform illumination solves the heat problem, which has critical importance in making the system cost-effective by introducing plastic optical fibers. The efficiency of the system is increased by collimated light, which helps to insert maximum light into the optical fibers. Furthermore, we find that the hybrid system of combining sunlight and light emitting diode light gives better illumination levels than that of traditional lighting systems. Simulation and experimental results have shown that the efficiency of the system is better than previous fiber-based Daylighting systems.
Joseph C Lam - One of the best experts on this subject based on the ideXlab platform.
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Daylighting and its effects on peak load determination
Energy, 2005Co-Authors: Joseph C Lam, S L WongAbstract:Abstract Daylighting is an important issue in modern architecture that has been characterized by the use of curtain walls in commercial buildings. In Hong Kong, the overall thermal transfer value (OTTV) calculations are mandatory requirements in the submission of building plans to control the building energy use, but Daylighting credits are not included in calculating the OTTV of building envelope designs. Natural daylight helps reduce the electricity use and the associated sensible cooling load due to artificial lighting. Hence, proper Daylighting designs can contribute to smaller air-conditioning system and lower the peak power demand of buildings. We use the computer simulation tool, DOE-2, to demonstrate the energy performance of a generic commercial building with different OTTV designs in terms of peak cooling plant requirement and peak building power demand due to various Daylighting systems. The peak loads are determined from the simulation results. Regression techniques are conducted to correlate the incremental peak electricity use and incremental peak cooling capacity with OTTV and Daylighting aperture (DA) (window-to-wall ratio (WWR) times light transmittance (LT)). Contours of equal incremental peak electricity use and incremental peak cooling plant demand for different building envelope parameters are developed. Important features for Daylighting schemes are highlighted and implications for OTTV designs discussed.
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an investigation of Daylighting performance and energy saving in a daylit corridor
Energy and Buildings, 2003Co-Authors: Joseph C LamAbstract:Daylighting has often been recognised as a useful source of energy savings in buildings. For daylit spaces, daylight-linked automatic lighting control can give excellent energy savings. The evaluation of energy efficiency due to Daylighting is best demonstrated by case studies. This paper presents field measurements on Daylighting for a fully air-conditioned daylit corridor. Electric lighting load, brightness of the fluorescent luminaires, daylight illuminance levels and the room parameters affecting Daylighting designs were recorded and analysed. Traditional Daylighting theories have been applied to illustrate how well Daylighting measures can perform in reality. It has been found that energy savings in electric lighting was about 70% using dimming control system. The results from this study provide some operational and energy performance data, which would be useful and applicable to other interior spaces with similar architectural designs.
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Daylighting and its implications to overall thermal transfer value ottv determinations
Energy, 2002Co-Authors: Joseph C Lam, S L WongAbstract:The overall thermal transfer value (OTTV) and Daylighting are two approaches controlling building energy use. In Hong Kong, although OTTV calculations are mandatory in the submission of building plans for approval, Daylighting credits are not included in building envelope designs. To promote energy-efficient building designs we use the computer simulation tool, DOE-2, to illustrate the energy performance of a generic commercial building due to various Daylighting schemes and OTTV designs. The year-round energy expenditures and loads are determined from the simulation results. Analysis is carried out in terms of the reduction in electric lighting requirement and the cooling penalty due to solar heat. Regression techniques are conducted to correlate the annual incremental electricity use with OTTV and Daylighting aperture (DA) (product of window-to-wall ratio (WWR) and light transmittance (LT)). Contours of equal annual incremental electricity use for different building envelope parameters are developed. Important features for Daylighting schemes are highlighted and implications for OTTV designs are discussed.
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evaluation of lighting performance in office buildings with Daylighting controls
Energy and Buildings, 2001Co-Authors: Joseph C LamAbstract:Lighting control integrated with Daylighting is recognised as an important and useful strategy in energy-efficient building designs and operations. It is believed that proper Daylighting schemes can help reduce the electrical demand and contribute to achieving environmentally sustainable building development. This paper presents field measurements on Daylighting for a fully air-conditioned office building in Hong Kong. Electricity consumption by the fluorescent luminaires, indoor illuminance levels and the room parameters affecting Daylighting designs were recorded and analysed. The measurements covered several cellular offices facing opposite orientations with and without Daylighting controls. The findings suggest that Daylighting schemes can result in substantial energy savings in air-conditioned office buildings in Hong Kong. Results are presented and the design implications are discussed.
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Measurements of solar radiation and illuminance on vertical surfaces and Daylighting implications
Renewable Energy, 2000Co-Authors: D. H.w. Li, Joseph C LamAbstract:There is a growing concern about the rapid development of infrastructure and building projects and their likely impacts on the environment. Particular concerns have been raised about office building developments and energy consumption issues. In recent years, there has been increasing interest in using daylight to save energy in buildings. Lighting control integrated with Daylighting is recognised as an important and useful strategy in terms of energy-efficient building design. It is believed that proper Daylighting schemes can help reduce the electrical demand and contribute to achieving environmentally sustainable building developments. This paper presents a simple method for estimating the likely energy savings in electric lighting due to Daylighting and the possible cooling penalty. Vertical solar radiation and illuminance data measurements are described. Cumulative frequency distributions of daylight availability are reported. The likely energy savings in office buildings are determined based on on–off and top-up controls, and the energy and environmental implications are discussed.
