No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The impact of the software’s choice on dynamic daylight simulations’ results: A comparison between Daysim and 3ds Max Design®
Abstract
Evaluating indoor daylight availability is extremely important in order to define the characteristics of an environment in terms of visual comfort and energy performances of lighting systems. The criticism of the static calculation approach based on Daylight Factor led to the development of the Climate Based Daylight Modeling (CBDM) one. Dynamic simulations are performed thanks to the use of specific software and the choice of a calculation tool or another could provide different output results. Therefore the aim of this paper is to compare results of dynamic daylight simulations carried out with two different software, Daysim and 3ds Max Design® and referred to a simple office located in 4 different cities and exposed according to the 4 main orientations. It demonstrates that differences in results are more or less significant depending on several factors: outdoor daylight conditions, window's orientation and considered internal calculation point.
... We conclude with a discussion of the limits of simulation speed and accuracy. 23 2 ...
... Computeraided design (CAD) emphasizes specificity and detail over abstract representation [21], and designers exhibit different design strategies when using CAD tools than when sketching, according to think-aloud design studies [22]. The choice of simulation tool may produce different performance results [23] and elicit different user behavior [24]. We use this literature review to set goals for the speed and accuracy of simulation software generally, and Accelerad in particular, to be most useful to designers. ...
... Several studies comparing daylit interiors to DAYSIM predictions found relative mean bias error (MBErel) under 20% and relative root mean square error (RMSErel) under 32% [9,111]. DAYSIM gave comparable results to 3ds Max in a study of one building interior under a number of sky conditions [110] but offered superior results at four other geographic locations [23]. ...
The conventional approach to predicting interior illumination and visual discomfort in buildings is to run a ray tracing simulation with high accuracy settings, wait while the simulation processes, and repeat as necessary with modifications to the scene and settings. This workflow lacks interactivity and usually occurs late in the design process to validate a completed design, if at all. For architecture to benefit from daylight as a practical, glare-free alternative to electric lighting, daylighting simulation and visual discomfort predictions must be available in real time during design. This thesis describes three innovations towards this goal: development of a parallel ray-tracing engine, validation against high dynamic range (HDR) photography and annual simulations, and human subject tests with interactive progressive rendering. Lighting simulation can be sped up more than an order of magnitude by running it in parallel on readily available graphics processing units (GPUs). Accelerad is a GPU-accelerated version of RADIANCE synthetic imaging software for global illumination simulation developed by the author, introducing a novel method for parallel multiple-bounce irradiance caching. In validation studies comparing simulated and measured luminance and visual discomfort, Accelerad achieves similar accuracy to RADIANCE at a speedup of 16 to 44 times. Applied to annual simulation methods to calculate climate based daylighting metrics such as daylight autonomy and annual sun exposure, Accelerad is 10 times faster than DAYSIM and 25 times faster than the five-phase method. Additionally, a progressive path tracing option is explored that calculates glare probability in seconds and enables interactive visual discomfort simulation. By providing accurate lighting simulation results to designers in real time, this information is expected to inform the design process in ways not previously possible. In human subject tests, the availability of realtime feedback was associated with increased exploration of the design space, higher confidence in proposed designs, higher satisfaction with the design task, and better performing designs with respect to daylight autonomy and daylight glare probability. This supports the theory that system response time affects users' cognitive states and suggests that designers will be more likely to adopt building performance simulation tools if they produce reliable results at interactive speeds.
... The incremental improvement and extension of Radiance's capabilities led to its being widely regarded as the "golden standard" for lighting simulation (Santos, Leitão and Caldas, 2018). Several authors use this simulation engine as the benchmark program in the validation of other daylighting simulation tools (Reinhart and Breton, 2009;Bellia, Pedace and Fragliasso, 2015;Jones and Reinhart, 2017;Reinhart, 2019). The following discussion focuses on Radiance and Radiancebased tools. ...
... DSM are also very susceptible to simulation parameters, particularly those that control ambient calculation of inter-reflected light in a model and consequently provide accuracy to the simulation. Standards for daylighting simulation (IESNA, 2012) and validation and comparative studies (Reinhart and Breton, 2009;Bellia, Pedace and Fragliasso, 2015;Jones and Reinhart, 2017) recommend specific guidelines to sensor grid size and simulation parameters that often result in computationally expensive DSM. Nevertheless, significant progress has been made in accelerating illuminance grid-based analysis using the Graphical Processing Unit (GPU) architecture (Nathaniel L. Jones and Reinhart, 2017). ...
The resources involved in the construction and operation of buildings represent nearly 40% of the global emissions of greenhouse gases (GHG), making the building sector one of the primary contributors to global warming. This reality has led to the creation of many prescriptive regulatory and voluntary programs that aim to mitigate the environmental impact of the building sector while ensuring high standards for Indoor Environmental Quality (IEQ), particularly those regarding the thermal and visual comfort of building occupants. Thus, the design of high-performance buildings, i.e., resource- and energy-efficient buildings that yield high levels of IEQ, is a pressing need. This scenario pushes architects to simulate their projects’ environmental performance to better support design tasks in a process referred to as performance-based design.
This dissertation studies the integration of daylighting and Building Energy Simulation (BES) tools into performance-based design supported by computational design (CD) methods, particularly parametric design and Building Performance Optimization (BPO). The assumption is that the early integration of parametric, BES, and daylighting simulation tools can be highly effective in the design, analysis, and optimization of high-performance buildings.
However, the research argues that the current daylighting and Building Energy Simulation (BES) tools pose critical challenges to that desirable integration, thus hindering the deployment of efficient exploratory design methods such as Parametric Design and Analysis (PDA) and BPO. These challenges arise from limitations regarding (i) tool interoperability, (ii) computationally expensive simulation processes, and (iii) problem and performance goal definition in BPO.
The primary objective of the dissertation is to improve the use of daylighting and BES tools in PDA and BPO. To that end, the research proposes and validates five modeling strategies that directly tackle the limitations mentioned above. The strategies are the following: (i) Strategy A: Automatically generate valid building geometry for BES; (ii) Strategy B: Automatically simplify building geometry for BES; (iii) Strategy C: Abstract Complex Fenestration Systems (CFS) for BES; (iv) Strategy D: Assess glare potential of indoor spaces using a time and spatial sampling technique; and (v) Strategy E: Painting with Light - a novel method for spatially specifying daylight goals in BPO.
The research work shows that the strategies address the research problem and current limitations by (i) improving the interoperability between design and BES and daylighting simulation tools (Strategies A, B, and C); (ii) producing quick and adequate feedback on the daylight, thermal, and energy behavior of buildings (Strategies B, C, and D); and (iii) facilitating the spatial definition of performance goals in daylighting BPO workflows (Strategy E). These three important merits of the proposed strategies effectively contribute to improving the efficiency of using daylight and BES tools in the design, analysis, and optimization of high-performance buildings.
Finally, the dissertation discusses the merits and limitations of each strategy, provides useful guidelines and recommendations for their use in building design, and suggests future directions for further research.
... 2 (f) ~ (j) shows data for the modified bin size (UDI500-2000 lux), which captures168 only data that meet the design illuminance of at least 500 lux. This provides greater detail than using the UDI100-2000 lux bin alone.The standard double glazed system shows similar daylight performance for each of the cities considered. ...
... These more sophisticated metrics are made possible through the use of dynamic simulation tools (e.g. RADIANCE[43,147,163,164], Daysim[165][166][167][168][169][170][171] etc.). In this section, the daylight assessment metrics, from basic metrics and their limitations to more advanced metrics and their advantages, are introduced and analysed. ...
Concerns over sustainability in the built environment have resulted in continuous efforts to improve the performance of window system or glazed façade and hence indoor comfort and building energy conservation. An innovative façade system where parallel transparent/translucent plastic slats are sandwiched between glass panes to form a Parallel Slat Transparent Insulation Material (PS-TIM) is proposed as a strategy to effectively reduce heat transfer between the panes of a double glazed window, while maintaining access to daylight. A holistic investigation of the window system with PS- TIMs is conducted in terms of thermal and optical properties, as well as detailed daylight and energy performance predictions of applying PS-TIMs in buildings. Firstly, an experimental investigation is undertaken in a large climate chamber, and the measurement results were used to validate a two-dimensional Computational Fluid Dynamics (CFD) model. Secondly, the validated 2D CFD model is used to solve the dynamic thermal properties of different configurations of PS-TIMs under various environmental conditions. The optical properties (i.e. Bidirectional Scattering Distribution Function (BSDF)) of PS-TIMs are obtained via a ray-tracing technique based on the structures’ geometries and the material optical characteristics of the interstitial structure. The detailed annual daylight performance in different climates and building orientations are predicted using RADIANCE. Finally, the optical and thermal properties obtained from the previous fundamental models are applied in EnergyPlus to predict the energy performance (i.e. heating, cooling and lighting energy consumption) of applying PS-TIMs in buildings in different climates. The investigation results provide a better understanding of the benefits of PS-TIM in terms of energy saving and daylight comfort improvement, as well as offer some tentative suggestions as to how architects and engineers might apply PS-TIM to window system or glazed façade.
... In order to let visitors know where they are browsing in the virtual art landscape of the city, a timely navigation map can be used to help visitors locate. Custom browsing is also possible by setting up walking, rotating, and flying cameras [24]. On the VR-platform editor interface, interactive production is used to realize the interactive functions of virtual scenes. ...
With the rise of some concepts such as “Digital Earth” and “digital city,” how to realize the three-dimensional reconstruction and visualization of the urban art landscape is becoming a current research hotspot. This study takes the VR-Platform as the development platform and combines it with 3dsMax technology to study the dynamic simulation technology of urban 3D art landscapes. Additionally, this study combines the dynamic simulation technology of urban three-dimensional artistic landscape, designs the urban three-dimensional artistic landscape dynamic simulation system from the aspects of landscape modeling, texture mapping, drive integration, and so on, and finally realizes the basic functions such as roaming interaction, map navigation, information measurement, and visual display of the urban three-dimensional artistic landscape dynamic simulation system, which has a certain practical application value.
... A study by Kharvari (2020), in terms of a fixed simulation and point-by-point comparison of the average illuminance with experimental measurements, proves that Radiance performs the most accurate calculations, which works based on Monte Carlo ray tracing and interpolation in honeybee plugin. Also, the annual simulation (dynamic) with DF, UDI, DA and sDA metrics is based on the combination of Radiance and Daysim in Honeybee, which Daysim is the (Bellia et al., 2015). Honeybee and Ladybug plugins based on Grasshopper can perform building-related analyses parametrically (Goharian and Mahdavinejad, 2020;Norouzi et al., 2021). ...
Urban congestion and the multiplicity of floors of buildings within densely populated cities have significantly reduced natural light penetration into spaces, especially in deep-plan buildings. One way to bring daylight into the spaces in deep-plan buildings is to prepare light-well to bring natural light to window-less spaces. The more light penetration into the bottom of the well depends on two main factors; reflection coefficient and configuration geometry, which this paper is focused on geometry specifically. Geometry can provide better performance as a reflector if it corresponds to the direction of the sun’s rays and sun path. In this study, using Ladybug plugin capabilities in Grasshopper parametric environment and in-depth study of the sky matrix, timelines are set to determine the main optimization indicators. This paper’s main purpose is to scrutinize the light-well configuration through a hierarchy of troubleshooting and finding advantages to prepare an optimization solution of adaptation of configuration with direct sun beams. For the optimization solution, by studying five latitudes that can cover low, medium and high-latitudes, a method has been developed that standardizes this solution as a comprehensive method. In other words, standardization of a methodology as an optimization solution for all latitudes. In order to implement and validate the methodology, a latitude is considered the basic-location (Tehran). Sun facing-wall on the well’s aperture in the role of a reflective device, with an angle of 65° and the other walls, are optimized with an angle of 70° in order to no shading (basic-location). The improved-model by the optimization methodology shows an improvement of the lower floors in DA’300, DA’150 and UDI’100 <X<2000 indices two times, compared to other models.
... There are a number of available software programs to assess daylighting and visual comfort according to the target of the study [29,60,61]. This includes; Daysim [62], RELUX [63] and DALEC [64]. Other software programs support the optimisation process through combined simulation methods for applying numerous permutations and combinations by altering its parameters [65,66]. ...
This study adopts an empirical research method to investigate a number of design parameters for achieving a balance of daylight availability and visual comfort in office buildings using a double skin façade (DSF). This includes its perforation ratio, depth and the gap width from the outer wall. The study refers to the guidelines and performance metrics of the latest Leadership in Energy and Environmental Design system; spatial daylight autonomy (sDA300/50%) and Annual Sunlight Exposure (ASE1000,250) to investigate the daylighting performance of an existing case study building in Egypt. Accordingly, 36 combinatorial simulations have been developed and statistical correlations have been carried out to scrutinize the interrelations between the defined parameters and their effect on the sDA and ASE values. The result indicated that acting on the perforation percentage and skin depths of a DSF provides the greatest influence on buildings’ daylight performance.
... It is combined with daylight coefficient to produce an accurate model to calculate daylight levels over a year. There is also DAYSIM -the engine of the RADIANCE simulation tool and both of them have been validated and used in practice [49]. Rhinoceros is another development analysis (a NURBS modelling program) that uses DIVA as a plug-in to link RADIANCE and DAYSIM. ...
This study reviews available guidelines and assessment methods for daylight performance for office buildings in Egypt to propose a Unified design guideline (UDG). Relevant literature studies are analysed, e.g. the local code for 'improving energy efficiency for commercial buildings' as well as a number of green building rating systems such as Leadership in Energy and Environmental Design (LEED), and The Green Pyramid Rating system. The UDG was tested for two local case studies using building simulation; a non-LEED building complying with a set of limited guiding principles of the local code, and a LEED-certified building with an additional set of guidelines, and compliance path using building simulation. The comparison showed that the integration of both prescriptive and performance-based guidelines and measurement criteria is necessary to develop the UDG tailored to address the particular requirements of office buildings in terms of daylight performance in similar climates. Ó 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Ain Shams University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
... Although it was one of the first backward raytracing programs developed for the light and building analysis, the incremental improvement and extension of Radiance's raytracing capabilities to both bi-directional [25,26] and forward raytracing [27][28][29] led to its being widely regarded as the "golden standard" for lighting simulation [30]. As a result, Radiance has been used in several interprogram comparisons and validation studies [24,[31][32][33]. Despite the recent advancements to integrate Radiance in current digital building design workflows, there are few works that use Radiance as an ancillary analysis tool in immersive environments [34,35]. ...
This work introduces RadVR, a virtual reality tool for daylighting analysis that simultaneously combines qualitative assessments through immersive real-time renderings with quantitative physically correct daylighting simulations in a 6DOF virtual environment. By taking a 3D building model with material properties as input, RadVR allows users to (1) perform physically-based daylighting simulations via Radiance, (2) study sunlight in different hours-of-the-year, (3) interact with a 9-point-in-time matrix for the most representative times of the year, and (4) visualize, compare, and analyze daylighting simulation results. With an end-to-end workflow, RadVR integrates with 3D modeling software that is commonly used by building designers. Additionally, by conducting user experiments we compare the proposed system with DIVA for Rhino, a Radiance-based tool that uses conventional 2D-displays. The results show that RadVR can provide promising assistance in spatial understanding tasks, navigation, and sun position analysis in virtual reality.
... The hormone, melatonin, which reaches its maximum concentration in the body at night, influences circadian rhythms. An inadequate melatonin production results in insufficient organism regeneration, insomnia, weakening of the immune system and decreased productivity [8]. Some studies deal with regarding the effect of daylight distribution from horizontal openings [9][10][11]. ...
Lighting in manufacturing plants is an integral part of a working environment and all industrial activities. Therefore, it is necessary to consider several aspects of these activities when designing and using industrial lighting. To comply with lighting requirements, hygienic and technical regulations, which set visual and lighting requirements to achieve safe and proper lighting conditions for all activities in industry buildings, need to be taken into account. The aim of this study is to evaluate the existing lighting of industrial premises through measurements. The measurements were carried out in two halls with the same floor plan and with the different types of side illumination and skylights. The measured values then served as input data into the RADIANCE simulation program, which was used to calculate daylighting and, subsequently, to evaluate visual conditions and illuminance levels in work spaces. Similar average levels of daylighting were observed in both halls. The hall with smaller lighting vertical openings and the arched shape of the skylight, was better lit by daylight. The daylighting evaluation of measurements results higher level of minimum and maximum daylight factor as well as illuminance uniformity.
... Various possibilities of different applications and the results obtained with their use was compared in [33][34][35]. In some studies, the model's accuracy was verified on the basis of measurements and, although most results were satisfactory [36,37], other studies demonstrate quite significant discrepancies for particular conditions [38][39][40]. ...
This paper deals with the impact of the use of daylight on the overall energy demand for heating, cooling, and lighting in educational buildings. The energy performance of buildings is currently of the utmost importance as current European regulations, starting from 31st December 2020 impose that all new buildings must meet nearly zero-energy building requirements. This paper presents a study of the illuminance distribution in an educational room obtained from measurements and simulation results using two different models. One of the models, integrated with a thermal simulation software, was used to estimate the impact of daylight on the energy demand. The analysis included the use of various window types, lighting control system, reference point location, and daylight calculation model for a sample room in an educational building. Results of the analysis indicate that, due to the high share of lighting demand (reaching up to 78% of the primary energy balance), there is a need to take into account the efficiency of lighting systems during the design process to correctly determine the actual energy balance of a building, increase the quality of the design of lighting systems, as well as to select the optimal parameters of windows.
... It must be reminded that DAYSIM does not consider many important aspects of the light analysis of real light pipes (e.g., the diffuser part). DAYSIM is a validated daylight analysis software [41][42][43][44][45][46][47] that calculates the annual availability of daylight in buildings based on RADIANCE raytracer backward, and it is able to calculate the mentioned daylight indices. The simulated case study is described in Section 3.3. ...
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 x 5 m
plant area room. All simulations are carried out in a DAYSIM environment, which allows calculating
the annual availability of daylight based on a RADIANCE raytracer backward. Several daylight
conditions were analyzed for different light pipe configurations, considering different pipe lengths and
a variable number of light pipes. The light pipes are tested also in the horizontal position, for different
orientations. The results of all the combinations were compared with the performances of a window
with dimensions equal to 1/8 of the internal surface, which was in accordance with the minimum
value to be guaranteed by the Italian Regulation (D.M. 5 July 1975 n. 190) for different orientations.
The results indicated a difference in daylight distribution, showing a strong correlation between the
percentage levels of DA and DAc with the length and number of pipes, during different periods
of the year. The simulated model is strongly influenced by the aspect ratio (R = diameter/length).
The results show that the illuminance levels decrease drastically, increasing the length.
... EvalDRC combines a coarse but efficient Daylight Coefficient (DC) calculation with a refined sun-model. The approach is similar to that of Daysim [12], but, other than the latter, supports data-driven BSDF models to describe irregular transmission. A recent modification of the Photon Map implementation in Radiance extends the application of the software to image synthesis for visual comfort assessments, including Climate-Based Daylight Modelling (CBDM) techniques. ...
Data-driven modelling provides a general means to represent optically complex fenestration in daylight simulation by its Bidirectional Scattering Distribution Function (BSDF). Radiance employs the tensor tree as a compact data structure to store the BSDF at high directional resolution. The application of such models under sunny sky conditions is, however, computationally demanding, since the density of stochastic backward samples must match the BSDF resolution. The bidirectional Photon Map is proposed to rapidly forward-sample the BSDF, starting from the known sun direction. Its exemplary application shows a potential speed-up of ≥ 98 % when compared to backward ray-tracing.
... The daylight simulations used in this work are well-known and widely used for daylight design investigations, and for which a variety of validation results exist. Based on the results from the reported validation studies, such as [13,25,33,[35][36][37] it was concluded that the accuracy of Diva is sufficient for the complexity of the daylighting design investigations enclosed in the study. ...
Point Daylight Factor (DF P) has been used for daylighting design in Sweden for more than 40 years. Progressive densification of urban environments, in combination with stricter regulations on energy performance and indoor environmental quality of buildings, creates complex daylight design challenges that cannot be adequately solved with DF P. To support a development of the current and future daylight indicators in the Swedish context, the authors have developed a comprehensive methodology for the evaluation of daylight levels in existing buildings. The methodology comprises sample buildings of various use and their digital replicas in 3D, detailed numerical simulations and correlations of diverse DF metrics in existing buildings, a field investigation on residents' satisfaction with available daylight levels in their homes, and a comparison between the numerical and experimental data. The study was deliberately limited to the evaluation of DF metrics for their intuitive understanding and easy evaluation in real design projects. The sample buildings represent typical architectural styles and building technologies between 1887 and 2013 in Gothenburg and include eight residential buildings, two office buildings, two schools, two student apartment buildings, and two hospitals. Although the simulated DF P is 1.4% on average, i.e., above the required 1%, large variations have been found between the studied 1200 rooms. The empirical data generally support the findings from the numerical simulations, but also bring unique insights in the residences' preferences for rooms with good daylight. The most remarkable result is related to kitchens, typically the spaces with the lowest DF values, based on simulations, while the residents wish them to be the spaces with the most daylight. Finally, the work introduces a new DF metric, denoted DF W , which allows daylighting design in early stages when only limited data on the building shape and windows' arrangement are available.
... DAYSIM was developed to provide more accurate results than that provided by Radiance in its original form. This tool has been tested by several researchers [19] [20]. Table 4 shows the calculation parameters used by this programme in this study. ...
... There are not many software that allow performing static and dynamic simulations at the same time and not all of them have been extensively tested to assess their degree of reliability. Many software are based on the Radiance simulation engine and among them Daysim is certainly the most widespread and studied one (Bellia et al., 2015). Daysim is a Radiance-based dynamic daylight simulation program which uses the Radiance to calculate annual illuminance and luminance profiles based on local climate data and daylight coefficient. ...
Increasing housing demand and the precious value of city land have caused to the construction of multi-storey, deep-plan and compact buildings. Architectural design needs to provide the appropriate penetration of daylight and ventilation into the deep-plan buildings. Therefore further researches are necessary in the field of natural lighting and ventilation systems. Light-well is an architectural daylight system to deep-plan building which is widely used in the residential buildings of the case study of this research (Tehran, Iran). In this study, effective factors in daylight performance of light-wells are investigated with dynamic daylight metrics. In this research, the continuous daylight autonomy (DAcon) is utilized for evaluating of annual illuminance for attached rooms to light-well.
The main goal of this research is to estimate the effect of some affecting variables on the daylighting performance of light-wells (the area and horizontal section form, the optimal height of the light-well, orientation variation and the slope of light-well surrounding wall) to provide suggestions for better utilization of light-wells in residential building. 352 computer simulations using Daysim software have been conducted to assess the expressed variables. Also, Autodesk Ecotect software has been used as graphical user interfaces for Daysim. The findings of this study show the better daylighting performance of cylindrical light-wells compared with the common square light-well in Tehran. Also, the optimal height of different types of light-wells in residential buildings has been suggested with regards to the adequate daylight autonomy (DA) in connected rooms to light-well. The results of this study show that the increasing of the suggested optimal height for different types of light-wells is possible with increasing the slop of walls of light-wells and the window size in the lower floors.
... This approach supports the importance of passive design with which optimal design can be achieved in combination with engineering. Developing an integrated passive design method can, therefore, accomplish functional facade design and the use of the traditional and innovative method can provide wise solutions by manipulating advanced daylight simulation tools [15,16]. External shading devices are reported as a simple, economical, and effective solution to manage incoming natural light. ...
This paper suggests a daylighting design method by combining a passive approach and advanced software to design external shading devices for daylighting in a classroom. A simplified method to predict and assess the indoor natural illuminance is a prerequisite for designers to design schools with better performance. Recently there has been growing demand for school refurbishment; mainly environmental improvement of classrooms in Korea. However, the passive approach of design has been neglected while the use of advanced simulation software has increased, requiring additional time and cost. Combining passive design methods with up-to-date numerical simulation is explored with shading devices to verify the daylighting distribution and daylight autonomy in classrooms with different orientations and shading forms. Weather tool Autodesk Ecotect, for the shading coefficient, and DaySim software (v3.0), for daylight autonomy, were adopted for the initial and the detail design stage, respectively. The findings support the linked design approaches of passive and advanced software would benefit designers in the strategic design process with further potential for design options and lighting electricity reduction.
... Daysim can be installed as an engine and used as a plug-in in various applications (Sketch up, Rhino, Ecotect) [77]. Daysim has been used and proven in many studies using its natural light modeling feature in various climatic and sky conditions [78,79]. In this study, Daysim was linked with the Autodesk Ecotect Analysis application. ...
Urbanization has intensified population concentration, and the quality of residential environments has deteriorated owing to the accelerated construction of high-rise and high-density buildings. In this study, a quantitative analysis is conducted regarding the natural lighting and outdoor thermal comfort of apartment complexes, and satisfactory improvement measures for both factors are investigated. Natural lighting and outside microclimate modeling simulations and statistical analyses are performed on 27 cases using the layout planning factors of an apartment complex. In addition, outdoor thermal comfort analysis is performed by applying heat island mitigation factors (greening and reflective asphalt pavement) to cases satisfying the condition of daylight factor (DF ≥ 75%). To improve natural lighting, the azimuth (correlation coefficient −0.812) should be considered, and to improve outdoor thermal comfort, the aspect ratio should be considered (−0.402). The results of applying heat island mitigation factors suggest that greening can improve outdoor thermal comfort to a greater extent than reflective asphalt pavement. The significance of this study is that the measures to improve residential comfort have been determined by considering the factors affecting the residential environment.
... Moreover, 589 differences in results due to rendering and computation algorithms in proprietary simulation 590 programmes (e.g. Bellia et al., 2015) can also be avoided to a certain degree. ...
Design optimisation problems of window size in buildings with regard to energy saving and comfort criteria have been investigated many times. To indicate daylight availability and energy consumption in indoor spaces, a number of metrics have been proposed, but so far there is no convention on which daylight and energy metrics are preferred. Meanwhile, evolutionary techniques such like genetic algorithm have long been used to optimise parameters in building design. In the optimisation process, however, different metrics or objectives normally lead to different degrees of uncertainty of the obtained results. This article presents a study to determine the most appropriate metrics for the case of daylight optimisation in a reference office space, by comparing various daylight metrics and lighting energy demand indicators, using genetic algorithm to optimise the window-to-wall ratio (WWR) and the room interior reflectance. To determine the appropriate metrics, the optimisation results were classified based on their computational precision. It is found that maximising spatial useful daylight illuminance (sUDI)100∼2000lx,50% − sUDI>2000lx,50% leads to objective function values with the highest precision, while minimising annual lighting energy demand + sUDI>2000lx,50% gives the most robust input variables. Therefore, these two pairs of metrics are suggested as the most appropriate for optimising daylight in the particular space.
Keywords:
Window-to-wall ratio; Room reflectance; Optimisation; Genetic algorithm; Daylight metrics; Lighting energy demand
... The approach is based upon the use of the 3ds Max Daylight Tool, an approachable interface to a validated (Osborne 2013;Reinhart and Breton 2009) simulation tool. While 3ds Max is, perhaps, less common in research than Radiance, it has seen use (Bellia, Pedace, and Fragliasso 2015), and a survey of architects in CONTACT James Sullivan James.sullivan@vuw.ac.nz School of Architecture, Victoria University of Wellington, 139 Vivian St, PO Box 600, Wellington, New Zealand Brisbane indicated that a significant number of them do use it for daylighting analysis (Panitz and Garcia-Hansen 2013). ...
A significant barrier to routine use of Climate-Based Daylight Modelling in early design is the long time that it takes to run full annual simulations. Quick checks of design ideas are thus inconvenient, which discourages examining large numbers of design options or doing routine sensitivity analysis. Two ways of reducing required simulation time are to not simulate all the daytime hours of the year, or to simulate far fewer grid ‘measurement’ points. This paper demonstrates the effectiveness of taking smaller samples of random days throughout the year to reduce simulation time. By using a selection process to select “representative” samples of hours, simulations using only 5 days/month provide results with <6% error in performance estimates – well within accepted tolerances. The paper also shows the insignificant difference in design information provided by oft-recommended dense sensor grids compared to a 5 × 3 or 10 × 5 grid across a room plan.
... Design for visual comfort is an open-ended problem that in many cases requires the use of simulation. The choice of simulation tool may produce different performance results (Bellia, Pedace, and Fragliasso 2015) and elicit different user behaviour (Liu and Heer 2014). It therefore plays a critical role in the success of design outcomes. ...
Building performance simulations and models of human visual comfort allow us to predict daylight-caused glare using digital building models and climate data. Unfortunately, the simulation tools currently available cannot produce results fast enough for interactive use during design ideation. We developed software with the ability to predict visual discomfort in real time. However, we know little about how users react to simulation feedback presented in real time. In our study, 40 subjects with backgrounds in building design and technology completed two shading design exercises to balance glare reduction and annual daylight availability in two open office arrangements using two simulation tools with differing system response times. Subjects with access to real-time simulation feedback tested more design options, reported higher confidence in design performance and increased satisfaction with the design task, and produced better-performing final designs with respect to spatial daylight autonomy and enhanced simplified daylight glare probability.
... Doulos, L. et al. [4] also describes the role of the spectral response of photosensors in daylight response systems. One of the well-known authors dealing with daylighting and its impact on building users is Belia, L. [5,6]. ...
This paper highlights the problems that are associated with daylight use in industrial facilities. In a case study of a multi-story textile factory, we report how to evaluate daylight (as part of integral light) in the production halls marked F and G. This study follows the article in the Buildings journal, where Hall E was evaluated (unilateral daylight). These two additional halls have large areas that are 54 × 54 m and are more than five meters high. The daylight is only on the side through the attached windows in envelope structures in the vertical position on the hall. In this paper, we want to present two case studies of these two production halls in a textile factory in the eastern part of Slovakia. These are halls that are illuminated by daylight from two sides through exterior peripheral walls that are against or next to each other. The results of the case studies can be applied in similar production halls illuminated by a "double-sided" (bilateral) daylight system. This means that they are illuminated by natural illumination through windows on two sides in a vertical position. Such a situation is typical for multi-storied industrial buildings. The proposed approximate calculation method for the daylight factor can be used to predict the daylight in similar spaces in other similar buildings.
... Several studies comparing daylit interiors to DAYSIM predictions found relative mean bias error (MBErel) under 20% and relative root mean square error (RMSErel) under 32% (Reinhart & Walkenhorst, 2001;Reinhart & Andersen, 2006). DAYSIM gave comparable results to 3ds Max in a study of one building interior under a number of sky conditions (Reinhart & Breton, 2009) but offered superior results at four other geographic locations (Bellia, et al., 2015). Validation of the three-and five-phase methods shows similar accuracy. ...
Architects must consider an entire year's worth of solar positions and climate data to design buildings with adequate daylight and minimal glare. However, annual simulations are time-consuming and computationally expensive, which makes them difficult to integrate into iterative design processes. In this paper, we compare the performance of several RADIANCE-based dynamic daylighting simulation methods, DAYSIM and the three-and five-phase methods and, perhaps more importantly, the potential to speed them up using parallel implementations on graphic processors. Using a model of a generic office, we achieve speedups of ten times with DAYSIM and twenty-five times with the five-phase method. Parallel implementations of three-and five-phase methods provide better scaling to multi-GPU environments and more accurate results for complex fenestration systems than parallelized DAYSIM.
... 3dS Max is cost-effective and also has low requirements of the hardware system. 3ds Max is friendlier to beginners, its production process is very simple and efficient [5]. Because its features of cost-effective and it is easy to use, it has a wide range of user base. ...
... RA-DIANCE and 3ds Max [Aut16] gave comparable results in a study of one building interior under a number of sky conditions [RB09]. However, RADIANCE offered superior results in a repetition of this study at four other geographic locations [BPF15]. ...
Building designers rely on predictive rendering techniques to design naturally and artificially lit environments. However, despite decades of work on the correctness of global illumination rendering techniques, our ability to accurately predict light levels in buildings—and to do so in a short time frame as part of an iterative design process—remains limited. In this paper, we present a novel approach to parallelizing construction of an irradiance cache over multiple-bounce paths. Relevant points for irradiance calculation based on one or multiple cameras are located by tracing rays through multiple-bounce paths. Irradiance values are then saved to a cache in reverse bounce order so that the irradiance calculation at each bounce samples from previously calculated values. We show by comparison to high-dynamic range photography of a moderately complex space that our method can predict luminance distribution as accurately as Radiance, the most widely validated tool used today for architectural predictive rendering of daylit spaces, and that it is faster by an order of magnitude.
Daylight dynamic metrics are useful tools for quantifying the switch-on time or the dimming of electric lighting according to the architectural scenario. A variant of these metrics can also be used to define strategies to control the lighting fixtures, dimming the luminous flux with no need for external input and reducing therefore the energy consumption of the lighting systems. Given this context, a new approach is proposed, Continuous Overcast Daylight Autonomy (DAo.con), defined as the percentage of occupied time when an illuminance threshold is met by daylight alone under continuous overcast sky conditions, considering a partial credit linearly to values below the threshold defined. This concept acts as an algorithm which adjusts the luminous flux of the luminaires according to the Daylight Factors measured or simulated, considering user requirements and ignoring any internal device for actively measuring the lighting conditions. The Daylight Factors can be modified according to the use of shading devices that affect to the indoor natural light. Accordingly, this algorithm can significantly reduce the embodied cost of the lighting smart controls, promoting their spread and its implementation in building refurbishment, while the energy consumption in electric lighting is reduced by up to 76% for large windows and by up to 65% for medium-sized openings. The results show that the use of this algorithm in office environments with LED fixtures can promote energy savings of up to 7.8 W/m² for locations with predominantly clear skies and up to 5.7 W/m² for northern latitudes with mainly overcast skies.
La performance d’un module photovoltaïque est conditionnée par l’environnement dans lequel il est installé. En effet, la quantité d’énergie solaire convertie en électricité dépend de l’irradiance incidente sur le module. Les progrès dans l’intégration des modules photovoltaïques sur bâtiment et la diminution de leurs coûts amènent à considérer le potentiel solaire en milieu urbain, en toiture mais aussi en façade. En milieu urbain, la densité des bâtiments limite les apports solaires en façade par la présence de masques. La volonté publique encourage une augmentation de la production locale d’énergies renouvelables. Il est alors nécessaire de se doter d’outils numériques permettant d’évaluer avec précision le potentiel solaire en ville, et ainsi évaluer la rentabilité d’installations photovoltaïques. Il s’agit en particulier d’évaluer les apports solaires issus des réflexions sur les différentes surfaces composant la scène urbaine. Les problématiques d’intégration visuelle, soulevant la question des couleurs et des spectres incidents sur les surfaces dans différentes gammes de longueurs d’ondes doivent également être considérées Enfin, ces outils doivent également permettre d’évaluer l’impact d’une intégration photovoltaïque en milieu urbain afin d’éviter de renforcer les phénomènes d’îlot de chaleur. Les travaux de thèse se sont donc focalisés sur les méthodes de simulation d’ensoleillement en milieu urbain, au travers du développement de deux stratégies de modélisation (radiosité et lancer de rayons). Les modèles de simulation sont comparés sous des hypothèses de réflexions optiques équivalentes, permettant une validation des hypothèses utilisées dans chacune des méthodes. Parallèlement, une qualification des propriétés optiques de matériaux typiques de l’environnement urbain permet la construction de modèles de réflexion optiques basés sur les distributions de réflectivité bidirectionnelles (BRDF en anglais). Ces modèles, injectés dans les modèles d’irradiance, permettent d’évaluer la part d’énergie issue des différents modes de réflexion. Par ailleurs, des mesures d’irradiances sont réalisées en milieu extérieur. Un banc de test est conçu de sorte à mesurer les irradiances perçues en façade et au sol. Différentes configurations sont testées dans via cette maquette. Les mesures obtenues sont alors confrontées aux résultats numériques sous conditions réelles, permettant une validation des modèles.
The human biological clock, also known as circadian rhythm, is mainly synchronized by the light perceived, specifically short-wavelength. Insufficient access to daylight or equivalent electric lighting can compromise human health and well-being. The effect of light on the circadian rhythm is greater in children and adolescents than in adults, making lighting design for classrooms important for good circadian entrainment for students. This research shows the results of circadian stimulus autonomy, that is to say, the percentage of days during the year when circadian stimulus is above a minimum threshold in typical classroom designs. Circadian stimulus, promoted by either natural or electric lighting, is quantified. The venue studied has a window of variable size, position and orientation, as well as different reflectance values of the inner surfaces for a classroom under three typical sky conditions. As deduced from the results, the reflectance of the environment has a noticeable effect on circadian entrainment, as well as on the spectral distribution of the light source. The results also serve to compare the impact of architectural design parameters on promoting good circadian rhythm for students.
Abstract. Industrial halls are usually subjects to high energy demand. It is due to the many manufacturing processes, lighting, and the corresponding amount spent on space conditioning. The industrial buildings is one of the heaviest consumers of energy. Natural daylight is a vital element in our daily life. Providing natural daylight into the working environment is of fundamental importance for the comfort, efficiency and safety for the people in that environment. This paper deals with visual comfort evaluation in selected hall. Its calculated by
the radiance simulation program.
Window systems play a key role in establishing both the thermal and luminous environments within buildings, as well as the consequent energy required to maintain these for the comfort of their occupants. Various strategies have been employed to improve the thermal and optical performance of window systems. Some of these approaches result in products with relatively complex structures. Thus, it becomes difficult to characterise their optical and thermal properties for use in building performance prediction. This review discusses the experimental and numerical methods used to predict the thermal and optical behaviour of complex window systems. Following a discussion of thermal characterisation methods available in the literature that include experimental test methods, theoretical calculation methods and Computational Fluid Dynamic methods, sophisticated optical methods, such as use of Bidirectional Scatter Distribution Functions (BSDF) to optically characterise complex window systems, are introduced. The application of BSDF allows advanced daylight assessment metrics along with daylight evaluation tools to be used to realise dynamic annual prediction of the luminous environment. Finally, this paper reviews methods that permit the prediction of the combined thermal, daylight and energy behaviour of buildings that make use of complex window systems.
In this paper, the solar spectrum matching in the visible range of 380–780 nm with white organic light-emitting diode (OLED) and monochromatic light-emitting diodes (LEDs) is investigated. The correlation index (R2) is used to evaluate the difference between the matching spectrum and the solar spectrum. The optimal combination is obtained by the least squares method. We also perform subtraction experiments to find the optimal combination. We utilize a common white OLED device design and just change the species of monochromatic LEDs used. We report and evaluate different degrees of matching effects. The results show that the correlation index of the best combination can reach 94.09% with white OLED and 36 monochromatic LEDs. We define three levels of performance as an evaluation system in accordance with the matching effect. The level is excellent with an R2 above 90.14%. The good level is from 86.65% to 58.28%. From 42.08% to 33.06% is the reasonable level. Compared with other methods, using white OLED combined with monochromatic LEDs achieves the best solar spectrum matching effect. The results can be applied to different requirements of engineering practice.
This work covers issues of realistic materials creation upon modeling of industrial design objects. As an industrial product, a decorative light fixture in the form of orchid flower is used. For the decorative light fixture modeling and materials creation, three-dimensional modeling graphic system 3 ds max is used. This
system is the most appropriate for creation of realistic scenes in design solutions.
Certain modeling methods provide creation of the flower components. After modeling of flower components, their corresponding pattern and material should be created and assigned. The materials under creation should be as realistic as possible; thus, the following basic material properties should be considered: object
surface pattern and texture, diffuse color of the surface, color of the specular highlights, opacity, beams reflection and refraction, illumination, glossiness, bump, and surface relief. In this case, we will assign to the petals a translucent material with real pattern of the petals based on beam tracing. Taking into consideration
a great nature variety of orchid flowers, divergent ornamental beaming strips will be added to petals pattern to improve their texture. Labellum material and flower stamens are of a heavier shade. In order to simulate the decorative light fixture, a self-illumination material is assigned to flower snout. On the next stage, in order to impart reality, omnidirectional and pointed light sources are created and installed.
The drive towards sustainable, low-energy buildings has increased the need for simple, yet accurate methods to evaluate whether a daylit building meets minimum standards for energy and human comfort performance. Current metrics do not account for the temporal and spatial aspects of daylight, nor of occupants comfort or interventions. This paper reviews the historical basis of current compliance methods for achieving daylit buildings, proposes a technical basis for development of better metrics, and provides two case study examples to stimulate dialogue on how metrics can be applied in a practical, real-world context.
This paper introduces a new paradigm to assess daylight in buildings called ‘useful daylight illuminance’, or UDI. The UDI paradigm preserves much of the interpretive simplicity of the conventional daylight factor approach. In contrast to daylight factors however, UDI is founded on an annual time-series of absolute values for illuminance predicted under realistic skies generated from standard meteorological datasets. Achieved UDI is defined as the annual occurrence of illuminances across the work plane where all the illuminances are within the range 100-2000 lux. These limits are based on reports of occupant preferences and behaviour in daylit offices with user-operated shading devices. The degree to which UDI is not achieved because illuminances exceed the upper limit is indicative of the potential for occupant discomfort. The relation between achieved UDI and annual energy consumption for lighting is examined.
The application of lighting simulation techniques for daylight illuminance modelling
in architectural spaces is described in this thesis. The prediction tool used for all the
work described here is the Radiance lighting simulation system.
An overview of the features and capabilities of the Radiance system is presented.
Daylight simulation using the Radiance system is described in some detail. The
relation between physical quantities and the lighting simulation parameters is made
clear in a series of progressively more complex examples. Effective use of the interreflection
calculation is described.
The illuminance calculation is validated under real sky conditions for a full-size office
space. The simulation model used sky luminance patterns that were based directly
on measurements. Internal illuminance predictions are compared with
measurements for 754 skies that cover a wide range of naturally occurring
conditions. The processing of the sky luminance measurements for the lighting
simulation is described. The accuracy of the illuminance predictions is shown to be,
in the main, comparable with the accuracy of the model input data. There were a
number of predictions with low accuracy. Evidence is presented to show that these
result from imprecision in the model specification - such as, uncertainty of the
circumsolar luminance - rather than the prediction algorithms themselves.
Procedures to visualise and reduce illuminance and lighting-related data are
presented.
The ability of sky models to reproduce measured sky luminance patterns for the
purpose of predicting internal illuminance is investigated. Four sky models and two
sky models blends are assessed. Predictions of internal illuminance using sky
models/blends are compared against those using measured sky luminance
patterns. The sky model blends and the Perez All-weather model are shown to
perform comparably well. Illuminance predictions using measured skies however
were invariably better than those using sky models/blends.
Several formulations of the daylight coefficient approach for predicting time varying
illuminances are presented. Radiance is used to predict the daylight coefficients
from which internal illuminances are derived. The form and magnitude of the daylight
coefficients are related to the scene geometry and the discretisation scheme.
Internal illuminances are derived for four daylight coefficient formulations based on
the measured luminance patterns for the 754 skies. For the best of the formulations,
the accuracy of the daylight coefficient derived illuminances is shown to be
comparable to that using the standard Radiance calculation method.
The use of the daylight coefficient approach to both accurately and efficiently predict
hourly internal daylight illuminance levels for an entire year is described. Daylight
coefficients are invariant to building orientation for a fixed building configuration. This
property of daylight coefficients is exploited to yield hourly internal illuminances for
a full year as a function of building orientation. Visual data analysis techniques are
used to display and process the massive number of derived illuminances.
This article compares daylight simulation results generated with two simulation programs, Autodesk® 3ds Max® Design 2009 (3ds Max Design) and Daysim 3.0 (Daysim), to indoor illuminance measurements in a sidelit space. The sidelit space was in a single location, but was configured with five fenestration and glazing options, and operated under a variety of sky conditions. The measurements form a set of ‘daylighting test cases’ that were recently developed to evaluate the simulation capabilities and limitations of different daylight simulation programs. Both 3ds Max Design and Daysim were given external direct and diffuse irradiances as simulation input, from which the programs predicted indoor illuminances on a grid of upward facing work plane sensors and downward facing ceiling sensors.
3ds Max Design is based on Exposure™ technology, a lighting analysis module that includes a ‘shader’ of the Perez sky model and that uses the mental ray® raytracer for the global illumination calculation. Daysim also uses the Perez sky model and is based on the Radiance backward raytracer combined with a daylight coefficient approach. The comparison of both programs with measurements demonstrated that 3ds Max Design simulated indoor illuminances for the daylighting test cases with reliability comparable to Daysim. Most mean bias errors and root mean square errors were in the range of those reported in earlier validation studies: both programs succeeded in reproducing measurements for a sidelit space with and without a lightshelf. While 3ds Max Design consistently underestimated the incoming light flux going through a translucent panel, Daysim results were lower than measurements for the internal venetian blind test case. The results suggest that the accuracy of both programs is sufficient for typical daylighting design investigations of spaces with complexity comparable to the five daylighting test cases.
Daylight coefficients are normalized contributions from discretized sky or ground segments, or preset solar positions, to solar quantities calculated at various building sensor points. Once generated, daylight coefficients can be folded against luminance efficacy and distribution models to calculate, for instance, time series of illuminances. Over about the last 25 years several daylight coefficient models have been published. The objective of this paper is to propose a standard daylight coefficient model for dynamic daylighting simulations (DDS), consolidating previously published methods. This entails the definition of a standard daylight coefficient data format and accompanying software concepts for dynamic simulation purposes; dynamic in this context meaning variable with time due to changing sky conditions and shading device settings, in contrast to static modelling concepts such as daylight factors. The DDS standard model defines daylight coefficient data independent of building location and scene orientation, and generated using either simulation or measurement. It provides functionality to take into account independently controlled daylighting sources (e.g. windows and skylights) and to query different daylighting quantities in a simulation context (e.g. illuminance at one or more sensors, annual daylight performance metrics). A Radiance-based intermodel comparison shows that DDS-based software outperforms the original validated Daysim approach, upon which DDS is based, notably in cases where sensors are subjected to sudden changes in solar exposure, e.g. in an urban canyon or for sensors located far from a window. The proposed DDS standard daylight coefficient model, including the data format and accompanying software concepts, can be adopted by daylighting and energy-simulation software as a common mechanism for efficiently sharing daylight coefficient data for simulation purposes.
A simulation algorithm is proposed that predicts the lighting energy performance of manually and automatically controlled electric lighting and blind systems in private and two-person offices. Algorithm inputs are annual profiles of user occupancy and work plane illuminances. These two inputs are combined with probabilistic switching patterns, which have been derived from field data, in order to predict the status of the electric lighting and blinds throughout the year. The model features four different user types to mimic variation in control behavior between different occupants.An example application in a private office with a southern facade yields that––depending on the user type––the electric lighting energy demand for a manually controlled electric lighting and blind system ranges from 10 to 39 kW h/m2 yr. The predicted mean energy savings of a switch-off occupancy sensor in the example office are 20%. Depending on how reliably occupants switch off a dimmed lighting system, mean electric lighting energy savings due to a daylight-linked photocell control range from 60% to zero.
The objective of this document is to promote the use of dynamic daylight performance measures for sustainable building design. The paper initially explores the shortcomings of conventional, static daylight performance metrics which concentrate on individual sky conditions, such as the common daylight factor. It then provides a review of previously suggested dynamic daylight performance metrics, discussing the capability of these metrics to lead to superior daylighting designs and their accessibility to non-simulation experts. Several example offices are examined to demonstrate the benefit of basing design decisions on dynamic performance metrics as opposed to the daylight factor. L?objectif visé par ce document est de promouvoir l'utilisation de mesures de la performance sous éclairage naturel dynamique aux fins de la conception de bâtiments durables. Comme point de départ, ce document explore les lacunes des paramètres de mesure conventionnels de la performance sous éclairage naturel statique, lesquels visaient les conditions de ciel prises individuellement, comme le coefficient d'éclairage diurne courant. On fournit ensuite un examen des paramètres de mesure de la performance sous éclairage naturel dynamique qui avaient été auparavant suggérés, et traite de la capacité de ces paramètres de mesure à générer des conceptions d'éclairage naturel supérieures et de leur accessibilité aux non-spécialistes en matière de simulation. Plusieurs types de bureaux sont examinés comme exemples de l'avantage découlant de décisions de conception qui soient fondées sur des mesures de performance dynamiques au lieu du coefficient d'éclairage diurne. RES
Daylighting is the practice of using natural light to provide illumination in interior environments. Fifty years ago, practically all schools and workplaces used daylight as the primary illumination source. With the advent of inexpensive electricity and widespread use of fluorescent lighting in the 1950s and 1960s, states began to abandon requirements for minimum daylight illumination in their building codes. As energy costs soared, starting with the energy crises of the 1970s, the glazed areas of buildings came to be regarded by many as an energy liability, seen as increasing heating and cooling loads. Since cooling loads typically dominate in non-residential buildings, solar gain through windows became a driving concern.
The present work discusses simulation results of annual indoor illuminance distributions for two office geometries situated in Freiburg, Germany, calculated with six different RADIANCE-based daylight simulation methods. These methods are the ubiquitous daylight factor method, ADELINE 2.0, the classified weather data according to Herkel and Pasquay and two simulation procedures based on daylight coefficients according to Tregenza, namely ESP-r version 9 series and a new accelerated method developed by the authors. The new method calculates 145 diffuse and three ground daylight coefficients in a single raytracing run which considerably reduces the required calculation times for an annual daylight simulation. An explicit calculation of the indoor illuminances under all 4703 annual hourly mean sky luminance distributions from the Freiburg test reference year (TRY) serves as a reference case against which the other methods are tested. The simulation results reveal that the accuracy of an annual daylight simulation method is not necessarily coupled with the required simulation time. The quality of an annual simulation rather depends on the underlying sky luminous efficacy model and whether the method considers the hourly mean direct and diffuse illuminances for each time period explicitly. The two methods relying on daylight coefficients exhibit the lowest relative root mean square errors (RMSEs) for the straightforward office geometry. The results for the advanced office show that internal illuminance contributions due to external ground reflections are only considered by the new method.
This paper describes the application of a new paradigm, called useful daylight illuminance (UDI), to assess daylight in buildings. The UDI paradigm is designed to aid the interpretation of climate-based analyses of daylight illuminance levels that are founded on hourly meteorological data for a period of a full year. Unlike the conventional daylight factor approach, a climate-based analysis employs realistic, time-varying sky and sun conditions and predicts hourly levels of absolute daylight illuminance. The conventional approach produces a single number – the daylight factor as a percentage – for each evaluation point in the space. In contrast, a climate-based analysis results in an illuminance prediction for every daylight hour of the year for each point considered. The UDI paradigm offers a way to reduce the voluminous time-series data to a form that is of comparative interpretative simplicity to the daylight factor method, but which nevertheless preserves a great deal of the significant information content of the illuminance time-series. The UDI paradigm informs not only on useful levels of daylight illuminance, but also on the propensity for excessive levels of daylight that are associated with occupant discomfort and unwanted solar gain. In a conventional analysis of daylight provision and solar penetration, the two phenomena are assessed independently using methods that are idealised (daylight factor) and qualitative (shadow patterns). The UDI paradigm offers a simple methodology whereby daylight provision and levels of solar exposure are quantified using a single evaluative schema. Thus, it is also well-suited for teaching purposes. Application of the UDI paradigm is demonstrated using an analysis of design variants for a deep-plan building with a light-well. Comparison is made with the conventional daylight factor approach, the LEED daylight credit and measures of daylight autonomy.
The study encompasses the validation of the dynamic, RADIANCE-based daylight simulation method DAYSIM, which uses the concept of daylight coefficients and the Perez sky model to predict the short-time-step development of indoor illuminances. Measured and simulated illuminances have been compared under 10,097 sky conditions in a full-scale test office with a double glazing and external venetian blinds. The additional planning effort for the designer compared to a conventional daylight simulation is addressed. It has been found that the treatment of direct sunlight strongly influences the accuracy of the daylight coefficient method. Three different simulation modes for the direct sunlight are investigated. The simulation results prove that indoor illuminances can be modeled with comparable accuracy for various blind settings under arbitrary sky conditions. Daylight autonomies are predicted with an accuracy below 2% points, where simulation errors stem with roughly equal parts from the raytracing and the sky model.
This study describes the development and validation of a Radiance model for a translucent panel. Using goniophotometer data combined with integrating sphere measurements, optical properties of the panel were derived and converted into a Radiance model using the trans and transdata material types. The Radiance model was validated in a full-scale test room with a facade featuring the translucent panel material. Over 120,000 desktop and ceiling illuminances under 24,000 sky conditions were measured and compared to simulation results using the Perez sky model and a Radiance-based daylight coefficient approach. Overall mean bias errors (MBE) below 9% and root mean square errors (RMSE) below 19% demonstrate that translucent materials can be modeled in Radiance with an even higher accuracy than was demonstrated in earlier validation studies for the plastic, metal, and glass material types. Further analysis of results suggests that the accuracy of around ±20% currently reached by dynamic Radiance/Perez/daylight coefficient calculations for many material types is sufficient for practical design considerations. A procedure is described showing how goniophotometer and integrating sphere measurements can be used to accurately model arbitrary translucent materials in Radiance using transdata function files.
Daylighting Metric Development Using Daylight Autonomy Calculations in the Sensor Placement Optimization Tool
- Z Rogers
Rogers, Z., 2006. Daylighting Metric Development Using Daylight
Autonomy Calculations in the Sensor Placement Optimization Tool.
Tratto da <http://www.archenergy.com/SPOT/download.html>.
International Weather for Energy Calculations (IWEC Weather Files) Users Manual and CD-ROM
ASHRAE, 2001. International Weather for Energy Calculations (IWEC
Weather Files) Users Manual and CD-ROM. ASHRAE, Atlanta.
The Benefits of Daylight Through Windows. Rensselaer Polytechnic Institute
- P Boyce
- C Hunter
- O Howlett
Boyce, P., Hunter, C., Howlett, O., 2003. The Benefits of Daylight
Through Windows. Rensselaer Polytechnic Institute, Troy, New York.
CIE 157: 2004. Control of Damage to Museum Objects by Optical
Radiation.
Daylight Simulation: Validation, Sky Models (PhD thesis) Retrieved from De Montfort University
- J Mardaljevic
Mardaljevic, J., 1999. Daylight Simulation: Validation, Sky Models (PhD
thesis). Retrieved from De Montfort University. <https://www.dora.
dmu.ac.uk/handle/2086/2388/browse?value=Mardaljevic%2C+John&
type=author>.
A Measuring Diagram for Daylight Illumination. B T Batsford Ltd
- P Waldram
Waldram, P., 1950. A Measuring Diagram for Daylight Illumination. B T
Batsford Ltd, London.
autodesk-3ds- max-design-software-exposure-technology-scientifically-validated
- Creativeplanetnetwork
CreativePLANETnetwork.com., n.d. Retrieved 09.06.14, from <http://
www.creativeplanetnetwork.com/the_wire/2009/02/03/autodesk-3ds-
max-design-software-exposure-technology-scientifically-validated/>.
EN 12464-1, 2011. Light and Lighting – Lighting of Work Places – Part I:
Indoor Work Places.
Light and Lighting -Lighting of Work Places -Part I: Indoor Work Places
- Com Creativeplanetnetwork
CreativePLANETnetwork.com., n.d. Retrieved 09.06.14, from <http://
www.creativeplanetnetwork.com/the_wire/2009/02/03/autodesk-3ds-max-design-software-exposure-technology-scientifically-validated/>.
EN 12464-1, 2011. Light and Lighting -Lighting of Work Places -Part I:
Indoor Work Places.