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Advances in Simulation Studies for Developing Energy-Efficient Buildings
Published in Amritanshu Shukla, Atul Sharma, Sustainability through Energy-Efficient Buildings, 2018
Karunesh Kant, Amritanshu Shukla, Atul Sharma
Radiance is envisioned to aid illumination designers and architects by forecasting the light levels and appearance of a space prior to construction of buildings. The package includes programs for modeling and translating scene geometry, luminaire data, and material properties, all of which are needed as input to the simulation. The lighting simulation itself uses ray tracing techniques to compute radiance values (i.e., the quantity of light passing through a specific point in a specific direction), which are typically arranged to form a photographic quality image. The resulting image may be analyzed, displayed, and manipulated within the package, and converted to other popular image file formats for export to other packages, facilitating the production of hard copy output. Radiance contains many of the features of popular computer graphics rendering programs with the physical accuracy of an advanced lighting simulation. This combination of flexibility and accuracy makes it unique in providing realistic images with predictive power for architects, engineers, and lighting designers. Its flexibility is demonstrated in applications as diverse as forensics (i.e., roadway accident re-enactment by Failure Analysis and Associates, CA) and aerospace (i.e., space station design by NASA, Goddard). Radiance has been compared to other lighting calculations, scale model measurements, and real spaces to validate its capabilities. No other lighting calculation has undergone a more rigorous validation. Many others have attempted to develop a lighting simulation system with similar capabilities, and there have been few notable successes. At least three major European firms (Ove Arup in London, Abacus Simulations in Glasgow, and Siemens Lighting in Germany) have abandoned their own in-house lighting simulations in favor of using Radiance.
Multi-phase framework for optimization of thermal and daylight performance of residential buildings based on the combination of ventilation and window design
Published in Journal of Asian Architecture and Building Engineering, 2021
Jiahe Wang, Masayuki Mae, Keiichiro Taniguchi, Yanmeng Cheng, Shigekazu Yagi, Koichiro Saito
For a start, annual energy consumption and thermal comfort under the state of free-running and air conditioned are included in the objective of this optimization method, and the simulation engine both of these two evaluation indicators are Energyplus. Meanwhile, part of passive strategies improves energy and thermal comfort performance by sacrificing daylight environment, one of the most important environmental factors in residential buildings (Li et al. 2006), such as mounting shading devices, lowering WWR, etc. And the daylight use also associates with the utilization of solar radiation, which serves as the most significant means to reduce cooling load and improve physical and psychological thermal comfort in winter. Consequently, on account of the snowy and cold climate characteristics in winter of case study location, daylight utilization performs as one of the optimization objectives in this study. The simulation engine of daylight environment is Radiance.
Calculating solar irradiance without shading geometry: a point cloud-based method
Published in Journal of Building Performance Simulation, 2021
Á. Bognár, R.C.G.M. Loonen, J.L.M. Hensen
Provided that a 3D surface model of the environment is available, ray-tracing is a widely used method to calculate the Plane Of Array (POA) solar irradiance or illuminance both on external and internal surfaces of buildings, taking into account the shading effect and the reflections from the surroundings (Brembilla et al. 2019; Wang, Wei, and Ruan 2020). Radiance is an open-source suite of validated tools to model and render luminous effects of building fenestration and interior lighting (Ward and Shaskespeare 2003). It is less commonly used for such purpose, but Radiance can also model solar irradiance on PV surfaces (Lo, Lim, and Rahman 2015). However, simulation with ray-tracing at every timestep can be time-consuming, especially for (annual) hourly or sub-hourly simulations. In order to reduce computation time for an annual calculation, the concept of the daylight coefficient was introduced in 1983 (Tregenza and Waters 1983). This concept was later developed further, by introducing multiple phases to the calculation of the flux transfer matrix between the sensor point1 and the discretized sky2 (Subramaniam 2017a) in order to speed up calculations, increase the spatial resolution or add the capability of modelling dynamic scenes.
Calibration and Validation of Climate-Based Daylighting Models Based on One-Time Field Measurements: Office Buildings in the Tropics
Published in LEUKOS, 2021
Geraldine Quek, J. Alstan Jakubiec
A third, but less utilized, approach to gathering experiential daylighting data inside of spaces has been to employ daylighting simulations, often using a validated Radiance-based engine (Ward 1994) such as Daysim (Reinhart and Walkenhorst 2001). Reinhart et al. (2014) used quasi-calibrated CBDM results paired with subjective data to identify annual lighting performance levels that correlate with perceptions of daylit. Jakubiec and Reinhart (2016) used a daylighting model based on measured material properties, exacting geometric reconstructions, and specific weather data to assess annual lighting and glare metrics for 123 participants in a POE study at 6-min time intervals, but the model’s calibration was not checked with measurements and contributions from electric lighting were ignored. Bellia et al. (2017) expressed the opinion that this approach was not feasible due to the complexity and time commitments of modeling data. Mardaljevic et al. (2016) noted that CBDMs are difficult to validate in practice due to obstructions on the workplane where sensors would ordinarily be placed for long-term monitoring and that illuminance data are not ordinarily a part of building management systems. They proposed to use a continuous luminance camera to derive illuminance on vertical surfaces in order to validate CBDM illuminance calculations. Other researchers have noted the importance of appropriate material properties in simulations to achieve accurate results (Brembilla et al. 2015; Jakubiec 2016).