Abstract
Climate-based daylight modelling (CBDM) is an effective means of assessing the performance of daylight redirecting components (DRCs) with highly directional scattering to determine their impact on daylight availability and visual comfort. Such a simulation imposes significant computational demands on commodity hardware as it requires high density luminance samples obtained by forward raytracing. We propose an out-of-core photon mapping method within the Radiance framework to compute high quality daylight coefficients as a basis for CBDM. The method is particularly suited to angularly selective DRCs exhibiting strong redirection in conjunction with non-uniform sky luminance distributions with high resolution subdivisions. Our implementation is a work in progress and currently accommodates up to 4.3G photons on disk, while optimizing the in-core memory footprint by loading only photons which actually contribute flux to sensor points. We also leverage the fact that photon paths are independent through parallelization.
Highlights
The accurate simulation of daylit interiors is essential in assessing a building’s daylight performance and energy saving potential
The rest of this paper is organized as follows: in Section 2 we cite previous work on which our ooC approach is based; in Section 3 we elaborate our methodology for computing Daylight coefficients (DCs); Section 4 presents results obtained with our implementation for a case study with a daylight redirecting components (DRCs) characterized by pronounced angular selectivity, including benchmarks comparing the ooC and iC photon map implementations; we conclude in Section 5 with an assessment and an outlook on future developments
We have presented an out-of-core implementation of the RADIANCE photon mapping module to efficiently handle large photon maps to compute high quality DCs on commodity hardware in support of annual daylight simulations
Summary
The accurate simulation of daylit interiors is essential in assessing a building’s daylight performance and energy saving potential. The daylight performance can be improved with daylight redirecting components (DRCs) which modulate the illuminance on a task plane, as well as increase visual comfort and reduce glare due to the luminance distribution within the field of view. DRCs bear characteristics which require precise simulation models for an accurate prediction of their impact on the building’s performance; these include angular selectivity, a highly localized distribution of transmitted and reflected light giving rise to caustics and visible shadow patterns. The accuracy of simulated luminance maps is highly dependent on the angular sampling density of the sky and the geometric resolution of the DRC model. This increases the complexity and computational demands of the simulation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
