Daylight simulation

Daylighting is still the most energy efficient lighting strategy, but filtering sunlight might conflict with maximization of solar gains in winter or reducing solar heat gain in summer. In passive solar homes occupants ideally balance visual and thermal comfort. This study explores the relationship of daylight and thermal comfort in a passive solar home using an extended case study method.

The objective of this paper is to highlight the effectiveness of light shelves in tropical office buildings to enhance interior daylighting quality. Daylight simulation was performed for custom light shelves for a typical office floor of Dhaka City in Bangladesh, to determine the best possible location under overcast sky conditions. Six alternative models of a 3m high study space were created with varying heights of light shelves. The 3D models were first generated in the Ecotect to study the distribution and uniformity of daylight in the interior space with split-flux method.

The daylight factor is usually one of the first daylight performance measures that simulation newcomers calculate. Apart from the intrinsic limitations of the daylight factor as a meaningful daylighting performance metric, little work has been done in the past as to how accurate one can actually expect simulation novices to simulate the daylight factor compared to an expert modeler. This paper presents the comparison of daylight factor predictions from a ‘best practice’ model of an L-shaped perimeter classroom to a total of 69 novice/student models.

This project investigated the feasibility of using existing software test cases to provide reliability scores for lighting simulation software. Estimation of lighting levels is a key element in commercial building design. And, many lighting programs claim to render light accurately. However, there is little published information on their accuracy. In thermal simulation, the IEA BESTEST (Judkoff et al), recently adopted by ASHRAE as Standard 140 (ASHRAE 140), certifies the acceptability of a thermal simulation code. (e.g.

The minimum illuminance requirement for New Zealand Building Code (NZBC) Clause G7 – Natural Light is currently not being met in some new apartments. Daylight simulation is the most effective method of predicting the performance of daylight in apartments, but due to the complexity and time required to gain accurate results, these simulations are not routinely done. This paper discusses an investigation into whether a tool could be created that will identify when daylight simulations may be required to prove compliance with NZBC G7.

Reliable prediction of daylight availability in indoor environments via computational simulation requires reasonably detailed and accurate sky luminance models. In this paper, we compare three calibration methods to derive detailed sky luminance maps from digital sky images. The results imply that digital sky imaging calibrated with parallel measurements of overall horizontal illuminance levels, can provide an efficient basis for the generation of detailed sky luminance models.