A direct method to assess daylighting quality of learning spaces in sub-tropical China

Abstract

This research is to investigate and propose a direct method to assess daylighting quality of learning spaces in sub-tropical China. Previous work in the field shows the knowledge gap of understanding the quality of daylighting and the relationship between quality and quantity of daylighting in learning spaces, and the lack of a direct tool to assess the daylighting quality of learning space.

In order to establish a comprehensive analysis method by computer simulation on quality of daylighting in learning spaces, the research includes a three-part study of discomfort glare analysis. In the first part of the study is conducted a validation of the RADIANCE-based glare analysis software Evalglare. The validation involves image-based lighting analysis procedures that operate with high dynamic range (HDR) luminance data for advanced simulation assessment. Vertical illuminace at eye level (Ev) calculated from HDR photos by two sets of different cameras (Nikon Coolpix 4500 with Fisheye lens FCE8 and iPhone 5c with Photojojo Super Fisheye lens), from simulated HDR images and Ev measured from reality are compared to determine the accuracy of the core components used in the development of proposed daylight glare assessment method. The Evalglare is validated with a reliable accuracy, and the data generated from HDR photos captured by iPhone 5c with Super Fisheye lens camera set was found with sufficient accuracy to use for daylight glare assessment.

The second part of the study describes and discusses results and findings gathered from the investigation of factors affecting daylight glare in learning spaces of sub-tropical china. This investigation is based on the simulation result of selected views of nine points evenly dividing the space of various learning spaces and results of a questionnaire survey. The learning spaces of 6 schools out of 42 reviewed schools are selected to perform daylight glare simulation for studying the design factors affecting daylight glare assessment. This part of study then summarizes the relationship between DGP and time and date, the impact of different orientation on DGP scores, and the relationship between DGP and different positions of a learning space. In order to examine the sufficiency of DGP method in an Asian context, the result of a user survey for the learning spaces of a school in Hong Kong and the results of computer simulation are also compares and discusses. A “division” concept is also developed to apply DGP method with a new daylight glare comfort classification for the glare assessment of learning spaces. The final part of the study outlines the development and validation of the proposed new direct daylight glare assessment tool, which is developed by integration of the codes of three major open sources. The performance and accuracy are tested to ensure this new tool is sufficient for the glare assessment of learning spaces in the post occupancy stage.

To conduct the direct daylight glare assessment method is successful for glare control of learning spaces during the design stage, which has an important role in determining the daylight glare condition for ensure good daylighting quality of learning space in subtropical China. The direct assessment tool is useful for glare detection and shading design for existing or built learning spaces that were not well designed with consideration of daylight glare. The use of this direct assessment tool can provide an interactive and user friendly control for designers to better understand the daylight quality of a space, and will have a significant impact on the improvement of efficiency of daylight glare evaluation for built space.