Conceptual framework for daylighting and facade design in museums and exhibition spaces

Abstract

Limited attention has been paid to daylight performance concerning layout design and human perception of luminance environments in museums. Assessments are focused on the illuminance preservation requirements in order to minimize the damage that can be caused by light. However, assessment criteria of current daylight performance metrics provide an indicator for the space as a whole, with no account for the spatial distribution. A few recent metrics have addressed the qualitative aspects through contrast measures to assess how exciting or calming the luminous environment is. Pointing to the quantitative daylighting design aspects (illuminance, distribution, and exposure), as well as qualitative aspects implied in spatial contrast, this paper proposes a simplified daylighting design workflow for facades to maintain preservation standards and to provide a more interesting spatial ambience for the visitors. The idea starts with pixelating the facade to provide random small openings that contribute to a higher spatial contrast. This workflow accounts for the layout design to overcome the averaging of current daylight metrics that may underestimate the overexposure to daylight in critical areas where sensitive objects are located. For daylighting assessment in exhibitions, this study suggests that Continuous Daylight Autonomy (CDA) and Annual Sunlight Exposure (ASE) are the most suitable metrics to be adapted to meet standards according to the light sensitivity of objects in the space. Furthermore, it provides an approach to integrate the recently developed modified spatial contrast (mSC5) metric to estimate a sense of visual interest of the exhibition space through daylight luminance maps.