Parametric Study of Light-Well Design for Day-Lighting Analysis under Clear Skies

 Abstract—Lightwells are vertical spaces used in multistory buildings to illuminate spaces without direct day light access. In many countries the building code allows for kitchen and bathroom to be mechanically ventilated and lighted, while in other countries and jurisdictions, building codes necessitate that such spaces be naturally ventilated and lighted. Therefore, lightwells become an integral part of the design especially in sites with min frontage and multistory residential buildings. Design requirement solely on the dimensions and area neglects several aspects that may affect the performance of the lightwell. Reflectivity, windows area and aspect ratio, building orientation, and the aspect ratio of the light-well itself are important factors in determining the performance. In order to assess and develop rational criteria for lightwell design, this study aims at conducting a parametric study to assess the effectiveness of light well design. Two famous lightwell index formulae are calculated and correlated to the day light performance. Various measures were used to test the day light performance including dynamic climate based measures. RADIANCE simulation models and an automated process using LUA code were used to perform the parametric variations. A physical building model was used to calibrate the RADIANCE simulation. This study will be of interest to building officials setting code requirements as well as practicing architects.