Daylight Performance of Classrooms in a Mediterranean School Heritage Building

In school buildings, natural light has considerable physiological benefits, and increases energy efficiency while reducing the operational energy consumption of buildings. It is thus crucial to maximize the amount of daylight, as well as to improve its quality, in educational premises. In Italy and other European countries, many historic buildings are reused as school buildings, changing their original function. This process of adaptive reusing is one method for conserving heritage buildings, however sometimes this process sacrifices the quality of daylight and well being of pupils. It has therefore become apparent that it is difficult to reconcile the cultural value of historic buildings with comfort standards. This study aimed to investigate the natural lighting performance of a school located in an historic building, and proposes different technological solutions to improve the visual comfort in classrooms whilst also respecting the cultural value of built heritage. Daylight performance was carried out in a representative classroom in the ‘Caserma Gaetano Abela’, an historical building located in Siracusa (Italy). A daylight model built in Radiance was first validated against an illuminance measurement campaign, and was then used to run detailed dynamic simulations. Climate Based Daylight Modelling (CBDM) metrics were used to show the achievable improvements in visual comfort conditions by means of proposed retrofit interventions. These interventions may also be used in other areas of southern Europe with similar climatic and constructive/distributive characteristics of architectural heritage.