Turkish D-light: accentuating heritage values with daylight

Historic buildings have their own cultural identity, which is often related to their aesthetic qualities such as period characteristics (geometry, size, colour, form and shape), materials and construction. Daylight is one of the primary elements contributing to the distinctiveness of the visual environment of many historic buildings, but is rarely considered as one of the components that shape the character of a building when adaptive preservation schemes of historical buildings are planned. Many historic buildings were originally designed to accommodate activities different to their new use and preserving the quality of daylight that originally contributed to their visual identity is a challenging task. Maintaining the ‘day-lit appearance’ of a building can be particularly problematic if the building is to be used as a museum or a gallery owing to the artefacts’ conservation requirements. This work investigated the opportunities of maintaining the original ambient conditions of renovated historical buildings while meeting the required daylight levels of the proposed new use. The study utilised an annual daylight simulation method and hourly weather data to preserve daylight conditions in renovated historic buildings. The model was piloted in a Turkish bathhouse situated in Bursa, Turkey, that is currently under renovation. The simulation model produces 4483 hourly values of daylight illuminance for a period of a whole year using the computer program Radiance. It is concluded that daylight characteristics should be taken into account when developing a renovation scheme. With increasing pressure on valuing historic buildings in many parts of the world, the work reported here should be beneficial to those concerned with the conservation and adaptive reuse of historic buildings. The study findings could also be useful to those interested in predicting potential energy savings by combining daylighting and electric lighting in historic buildings.