An examination of the role of design and operational parameters in a night ventilated library building located in Ireland, and which is Subject to a maritime type climate, is considered. For this investigation, a self-contained space within the library building is analysed. A dynamic model of the space is created using the ESPr simulation package, which is compared with building data obtained from an experimental monitoring programme. Calculation of the mean bias deviation between the predicted and experimental data indicates agreement better than 0.45 degrees C for the dry bulb temperature and 1. 1 degrees C for the mean radiant temperature. Using ESPr predictions, the role of different building design and operational parameters are examined by means of parametric analysis including building mass, ventilation duration, internal gain and ventilation rates. Compared to a reference base of the existing building, increasing the building mass was found to achieve a significant reduction in internal dry resultant temperatures, with a decrease of between 2 and 3 degrees C observed when mass was increased from 800 k g/m(2) to 1600 kg/m(2). Reducing building internal gains from 40 W/m(2) to 20 W/m(2) was observed to have the potential of further reducing dry resultant temperatures by up to 1 degrees C. Examination of night ventilation rates indicated that increasing night ventilation up to 10 ACH was observed to have a significant affect on reduction of dry resultant temperature, but further increases of air changes were observed to have a negligible effect. (c) 2006 Elsevier Ltd. All rights reserved.