A Simplified Tool for Predicting the Thermal Behavior and the Energy Saving Potential of Ventilated Windows

Currently, the studies of ventilated windows mainly rely on complex fluid and thermal simulation software, which require extensive information, data and are very time consuming. The aim of this paper is to develop a simplified tool to assess the thermal behavior and energy performance of ventilated windows in the early design stage. The simplified tool is developed to treat different ventilation modes: pre-heating, self-cooling and by–pass, and an operational strategy is established to determine the most energy efficient mode in each time step. Cavity air temperature and energy demand are calculated based on hourly weather data. The accuracy of the simplified tool is validated by full-scale experiments and numerical simulation. In addition, a case study on a single family house with ventilated windows in the Danish climate is present. The results indicate that ventilated windows have apparent advantages over conventional windows on the indoor thermal comfort and energy saving.