Application of the PHACES Tool in the Design of Natural Ventilation for Passive Cooling

Natural ventilation associated with shading techniques is an alternative way to reduce the use of expensive and environmentally harmful active systems, while providing summer thermal comfort and good indoor air quality. However, there is still a lack of knowledge concerning the design of such systems. The tool presented in this paper provides guidelines on natural ventilation and shading control strategies. This tool (called PHACES) has been developed under the MATLAB/SIMULINK environment by modelling an experimental device (HYBCELL) designed at the LASH/ENTPE laboratory. The thermal model used is based on finite difference methods and the airflow model is based on pressure analysis. Several control strategies for shading and ventilating based on temperature, CO2, occupancy, outdoor solar radiation and time have been implemented in PHACES. Simulations carried out using this tool revealed the key role of the tuning process in order to adapt control parameters such as set points and dead bands to the building and climate.