Design of a hybrid ventilation system: the Cli'Nat project

Ventilation has a major impact on the global performance of buildings, in terms of energy consumption as well as regarding indoor climate: thermal comfort, indoor air quality, acoustics. The objective of the Cli'Nat project is to design, within a systemic approach, and to evaluate, by simulations and experiments, the performance of a ventilation and passive cooling system including a dedicated building envelope component and specific control strategies. Such a hybrid ventilation component has to be designed to be used as a ventilation opening for indoor air quality and as a passive cooling opening for night ventilation. Control strategies will allow maintaining satisfactory indoor environment while avoiding energy penalties. Three industrial partners and a university R&D laboratory constitute the team in charge of this project. A first step of the project has shown the feasibility of the Cli'Nat system. A two-zone educational building model has been developed and used to test basic control strategies of the Cli'Nat ventilation system. Simulations have been conducted to evaluate the performance of this system in terms of thermal comfort, indoor air quality and energy consumption. During the second step of this project, prototypes will be designed and tested using laboratory test facilities, to be characterized as a building envelope component, regarding thermal performance, acoustics, air flow A detailed model of these prototypes will then be validated to test advanced control strategies of the whole ventilation and cooling system.