In France, energy consumption due to buildings heating is an important part of the global primary energy consumption. The tertiary sector represents an unavoidable source of economy in order to reduce energy dependency of France. The turnover of French real estate being relatively low, an effort must be focused on the existing. In this work, we investigate on an innovative process of internal thermal renovation, whose main element is a multifunctional ventilated wall, providing insulation, low temperature heat emission and the wall surfaces finishing. The first works on this ventilated wall were conducted on a prototype designed using a simplified numerical model. Two series of experiments conducted in a climatic cell allowed us to quantify the heat flow through the system. The smooth functioning of the ventilated wall is based on the natural convection in a vertical channel and the results from the prototype showed the presence of complex phenomena within the flow. We therefore chose to study in detail the thermoconvective phenomena in a chimney-like system before continuing the study of the overall component. A theoretical study and PIV experiment were conducted on an academic case of the problem. At the end of the experimental results, we observed several flow regimes, depending on the channel aspect ratio and the outlet Richardson number. Finally, we propose an analytical model of the ventilated wall including all influential geometrical variables. This model has been implemented in the simulation environment Trnsys with the perspective to make annual simulations on a building scale.
