This work lies within the concept of positive energy buildings. The aim is to develop an activemanagement of local free energy (solar, air and earth) inside the envelops by convection heat transfer and by the use of phase change materials (PCMs) in order to store or release heat when needed. A 1D RC network simulation tool has been developed for different standard fronts including a solar air collector and a double skin faade (south frontage), leading to the thermal simulation of a room with different configurations, with or without PCMs integration and for ventilated envelops. The first results for summer conditions are very encouraging. The management of the air flow inside envelops helps the indoor temperature to be maintained at a reasonable level. An experimental cell is being held at CSTB outdoor site, it will allow us to calibrate the model.