Wall building Efficiency evaluation by exergy analysis – WALL-E

The building sector is one of the most energy-intensive sectors in Europe. In order to reduce its energy consumption, it is necessary to improve the efficiency of the building envelope in a framework of renovation of old buildings and construction of zero emission ones. In this context, it is necessary to characterize what is a "good" wall. It must provide effective thermal insulation for cooling or heating configurations, i.e., in summer or winter. However, during the intermediate seasons such as spring or fall, increased heat transfer is required for certain configurations. Therefore, the control of heat and mass transfer is crucial to designing efficient buildings. Until now, all measurements have been based only on heat transfer and have not taken into account the influence of humidity. Indeed, humidity is also a key parameter since it has a non-negligible effect on energy efficiency, durability of the construction and indoor air quality. The objective of this project is therefore to develop an innovative thermodynamic indicator to evaluate more precisely the energy performance of the whole building, considering the coupled heat and mass transfers through porous walls as well as the interactions between the building including with the heating, ventilation, and air conditioning systems. This approach will be based on laboratory experiments, in-situ measurements and numerical modeling for several scales (wall, building envelope, building with systems). The originality is, through an understanding of the indicators classically used in the building field and those derived from the laws of thermodynamics, to design the best building envelope (thickness, materials, shape, ...) and the most relevant HVAC control strategies for efficient building performance assessment under different dynamic weather conditions.