Etienne Wurtz

Study of moisture transfer in a double-layered wall with imperfect thermal and hydraulic contact resistances

The objective of this work is to study the effect of taking into account interface contact resistance on the prediction of moisture distribution through multilayered building envelope. Therefore, two mathematical models to describe coupled heat and mass transfer in double-layered porous materials have been investigated: one that considers imperfect contact between layers and another that ignores this phenomenon. Both models are one-dimensional and were implemented using finite difference technique with an implicit scheme. Numerical results are presented in terms of moisture distribution for a double-layered wall and compared with the experimental data available in the current literature. The comparison has shown that the model that disregards interface contact resistance between layers cannot predict correctly one-dimensional heat and moisture transfer within double-layered porous materials. The sensitivity analysis of the simulation parameters and the impact of contact resistances at the whole building level are presented in detail and their effect on the whole building level was analysed. Our results suggest that the thermal contact resistance is the most influent parameter on the moisture flux across the hydraulic contact interface. On the whole building level, simulations indicate that taking into account contact resistances had a slight effect on the indoor relative humidity but a noticeable effect on heating input energy. A decrease of 10% in energy consumption is obtained when contact resistances are considered.

Overall cooling efficiency of a solar desiccant plant powered by direct-flow vacuum-tube collectors: simulation and experimental results

Using solar thermal energy is an interesting option for heat-driven air conditioning, e.g. desiccant cooling. In this article, the autonomous operations of a solar desiccant cooling plant powered by direct-flow vacuum-tube collectors are investigated. A model of the solar installation and the desiccant air handling unit is presented and implemented in the SPARK simulation environment and then it is validated experimentally. The overall cooling efficiency of the system is evaluated using simulation for humid and moderately humid climates and the effect of increasing the regeneration temperature on the cooling capacity, the overall cooling efficiency is studied and finally the overall efficiency of the collectors is calculated for the studied cases.

Assessment of district projects : Quality of the physical environment in the Espaces Gare (project in La Rochelle)

ABSTRACT The fast and uncontrolled emergence of a will to promote sustainable development in the field of building construction generates new requirements for urban development. Besides technical solutions, project managers or urban planners must take into consideration the overall impact of their project on the local and global environment as well as social trends, economic development, health and safety for users. Integration of a huge number of evaluation criteria makes the assessment of such strategy very hard to carry out without a real methodological work. This paper proposes a first methodological approach in order to evaluate sustainability at the district scale and is based on 8 objectives. It is also a contribution to the French research project ADEQUA. This article presents a comparison between two district projects through the objective “quality of the physical environment”. This objective is defined and applied to a case study: the project “Espaces Gare” which concerns the planning of districts near La Rochelle train station (France).