No abstract

Wood-framed buildings are considered to have low energy consumption since their construction mode generally gives high U-values and limited thermal bridges. Although the construction mode results in low heating consumption, the lack of storage capacity in the internal walls makes passive cooling designs such as night ventilation inappropriate. Consequently, the interior is subject to considerable temperature swings and higher temperatures than those of buildings with more massive internal surfaces. This paper investigates the possibility of reducing the energy used for cooling buildings by linking a so-called "phase-shifter" air/mass system to the HVAC system. This system is capable to restore the night cooling potential in the daytime by shifting the input temperature oscillation to around half a day, whereas temperature swing is conserved. The numerical model implemented on the SimSpark platform has been validated against the analytical solution for the constant airflow and harmonic temperature profile; then experimental data (obtained from the full-scale prototype designed and installed at the CSTB) has been used to assess its predictive capability with non-constant airflow. Using reduced ventilation periods has been numerically studied regarding environmental air resource and thermal storage efficiently of the system. The size and electricity consumption were optimized by this way. A comfort analysis was carried out on an experimental building with very high energy efficiency (INCA, INES, Le Bourget-du-Lac, France) based on the EN ISO 15251 adaptive model. Energy building simulations demonstrate that associating a phase-shifter to a low-inertia building gives it similar internal conditions to those of a more massive night-ventilated structure. Furthermore the proposed optimization greatly reduces the size of the system (by 30%) and the electricity consumption (by at least 38%) while the temperature is out of the comfort range for an extra 5% of the time.

International audienceIn the last years, several innovations have been introduced in the field of building envelope research and development. To bridge the gap between research and commercially available products, one of the key step is to evaluate these technologies in 1:1 scale and under real boundary conditions. For this purpose, test in outdoor full-scale facilities in complement with dynamic numerical simulation, allow to assess the performances of these complex envelope components, systems or whole building. In this framework a new versatile facility, named FACT (FACade Tool), is under construction in the southeastern France (CEA-INES platform – Le Bourget du Lac) for building envelope components test. This new full-scale tool will be dedicated to infield evaluation of: opaque and transparent elements, lightweight and massive façades, different thickness and heights and different geometry of the indoor environment. In this paper it is presented the design phase, the concept and the working principle of the facility. The layout definition was supported by preliminary simulations and the results of this modelling activity are discussed in order to guide the construction of the facility and to outline the experimental protocol for the next campaigns in FACT