performance

More and more single-family houses are being retrofitted to achieve better energy efficiency levels. In this retrofitting process, the building envelope's airtightness is usually improved, and a ventilation system becomes necessary to create and sustain a healthy indoor air quality (IAQ). However, in France, as in many other western countries, ventilation requirements exist for new dwellings but not for residential retrofitting.

The objective of this study is to assess the ability to mitigate the airborne particle concentration in a mechanically ventilated meeting room with stand-alone air cleaners (ACs) as function of the amount and type of devices, the total airflow rate, the location(s) of the device(s) in the room and their flow pattern. Six commercially available ACs, selected to be representative of the French market, are included in the study, each featuring distinct airflow patterns for both air inlet and outlet.

The context of climate change and the need of saving energy has required rethinking the ventilation and the air change rates in buildings, because of their increased impact on thermal losses. Indeed, ventilation plays a crucial role estimated around 30-50% of the energy delivered to buildings, becoming an even higher part in high-efficient buildings.  

Smart ventilation which provides air renewal thanks to its variable airflows adjusted on the needs can improve both indoor air quality (IAQ) and energy performance of buildings. However, such performance gains should be quantified with performance-based approaches. In this paper, we propose to extend the performance-based approach with a robust methodology to rank the ventilation systems performance. Such a methodology could be used in a decision-making tool at the design stage of buildings.

The buildings ‘sector is facing multiple challenges due to the need to generalize a sober approach and to reduce its energy consumption, its CO2 emissions and its impact on climate change, to reduce its environmental impact and its carbon footprint, to reduce the burden of disease due to exposure to unhealthy indoor environments and to adapt and be resilient in the face of climate change and environmental changes such as the increase in pandemics, the urban heat island and outdoor pollution.

The energy performance of new and existing residential buildings needs to be radically improved to meet ambitious climate change goals and residential buildings are by far the largest component in the total building stock. A central boundary condition in constructing energy efficient buildings is doing so while maintaining a healthy, acceptable and desirable indoor environment.

In future building regulations 2020, building performance is going to be extended to global performance, including indoor air quality (IAQ). In the energy performance (EP) field, successive regulations pushed for a "performance-based" approach, based on an energy consumption requirement at the design stage. Nevertheless, ventilation regulations throughout the world are still mostly based on prescriptive approaches, setting airflows requirements. A performance-based approach for ventilation would insure that ventilation is designed to avoid risks for occupant’s health. 

In the field of energy performance, successive regulations pushed a "performance-based" approach, based at least on an energy consumption requirement at the design stage for heating and/or cooling systems (Spekkink 2005). Nevertheless, in the field of building ventilation, regulations throughout the world are mainly still based on “prescriptive” approaches, using airflows or air change rates requirements.  

Humidity-based DCV systems have been widely used in France for 35 years and are considered as a reference system, including for low-energy residential buildings. Indeed, most of the new residential buildings, which must be low-energy buildings to comply with the RT 2012 energy performance regulation, are equipped with such systems. Feedbacks from two long-term studies show the durability of the humidity sensitive components and show the robustness of this system to bad maintenance or use by occupants.