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Smart-ventilation with airflows adapting to the need of buildings reduces energy consumptions and can improve IAQ. In some countries, smart ventilation strategies have been widely used for a long term (like Belgium, France,…). We still need to quantify IAQ and energy benefits of smart ventilation through a common internationally validated performance assessment scheme, still under development, notably in the framework of the IEA-EBC Annex 86.

The protection from chronic harm provided by exposure limit values (ELVs) is evaluated for indoor air contaminants set by regulatory bodies of member countries in the Air Infiltration and Ventilation Centre (AIVC). Significant variability was found in the regulated harm levels from ELVs for the same contaminants across different countries, highlighting inconsistencies in public health protection. The concept of a regulated harm budget (RHB) is introduced, representing the total allowed harm from regulated contaminants implicitly set by a regulatory body.

The inclusion of health-based performance indicators and metrics in ventilation system design and research is a widely discussed topic in recent years. This is due to increased awareness about the health implication of indoor air quality and due to the need for innovative ventilation system control (smart ventilation) to limit building energy use.  

Ensuring an indoor environmental quality that is acceptable to the majority of users, while also being energy efficient is a challenge. In addition, both user demands and the climate change are making it even more difficult to ensure good indoor environmental quality. One of the solutions to combat climate change is free cooling systems, such as ventilative cooling. 

The global increase in building cooling demands poses a challenge for designers striving for net zero energy consumption. The prevalent use of mechanical cooling underscores the necessity for designers to consider Ventilative Cooling as a viable alternative in the early stages of building design. Recent research findings suggest that the pre-design stage has the same influence for promoting Ventilative Cooling strategies as the schematic and detailed design stages for practitioners, yet limited impactful decision making occurs at this stage.

Ventilative cooling is a free cooling methodology, harnessing the cooling potential of the outdoor air to remove excess heat, without the use of thermodynamic process, thereby saving valuable cooling energy in buildings. In future zero energy buildings it is essential to lower the energy consumption for cooling and here ventilative cooling is one good option.

This study utilized a CONTAM simulation to assess the effects of airtightness improvements in TNPI rooms. Sobol sensitivity analysis was used to evaluate the impact of building envelope elements on pressure differentials and contaminant dispersion. Results showed that inter-room penetrations, ward doors, and ward ceilings significantly influenced differential pressure, while exterior walls and inter-room penetrations predominantly affected contaminant dispersion.

Although the physics concerning air pressures in buildings don’t differ between countries, often different reference values of the pressure difference over the envelope are used to determine air tightness and ventilation characteristics. The air transfer devices for natural ventilation, integrated in the façades or the internal building structure, are characterized at a pressure difference between 1 and 20 Pa depending on the country. For example, Belgium uses 2 or 10 Pa as a reference, the Netherlands adopts 1 Pa, whereas France applies 10 or 20 Pa.

Ensuring the airtightness of building envelopes is crucial for enhancing the energy efficiency of buildings. The prompt detection of leaks is essential, particularly when undertaking building renovations. Consequently, efforts have been made in recent years to implement new measurement techniques that facilitate the rapid, straightforward, and wide-scale identification of leaks in building envelopes. Two notable methods are the use of acoustic and thermographic technologies.

Improving the energy efficiency of buildings and the quality of indoor air requires accurate assessments of airtightness. The conventional regression method, Ordinary Least Squares (OLS) regression—as shown in ISO 9972—encounters challenges in the occurrence of fluctuating wind conditions, affecting the reliability of air permeability measurements.