Numerical simulation guided design of novel experimental chamber used to assess the effectiveness of ventilation strategies with hygro-regulated air terminals

Ensuring acceptable indoor air quality (IAQ) is critical for managing built environments. This is done by ventilating spaces with outdoor air to keep indoor pollutants like CO2, humidity, particulate matter, and VOCs within healthy levels. The effectiveness of ventilation strategies depends on factors like occupancy, pollutant types, and air terminal devices, which can be influenced by outdoor air quality, especially in urban areas with particulate matter and NOx. Ventilation devices can operate with constant airflow or adjust based on occupancy. Demand-controlled ventilation, using indoor CO2 levels as an indicator, is more energy-efficient than constant-flow methods. For over 40 years, humidity-sensitive terminals (HST) have been used in French homes, mainly characterized by their flowrate and humidity control, but rarely in terms of IAQ. To optimize IAQ at minimal energy cost, it's essential to understand how HSTs transfer indoor and outdoor pollutants. This study aims to design an experimental chamber to test ventilation strategies using HST. First, a literature review of the existing experimental chamber highlighted the limitations to be overcome by the current developed testing facility. Second, numerical models were developed on CONTAM and computational fluid dynamics (CFD) to guide the chamber design. On one hand, CONTAM model was used to determine the emission rates of pollutants and the corresponding sizing of the generators and the proper selection of the control equipment (sensors, mass flow controllers). On the other, the CFD model assisted in determining the appropriate location of these various instruments for better control as well as proper functioning of the experimental chamber.