Purpose of the work
This paper deals with the feedback of a full of a ventilation system reconditioning in a non- standard sealed building. This volume was previously retrofitted and immediately shows many difficulties to maintain good indoor air quality in some parts of the occupied volume. Indeed, a permanent well functioning of the ventilation system is essential in a sealed building without openings to ensure a good indoor air quality.
Method of approach
The method and results are based on an experimental approach with measurements (pressure and airflow rate in the ductwork, airtightness testing of the ductwork), calculation of pressure drops, and observations (duct and internal envelope leakages search, airflow pattern) in order to identify the causes of the current ventilation dysfunctions.
Content of the contribution
An assessment of ductwork and HVAC system performance was first realized, conducted by the SNIA (National Airport Engineering Service). This analysis enabled to explain both the poor performance of the ventilation system observed by facility managers at the building scale, and the local Indoor Air Quality (IAQ) discomfort mentioned by occupants.
Results and assessment of their significance
The diagnosis showed that the major problem was due to the poor performance of two supply ventilation ducts (leakages and pressure drops) called A & B, with impact on the fan blowing pressure and on pressure along ducts. Reconditioning measures were proposed by SNIA, including the near-full replacement of ventilation ductwork A and its Air Handling Unit (AHU - 2200 m3/h), the use of a duct sealing solution for ventilation ductwork B and the installation of a fan speed controller on its AHU (1900 m3/h).
The full paper illustrates the results based on commissioning period after the 2017 upgrading to check all the installation with duct pressure test, airtightness testing, airflow measurements, electric power input for fans and sound pressure level.
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