Indoor air quality vs. Energy use in a beer brewery: Assessment of ventilation methods and systems using CFD

The production in industrial buildings can have a large impact on the indoor air quality. For example, in beer breweries several processes influence the indoor air quality to a large extent, such as the fermentation process, which is accompanied by a strong emission of CO₂ gas. Employees working inside this kind of rooms can be exposed to high CO₂ concentrations. Ventilation of such large enclosures should be designed with both indoor air quality and energy use in mind. This paper presents Computational Fluid Dynamics (CFD) simulations to analyze three different ventilation configurations for an enclosure in which a fermentation process results in high CO₂ emission levels. High-resolution steady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were used to assess different ventilation methods and system designs, with the aim to realize a healthy indoor environment using a minimal amount of energy. The results showed that the ventilation configuration should be designed in such a way that it optimally takes advantage of the density difference between the ambient air and the released CO₂ gas. In this particular case, a highly uniform downward directed flow using a low supply velocity showed the best performance (lowest CO₂ concentrations), with a similar supply volume flow rate as used for the other configurations. This specific ventilation configuration therefore results in a more healthy working environment inside the enclosure, while limiting the ventilation flow rate, and thus energy demand.