Fluid dynamic based modelling approach for indoor air quality assesment in buildings

Laburpena

There is a conflict of interests between making an indoor space both energy efficient, and well ventilated. In a room that is effectively sealed or poorly ventilated, there is low energy consumption in air conditioning. Contaminants such as CO2 and airborne viruses remain and accumulate in the room, potentially causing health issues or exacerbating existing medical conditions. The increase of room ventilation will decrease the contaminant accumulation, but the energy consumption related to air conditioning systems will be increased. Therefore, an equilibrium between both is desirable. In this work, the effectiveness of Computational Fluid Dynamic (CFD) is analyzed predicting the behavior of air and the diffusion of contaminants, CO2, in an indoor space. By ANSYS Fluent software a 3D modelling is carried out. Appropriate grid size (to provide reliable results from multiple locations) is determined based on room dimensions prior to running the modelling. This methodology provides data for the whole room, not just where the sensors are situated, as in the in-situ measuring method. The CFD modelling is based on the dimensions and layout of a dedicated test room located in KUBIK experimental building of Tecnalia. The CFD results are compared to experimental data obtained from standard measuring equipment used in the test room. The test room is equipped with CO2 exhaust ports to simulate the CO2 emissions emitted by plants and people. Additionally, there are strategically located sensors for recording CO2 levels. If good agreement between modelling results and experimental data are obtained, the developed CFD model will be of interest at the design stage of new buildings to find the best solution that guarantees both air quality and energy efficiency