Numerical and experimental evaluation of ventilation in laboratories: a case study

Ventilation is a key performance requirement in laboratory design as it has to guarantee a safe and comfortable indoor environment. Current standards and guidelines on laboratory ventilation often impose high ventilation rates, increasing the energy need for ventilation, the environmental impact and the energy costs, at many large research facilities. This research focuses on the intra-zonal airflow in a standard laboratory set-up. The airflow and ventilation efficiency is computed with Computational Fluid Dynamics (CFD) and an extensive in-situ experimental case, in which different ventilation strategies are evaluated, has been conducted. The results indicate that the current design standards, which impose a minimal number of air changes per hour, cannot guarantee an optimal, energy efficient design. An optimal design starts from a comprehensive risk analysis. The CFDsimulations and experimental study show that an optimal design should not only be based on a minimal ventilation rate but also has to include an analysis of the impact of the location and type of the ventilation inlet and outlet, the room geometry and ideally the influence of occupants and laboratory appliances. Therefore, it can be concluded that a reformulation of the requirements for laboratory ventilation is appropriate, which in practice will lead to an increasing complexity of the ventilation design process. Although they require a good comprehension and implementation of correct physical properties, CFD-simulations are expected to become an interesting and even mandatory design tool for future, energy efficient laboratory ventilation.