2017 ASHRAE Annual Conference

In this case study, CFD was used to evaluate roof modifications of an aluminum foundry. The study shows the strategies used to provide an efficient and effective computational model that will provide the key data needed to evaluate the large space and make the right modifications to maintain air temperature limits. The modeler’s understanding of fluid dynamics will be a critical element towards applying appropriate strategies in the development of the CFD model to provide a robust design evaluation tool. Care must be taken in specification of the inputs to a CFD model, and interpretation of results and associated implications.

Natural ventilation is characterized by low driving pressures leading to the need for large ventilation openings. In addition, natural ventilation systems must remove sufficient heat to ensure thermally comfortable conditions. This is particularly challenging in high heat gain spaces such as raked-seat auditoria where heat gains can be as high as 90W/m2. This presentation talks through the design and CFD modeling of a 500-seat theatre in the UK which harnesses buoyancy-driven displacement ventilation to deliver a comfortable and ‘atmospheric’ performance space. Two modeling techniques are used: traditional Reynolds Averaged Navier Stokes and Large Eddy Simulation.

Displacement ventilation (DV) has a become a commonly used system in a broad range of applications due to its energy saving potential and superior indoor air quality. There are various rules of thumb that dictate the maximum cooling load that the system can handle. Although using the system for higher cooling loads is not recommended, there are cases where it is still advantageous to do so. This seminar explores the performance of a DV system outside of its normal operating range using CFD. Design guidance will be provided and application-specific trade-offs will be explored.

Natural ventilation is an efficient way of removing high internal heat gains for buildings and its energy saving potentials however depend on many parameters. This presentation reports a series of GIS maps for natural ventilation potentials of North America, similar to the well-known solar potential maps. These maps provide key graphical information of energy saving potentials of both single sided and cross natural ventilation in terms of total hours suitable for natural ventilation and associated energy savings for over 50 cities in the US and 10 cites in Canada.