From CAD to simulation results
The Qatar University requested Nabtaker’s services to help them tackle a problem with thermal comfort in their building. The temperature in one of their auditoriums was too high, especially during summer and when it was fully occupied. Taking into consideration the maximum capacity of 239 people which was easily reached during class period, they decided to invest in a thermal cooling study and fix the problem.
Their goal was to make sure that the auditorium was comfortable in any situation and season. By using computational fluid dynamics simulation, Jafer Arar—CFD engineer at Nabtaker—was able to measure the thermal comfort profile of this facility and assess how many people would not be comfortable in the auditorium and propose a new design configuration without changing the HVAC system.
For the occupants of such a facility, feeling comfortable impacted their performance. Working or studying in optimal conditions enables people to think better and be more efficient. Hence, thermal comfort contributes not only to well-being but also productivity.
The fact that we could run several simulations in parallel in the cloud with 96 cores using SimScale saved us a huge amount of time in the first stage of this project.
By using CFD, Jafer was able to assess the temperature and velocity inside the auditorium when used in full capacity, as well as the EDT (effective draft temperature), PMV (predicted mean vote) and PPD (predicted percentage dissatisfied) by downloading the results from the SimScale platform and post-processing them with special scripts created in ParaView by the SimScale support team.
With SimScale, Nabtaker simulated two configurations of the auditorium—the original one and a first proposal. The inlets and outlets were extended to avoid backflow and to help in convergence. The fluid flow was considered incompressible and a hex-dominant parametric mesh was selected with multiple types of refinements, resulting in meshes of around 18 million elements. This was expected, considering the fluid domain of such an auditorium.
The main challenge was to assess the thermal comfort around the 239 occupants and see how many of them would be uncomfortable. Based on the simulation results, Nabtaker presented new proposals to their client and then used SimScale for one more round of analyses before concluding the project.
For the first stage of the project, two designs were tested in parallel. With 96 cores, each run took less than 9 hours to complete, significantly reducing the project time. Nabtaker was able to assess the thermal comfort inside the auditorium and create a first proposed new configuration for the Qatar University following the ASHRAE standard.
The CFD simulations performed in the cloud with SimScale gave Nabtaker’s team valuable insights into the thermal comfort of the auditorium. Based on the results, they were able to propose additional design changes to position the inlets and returns of the HVAC system and prepared them for further testing. This was done without the need of actually changing the HVAC system’s energy efficiency.
“SimScale made the visualization of the current thermal comfort conditions inside the Qatar University’s auditorium possible, helping us propose a new design in order to achieve the minimum requirements for acceptable thermal indoor environments. Also, SimScale’s support was essential for this project. The team gave us many hints on how to mesh the geometry and perform the analysis. The close collaboration with the customer success engineers only added value to our project.”
Nabtaker plans to keep using SimScale for future projects due to the affordability of the subscription plan as well as to the fact that they can perform simulations in the cloud with high computational power, which eliminates the need to spend money with hardware. The fact that they can test several designs in parallel is of great value to them as well.
“SimScale makes it possible to run different design approaches in parallel with 96 cores, which would be not possible to be done locally.”