Gruner Roschi AG determined the best architectural solution through parallel processing with SimScale

Gruner Roschi’s Case

Natural Cross Ventilation in the Classroom

Gruner Roschi’s project involved creating a suitable classroom ventilation design for a newly constructed building. Working closely with the chief architect on the project, it was determined that the design needed to be cost-efficient, eco-friendly, and ultimately low-tech. This meant as little technical installation needed to be used as possible in the design.

This posed an interesting challenge, as it eliminated the possibility of a mechanical ventilation system that would be able to control the building climate as well as airflow. As the team at Gruner Roschi aimed to discover, create, and validate the best natural ventilation design possible to be implemented, they turned to online simulation.

How Gruner Roschi Solved it With SimScale

Cloud-Based CFD and Convective Heat Transfer

As a first step, the team simplified a Revit model of the original building and focused on one classroom with several different window designs and room heating strategies. The team wanted to understand how the different designs affected the natural ventilation of the space, through the different window openings in the classroom. The goal was to test multiple designs, and then choose the best design to be implemented for construction.

Once in the SimScale platform, they used transient convective heat transfer simulation to evaluate four design versions. The team at Gruner Roschi initially found it difficult to strike the right balance between the level of detailing in the CAD, and obtaining the coarsest mesh without compromising on the accuracy of the results, hence keeping the simulation time as less as possible. One factor that helped to find the best balance between mesh, accuracy, and time was being able to run dozens of mesh variants and simulations in parallel.

Results for Gruner Roschi AG

The Best Ventilation Design Was Chosen

For each design variant, 5-10 simulations were ran using different meshes and settings. The simulation runtime varied between 8 and 17 hours with a usage of 8 to 32 cores.

The team simulated the winter case for each design, with an outside air temperature of -5°C and the room air temperature at 21°C. After the simulation, they took a closer look at a time frame of 300 seconds in time steps of 30 seconds. The simulation results showed, in each time step, what occurred when the window of the schoolroom opened and cold air from the outside flowed through the space.

Finally, the simulation showed that the two different heating systems (convectors or floor-heating) hardly had any influence on the incoming flow. Instead, it was found that the type of window design in the separate simulations made a bigger difference in terms of air exchange. With this insight, Gruner Roschi could clearly see from the results that the variant with the tilted upper windows allowed for better airflow, and thus, better ventilation.

Next Steps for Gruner Roschi AG

Continued Collaboration

The chosen design variant for the classroom will be utilized, and will come to fruition in about two years when the building is completely constructed. As for Gruner Roschi and SimScale, more collaborations and projects to come!