The building has a large room where the height is greater than five meters, and the ceiling is immediately below the roof. Roof insulation is minimal, and air ex-filtration is high.
A ceiling mounted fan system should be mounted to reduce stratification in the room. The heat collecting in the ceiling will be re-distributed to the floor level.
The fans are variable speed, and can change speed based on the difference in temperatures at the two heights. This will reduce fan electricity use compared to full-speed operation.