Briefly to explore the performance of Roof terminals in the VE consider the following.
- Make sure you are in VistaPro.
- Pick a results file.
Select a target room:
- Set categories weather & room ON.
- Pick Dry bulb temperature (also consider wind speed & direction).
- Pick Operative temperature (TM52/CIBSE).
- Pick Macroflo internal vent (& Macrofo external vent if windows are utilised).
- Chart the results.
Fig 12: VistaPro – room results
- Use the calendar controls to drill down from the annual results.
- You can also pick a space or part of the Roof terminal move down a level, pick a door (damper or louvre) and plot the equivalent area or flow rate.
Fig 13: VistaPro – Roof terminal damper results
Select nothing:
- Select the Macroflo arrows tool icon.
- On the viewer icon bar pick X-Ray or wire frame effect.
- Use the calendar to zoom in to a period like a day and use the drag bar to animate the timesteps.
- Use the mouse over the view to change the viewpoint, orientation and zoom to better view the visualisation.
- The screenshot below shows each opening with two directional arrows drawn at the opening plane to show the sum of inward and outward airflow over the current timestep.
Fig 14: VistaPro – Macroflo arrows results
The next two images, for the same timestep, show Roof terminal performance with wind from the south (from the left of the image) firstly with a roof terminal (with low level inlets) and secondly the same roof terminal but with an opening window on the room south wall.
In the first image you can see the wind driving the air down and into the room via the south windward roof terminal quadrant and being drawn out of the other three quadrants:
Fig 15: VistaPro – Roof terminal (with low level inlets)
In the second image you can see the wind driven flow into the room greatly reduced in the south windward roof terminal quadrant as wind driven flow comes through the room so driving pressure is reduced. The airflow through the room via the window increases flow out of the east and west roof terminal quadrants. In this state the roof terminal acts mostly as an exhaust unit.
Fig 16: VistaPro – Roof terminal with opening room window
