Default height of mechanical vent is beyond the height of the compartment

[mcgratta]

When I Add a Mechanical Vent, the default height is 2.75 m, which is higher the ceiling of the default compartment. The editor flags this as an error, which is good, but I wonder where the 2.75 m value comes from.

[rmcdermo]

I believe this is fixed, please check and close if so. Thanks

[mcgratta]

Yes, the height is now fixed, but the Vent Offset Y is 4 m by default when the room is only 2.4 m. Is it possible to make the Vent Offset be half the depth of the compartment?

Here is the namelist entry for the mechanical vent that I added:

!! Mechanical Ventilation
&VENT TYPE = 'MECHANICAL', ID = 'MechanicalVent_1', COMP_IDS = 'OUTSIDE' 'Comp 1', AREAS = 0.25, 0.25,
      HEIGHTS = 1.2, 1.2, ORIENTATIONS = 'VERTICAL', 'VERTICAL', FLOW = 0.02, CUTOFFS = 200, 300, OFFSETS = 0, 4,
      FILTER_EFFICIENCY = 0, FILTER_TIME = 0 /

I suggest that the OFFSETS for a vertical (wall) vent be (0,DEPTH/2) and for a horizontal (ceiling) vent (WIDTH/2,DEPTH/2).

[rmcdermo]

Please try latest.

[mcgratta]

The image below shows the default Ceiling/Floor vent. Its OFFSETs are 0, 0:

!! Ceiling/Floor Vents
&VENT TYPE = 'FLOOR', ID = 'CFVent_1', COMP_IDS = 'OUTSIDE' 'Comp 1', AREA = 1, SHAPE = 'ROUND', OFFSETS = 0, 0 /

I suggest that the OFFSETS for a ceiling vent should be half the WIDTH (x direction) and half the DEPTH (y direction).

The default OFFSETS for the Mechanical vent are good:

[mcgratta]

Here is case that you can work with:

&HEAD VERSION = 7600, TITLE = 'CFAST Simulation' /
!! CFAST input generated by CEdit 8

&TIME SIMULATION = 3600, PRINT = 60, SMOKEVIEW = 15, SPREADSHEET = 15 /
&INIT PRESSURE = 101325, RELATIVE_HUMIDITY = 50, INTERIOR_TEMPERATURE = 20, EXTERIOR_TEMPERATURE = 20,
      INTERIOR_O2_MASS_FRACTION = 0.23, EXTERIOR_O2_MASS_FRACTION = 0.23 /
&MISC ADIABATIC = .FALSE., LOWER_OXYGEN_LIMIT = 0.15, MAX_ITERATION = -1, OVERWRITE = .TRUE.,
      SPECIFIC_EXTINCTION = 8700, 4400 /

!! Compartments
&COMP ID = 'Comp 1', DEPTH = 2.4, HEIGHT = 2.4, WIDTH = 3.6, ORIGIN = 0, 0, 0, GRID = 50, 50, 50,
      CEILING_MATL_ID = 'OFF', 'OFF', 'OFF', CEILING_THICKNESS = 0, 0, 0, WALL_MATL_ID = 'OFF', 'OFF', 'OFF',
      WALL_THICKNESS = 0, 0, 0, FLOOR_MATL_ID = 'OFF', 'OFF', 'OFF', FLOOR_THICKNESS = 0, 0, 0, HALL = .FALSE.,
      SHAFT = .FALSE., LEAK_AREA_RATIO = 0, 0, FLOW_COEFFICIENT = 0.07 /

!! Wall Vents
&VENT TYPE = 'WALL', ID = 'WallVent_1', COMP_IDS = 'Comp 1' 'OUTSIDE', BOTTOM = 0, HEIGHT = 2, WIDTH = 1,
      FACE = 'FRONT', OFFSET = 2 /

!! Ceiling/Floor Vents
&VENT TYPE = 'FLOOR', ID = 'CFVent_1', COMP_IDS = 'OUTSIDE' 'Comp 1', AREA = 1, SHAPE = 'ROUND', OFFSETS = 0, 0 /

!! Mechanical Ventilation
&VENT TYPE = 'MECHANICAL', ID = 'MechanicalVent_1', COMP_IDS = 'OUTSIDE' 'Comp 1', AREAS = 0.25, 0.25,
      HEIGHTS = 1.2, 1.2, ORIENTATIONS = 'VERTICAL', 'VERTICAL', FLOW = 0.02, CUTOFFS = 200, 300, OFFSETS = 0, 1.2,
      FILTER_EFFICIENCY = 0, FILTER_TIME = 0 /

!! Fires

!! Fire Properties

&TAIL /

[rmcdermo]

Should be fixed with PR #2496