TM52 Summer Elevated Air Speed

[ScottIES]

Where can I get the value for the summer elevated air speed when running the TM52 ?

0.8m/s-1 is in as standard, why?

[JohnM]

Hi Scott,

In case you missed it, see here.

John

[Wasted Energy]

I think what s3.6 of CIBSE TM 59 is now saying is that this should be set to 0.1 m/s unless there are ceiling fans present.

Wasted

[VirtualEngineer]

That's how I read TM59. Also TM52 refers to BS EN 15251 which says increased air speed may be used to compensate for increased temperatures when fans are controlled by occupants or other means eg Personal Ventilation systems. TM52 Figure 7 shows the BS EN graph of allowance for air movement when fans are under the control of occupants.

VEng

[RossThompson87]

Hi All,

Just picking up on the ceiling fans...

I have been asked in the past if these can be used to help pass TM52.

From experience on recent new builds, the air temperature and radiant temperature are very similar. So changing this elevated air speed variable makes very little difference on the operative temperature and TM52 results. (Particularly as IES limits the range to between 0.1 and 0.9 m/s.)

Hence "adding ceiling fans", made no noticeable difference to my model. However in some buildings they seem to make a big difference to the comfort level.

I think this is something that needs a CFD model, and isn't fully appreciated with operative temperature.

I'd be interested to know if there was a good way to use them to pass TM52 though.