HVAC Performance test. HELP!

[chiller man]

Dear friends, are there any hvac Engineers in the forum who can help me out here? In the late 80s I worked offshore on gas production platforms, part of the refrig contract was to carry out hvac perfomance testing. I feel a complete twonk,asking because Ive done it hundreds of times, However Ive forgotten the procedure and the math to get air change rates per hour, I know I used to record inlet velocity in mps, and work out the room total area but thats all I can recall, mind you, It was a long time ago,anyway, it may be needed again soon so if you can help, drop me a line. many thanks.

[Brian_UK]

Room volume is W x H x L, do in metric, eg 4m x 2.4m x 5m = 48 cu.m

Duct/grille size 0.25m x 0.3m = 0.075 sq.m

Air velocity in duct measured at 2.5 m/s

Air volume (air flow rate) = 2.5 m/s x 0.075 sq.m = 0.1875 cu.m/s

Flow rate per hour = 0.1875 x 3600 = 675 cu.m/h

AIr change rate = 675 cu.m/h / 48 cu.m = 14

I think

[chiller man]

Hello Brian, I think you have nailed it in one. Its all starting to make sense again. Sorry for delay in reply, been busy. I remain in your debt, Thankyou very very much.Now off to buy an anemometer,and thanks again.


****.

[Magoo]

Brian UK.
You are a legend. The only thing I would add is to use a hood arrangement when testing grille flow rate,so as to accurately check air volume.
magoo

[Brian_UK]

Thank you one and several, I will now sit in the corner with a warm beer