air flow sizing

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Last post

Hi All,
The cfm for zone is sized based on room and supply air
temperature deltaT and room sensible heat load ie

similarly the cfm for the latent load is
cfm=RLHL(btu/hr)/(4840XdeltaW) Where deltaW is Ws-Wr ,Ws is humidity
ratio lb of water/lb of dry air of supply air at 55F and Wr is room
design humidity and RLHL is latent load in btu/hr

the total cfm should be sum of both due to deltaT and deltaW

But equest takes only due too sensible load because there is no where
option to input supply air humidity and room design humidity
then how it takes in account of cfm due to deltaW?


sambhav tiwari's picture
Joined: 2011-09-30
Reputation: 0

Hi Tiwari,

As per my knowledge there is no separate Cfm calculation for Latent load,
Latent load accounts in cooling capacity of AHU only(BY coil surface
temperature)i.e dehumidification takes place at coil itself.

Simply CFM calculated based on room sensible heat gain.


Uday Gorre's picture
Joined: 2012-05-10
Reputation: 0