Cfm ------> gpm

[harsen]

Hai,
How to related the amount of air required for a room (CFM) into the chilled water flow rate (GPM)

[Brian_UK]

Hi Harsen, still reading and learning ?

Some data here...
http://books.google.com/books?id=ywv...yiBI8#PPA69,M1

Also copied this from another forum (hvac-talk)which may help..

For chilled water comfort cooling/dehumidification, have you ever seen chilled water entering a coil that is higher than 55 degrees be able to maintain a target indoor condition of, say, 75 degrees dry bulb @ 50% relative humidity? That's not going to happen. To reach this condition, the surface temperature of the cooling coil needs to be at least 55 degrees (dewpoint of target environmental condition of 75/50) or lower, and the entering chilled water temperature needs to be colder than that to assure a coil surface temperature of 55 degrees, say 42 to 45 degrees entering chilled water temp, with about a 10 degree rise across the coil at design load being common.

Therefore, if you know the CFM of your air handler, you can know the air side sensible cooling load by the equation 1.08 * CFM * delta T. For example, to keep the numbers small, let's go with 1.08 * 2000 * 20 = 43,200 (divided by 12000 = 3.6 tons). You now know how much heat you need to remove to meet target conditions at the given CFM, so it's a matter of finding the right GPM: 500 * 8.7 gpm * 10 degrees F delta T = 43500 sensible cooling BTUH.

Of course, other factors come into play, such as coil bypass, latent heat removal, etc. so coil sizing is likely done to accommodate these factors in addition to the sensible cooling load.

[Abby Normal]

GPM = total cooling (btu/hr)/ (500 x temperature differential)