System Volume in HVAC

The total CFM that that your unit/system can supply/requires.

i read this in relating to a calculation for capacity of chemical dozing tank (chilled water system) .it was written that capacity of tank will be 1/1000 of the system volume.So in this regard the meaning of System Volume?

I see. Then this refers to 1/1000th of the total capacity of the chilled water system (you know, in gallons per minute (GPM) or liter per minute (LPM)). Do you have the chiller data. If you don't, do you know the pipe size of the mean supply header. One can make a reasonable estimation from that as well.

as per my knowledge.2.4gpm requires per ton of refrigeration.so we can easly calculate the total gpm.and i have main supply header size also.and i have chiller details also.so how to calculate from these information the system volume.

What I feel you are interested in system volume and not system flow. SYSTEM VOLUME is simply the volume occupied by the working fluid in the system,be it chilled water,hot water or air. As such there is no formula or thumb rule to calculate it.You need to calculate fluid content in system piping,source equipments ,user-end equipments and so on as per your plan and schematic drawings for the system/project.Equipment manufacturers may give you some data while for while for piping some estimation may be made.

That is correct. You have to do a similar type of calculation when you have to size an expansion tank.

I'm in the same situation, trying to size an expansion tank, I am trying to calculate the chilled water volume connected to a RUP on the camus I'm working for. I have contacted the supplier but they have been particularly difficult to deal with, more than usual, and I have not been able to attain any information on Air Handler Units, I've already found volume for all the other components, so I was wondering, is there any mathematical formula or possibly rule of thumb to calculate or estimate the volume in gallons of an AHU? I have some design specifications for the units from the CD to use.