Chiller system total volume

[kmtswims]

I am trying to figure out how to size an expansion tank for a chiller system. I know all my gpm but I need the total system volume. Is there a quick and easy way to figure this out?? Are there charts out there that I can look at the Chiller tons and get a quick approximation of the total system volume???

 

[walkes]

Every system is different, you may have miles of piping in one system with distributed equipment, or all of your loads may be close to the chiller.

In short no quick ways. Spend the time to do it right.

 

[RossABQ]

A simple spreadsheet with the volume of each size of pipe on a per-foot basis, and a column to enter the length of each size, plus a table of all equipment volumes, will get you there. Make the s'sheet once, you'll have it for life. I wouldn't go overboard, tho; depending on the total size of the system, you can ignore a lot of the small diameter stuff (i.e., 1/2" around coils).

As an aside, once the system is being constructed, ask the Contractor if he has a Bill of Materials for the system. It's a useful cross-check of the amount of each size (but keep in mind they allow for waste).

 

[marcoh]

How long is a piece of string? or more accurately how long is a bit of pipe?

As a very rough rule of thumb, the minimum system water volume required is 3.5L/kWr and a stock standard commercial type building generally (but not always)seems comes in just a bit above this. As soon as you have a rough idea of the piping routes and sizes, it doensn't take long to do a quick estimate.

 

[atlas06]

A conservative figure:
Height (X=30'), length (Y=200'), width (Z=100'): you sum the two largest sides of the three = 300'in our example.

you multiply 300x4=1200'
multiply by volume per foot of largest pipe (say 4" main at 2.5 gallons/foot or whatever it is)
that's 1200x2.5=3000 gallons.
The above is used by Amtrol, check their rep for some quick sizing data.

Another way is that the average pipe in most buildings in 1.5" diameter (i'd use a 2" average anyway), you multiply gallons/foot of 1.5" pipe by your length, then add you coils and chiller volumes.

This is typically done when we want to have a quick and dirty cost estimate.

But ultimately, we go by volume for each pipe size plus coil and chiller volume for the 100% CD documents.