kW/Ton for typical older chillers 1

[KeepCool]

I am trying to work up a "quick and dirty" energy savings calculation that is based on industry average kW/Ton for older chillers and the vintage (year).

I know I have seen a list of typical kW/Ton for older air-cooled and water-cooled chillers but I can't seem to find it. Any ideas where I can find this info?

 

[aircond]

Hallo KeepCool,
You can try to calculate kw/ton from your old chiller logsheet data,
kw=ampere x voltage x cos phi
ton=gpm x chilled water temp.diff (in/out chiller)

in one day operation you can see in logsheet that your ampere chiller will be varried according to the load and chw temp difference as well.

 

[aircond]

what I mean is ton=gpm/chw temp diff(in/out chiller)

 

[KeepCool]

I am trying to build a calculation that would allow the users to enter the vintage of the existing chiller and then estimate energy savings by going with a new efficient chiller so I don't have the luxury of delta T or amp readings. It is a real rough calc and I am having problems finding historical efficiency data. The best source I can find are old ASHRAE standards.

 

[stevenw]

here are my "rule of thumb" for centrifugal chillers.

25 years old - 0.90
20 years old - 0.85
15 years old - 0.80
10 years old - 0.75
5 years old - 0.70
2 years old - 0.65

 

[poetix99]

stevenw,

Huhh!??

Did you somehow get this exactly sdrawkcab? (Sorry, that's "backwards&quot

 

[KenRad]

stevenw,

Your "rules of thumb" look about right to me, although the newer Trane centrifugals can do a lot better than .65 -- I have a couple of 700 ton units installed in the last 4 years that are .5 to .6 for most of the load range, and as low as .43 when doing condenser water reset (ie, lowering condenser water setpoint when outside conditions are mild).

---KenRad