[Bldg-sim] Scroll Chiller

[W. Peter Anderson]

Not having looked too closely at the options, I would suggest not centrifugal.  

Centrifugals are almost always water cooled, have modulating capabilites from10% to 100% capacity, and generally dont go below 200 tons capacity.  They are positive displacment compressors and will follow the "fan laws", meaning there is a cubic relationship between energy used and cooling capacity (tons).  Similar to a centrifugal pump and fan.

Scrolls are (until the very near future) air cooled and on/off control.  They are staged.  You wont see them over about 150 tons total chiller size.  Part load capacity is pretty constant, in terms of kW/ton.  There are usually multiple stages.  At 50% load, half the compressors (therefore power requirement) is used.

Generally speaking, scroll IPLVs run about 1.1 kW/ton
water cooled centrifguals operate at around .50 kW/ton.  But cooling towers need to be added, as well as condenser water pumps.  

Lots of variables to consider.  

Hope this was helpful.

W. Peter Anderson, P.E
JP Engineering
41 Mechanic Street
Windsor, CT 06095
Ph: 860/688-5223
Fax: 860/688-5269


  ----- Original Message ----- 
  From: Eric Youngson 
  To: bldg-sim at lists.onebuilding.org 
  Sent: Monday, May 19, 2008 12:47 PM
  Subject: [Bldg-sim] Scroll Chiller


  SIM List,

                  I need to model a scroll chiller (. Does anyone have an opinion on which eQUEST chiller is a reasonable choice for this? I was thinking that centrifugal would be the closest but this is simply based on mechanical operation. I would like to choose the closest model based on performance.

   

   


       Eric Youngson 
       
       PAE Consulting Engineers, Inc. 
       
       503.226.2921 Main
        503.542.0567 Direct
        503.226.2930 Fax
        ericy at pae-engineers.com 
       
        Mechanical 
       808 SW Third Avenue - Suite 300
        Portland, OR 97204-2426
        www.pae-engineers.com 
       
        inspire  interpret  integrate 
       









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