[Bldg-sim] Chiller Curves & NPLV

Robby Oylear robbyo at rushingco.com
Tue Jan 22 15:48:46 PST 2008

Hi everyone,


I'm working on an energy model for LEED submission.  It's a high rise
office building with CHW and electric heat.  The baseline building is also
a centrifugal chilled water system with electric heat and from Table
6.8.1J it should have a COP of 6.1 & IPLV of 6.4.  COP is a straight
forward input into the chiller as an EIR, but up until now I had assumed
that eQUEST default curves handled the IPLV portion of the efficiency.
When I took a look at the hourly report for the chillers though, the NPLV
(calculated by the ARI 550/590-2003 equation) was 12.1, almost double the
value from the table.


In trying to match the NPLV requirement of 6.4 I tried to create an
EIR-FPLR performance curve.  I did this by inputting values of A, B, C,
and D in the ARI equation that would net a value of 6.4 and then using
these four values as inputs for a custom baseline performance curve.
However when I look at the hourly report the Corrected EIR is not what I
calculated.  From what I understand, Corrected EIR = EIR (input at the
chiller) * EIRFT * EIRFPLR, yet when I multiply the EIR * EIR-FT *
EIR-FPLR I get a value almost twice as large.  My EIR is input at rated
conditions, so there shouldn't be any conversion going on within the


My questions are:


1)       How do you achieve the required NPLV for an Appendix G baseline
building in eQUEST?

2)       What other factors besides EIR-FT & EIR-FPLR affect the Corrected


Robby Oylear

Project Engineer

direct: 206.788.4571

cell: 206.354.2721

 <http://www.rushingco.com/> www.rushingco.com

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