[Bldg-sim] Chiller Curves & NPLV

2 posts / 0 new
Last post

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
program.

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
EIR?

Robby Oylear

RobbyO's picture
Offline
Joined: 2010-11-03
Reputation: 0

Does appendix G mention the zone reheat temp to use for a baseline? Seems
like it should in G3.1.2.8. Should we use the reheat values for the
proposed design? What if the proposed system does not have reheat? I just
might not be seeing, please advise.

Kevin Kyte, LEED AP

Kevin Kyte's picture
Offline
Joined: 2011-09-30
Reputation: 0