Hi Afaan,

The first table below contains the sort of information you will need to
make a centrifugal EIR curve, but as David says you're lacking in the
minimum # of data points. I believe the bare minimum to extrapolate an
accurate bi-quadratic curve would require 9 rows of data (minimum 3
PLR's for a minimum 3 dT's), though you should probably use the maximum
number of data entry points permitted when allowing eQuest to determine
the coefficients (20 per curve).

dT is simply the difference between the chilled and condenser water
temps.

I'm not sure exactly what we're looking at in the second table, but it
doesn't look like data for creating a curve... If you want to make
CAP-FT and EIR-FT curves (and if you don't, that's okay too - see below)
you'll need a rep who understands and can provide you with "maximum
capacity" (not the designed capacity, or where PLR = 1.0) and power
drawn under different conditions. I've previously selected 5 CW temps
and 4 CHW temps around and including the design conditions being
normalized to, totaling the maximum 20 data entry points we're permitted
to input.

The attached email contains an overview of materials you should review
to understand the process of custom chiller curve creation (includes a
reference to the same EDR guideline David brings up below). Once you
feel comfortable understanding the required data collection described
towards the end of the referenced EDR chapter, you might do well to also
read through a fairly lengthy discussion on this list that I started:
"Chiller Curves (oh boy!)." There, I eventually provided an
illustrated breakdown of each default curve and its
function/implications, eventually realizing and providing visuals of
their combined effects analogous to what equipment reps often provide
for "chiller efficiency curves." You should be able to follow this
discussion from start to finish, and should come away knowing exactly
what eQuest is doing "under the hood" moving forward. Carol Gardner
also provided a writeup within that discussion that is similar to the
EDR... oh I see she just posted it again =)!

One final suggestion: Your collected data suggests a possible pitfall -
if you want to make the CAP-FT and EIR-FT curves, you MUST gather data
for multiple CHW temps, even if the design should only ever call for 44
degree water to be produced. If you don't understand why, then honestly
you need further review of what the curves are functionally doing - see
suggested reading above and attached.

If you and your reps are struggling with producing the data required to
make CAP-FT and EIR-FT curves, it's advisable to stick with the
defaults, and ensure your custom EIR-fPLR&dT curve entries are all
normalized to ARI rather than a design condition.

Best of luck!

~Nick

NICK CATON, E.I.T.

Hi all,

I agree with all the strategies listed in these emails. HOWEVER, please do
not pass by the article I attached again today, and will attach to this
also.

This article was not written by me but rather by Steve Gates, the same guy
that writes and maintains the HVAC portion of eQUEST. I was working with a
client on chiller curves when the original Chiller Curves (Oh Boy!), thanks
Nick, chain of emails began. There was something about the EDR article that
bothered me and I talked to Steve about it. Steve, being nothing if not
thorough, read the article and wrote the new article with some amendments
and additions.

This article, the contents of the DOE2 Manuals and the EDR article should
provide you with everything you need to create chiller curves. I would
suggest reading all of them starting with everything in the DOE2 Manuals,
moving on the the EDR article and finishing with the Chiller Curves SDG,
etc., as it is, more or less, the final word.

Best,

Carol