DOE 2.3 Water-side Economizer in Series

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I'm working on a model which has two chillers in parallel with a water-side economizer in series to both of them; i.e. the economizer is 'upstream' and the chillers are 'downstream.'

I know DOE 2.2 will not allow this configuration to be explicitly modeled, but after some research, it appeared DOE 2.3 would (see page 83 of DOE 2.3 Manual).

When I get things setup (CHW Loop in SERIES, Chillers in DOWNSTREAM) the keyword to place the economizer UPSTREAM is unavailable, and the run errors out with "No upstream equipment specified."

I have attached the INP and PD2 file for reference. You may find it interesting in this model that I have more than one system assigned to a single zone (Thanks for adding this eQUEST team!).

Am I being overly optimistic about what DOE 2.3 can do, or am I missing something? Has anyone else tried to model this in DOE 2.3 and been successful?

Let me know.

Thanks,

[ARCH | NEXUS]
DAVID W. GRIFFIN II
BEMP
ENERGY ANALYST
2505 E Parleys Way
Salt Lake City, UT 84109
Office 801.924.5028
archnexus.com
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via Equest-users's picture
Joined: 2016-07-15
Reputation: 400

I gave the series chiller configurations a cursory overview a month or
so back when I first saw it in the documentation. I haven't tried
putting it to practice just yet myself.

A factor that's possibly in play: I think this is a case where the
engine (doe2.3) is presently a bit ahead of the interface (eQUEST), so
leveraging these series configurations will necessitate manual INP
additions/edits behind what eQuest can currently display & permit to
edit. Those inputs should stick around, but be mindful some actions in
eQUEST (such as removing & re-creating chillers/loops, or changing
types) could have the effect of stripping the associated inputs in the
INP - so it's something to keep an eye on. Perhaps reason enough to
push this towards the end of your development timeline.

I don't have the most-current version of 3.65 presently installed, so I
can't easily verify, but I think what you might need to do is to assign
your economizer chiller as "UPSTREAM" in the INP file - note the missing
CHW-SERIES-LOCN keyword present in the other two chillers:

There is some more explicit documentation regarding the new keywords and
inputs somewhere between the new 3.65's documentation and the "what's
new" PDF... I can't recall immediately but finding and reviewing that
against your INP is the natural next step.

Worth mentioning: I also am not terribly clear on how well the native
WATER-ECONOMIZER chiller works in the most current version, and whether
it has advanced beyond it's previous operational trappings... you may
want to monitor behavior carefully to be sure it's acting as you'd
expect in any case. As you might know I'm a proponent of "rolling my
own" waterside economizer chillers with load-management/sequencing for
more operational control... write-ups on procedure are floating about in
the archives ;).

Best of luck, and let us know how this shakes out!

~Nick

Nick Caton, P.E.

Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric

D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com

F 913.564.6380

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

via Equest-users's picture
Joined: 2016-07-15
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Thanks for the reply Nick!

I did a little more research and found that DOE 2.3 only allows the water-side economizer to be 'upstream,' so I don't need to explicitly state this as an input. Therefore, I switched my CHW Loop back to Parallel which operates my chillers appropriately, and the economizer will automatically operate 'upstream' from them. I'm now exploring the hourly reports to verify the loop's operation is actually doing what I want it to.

Fortunately, you may not have to 'roll your own' anymore.

I'll keep you posted.

[ARCH | NEXUS]
DAVID W. GRIFFIN II
BEMP
ENERGY ANALYST
2505 E Parleys Way
Salt Lake City, UT 84109
Office 801.924.5028
archnexus.com
[Twitter][Facebook][Youtube][LinkedIn]

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400