[Equest-users] eQuest - District Steam/CW Meters

Thu Dec 12 11:28:07 PST 2019

Hmm...

You seem to be describing a 2-pipe system in reality, with district/campus loop HX's diverted/engaged via 3-way valve depending on whether predominant heating vs. cooling mode?

I'm running with this markup of a 2-pipe FC system in my mind, so that we're on a similar wavelength:
[cid:image009.png at 01D5B0EF.FAA64290]

The vol2 dictionary entry for CIRCULATION-LOOP includes the following for TYPE = WLHP:
[cid:image002.png at 01D5B0E9.42B51590]

That last, highlighted line suggests we should be able to attach a CHW and/or HW/Steam Meter... but indeed eQuest interface throws an "incompatible type" error when trying to attach these components.

eQuest interface does provide this on right-clicking the circ-loop selection dropdown for a CHW-METER:
[cid:image006.png at 01D5B0EA.31AB8DA0]

The loop assignment dropdown for an airside HP system helps us source the following from the reference volumes.  The highlighted line seems to seal the deal in that there may not be a way to bridge these components:
[cid:image008.png at 01D5B0EA.31AB8DA0]
All that's to say - you aren't crazy, and if you're missing something so am I.

In lieu of a direct fix, I'll volunteer that I was attempting to simulate DES systems for years before realizing that CHW and Steam/HW meters were a thing... which is to say there are workarounds!

  1.  In this instance, I'd stick with a WLHP and tower/boiler as the wizards spit out a WLHP system:
[cid:image007.png at 01D5B0ED.3B7AF7F0]

  1.  ... then just make the heat rejection and heating equipment "magically efficient" so that they do not contribute meaningful energies to your electric/fuel meters.
  2.  ... then tweak the associated pump power and operating inputs for this loop to match those of the real-world 2-pipe circulation.
  3.  Alternative A
     *   Set up some custom reports to track Btu's delivered/rejected (for free) on the WLHP loop
     *   You can then use those custom outputs in combination with your district/campus steam/CHW rates in post-processing to work out associated costs.
  4.  Alternative B
     *   Presuming fixed CHW/Steam rates per Btu added/removed from the WLHP loop, you could try to "flatten" the performance curves for the attached primary equipment, with the goal being to ensure the simulated input energies (electricity/fuel) to these components will always match the Btu's moved, 1 for 1.  Some trial and error testing is implicit here (I vaguely recall writing up a guide to this effect, but it would have been many years ago - might be worth a search).
     *   Then, you could use the native output reports from eQuest, with the understanding that the end use allocations for heat rejection and space heating may be mis-intepreted and will require conversion of units likely for use against your metered steam/CHW rates.

Neither alternative is particularly pretty/elegant, but I hope one of these workarounds will help get you over the finish line.

Perhaps with this thread on the record, we may see a future patch that unlocks loop type assignments for district meters?  Failing that, the reference manual apparently appears to require at least a little editing in this area for consistency.

~Nick

[cid:image005.png at 01D515A3.47EDD880]
Nick Caton, P.E., BEMP
  Senior Energy Engineer
  Energy and Sustainability Services
  Energy Performance Contracting
D
M
E

913 . 564 . 6361
785 . 410 . 3317
nicholas.caton at se.com<mailto:nicholas.caton at se.com>
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219

[cid:image006.png at 01D515A3.47EDD880]

From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Tom Mickley via Equest-users
Sent: Thursday, December 12, 2019 10:19 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] eQuest - District Steam/CW Meters

[External email: Use caution with links and attachments]

________________________________

Hello all,

Is there a way to use a district chilled water meter and a steam meter w/ HX as the source for water source heat pumps?  It looks like I'm only able to use those meters with HW, CW or 2-pipe loops.

Is there a workaround for this?

I am using 3.65 build 7173 with DOE 2.2

Thanks in Advance,

Tom

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