[Equest-users] BEST PRACTICES: Wild Coils

Fri Jun 21 11:56:59 PDT 2019

Hey Nick,

TL;DR I usually play on the infiltration rate, bumping it higher as needed.

Something I've encountered a lot while working on Multifamily existing buildings in NYC, where you'll encounter most often than not steam systems, one or two pipe. The "wild" coil situation is exacerbated to unreal levels, because these systems are very old, out of tune, hard to balance, and the ancient knowledge of steam systems is getting lost.
Part of our audit checklist in the winter involved walking around the building to map the windows (usually no building plans exists...) and flag the ones that  were opened (you could get in the 30% easily even a deadly cold winter day. I've personally lived on a run down building when i first got to nyc and on a well below freezing point our windows were opened to avoid sweating to death: the good old "double-hung zone valve" was the only option we had).
We'd take space temperature readings (and ideally install sensors for a couple of weeks), to set the thermostat setpoints accordingly, and play with infiltration to match our understanding of how people reacted.

The opposite is true too though, I've seen people run their gas stoves with the door open as a supplemental space heater because it was too damn cold. The cooking gas account is more often than not separated from the boiler room one in nyc thankfully, so if you find a huge spike in the cooking gas bill in the winter (a HDD correlated component of your bill when you run a regression) it probably can't be explained by "people don't go out as much and stay in to cook".

Just my two cents/a rant, but i hope this sparks a conversation anyway :)

Y'all enjoy the weekend!

Best,
Julien
⁣--
Sent from a mobile device, please excuse the brevity.

Julien Marrec, EBCP, BPI MFBA
Owner

Direct: +33 6 95 14 42 13
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On Jun 21, 2019, 19:37, at 19:37, Nicholas Caton via Equest-users <equest-users at lists.onebuilding.org> wrote:
>Apologies for the cross-post, however I wanted to ask this question
>from 2 angles and I feel both communities may benefit from the
>discussion (if I can spark one).
>
>A common reality I've observed with "real-world" hydronic systems is
>that system coils and baseboard/radiator loops fall into a state coined
>wild coils.  Rather than modulating flow to maintain a measured supply
>air or room temperature setpoint, flow is uncontrolled.  A heating or
>reheat coil for example will end up dumping heat at all times the
>associated circulation loop is active, independent of its associated
>system's fan operation, cooling coil activity, or thermostat signals
>requesting more/less heating.  Occupants in response to wild coils,
>when they cay, will end up using windows, propping open doorways,
>plugging in local space heaters / circ fans, and generally suffering in
>terms of comfort.  In just about every case, this scenario presents a
>win-win in terms of improved occupant comfort potential in parallel
>with energy savings potential for whoever is paying the bills.
>
>Causes for this situation I've encountered more than once include:
>
>*   Manual Control valves left in an open state, with dusty cobwebs
>suggesting their presence is unknown to the occupants/building
>operators
>*   Automated valves (electric or pneumatic) which have become
>mechanically stuck in an open, or partially open position
>*   Automated valves (electric or pneumatic) which are otherwise busted
>due to upstream pneumatic line/system issues or mechanical failures of
>the moving parts at the valve
>*   A valve was never designed and/or installed and/or wired up for
>control in the first place
>
>
>For all of this however, I have always struggled in approximating the
>energy and comfort impacts of "wild" coils in my building energy
>simulations.  Quantifying this impact with some degree of confidence is
>difficult, but desirable in cases where I am calibrating to existing
>utility bills (read: always) and/or asserting the utility savings and
>comfort improvement impact for fixing/addressing such situations.
>
>For the [bldg-sim] family:  Are there any 3rd party tools, models, or
>other energy simulation platforms with explicit options for evaluating
>the comfort and energy impacts of wild coil situations?  Is there any
>research I could be pointed towards exploring this topic?
>
>For the [eQuest-users] crowd:  Can anyone share a best practice or
>recommendation for simulating this sort of problem-state within a
>doe2/eQuest model?  As far as I know, the native input options are
>essentially limited to a pair of "working" coil modulation states:
>TWO-WAY and THREE-WAY.  Here's an example doe2 reference entry, with
>language that repeats a couple times over for different scenarios:
>[cid:image003.png at 01D5281B.FBA76FA0]
>I personally have taken different approaches, with none being
>particularly satisfactory.  These have included introducing process
>loads onto the loops concurrently with "free" internal energy source
>definitions to get those losses dumped into the spaces experiencing
>discomfort.  I have also played with artificially bumping the
>thermostat schedules around to reflect measured, uncomfortable
>temperature states...
>
>Any solutions/experiences/shared-commiseration would be very welcome!
>
>~Nick
>
>[cid:image005.png at 01D515A3.47EDD880]
>Nick Caton, P.E., BEMP
>  Senior Energy Engineer
>  Regional Energy Engineering Manager
>  Energy and Sustainability Services
>  Energy Performance Contracting
>D
>M
>F
>E
>913 . 564 . 6361
>785 . 410 . 3317
>913 . 564 . 6380
>nicholas.caton at se.com<mailto:nicholas.caton at se.com>
>15200 Santa Fe Trail Drive
>Suite 204
>Lenexa, KS 66219
>United States
>[cid:image006.png at 01D515A3.47EDD880]
>
>
>
>
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