[Equest-users] baseboards activating when zone is already above heat setpoint?

Nicholas Caton Nicholas.Caton at se.com
Thu Aug 27 11:53:09 PDT 2020 

Ah – fair point Erik!

The RESET-RATIO schedule type is intended to allow for a scaling of the baseboard output in relation to OADB, and that certainly could a degree of functionality you don’t truly need.  If you do need (only) seasonal ON/OFF availability control, that’s probably more simply/intuitively accomplished with a schedule on a baseboard loop, oftentimes.

That said, I’ve perhaps “misappropriated” the RESET-RATIO scheduling option, above and beyond its intended functionality, to solve the simulation of a variety of baseboard operational situations.  You can for example:

  *   Set up a RESET-RATIO DAY schedule to scale its output between a factor of 0.0 and 0.0 (not a typo) to effectively make the baseboard unavailable for a certain portion of the year, then use a “normal” day schedule scaling up to 1.0, for the times it’s supposed to be active.
  *   Set a minimum turndown of something like 0.2 or 0.5 to explore and simulate the reality of stuck/leaky valves that result in the introduction of heat independent of ZONE comfort needs (sometimes generating unmet hours and/or simultaneous heating/cooling).
  *   Tightening the temperature thresholds on a DAY schedule (i.e. 55.0 Low and 55.1 High) can effect a binary “ON/OFF” availability, similar to SNAP scheduling.  This is sometimes a more appropriate reality for baseboard thermostatic valves than a gradual introduction of HW flow over a range of temps.
  *   You can if needed layer any of this with parallel scheduling on the baseboard loop to capture independent boiler scheduling and/or circulation loop valve controls.
  *   It’s appropriate to note – this flexibility/granularity of baseboard operational behavior can sometimes toe or cross the line of “more than the modeler can know/measure.”  Keep that perspective in mind to temper your presented findings and personal expectations, as you leverage these techniques to explore building system behavior and energy savings opportunities.


So granted, a RESET-RATIO schedule may end up being a case of hammering a nail with a wrench in some contexts… but it’s a relatively flexible tool to get the job done for a variety of real-world circumstances.  This might also be the case of “when all you have/know is a hammer, then every problem looks like a nail.”

~Nick

[cid:image002.jpg at 01D67C79.62603E90]
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:image003.png at 01D67C73.2BBBA790]


From: Erik Kolderup <erik at kolderupconsulting.com>
Sent: Thursday, August 27, 2020 12:39 PM
To: Nicholas Caton <Nicholas.Caton at se.com>
Cc: Matthew Yarmon <matthewy at fastmail.com>; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] baseboards activating when zone is already above heat setpoint?


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I suggest removing the baseboard schedule. It is supposed to be used only when baseboard output is controlled based on outdoor temperature, independent of zone temperature. So leave the baseboard schedule as "undefined" and set the zone control to "thermostatic". Does that work?

-Erik

Erik Kolderup, PE, LEED AP
erik at kolderupconsulting.com<mailto:erik at kolderupconsulting.com> | 415.531.5198 | www.kolderupconsulting.com<https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.kolderupconsulting.com%2F&data=02%7C01%7CNicholas.Caton%40se.com%7Cfb330d18c8714a6d68f008d84ab00d8c%7C6e51e1adc54b4b39b5980ffe9ae68fef%7C0%7C0%7C637341467287928140&sdata=Hm3wukatGqwrneRmZVX%2Ff1VNjnP1KPHKZXrSpoQkqqs%3D&reserved=0>


On Thu, Aug 27, 2020 at 10:34 AM Nicholas Caton via Equest-users <equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>> wrote:
Hi Matthew!

A couple thoughts:

  *   Baseboard operations can be specified at both ZONE and SYSTEM levels.  I’m not entirely sure (intuition alone) which takes precedent if you have both.  You may want to review what is entered at the SYSTEM level under the heating tabs… that could explain the delivery of heat at a time when the zonal temp conditions do not warrant the baseboard’s operation.
  *   Regardless, applying a schedule to the baseboards (and/or baseboard loop, if you have that set up as a distinct loop in the hydronic tab) can probably override this behavior by making the baseboards only available when seasonally appropriate (by calendar) and/or by utilizing an OADB snap temperature threshold to limit baseboard heating availability.
  *   An error popping up in application of a schedule is possibly what it’s saying on the tin: the schedule may simply an incompatible type (the only valid option for BASEBOARD-SCH is RESET-RATIO)… but sometimes the eQuest interface is just behaving badly.  If you’re uncertain the schedule (annual/week/day schedules inclusive) are of an appropriate/compatible type, then I’d advise starting from scratch by first loading in a compatible library schedule, and adjusting from there.  If you are confident the schedule is of the correct type, then I might try “forcing” this assignment by saving a separate copy of your project, closing eQuest, adding the appropriate assignment to 1 zone via the INP file in a text editor of your choosing, then opening that modified project to see if it “sticks.”  If so, then you may likely be able to proceed with assigning that schedule to the remaining zones as appropriate.
  *   Might be worth noting, if you want to control baseboard heating availability at the circulation loop level, you’ll have a couple few more viable options in terms of schedule type.

I hope this is helpful!


~Nick



[cid:image004.jpg at 01D67C73.2BBBA790]
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:image003.png at 01D67C73.2BBBA790]


From: Equest-users <equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>> On Behalf Of Matthew Yarmon via Equest-users
Sent: Thursday, August 27, 2020 12:16 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] baseboards activating when zone is already above heat setpoint?


[External email: Use caution with links and attachments]

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Hi all,

I hope you're able to see the image below. If not, I uploaded it here: https://imgur.com/a/WpQ8FSR<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2Fa%2FWpQ8FSR&data=02%7C01%7CNicholas.Caton%40se.com%7Cfb330d18c8714a6d68f008d84ab00d8c%7C6e51e1adc54b4b39b5980ffe9ae68fef%7C0%7C0%7C637341467287938144&sdata=ShNvZFxPIwqGsioi5uN5Miz56dzs%2F2MsC7jZSWBQl00%3D&reserved=0>   It shows eQuest 'hourly results', specifically it shows a warm day in the year, July 3rd, for a model I'm looking at.

In my model, from 1pm-4pm on July 3rd, the heating setpoint is 71 °F (grey column), cooling setpoint is 76 °F (blue).  Outdoor temp is ~84 °F (orange), zone temps are ~75-77 °F.  The question is, why are my baseboards (yellow column) activating and heating the zone?  The temp in the zone is above the heating setpoint, so the baseboards should not be turning on.

The baseboards are set to 'thermostatic' control.  I've been unable to set  baseboard schedule (see 2nd screenshot below - if anyone has a suggestion for this problem, I'd love to hear it).  But regardless of the schedule, if the zone heat setpoint is 71 °F, and zone temp is above 74 °F, why are baseboards turning on?

Cheers,
Matthew
[cid:image005.png at 01D67C73.2BBBA790]

[cid:image006.png at 01D67C73.2BBBA790]

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