[Equest-users] Zones with Insufficient Heating Capability

[Haberl, Jeff]

Hello Chad:

Sounds like you've got yourself in a pickle. Although you only have 24 zones, you don't know which one is causing the trouble. However, the key thing to remember is that this is a simulation that follows specific rules. So, it may or may not represent the building you're simulating.

I'd start by resetting all systems back to SYSTEM = SUM and see if this works. What you'll have at this point is the loads on the systems, but not the system reactions themselves. If this doesn't work then you have an issue with your zone assignments or space loads. If it does work, then you can add back into the simulation each system, one at a time, until you find the offending system. Remember to let DOE-2 autosize.

Or, you could just us a VAV for all 24 zones and see if this works...then go back to separating it out the systems.

Jeff


Jeff S. Haberl, Ph.D., P.E.inactive, FASHRAE, FIBPSA               We are like fluttering leaves on the branches of trees

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Texas A&M University                                                                  we could lift the earth up to be a better place.  JSH 2022

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________________________________
From: Equest-users <equest-users-bounces at lists.onebuilding.org> on behalf of Chad Langille via Equest-users <equest-users at lists.onebuilding.org>
Sent: Tuesday, September 5, 2023 7:53 PM
To: equest-users at lists.onebuilding.org <equest-users at lists.onebuilding.org>
Subject: [Equest-users] Zones with Insufficient Heating Capability

Hi All, I’m working on a multi-level recreation building with VRF serving offices on each floor and packaged RTUs with DX cooling/furnace heating serving large open convention spaces per floor. I ran into this issue without changing anything
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Hi All,



I’m working on a multi-level recreation building with VRF serving offices on each floor and packaged RTUs with DX cooling/furnace heating serving large open convention spaces per floor.



I ran into this issue without changing anything in my model, besides adding some exhaust fan information to a handful of zones:



This box pops up:



[cid:image001.png at 01D9E01F.9E4BDC40]



“Error: 1 standard file writing errors encountered”



The simulation does not run, and in the Detailed Simulation Output File, 24 zones have the following warning:



**WARNING**********************************************************************

             ZONE E2 Core Zn (G.C10)

             might have insufficient heating capability.

             Check that the SYSTEM or ZONE HEATING-CAPACITY plus this

             ZONEs BASEBOARD-RATING is adequate to maintain the ZONE

             specified DESIGN-HEAT-T for the calculated peak ZONE load

             (see LS-A or LS-B for the ZONE peak load.)



I increased my throttling rage from 2 to 6 degrees, tried increasing my Heating Control and Reset Zone Entering Max Supply Temp from 90 to 105 degrees under Zone Heating, Coil Cap / Control, tried forcing previously greyed-out n/a to 50 degrees for reheat delta T, and tried changing thermostat to Reverse Action. No change and I’m out of ideas. Any assistance would be greatly appreciated!



Thank you,



Chad


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