[Equest-users] sequencing chillers using Equipment Controls

[Daric Adair]

Chris;

The issue is not with Equipment Controls but with the Water Side economizer ‘chiller’.

I thought the water side economizer was an all or nothing element, so your mention of Equipment Controls gave me hope that someone had found a way around this limitation. But I’m afraid it wouldn’t appear that’s true.

Per the Help files ‘ Volume 2: Dictionary<mk:@MSITStore:c:\eQUEST%203-65%20Data\Help\DOE22\DOE-2.chm::/Docs/volume2dictionary.htm> > HVAC Components<mk:@MSITStore:c:\eQUEST%203-65%20Data\Help\DOE22\DOE-2.chm::/Docs/hvaccomponents.htm> > CHILLER<mk:@MSITStore:c:\eQUEST%203-65%20Data\Help\DOE22\DOE-2.chm::/Docs/chiller1.htm>’  and ‘Chiller Water-Economizer’ :
The program assumes a water-side economizer is used in an “all or nothing” mode. If the water-side economizer can handle the entire cooling load, then it will be used. Otherwise, the loop will use its other chillers. A water-side economizer cannot precool the return flow prior to entering the chillers.

The “all or nothing” mode precludes the use of an EQUIP-CTRL sequence to coordinate the operation of an economizer chiller with other chillers. If you list a water-side economizer chiller in an EQUIP-CTRL sequence, it will be ignored.
…

So, Sad day. Super creative – which is awesome and exciting. But can’t do it. bummer


Thanks,
DARIC R ADAIR PE, CEM, BEMP
Mechanical Engineer, Energy Analyst

Henderson Engineers
Tel (913) 742-5530
daric.adair at hendersonengineers.com<mailto:daric.adair at hendersonengineers.com>

Licensed in KS

From: Chris Hadlock <cjhadlock at gmail.com>
Sent: Tuesday, October 23, 2018 4:05 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] sequencing chillers using Equipment Controls

Hi All,

I'm using eQuest version 3.65 and am having trouble with sequencing my chillers - I've combed through the archives but haven't found anything that has helped.

I have 3 chillers in my model, a water-side economizing chiller and two air-cooled scroll chillers. I would like to control them such that my WS economizing chiller runs up to a certain capacity only (175 Tons = 2.1 MBtu/h). Without any controls, eQuest is ignoring the capacity I have entered, and is meeting my building's entire cooling load. Beyond the 2.1 MBtu/h, I would like my 2 other chillers to run to meet the remaining load.

I've created an Equipment Control (and selected it on my CHW loop) that has my WS Econo Chiller as sequence no. 1 with a max load of 2.1 (I believe units of MBtu/h). Then I have my other chillers as sequence 2/3 and left max loads as "999". I've played around with the "Max Load" values and also the "Loads Through" value and nothing I do changes the outcome. Is anyone able to help me figure out why eQuest is not capping my WS Econo Chiller at the 2.1 MBtu/h and why it continues to meet the entire cooling load (with a peak approaching 4 MBtu/h)?

Thank you in advance.

---
Chris Hadlock, M.A.Sc<http://m.a.sc/>., P.Eng, LEED AP BD+C
Founder & Senior Energy Consultant

HADLOCK CONSULTING
201 Candlewood Cr
Waterloo, ON N2L5T3
tel: (519) 804-1223
cel: (226) 343-5599
www.hadlockconsulting.ca<http://www.hadlockconsulting.ca/>

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