[Equest-users] Active Chilled Beams, DOAS and geothermal system

[Fred Betz]

Jessica,

Using eQuest to model DOAS and chilled beams is highly problematic. I coauthored an IBPSA paper for SimBuild 2012 earlier this month that elaborates on this process. See session 10b for the paper titled, "Issues Arising from the Use of Chilled Beams in Energy Models".
http://www.ibpsa.us/simbuild2012/technical_sessions.shtml


Modeling any sort of complex plant system in eQuest is also problematic. I've never used the method described by Dana, but I'm skeptical about any complex plant controls in eQuest.

For complex plants we use TRNSYS, which is moderately difficult to use, but allows total flexibility for plant design. What we do is export hourly loads from eQuest and read those into TRNSYS. Modeling buildings in TRNSYS isn't the easiest task either so the combination of the two software is what we've settled on.

You can then create performance maps, stage equipment on/off, etc. I have used Multistack heat pumps based on performance maps I created with Multistack's data frequently within TRNSYS with promising results.

Unfortunately there aren't easy solutions to this type of modeling problem.

Good luck in your modeling efforts.

Fred


Fred Betz  PhD., LEED AP
Sustainable Systems Analyst



AEI | AFFILIATED ENGINEERS, INC.
5802 Research Park Blvd. | Madison, WI  53719

P: 608.236.1175 | F: 608.238.2614
fbetz at aeieng.com<mailto:fbetz at aeieng.com>  |  www.aeieng.com<http://www.aeieng.com/>



From: Miller, Jessica [mailto:JMiller at trojb.com]
Sent: Friday, August 24, 2012 7:36 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Active Chilled Beams, DOAS and geothermal system

Good morning,

The project I am working on has a geothermal water source heat pump system with back up boilers and fluid cooler.  We have a VAV unit serving the majority of core spaces and DOAS units serving chilled beams for perimeter spaces.

I am considering modeling the geothermal system after the multistack units in eQUEST described by Dana (http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/2011-February/007763.html) because the method I am currently using with the chillers set to LOOP-TO-LOOP-HP seems like it might not be the best way.  I also have problems attaching the fluid cooler to the system with this method (the simulation won't go past 18%).

I am modeling an active chilled beam system served by a DOAS.  I've been seeing both an IU and PIU system used.  Can anyone tell me which one they think is better?  And some tips they can give about using this method?  I've searched through the forums but some of the information seems like it is from a few years ago so I wanted to see if anyone made any more progress!

Any help is much appreciated!  Thank you!

Jessica K. Miller, EIT, LEED(r) AP
Associate
HVAC Engineering

TRO Jung|Brannen
22 Boston Wharf Road
Boston, Massachusetts  02210

t     617.502.3400
f     617.502.3401

www.trojungbrannen.com<blocked::http://www.trojungbrannen.com/>

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