[Equest-users] Active Chilled Beam/Fan Coil System

[Grando, John]

Greg,

what the error message should say is that you need MORE THAN 6 degrees.  I simply changed your ECHWT to 55.9 so the approach was now 6.1 degrees and the simulation worked with the IU system.  I also changed your CHW DT to 6 degrees instead of the default 10 but I'm not sure whether eQUEST forces you to keep it at that number or not..


John Grando LEED AP| Mechanical Engineer





________________________________
From: Greg Collins [mailto:GCollins at glumac.com]
Sent: Friday, April 09, 2010 6:00 PM
To: Bruce Easterbrook
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Active Chilled Beam/Fan Coil System

Thanks to everybody for the interest and feedback so far..

Chilled water supply to the beams is 56F.

I've attached my inp and pd2 files in case anybody wants a closer look.

Greg

From: Bruce Easterbrook [mailto:bruce5 at bellnet.ca]
Sent: Friday, April 09, 2010 2:24 PM
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Active Chilled Beam/Fan Coil System

Maybe you are now running into what eQuest uses to prevent condensation on the chilled beam coil.  Condensation would be allowed in the FCU as it could/would have a drain tray.  Where the mixing takes place is important on the chilled beam.  eQuest should consider the mixing takes place after the coil and the warm humid air is entering the coil.  I would think eQuest would be set up to prevent condensation on the coil, you don't want water dripping out of the unit.  What is the temperature of your chilled water supply?
Bruce

On 09/04/2010 04:32 PM, Greg Collins wrote:
I have tried it, but I end up getting an error saying the leaving air temp off the coil needs to be at least 6F higher than the entering water temp to the coil, and for some reason I don't get the same error for the FCU.  In an active chilled beam, the coil is actually just cooling the room induction air, then mixing it with the primary air from the DOAS.  I think that equest assumes the air mixes before entering the coil, which fundamentally is the same thing, but the numbers trip this error message.  I'll look into more why the FC system doesn't make that happen, but the two seem to be essentially the same system except for the fan (which I make 0.000001 kW/cfm anyway).

From: Grando, John [mailto:JGrando at cosentini.com]
Sent: Friday, April 09, 2010 1:00 PM
To: Greg Collins; Bruce Easterbrook
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: RE: [Equest-users] Active Chilled Beam/Fan Coil System

Have you looked into SYSTEM TYPE = IU (Induction Unit).  This may be a better path to try.


John Grando LEED AP| Mechanical Engineer





________________________________
From: Greg Collins [mailto:GCollins at glumac.com]
Sent: Friday, April 09, 2010 2:00 PM
To: Bruce Easterbrook
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Active Chilled Beam/Fan Coil System
Bruce,

I agree with your theory and the justification, but the question is ultimately "how to model it?"  I don't think you can put in negative heat for a baseboard system, hook it up to a chilled water loop and get results you can count on.

Greg

From: Bruce Easterbrook [mailto:bruce5 at bellnet.ca]
Sent: Friday, April 09, 2010 8:59 AM
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Active Chilled Beam/Fan Coil System

    I'm not totally up on using DOAS with eQuest or with chilled beams being in Canada but it would seem to me the OA will have to be used to control humidity in the space.  The chilled beam should not be used for latent cooling, sensible only, to prevent condensation issues.  The DOAS will need to control the dewpoint of the room air and maintain it below the operating temperature of the coil in the chilled beam.  The chilled beam would only be dealing with the sensible load from the space.  The DOAS would do everything else.  The question would be will eQuest allow a single zone AHU c/w economizer and a baseboard system with negative heat?  I have never tried that with eQuest.
Bruce Easterbrook
Abode Engineering

On 08/04/2010 04:46 PM, James Hansen wrote:
I'm interested in this as well - I know that in DOAS systems like active chilled beams, the primary air often takes on a fairly large chunk of space latent cooling, and if this can't be passed on from the DOAS system to the space, then I don't see how we can believe the results.

GHT Limited
James Hansen, PE, LEED AP
Senior Associate
1010 N. Glebe Rd, Suite 200
Arlington, VA  22201-4749
703-338-5754 (Cell)
703-243-1200 (Office)
703-276-1376 (Fax)
www.ghtltd.com<http://www.ghtltd.com/>


From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Greg Collins
Sent: Thursday, April 08, 2010 4:39 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Active Chilled Beam/Fan Coil System

Hi all,

I'm working on modeling an active chilled beam system.  It consists of the chilled beams and a dedicated unit to provide primary air (mainly ventilation air) to the beams at 55 degrees.  I've modeled the chilled beam system as a fan coil system, but am wondering about my options for modeling the primary air.

My question is this:  If I attach the primary/ventilation air unit to the fan coil system in the FC's Outdoor Air tab under "Outside Air from System" will the temperature of the air coming from that unit have an impact on the load in the space?  I have a ton of hours at very low load during the winter months, and I want eQuest to use the 55 degree primary air as the first stage of cooling for the space and not "double up" the cooling energy by cooling the 55 degree air and then not use that for cooling in the zones.

If anybody has some input, it would be appreciated.

Greg Collins
Design Engineer / Energy Analyst
Mechanical Department
LEED(r) Accredited Professional

[cid:833194912 at 12042010-24DF]<http://www.glumac.com/>
________________________________
NOTE OUR NEW ADDRESS
18200 Von Karman Ave., Suite 100
Irvine, CA 92612
T.  949.833.8190  F. 949.833.0252

Thinking. Inside the building.
www.glumac.com<http://www.glumac.com/>

________________________________
The information contained in this communication is confidential, may be privileged, and is intended only for the use of the addressee.  It is the property of GHT Limited.  Unauthorized use, disclosure or copying of this communication or any part thereof is strictly prohibited and may be unlawful.  If you have received this communication in error, please notify me immediately by return e-mail or by e-mail to ght at ghtltd.com<mailto:ght at ghtltd.com>, and destroy this communication and all copies thereof, including all attachments.  Thank you.





_______________________________________________

Equest-users mailing list

http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org

To unsubscribe from this mailing list send  a blank message to EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG<mailto:EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG>



NOTICE OF CONFIDENTIALITY This E-mail message and its attachments (if any) are intended solely for the use of the addressees hereof. In addition, this message and the attachments (if any) may contain information that is confidential, privileged and exempt from disclosure under applicable law. If you are not the intended recipient of this message, you are prohibited from reading, disclosing, reproducing, distributing, disseminating or otherwise using this transmission. Delivery of this message to any person other than the intended recipient is not intended to waive any right or privilege. If you have received this message in error, please promptly notify the sender by reply E-mail and immediately delete this message from your system.


NOTICE OF CONFIDENTIALITY

This E-mail message and its attachments (if any) are intended solely for the use of the addressees hereof.  In addition, this message and the attachments (if any) may contain information that is confidential, privileged and exempt from disclosure under applicable law.  If you are not the intended recipient of this message, you are prohibited from reading, disclosing, reproducing, distributing, disseminating or otherwise using this transmission.  Delivery of this message to any person other than the intended recipient is not intended to waive any right or privilege.  If you have received this message in error, please promptly notify the sender by reply E-mail and immediately delete this message from your system.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100412/cccf87d1/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.gif
Type: image/gif
Size: 6582 bytes
Desc: image001.gif
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100412/cccf87d1/attachment-0002.gif>