[BLDG-SIM] Active Chilled Beam Model

[gems at spiritone.com]

This discussion has been very helpful to me since I have just been asked to model this system.  

For clarification, you are setting up a dummy space & zone served by a SZRH sytem, right Graham?  What does your outdoor air reset schedule look like?

I am also curious about Paul's statement that the induction ratio doesn't matter.  Have other people experienced this?  

Carol

Graham & Megan wrote:

> This is a good discussion, I am glad others are trying to find work arounds=
>  as the humidity control and central heating aspects are not straight forwa=
> rd.
> I am not fmailiar with the fan energy problems, but I am familiar with the =
> following:
> 
> 1) There is a lower limit on CHW DT across the chiller which I believe is 6=
> DegF.
> 
> 2) The OA-FROM-SYSTEM is the way to go in EQuest/2.2.  TAS, Apache and I su=
> spect other programs allow the heating / humidity control to be handled mor=
> e easily and accurtely but fall down on the waterside.
> 
> 3) The OA-FROM-SYSTEM cannot 'see' the zones you are passing the air to so =
> therefore off-coil temperatures cannot be directly controlled from the zone=
>  unless you replicate a dummy building that mimics your actual model's late=
> nt loads etc.
> 
> 4) Further to #3 the OA-FROM-SYSTEM cannot see the zone heating demands thu=
> s space heating must be local by baseboards or by a 4-pipe IU/FCU.
> 
> 5) Given above I have tended to se up my OA-FROM-SYSTEM as a SZRH system wi=
> th the cooling coil off-coil controlling to an outdoor air reset schedule t=
> o dehumidify and the zone heating coils reheating to maintain a minimum zon=
> e supply temperature (nominally 15C).  In Australia we use this configurati=
> on as we have warm to hot and humid climates with a small heating load in c=
> omparison to most North American climates.  In winter the central heating c=
> oil (zone coil in this case on a SZRH) would heat to satisfy zone of greate=
> st heating demand and other zones would recool.  Reheat and recool sounds i=
> nefficient but when the heating is done with CW heat recovery and periods o=
> f simultaneous heating and cooling are in cooler months when plant effciein=
> cy is at a maximum, the whole system is actually quite efficient.
> 
> 6) I then iterate on the outdoor air reset schedule and observe humidity le=
> vels in key zones to satisfy myself that I am getting space dewpoint contro=
> l.
> 
> 7) Ultimately with a chilled beam system that is most sensitive to space de=
> wpoint control this is still only a good approximation that is time consumi=
> ng to ensure it is right.
> 
> I mentioned last week that the EQuest/2.2 team could fix this up (IU system=
>  with no OA-FROM-SYSTEM, dewpoint contrl and central heaing / reheat) if th=
> e $ could be found - keep in mind we enjoy freeware.  Speaking with Jeff Hi=
> rsch over the years we aren't talking a lot of money but it is too much for=
>  me to justify paying 100%.  Anyone feeling generous or like me, frustrated=
>  at the time consuming work arounds, please contat Jeff and/or myself as th=
> is enhancement would extend the application of EQuest/2.2 dramatically (fro=
> m my point of view).
> 
> Regards,
> Graham Carter
> ----- Original Message -----=20
>   From: Paul Erickson=20
>   To: BLDG-SIM at GARD.COM=20
>   Cc: Eric.Yang at smithgroup.com=20
>   Sent: Wednesday, September 13, 2006 12:23 AM
>   Subject: [BLDG-SIM] Active Chilled Beam Model
> 
> 
>   Eric,
> 
>   As Peter stated, an induction unit can have a dedicated system supply sou=
> rce (for Trace it is OA; for eQUEST/DOE-2 you specify source...OA or rom a =
> chosen AHU).  The same is true with the fan coil unit.=20=20
> 
>   For DOE-2.2/eQUEST specifically, there are a few of snags that one runs i=
> nto.  One, the induction ratio doesn't really matter...play around and you'=
> ll see.  Two, DOE-2 doesn't seem to account for the fan energy used to pull=
>  off the CFM that goes to the beams...I'd love for someone to prove I'm wro=
> ng.  Three, I've had difficulties with loop temperatures and delta T for th=
> e loops...i.e. DOE-2 didn't seem to like the higher water temps going to th=
> e IU/FCU.  I'd like to hear feedback if someone else got around this.
> 
>   Trace had some similar drawbacks...I'll work on recalling them.
> 
>   Paul
> 
> 
>   >>> "Peter Simmonds" <peter.simmonds at ibece.net> 9/12/2006 8:48 am >>>
> 
> 
> 
>   Peter Simmonds Ph.D.
>   Associate
>   IBE Consulting Engineers
>   14130 Riverside Drive Suite 201
>   Sherman Oaks, CA 91423
>   p:   (818) 377-8220
>   f:    (818) 377-8230
>   m:  (818) 219-1284
>   IDEAS FOR THE BUILT ENVIRONMENT
> 
>   This e-mail message, including any attachments, is for the sole use of th=
> e intended recipient(s) and may contain confidential and privileged informa=
> tion. Any unauthorized review, use, disclosure, or distribution is prohibit=
> ed. If you are not the intended recipient, please contact the sender by rep=
> ly e-mail and destroy all copies of the original message.
> 
> 
> 
> 
> ----------------------------------------------------------------------------
>     From: Peter Simmonds=20
>     Sent: Monday, September 11, 2006 3:47 PM
>     To: 'Eric Yang'
>     Subject: RE: [BLDG-SIM] Active Chilled Beam Model
> 
> 
>     OK so you are talking about an active beam and not a static beam, right=
> . Then you need an outside air supply to be incorprated into the conditioni=
> ng system, so I guess the induction unit will suffice, just check the minmu=
> m turndown ratio and check the induction rate to match the profile of the a=
> ctive beam.
> 
>     Peter Simmonds Ph.D.
>     Associate
>     IBE Consulting Engineers
>     14130 Riverside Drive Suite 201
>     Sherman Oaks, CA 91423
>     p:   (818) 377-8220
>     f:    (818) 377-8230
>     m:  (818) 219-1284
>     IDEAS FOR THE BUILT ENVIRONMENT
> 
>     This e-mail message, including any attachments, is for the sole use of =
> the intended recipient(s) and may contain confidential and privileged infor=
> mation. Any unauthorized review, use, disclosure, or distribution is prohib=
> ited. If you are not the intended recipient, please contact the sender by r=
> eply e-mail and destroy all copies of the original message.
> 
> 
> 
> 
> --------------------------------------------------------------------------
>       From: Eric Yang [mailto:Eric.Yang at smithgroup.com]=20
>       Sent: Monday, September 11, 2006 3:40 PM
>       To: Peter Simmonds
>       Subject: RE: [BLDG-SIM] Active Chilled Beam Model
> 
> 
>       Thanks for your inputs.  How about the air which is induced into the =
> beams?   For example, I supply only 105 CFM per beam, but I will have aroun=
> d 300 CFM total supply air.=20=20
> 
> =20=20=20=20=20=20=20
> 
>       Eric
> 
> =20=20=20=20=20=20=20
> 
> 
> --------------------------------------------------------------------------
> 
>       From: Peter Simmonds [mailto:peter.simmonds at ibece.net]=20
>       Sent: Monday, September 11, 2006 6:36 PM
>       To: Eric Yang; BLDG-SIM at GARD.COM
>       Subject: RE: [BLDG-SIM] Active Chilled Beam Model
> 
> =20=20=20=20=20=20=20
> 
>       Very simple. Model the chilled beam as a fan coil for cooling only an=
> d remove the associated fan power.
> 
> =20=20=20=20=20=20=20
> 
>       Peter Simmonds Ph.D.
> 
>       Associate
>       IBE Consulting Engineers
> 
>       14130 Riverside Drive Suite 201
> 
>       Sherman Oaks, CA 91423
>       p:   (818) 377-8220
>       f:    (818) 377-8230
>       m:  (818) 219-1284
>       IDEAS FOR THE BUILT ENVIRONMENT
> 
>       This e-mail message, including any attachments, is for the sole use o=
> f the intended recipient(s) and may contain confidential and privileged inf=
> ormation. Any unauthorized review, use, disclosure, or distribution is proh=
> ibited. If you are not the intended recipient, please contact the sender by=
>  reply e-mail and destroy all copies of the original message.
> 
> =20=20=20=20=20=20=20
> 
> =20=20=20=20=20=20=20=20=20
> 
> 
> ------------------------------------------------------------------------
> 
>         From: BLDG-SIM at GARD.COM [mailto:BLDG-SIM at GARD.COM] On Behalf Of Eri=
> c Yang
>         Sent: Monday, September 11, 2006 2:34 PM
>         To: BLDG-SIM at GARD.COM
>         Subject: [BLDG-SIM] Active Chilled Beam Model
> 
>         Greetings
> 
> =20=20=20=20=20=20=20=20=20
> 
>         I am seeking for any suggestions or input on the model of active ch=
> illed beam system.   In my previous Trace model, it can not handle it very =
> well by induction system.  I am very curious to get inputs and helps from o=
> ther folks.   Thanks in advance.
> 
> =20=20=20=20=20=20=20=20=20
> 
> =20=20=20=20=20=20=20=20=20
> 
>         Eric=20
> 
> =20=20=20=20=20=20=20=20=20
> 
>         Eric Yang
> 
>         Mechanical Engineer, LEED.A.P.
> 
>         SmithGroup
> 
> =20=20=20=20=20=20=20=20=20
> 
>         1850 K Street, NW, Suite 250
> 
>         Washington, DC 20006
> 
>         t  202.974.4555 (direct)
> 
>         f. 202.974.4500
> 
>         eric.yang at smithgroup.com=20
> 
>         www.smithgroup.com
> 
> =20=20=20=20=20=20=20=20=20
> 
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