[BLDG-SIM] Active Chilled Beam Model

[Graham & Megan]

Yes connect the OA system to the dummy zone and the IU or FC system (using
OA-FROM-SYSTEM) to the actual zones.

Provided you set your primary air volumes (the usual practice) then setting
the induction ratio very high (10 is the limit I think) is inconsequential
for a passive chilled beam system.  DOE-2.2 doesn't care about the amount of
induced air, it cares about the beam output.  I believe the zone coils /
beams will deliver the output needed regardless of the room to mean wate
temperature difference.

Thinking this through there are two ways to go about this depending on your
heating configuration:
1) Use the IU system only (no OA-FROM-SYSTEM) and use an outdoor air reset
schedule to ge the space humidity control you desire.  The optimal reset
schedule is very climate sensitive.  You will need to try a few and you may
need to bound the results using cooling from one and heating from another
... This configuration relies on zone heating (baseboards or other) to
maintain space temperatures and thus does not worry about cold primary air
potentially overcooling space sor creating drafts.

2) Where you want to control the zone supply temperature above a minimum,
and thus place more cooling load onto the beams, then you need to resort to
teh OA-FROM-SYSTEM I described.  In this case I have set the off-coil
temperature to a constant (conservative) rather than a floating off-coil in
response to the space humidity.  You can't do the latter without a dummy
building that closely mimics space sensible and latent loads.  I then
sometimes dump teh hourly results to a spreadsheet (coil temperatures and
outputs and zone humidity ratios) and calculate an adjustment to adjust the
cooling and reheat.

Regards,
Graham

----- Original Message ----- 
From: <gems at spiritone.com>
To: <BLDG-SIM at GARD.COM>
Cc: <BLDG-SIM at gard.com>
Sent: Wednesday, September 13, 2006 4:33 PM
Subject: [BLDG-SIM] Active Chilled Beam Model


> 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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