[Equest-users] [BLDG-SIM] Active Chilled Beam Model

[Vikram Sami]

Apologies for raking up the past, but I'm trying to model a chilled beam
in EQUEST and have a  follow up question. If you use the Induction unit
model (see diagram below), why do you need an OA-from system? Doesn't it
allow you to run and control outside air within the system?

 

 

 

 

-----Original Message-----
From: BLDG-SIM at GARD.COM [mailto:BLDG-SIM at GARD.COM] On Behalf Of Graham &
Megan
Sent: Wednesday, September 13, 2006 5:17 PM
To: BLDG-SIM at GARD.COM
Cc: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Active Chilled Beam Model

 

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

> >

> >  =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3DYou received
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