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[EnergyPlus_Support] Re: Electric Chiller: air cooled
Hi Richard,
I checked that out and I am still getting all the same problems.
I've subbitted the file called in CC.idf to the problems submittals
section. I really appreciate the help.
Kind regards
-Elmer
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad
<RRaustad@...> wrote:
>
> Even a constant volume plant should shut down when there is no
call for
> cooling. Are you sure there is no flow through any of the cooling
coils?
> Is the demand side bypass pipe flow rate EQUAL to the supply side
flow
> rate at these times? If there is no flow through any cooling coils
and
> the demand bypass is equal to the supply flow rate (these are the
first
> checks to be verified), then submit your file to the EnergyPlus
Support
> Group for further study.
>
> Elmer Morrissey wrote:
>
> > Hi,
> >
> > That makes sense. I had a constant volumetric flow rate, so even
> > though the unit was not required to do any work (the cooling
coil's
> > operations was never requested), the system WAS requesting 7C at
the
> > outlet of the loop year round.
> >
> > I scheduled this loop to off during the winter months. This took
> > care of the errors however I noticed that there is still a flow
> > through the system!!!? Any idea why this would remain operating?
> >
> > However, I still have two issues with the system.
> >
> > (1) In the summer, the system is not pulling the cooling coil air
> > outlet node temp to 12C. It gets close, but never all the way
during
> > peak times. The system if fully autosized..
> >
> > (2) The .err file says that "Loads Initialization did not
Converge
> > (CheckWarmupConvergence)"
> >
> > I've tried increasing the warmup days to 40 but this doesn't
seem to
> > have an effect.
> >
> > Kind regards
> >
> > -Elmer
> >
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad
> > <RRaustad@> wrote:
> > >
> > > The message is warning you that an "air cooled" chiller is
> > operating
> > > when outdoor temperatures are below 0C. This type of operation
> > could
> > > freeze the chiller barrel and damage the unit. Good thing it is
> > only a
> > > simulation. What type of loads are in your building that
require
> > cooling
> > > when it is 0C outside? How about scheduling you chiller off in
the
> > > winter and using an economizer.
> > >
> > >
> > > Elmer Morrissey wrote:
> > >
> > > > Hello all,
> > > >
> > > > I'm am getting the following error from an electric chiller
(air
> > > > cooled) which supplies the cool water at 7C for the cooling
coil
> > in
> > > > the AHU...
> > > >
> > > > ElectricChillerModel:Air Cooled Condenser Inlet Temperature
> > below 0C
> > > > continues
> > > >
> > > > Can anyone point me where I would remove this error?
> > > >
> > > > My chiller definition looks like this
> > > >
> > > > CHILLER:ELECTRIC,
> > > > Z1:Plant1, !- Chiller Name
> > > > AIR COOLED, !- Condenser Type
> > > > autosize, !- Nominal Capacity {W}
> > > > 3.2, !- COP
> > > > Z1:Plant1In, !- Plant_Side_Inlet_Node
> > > > Z1:Plant1Out, !- Plant_Side_Outlet_Node
> > > > ZC1:Plant1In, !- Condenser_Side_Inlet_Node
> > > > ZC1:Plant1Out, !- Condenser_Side_Outlet_Node
> > > > 0, !- Minimum Part Load Ratio
> > > > 1, !- Maximum Part Load Ratio
> > > > 0.65, !- Opt Part Load Ratio
> > > > 35, !- Temp Design Condenser Inlet
{C}
> > > > 2.778, !- Temp Rise Coefficient
> > > > 6.67, !- Temp Design Evaporator
Outlet {C}
> > > > autosize, !- Design Evaporator Volumetric
> > Water
> > > > Flow Rate {m3/s}
> > > > autosize, !- Design Condenser Volumetric
Water
> > > > Flow Rate {m3/s}
> > > > 0.9949, !- Coefficient1 of the capacity
> > ratio
> > > > curve
> > > > -0.045954, !- Coefficient2 of the capacity
> > ratio
> > > > curve
> > > > -0.0013543, !- Coefficient3 of the capacity
> > ratio
> > > > curve
> > > > 2.333, !- Coefficient1 of the power
ratio
> > curve
> > > > -1.975, !- Coefficient2 of the power
ratio
> > curve
> > > > 0.6121, !- Coefficient3 of the power
ratio
> > curve
> > > > 0.03303, !- Coefficient1 of the full load
> > ratio
> > > > curve
> > > > 0.6852, !- Coefficient2 of the full load
> > ratio
> > > > curve
> > > > 0.2818, !- Coefficient3 of the full load
> > ratio
> > > > curve
> > > > 5, !- Temp Lower Limit Evaporator
> > Outlet
> > > > {C}
> > > > ConstantFlow; !- Chiller Flow Mode
> > > >
> > > > I've attempted reducing the design inlet temperature into the
> > > > condenser but it doesn't appear to be making a difference.
Also
> > the
> > > > cooling coil is not reducing the temperature of the outlet
air
> > > > stream to the desired temp of 12C. It gets close (13C) but
never
> > > > quite down there at peak times.
> > > >
> > > > I appreciate the help, kind regards
> > > >
> > > > -Elmer
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > The primary EnergyPlus web site is found at:
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> > > >
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> > > >
> > >
> > > --
> > > Richard A. Raustad
> > > Senior Research Engineer
> > > Florida Solar Energy Center
> > > University of Central Florida
> > > 1679 Clearlake Road
> > > Cocoa, FL 32922-5703
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> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
>
>
> [Non-text portions of this message have been removed]
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