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Re: [EnergyPlus_Support] No Chilled or Hot water flow through coils.
It is hard to say at this point without seeing the current state of the input
file. The system appears to be a standard VAV system with chilled water and
hot water loops.
The next thing I would suggest is to make a copy of the input file, delete all
HVAC objects, and add a fully autosized system using COMPACT HVAC objects,
similar to example file CompactHVAC-5ZoneVAVWaterCooled.idf. If this functions
properly, then you may wish to take the expidf file and make further changes as
desired, but always keeping a trail to go back to a working file if it stops
working at some point.
Mike
On 24 Sep 2007 at 13:53, Wenshu Fan wrote:
> Thank you so much for your help.
> I have fixed the envelope problems and change the settings you mentioned in the
> SYSTEM SIZING. However, there still come out no flow through the pipe.
>
> In the error file, it has following result:
> ** Warning ** Check input. Calculated Pump Efficiency=9.97% which is less
> than 50%, for pump=HW CIRC PUMP
> ** ~~~ ** Calculated Pump_Efficiency % =Total_Efficiency % [8.7] /
> Motor_Efficiency % [87.0]
> ** ~~~ ** Total_Efficiency % =(Rated_Volume_Flow_Rate [9.0E-002] *
> Rated_Pump_Head [250000.0] / Rated_Power_Use [259500.0]) * 100.
> ** Warning ** Check input. Calculated Pump Efficiency=3.38% which is less
> than 50%, for pump=CHW CIRC PUMP
> ** ~~~ ** Calculated Pump_Efficiency % =Total_Efficiency % [2.9] /
> Motor_Efficiency % [87.0]
> ** ~~~ ** Total_Efficiency % =(Rated_Volume_Flow_Rate [3.0E-002] *
> Rated_Pump_Head [254072.6] / Rated_Power_Use [259500.0]) * 100.
> ** Severe ** Temperature out of bounds (-28268019.28) for surface=SOUTH-1
> ** ~~~ ** in Zone=EXTERIOR-1
> ** ~~~ ** Occurrence info=HOUSTON TX USA TMY2-12960 WMO#=722430,
> 07/03 09:00 - 09:01
>
> I really don't know what's the problem, cause the construction parameters in my
> input file is based on the architecture information I got from the building
> owner. Moreover, comparing with the example file, I can not find anything wrong
> with my control strategy. Is there any chance that anyone can help me? Thanks a
> lot.
>
> Wenshu
>
>
> On 9/14/07, Michael J. Witte <mjwitte@xxxxxxxx> wrote:
> >
> > More information from the developer. This should help get you going. MJW
> >
> > There is a program problem. It's coming from the System Sizing input.
> > Look at:
> >
> > SYSTEM SIZING,
> > AHU1, !- name of an AIR PRIMARY LOOP object
> > sensible, !- type of load to size on
> > autosize, !- Design (minimum) outside air volumetric
> > flow rate {m3/s}
> > 0.2, !- minimum system air flow ratio
> > 7.22222241354578, !- Preheat design set temperature {C}
> > 12.7777781162733, !- Central cooling design supply air
> > temperature {C}
> > 37.7777787785472, !- Central heating design supply air
> > temperature {C}
> > noncoincident, !- Sizing Option
> > yes, !- Cooling 100% Outside Air
> > yes, !- Heating 100% Outside Air
> > 0.008, !- Central cooling design supply air
> > humidity ratio {kg-H2O/kg-air}
> > 0.008, !- Central heating design supply air
> > humidity ratio {kg-H2O/kg-air}
> > design day, !- cooling design air flow method
> > 5.66400071906259E-04, !- cooling design air flow rate {m3/s}
> > design day, !- heating design air flow method
> > 4.72000059921883E-04; !- heating design air flow rate {m3/s}
> >
> > The program for some reason ignores the field "cooling design air flow
> > method" and looks only at
> > "cooling design air flow rate {m3/s}". If the latter is > 0 it uses it
> > as a user specified design flow rate.
> > Since this input is tiny (the actual number should be around 10 m3/s) it
> > basically zeros out the design flow rates. Ditto for heating.
> > Removing these numbers results in a more normal attempt at autosizing,
> > hampered by the lack of zone areas (no floors) in
> > 2 of the zones. My run then aborts with temperature out of range. Some
> > serious geometry problems I guess.
> >
> > On 12 Sep 2007 at 16:35, wenshufan1983 wrote:
> >
> > > I'm confused that there is no chilled or hot water flow through the
> > > coils. According to Micheal's email to me, I've checked all these below
> > > 1.ZONE CONTROL:THERMOSTATIC to request heating/cooling from the HVAC system.
> > >
> > > 2.The HVAC controls must request flow in the the coil - could be a VAV
> > > terminal unit with built-in controls for a reheat coil, or a
> > > CONTROLLER:SIMPLE with a
> > > SET POINT MANAGER:*.
> > >
> > > 3.The coils must be ACTIVE components on their branches.
> > >
> > > 4.The loop pump must be scheduled on (or the schedule omitted
> > completely).
> > >
> > > But there is still no flow in the report. Is any one by chance can
> > > help me out. My IDF file has been upload under Files:Problem
> > > Submittals:Gil_5.idf. Thanks
> > >
> > >
> > >
> > > The primary EnergyPlus web site is found at:
> > > http://www.energyplus.gov
> > >
> > > The group web site is:
> > > http://groups.yahoo.com/group/EnergyPlus_Support/
> > >
> > > Attachments are not allowed -- please post any files to the appropriate
> > folder
> > > in the Files area of the Support Web Site.
> > >
> > > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the
> > > Documentation link and press the "search" button.
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
>
> EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the
> Documentation link and press the "search" button.
>
> Yahoo! Groups Links
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
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