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[EnergyPlus_Support] Re: Combination of the OA unit system and Fancoil unit system

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Combination of the OA unit system and Fancoil unit system
From: "hbn_pch" <hbn_pch@xxxxxxxxxxxx>
Date: Fri, 21 Oct 2005 11:52:34 -0000
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Mike,i add the FPIU unit to my model just now .After simulation,it 
presented some warnings that i can't fix.

 1.   ** Warning ** SizeWaterCoil: Coil="1F_18_FPIU_CW_COIL", Cooling 
Coil has leaving humidity ratio > entering humidity ratio.
   **   ~~~   ** ..will be sized for 50% of design entering humidity 
ratio.

 
Some zones had such warning.I suspect that zone sizing for humidity 
ratio is referenced but i don't know how to correct it.I input the 
humidity ratio for cooling in zone sizing as 0.008 similar to 
examples.I'm 

 2.   ** Warning ** For COIL:Water:Cooling 1F_5_FPIU_CW_COIL
   **   ~~~   ** CalcCoilUAbyEffectNTU:Given Q impossible for given 
inlet states,Proceeding With MaxHeat Transfer

Some zones had such warings and i don't know what does it mean.I 
did't not encounter it before.

 3.   ** Warning ** Hot water coil control failed in 4 pipe induction 
unit 3F_20_FPIU
   **   ~~~   **   Iteration limit exceeded in calculating hot water 
mass flow rate

Just several zones had such warning,but each had many identical 
warning.


  I'm sorry for giving you so much trouble,but time will be out for 
my paper.Appreciated your kind help.
 
  thanks very much
  pch

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "hbn_pch" <hbn_pch@y...> 
wrote:
>
> Thanks very much,Mike.I will have a try according to your 
suggestion.
> 
>   pch
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
> <mjwitte@g...> wrote:
> >
> > If I understand the system correctly, this is very much like a 4-
> pipe induction 
> > unit.  There is central outside air which is preconditioned, then 
> this air is 
> > mixed with zone air and conditioned by heating/cooling coils in 
the 
> zone 
> > (fancoil unit).  I would recommend using SINGLE DUCT:CONST 
VOLUME:4 
> PIPE INDUC, 
> > see 5ZoneFPIU.idf example file.  In your case, the central unit 
is 
> 100% outside 
> > air.  EnergyPlus requires a return path in this case, even though 
> all of the 
> > "return air" will become "relief air" (exahusted) at the outside 
> air mixing 
> > box. (Note that HVAC Diagram is unable to draw this type of 
system.)
> > 
> > Mike
> > 
> > 
> > On 18 Oct 2005, at 11:01, hbn_pch wrote:
> > 
> > > Thanks for your response,Mike.According to your suggestion,i 
have 
> > > modified the model.Waiting and appreciated your further 
response.
> > > 
> > > Now i have a expanded issue for the model.In the original 
> model,the 
> > > oa unit supply air to the zone directly.In reality,i want to 
mix 
> the 
> > > oa system supply air and the zone exhaust air.The mixed air 
will 
> be 
> > > cooled/heated by fancoil unit and then supplied to zone.But i 
> don't 
> > > know how to connect the nodes.In fact,there is no return air 
for 
> the 
> > > oa unit.I'm puzzled.
> > > 
> > > I have a supposition that i can divided the model into two 
single 
> > > models.
> > >   The first:fancoil units serve zone only.In this case,i tried 
to 
> set 
> > > the outside air temp of the fancoil to 14(cooling supply temp)
or 
> 50
> > > (heating supply temp).It seems that the outside air of fancoil 
is 
> > > just the oa supply air.(In fact,there is no outside air 
specified 
> for 
> > > fancoil unit).The problem is that i can't find a approach to 
> specify 
> > > the fancoil outside air inlet temp.Can it be specified?
> > >   The second model:outside air unit serve zone only. 
> > > 
> > > Then i can combine the two models for analysis.I don't know 
> whether 
> > > it is available.If yes,how to specify the outside air inlet 
temp 
> for 
> > > the fancoil?If no,can you give me a correct approach?
> > > 
> > >   Thanks in advance.
> > >    pch
> > > 
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
> > > <mjwitte@g...> wrote:
> > > >
> > > > Whenever there is a sizing question, the first place to look 
is 
> in 
> > > the eio 
> > > > output file at the sizing reports.  One this to note (which 
is 
> not 
> > > discussed in 
> > > > the Input Output Reference) is that the sizing algorithms do 
no 
> > > know how to 
> > > > split loads between multiple systems.  Each system serving a 
> zone 
> > > will be sized 
> > > > to meet the full load of the zone.  For this system type to 
> work, 
> > > you will 
> > > > probably need to specify the supply air flow rate for one 
> system or 
> > > the other.  
> > > > Some issues I've noticed so far:
> > > > 
> > > > 1.  The coil component sizing report 
lists "COIL:Water:Cooling, 
> > > RESISTIVE 
> > > > ZONE_FANCOILCOOLINGCOIL, Design Air Inlet Temperature [C],   
> > > 13.000" and 
> > > > "Design Air Outlet Temperature [C],   14.000".  This is why 
the 
> > > coil water flow 
> > > > is sizing to zero.  The 13C inlet temperature is coming from 
> the 
> > > SYSTEM SIZING 
> > > > object - this appears to be a program error.  I will ask 
> someone 
> > > else to look 
> > > > at this more closely.  Changing the SYSTEM SIZING cooling 
> supply 
> > > air 
> > > > temperature to 15C allows the run to continue past this point.
> > > > 
> > > > 2.  The CONTROLLER:OUTSIDE AIR, OA CONTROLLER, minimum 
outside 
> air 
> > > flow rate 
> > > > [m3/s] is 0.0000.  There is no outside air in the OA system.  
> The 
> > > ZONE SIZING 
> > > > objects indicate an outside air flow per person, but there 
are 
> no 
> > > PEOPLE 
> > > > objects, so this becomes zero.
> > > > 
> > > > Mike
> > > > 
> > > > 
> > > > On 17 Oct 2005, at 9:14, hbn_pch wrote:
> > > > 
> > > > > Dear,
> > > > >    Cry!
> > > > >    According to above two issues,i test more and more 
time.I 
> > > tried to 
> > > > > change the priority of the OA unit and FanCoil unit.But i 
> found 
> > > the 
> > > > > fancoil did't work yet.It also appeared that the design 
coil 
> load 
> > > is 
> > > > > zero for cooling coil and heating coil in the zone fancoil 
> unit.
> > > > >   Now i really don't know how to fix the problem.
> > > > > 
> > > > >   Waiting your kind help.thanks very very much.
> > > > >   pch
> > > > > 
> > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "hbn_pch" 
> > > <hbn_pch@y...> 
> > > > > wrote:
> > > > > >
> > > > > > Hi,
> > > > > >    I'm sorry that i had another doubt.If all element are 
> > > > > autosized,it 
> > > > > > seems that the oa unit always trid to meet the load 
because 
> of 
> > > its 
> > > > > > high priority for heating and cooling.And then all of the 
> > > fancoil 
> > > > > > unit will not work at all.Is it right?But the real 
> anticipant 
> > > > > result 
> > > > > > is : oa unit tried to meet load first,and if it could't 
> > > produced 
> > > > > > adequate energy,then fancoil will try to meet excess 
> load.How 
> > > to 
> > > > > > realize above controlld operation??
> > > > > > 
> > > > > >   Thanks very much! appreciated your kind help.
> > > > > > 
> > > > > >   pch
> > > > > > 
> > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "hbn_pch" 
> > > <hbn_pch@y...> 
> > > > > > wrote:
> > > > > > >
> > > > > > > Dear sir,
> > > > > > >    I created a 3-zone model.Each zone has own fancoil 
> unit to 
> > > > > serve 
> > > > > > > and there is a indepent outside air unit to serve the 
> three 
> > > > > > > zones.Fancoil units specifies no outside air(maximum 
> outside 
> > > air 
> > > > > > rate 
> > > > > > > set to 0),and their cooling source is a chiller,heating 
> > > source is 
> > > > > > > purchased heating.
> > > > > > > The OA unit used another purchased cooling and 
purchased 
> > > heating 
> > > > > as 
> > > > > > > its cooling&heating source. The OA unit had high 
priority.
> > > > > > > 
> > > > > > >   After simulation,there are some warnings and severes 
as 
> > > follows:
> > > > > > > 
> > > > > > >    ** Warning ** The design coil load is zero for 
> > > > > > COIL:Water:Cooling 
> > > > > > > RESISTIVE ZONE_FANCOILCOOLINGCOIL
> > > > > > >    **   ~~~   ** The autosize value for max water flow 
> rate 
> > > is 
> > > > > zero
> > > > > > >    ** Warning ** The design coil load is zero for 
> > > > > > COIL:Water:Cooling 
> > > > > > > EAST ZONE_FANCOILCOOLINGCOIL
> > > > > > >    **   ~~~   ** The autosize value for max water flow 
> rate 
> > > is 
> > > > > zero
> > > > > > >    ** Warning ** The design coil load is zero for 
> > > > > > COIL:Water:Cooling 
> > > > > > > NORTH ZONE_FANCOILCOOLINGCOIL
> > > > > > >    **   ~~~   ** The autosize value for max water flow 
> rate 
> > > is 
> > > > > zero
> > > > > > >    ** Warning ** Check input. Pump nominal power or 
motor 
> > > > > > efficiency 
> > > > > > > is set to 0, for pump=CW PUMP
> > > > > > >    ** Warning ** Check input. Pump nominal volumetric 
> flow 
> > > rate 
> > > > > is 
> > > > > > > set or calculated = 0, for pump=CW PUMP
> > > > > > >    ** Warning ** Check input. Pump nominal power or 
motor 
> > > > > > efficiency 
> > > > > > > is set to 0, for pump=OA HW PUMP
> > > > > > >    ** Warning ** Check input. Pump nominal volumetric 
> flow 
> > > rate 
> > > > > is 
> > > > > > > set or calculated = 0, for pump=OA HW PUMP
> > > > > > >    ** Warning ** Check input. Pump nominal power or 
motor 
> > > > > > efficiency 
> > > > > > > is set to 0, for pump=COND PUMP
> > > > > > >    ** Warning ** Check input. Pump nominal volumetric 
> flow 
> > > rate 
> > > > > is 
> > > > > > > set or calculated = 0, for pump=COND PUMP
> > > > > > >    ** Severe  ** COOLING TOWER:SINGLE SPEED "CENTRAL 
> COOLING 
> > > > > > TOWER". 
> > > > > > > Free convection air flow rate must be less than the 
> design 
> > > air 
> > > > > flow 
> > > > > > > rate.
> > > > > > >    ** Severe  ** COOLING TOWER:SINGLE SPEED "CENTRAL 
> COOLING 
> > > > > > TOWER". 
> > > > > > > Free convection UA must be less than the design tower 
UA.
> > > > > > > 
> > > > > > >   It seems that the oa unit has produced adequate 
energy 
> and 
> > > the 
> > > > > > > fancoil units did't need to work(Is it right???).But 
> there is 
> > > a 
> > > > > > > problem for the OA HW Pump,it did't work at all.The 
> cooling 
> > > tower 
> > > > > > > did't work yet.Why???? 
> > > > > > > 
> > > > > > >   In ordoer to urge the oa unit and fancoil unit 
working 
> > > > > together,i 
> > > > > > > tried to reduce the zone sizing temp from 14 to 4.And 
two 
> > > units 
> > > > > > work 
> > > > > > > together as anticipant.Only leaving warnings of the OA 
HW 
> > > > > Pump.But 
> > > > > > > changing the zone sizing temp to 4 is illogical,then 
what 
> can 
> > > i 
> > > > > > do???
> > > > > > > 
> > > > > > >   All of values are autosized.Can i specify the load 
> produced 
> > > by 
> > > > > oa 
> > > > > > > unit(eg.specify maximum air flow rate of the direct air 
> > > unit),and 
> > > > > > > auotsize the fancoil unit to decide their on/off????
> > > > > > > 
> > > > > > >   I don't know whether the combination of the two unit 
> system 
> > > is 
> > > > > > > correct.I hope somebody can help me.Thanks very much.
> > > > > > >   I've upload the file(pch.idf) to file area.
> > > > > > > 
> > > > > > >   Thanks again.
> > > > > > >   pch
> > > > > > >
> > > > > >
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 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.idf 
> > > and press the
> > > > > "search" button.
> > > > > 
> > > > > Yahoo! Groups Links
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > 
> > > > 
> > > > 
> > > > ========================================================
> > > > Michael J. Witte, GARD Analytics, Inc.
> > > > EnergyPlus Testing and Support      
> > > > EnergyPlus-Support@g...
> > > >
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 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.idf 
> and press the
> > > "search" button.
> > > 
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support      
> > EnergyPlus-Support@g...
> >
>






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References:
- [EnergyPlus_Support] Re: Combination of the OA unit system and Fancoil unit system
  - From: hbn_pch

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