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[EnergyPlus_Support] Re: rated air volume flow rate of CoolingBypassFactorEmpirical
Mike,
I also had the same problem on the model I was working on. I had
autosized both the airflow and the DX coil size. I tried pretty much
everything to get rid of the error, I set the airflow and autosized
the coil, I set the coil and autosized the airflow, I set both
airflow and coil. I never was able to get rid of the error.
So my results are most likely not accurate? Why when I set both the
airflow and the coil size, I still had the error?
Any suggestions?
Thanks,
Michelle Smith
Belle Engineering, LLC
--- In EnergyPlus_Support@y..., "Michael J. Witte" <mjwitte@g...>
wrote:
> On 17 Sep 2002, at 4:38, rmp4aup6 wrote:
>
> > Hi, everyone:
> > Especially for Mike Witte, thank you very much!!
> >
> > B-1.
> > I have checked the maximum air flow rate in the Window AC object
is
> > the same as the Rated air volume flow rate in the DX coil
object. but
> > the error message still showed after simulation.
>
> You must compare the ratio of air flow to cooling capacity and
make
> sure that it is within the limits specified in the I/O reference.
If
> you are still receiving the error message, then your airflow rate
is
> either too high or too low for the specified cooling capacity.
>
>
> >
> > Further, I tried to change the setting cooling temperature from
26C to
> > 24C in DAYSCHEDULE object, then the simulation ran successfully.
Do
> > you have any ideas about that??
> >
> > but even the simulation ran susscessfully for the case of 24C
setting,
> > the mean air temperautre in that zone is not fixed as the setting
> > cooling tempertuare(24C).
>
> As long as you are receiving the above error message, your
simulation
> results are probably not valid.
>
> >
> >
> > by the way, Is there any simple example talking about the central
> > cooling system in a zone or for one building??
> >
>
> The files in the Examples folders.
>
> Mike
>
>
> >
> >
> > --- In EnergyPlus_Support@y..., "Michael J. Witte" <mjwitte@g...>
> > wrote: > A. If you have windows, solar gains will heat the
space to
> > be warmer > than the outside air. Also, internal gains such as
people
> > and > equipment will heat the space. So it is quite possible
for an >
> > unconditioned space with no ventilation to get this warm. For >
> > example, think of a closed up car sitting in the hot sun. > > B-
1.
> > The restriction on airflow is "Rated Air Volume Flow of >
> > CoolingBypassFactorEmpirical should be between 0.00004699-
0.00006041 >
> > m3/s PER WATT OF RATED TOTAL COOLING CAPACITY." The error
message is
> > > indicating that your airflow rate is not consistent with the
rated >
> > capacity of the DX coil. Note that you must make sure that flow
>
> > rates and capacities are consistent in the Window AC object and
the >
> > DX coil object. They are not automatically matched. > > B-2.
You
> > should see the setpoint properly maintained once you get > rid
of the
> > air flow errors. > > Mike Witte > > > > On 13 Sep 2002, at 12:11,
> > rmp4aup6 wrote: > > > hello, sorry to bother you everyday!! > >
> > I
> > am running a simulation for a room with 24m*11m*4m > > > > what
> > strange is that > > A. for the case without air conditioners > >
the
> > outdoor dry bulb is 35C at noon, but the mean air temperature in
> >
> > that at noon is about 54C, is it normal?? > > > > B. for the
case with
> > 5 window air conditioners > > Although the simulaiton completed
> > successfully , it shows some warning > > messages that I don't
know
> > how to solve. As below: > > > > ** Warning **
> > COIL:DX:CoolingBypassFactorEmpirical "ZN001WINDACDXCOIL" > > -
Air
> > volume flow rate per watt of rated total cooling capacity is out
> >
> > of range on MM/DD HH:MM.mm= 7/31 07:35.00 > > > > ** Warning **
> > COIL:DX:CoolingBypassFactorEmpirical > > "ZN001WINDACDXCOIL5" -
Air
> > volume flow rate per watt of rated total > > cooling capacity is
out
> > of range error continues...100 > > > > ** Warning ** AIR
> > CONDITIONER:WINDOW:CYCLING -- Exceeded max > > iterations while
> > adjusting compressor runtime to meet the zone load > > within the
> > cooling convergence tolerance. ** ~~~ ** For > >
> > WindowAC=ZN001WINDAC, Iterations=15 > > > > B-1 > > the
reference said
> > that the Rated Air Volume Flow of > >
CoolingBypassFactorEmpirical
> > should be between 0.00004699-0.00006041 > > m3/s, but I set it
as 0.6,
> > the same as the Example WindAC.idf. > > something wrong?? > > >
> B-2
> > > > I set the cooling setpoints to be 24C, but I found that the
mean
> > air > > temperature is not steady. most of the time is below 23C
> > >
> > > thank you very much > > thank you very much > > > > > > > >
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