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[EnergyPlus_Support] Re: Multispeed DX Cooling Coil
I followed your suggestion, but E+ returns a severe error, instead of
the warning:
** Severe ** IP: IDF line~15835 Error detected in
Object=UNITARYSYSTEM:MULTISPEEDHEATPUMP:AIRTOAIR, name=ROOFTOP AHU
MULTISPEED HP
** ~~~ ** Field [Supply air volumetric flow rate during
heating operation, Speed 3] is required but was blank
I now usually leave the inputs that E+ pre-sets, even if they are not
required for my model, because this new version of E+ (2.2) seems to
be quite picky about missing values, even when they are not used (it
happens with other objects and values). Perhaps the warnings didn't
show up in your trial because you're using version 2.1?...
If the warnings are caused by the unused speeds, is there any reason
why I shouldn't keep those autosize values and ignore the warnings?
Although, the truth is that the warnings referred to Speeds 1 and 2,
but I guess it could be some sort of bug?...
Thank you for the help,
Ana.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Ana Rui:
>
> I ran the input file and could not repeat the warnings using the
> PRT_BRAGANCA_IWEC.epw weather file specified in the input. However
I found
> some inputs which may cause the warnings.
>
> The numbers of speeds for heating and cooling are 2 in the
> UnitarySystem:MultiSpeedHeatPump:AirToAir object. The next four
inputs
> should be:
> 2.0833, !- Supply air volumetric flow rate during heating
operation, Speed 1
> {m3/s}
> 4.1667, !- Supply air volumetric flow rate during heating
operation, Speed 2
> {m3/s}
> 2.0833, !- Supply air volumetric flow rate during cooling
operation, Speed 1
> {m3/s}
> 4.1667; !- Supply air volumetric flow rate during cooling
operation, Speed 2
> {m3/s}
> There is no need to input values for Speeds 3 and 4.
>
> Your inputs are:
>
> 2.0833, !- Supply air volumetric flow rate during heating
operation, Speed 1
> {m3/s}
> 4.1667, !- Supply air volumetric flow rate during heating
operation, Speed 2
> {m3/s}
> autosize, !- Supply air volumetric flow rate during heating
operation, Speed
> 3 {m3/s}
> autosize, !- Supply air volumetric flow rate during heating
operation, Speed
> 4 {m3/s}
> 2.0833, !- Supply air volumetric flow rate during cooling
operation, Speed 1
> {m3/s}
> 4.1667, !- Supply air volumetric flow rate during cooling
operation, Speed 2
> {m3/s}
> autosize, !- Supply air volumetric flow rate during cooling
operation, Speed
> 3 {m3/s}
> autosize; !- Supply air volumetric flow rate during cooling
operation, Speed
> 4 {m3/s}
>
> Two additional field inputs of autosize (Supply air volumetric flow
rate
> during heating operation, Speed 3 and 4) are recognized by E+ as
cooling
> flow rates. Since the inputs are autosize, E+ calculated flow rates
as
> 1.18959 at Speed 1 and 2.37918 at Speed 2. The ratio of flow rate
(1.18) to
> the rated capacity at 42900 may be out of range.
>
> By the way, E+ uses the flow rate in the
> UnitarySystem:MultiSpeedHeatPump:AirToAir object at each speed. The
rated
> flow rate in the Cooling object is used to calculate flow fraction,
which is
> used to calculate flow fraction modifier.
>
> Please delete autosize inputs. I expect the warnings may go away.
At the
> same time, I am going to revise the program to catch unmatched
inputs.
>
> Best regards,
>
> Lixing Gu
>
>
> ----- Original Message -----
> From: "anarui.oliveira" <anarui.oliveira@...>
> To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
> Sent: Tuesday, June 17, 2008 12:33 PM
> Subject: [EnergyPlus_Support] Re: Multispeed DX Cooling Coil
>
>
> >I uploaded the file with the name "Loja2_cUnitaryMSHP". Thanks.
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@> wrote:
> >>
> >> Ana Rui:
> >>
> >> Please upload the input file. I am going to take a look.
> >>
> >> Thanks.
> >>
> >> Lixing Gu
> >>
> >> ----- Original Message -----
> >> From: "anarui.oliveira" <anarui.oliveira@>
> >> To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
> >> Sent: Tuesday, June 17, 2008 11:06 AM
> >> Subject: [EnergyPlus_Support] Multispeed DX Cooling Coil
> >>
> >>
> >> > Hi.
> >> >
> >> > Why would a get the following error message:
> >> >
> >> > Warning ** COIL:DX:MULTISPEED:COOLING "ROOFTOP AHU DX COOLING
> > COIL" -
> >> > Air volume flow rate per watt of rated total cooling capacity
is
> > out of
> >> > range at speed 1
> >> >
> >> > if
> >> > - Rated Total Cooling Capacity at Speed 1 = 42900 W
> >> > - Rated volumetric flow at speed 1 = 2.0833 m3/s
> >> > i.e.
> >> > ratio = 0.000049 (m3/s) / W ???
> >> >
> >> > Am I missing something?
> >> >
> >> > Thanks in advance,
> >> > Ana Rui.
> >> >
> >> >
> >> >
> >> > ------------------------------------
> >> >
> >> > The primary EnergyPlus web site is found at:
> >> > http://www.energyplus.gov
> >> >
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> >> >
> >> > Attachments are not allowed -- please post any files to the
> > appropriate
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> >> >
> >> > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf
> > under the
> >> > Documentation link and press the "search" button.
> >> > Yahoo! Groups Links
> >> >
> >> >
> >> >
> >> >
> >>
> >
> >
> >
> > ------------------------------------
> >
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> >
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> >
> > Attachments are not allowed -- please post any files to the
appropriate
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> >
> > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf
under the
> > Documentation link and press the "search" button.
> > Yahoo! Groups Links
> >
> >
> >
> >
>
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