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Re: [EnergyPlus_Support] Re: Multispeed DX Cooling Coil
Ana:
I think you use IDF editor and Version 2.2. I am using the same version. It
is better to show you how E+ reads inputs of the
UNITARYSYSTEM:MULTISPEEDHEATPUMP:AIRTOAIR object. When the number of speed
for heating is 2, E+ reads two field values:
Supply air volumetric flow rate during heating operation, Speed 1
Supply air volumetric flow rate during heating operation, Speed 2
Any values below could not be blank. Otherwise, the IDF editor should
complain. This is what you got. When the number of speed for cooling is 2,
then E+ reads values of flow rates for cooling, just below the flow rates
for heating. The main issue is that the IDF editor requires static inputs,
while E+ requires dynamic inputs based on the number of speeds.
If you use the IDF editor, you may enter the input values like below:
2, !- Number of speeds for heating
2, !- Number of speeds for cooling
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 heating operation, Speed 3
{m3/s}
4.1667; !- Supply air volumetric flow rate during heating operation, Speed 4
{m3/s}
After completing inputs using the IDF editor, please use a text editor to
verify the inputs as shown above. Please let me know what happens.
Best regards,
Lixing Gu
----- Original Message -----
From: "anarui.oliveira" <anarui.oliveira@xxxxxxxxx>
To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Wednesday, June 18, 2008 4:20 AM
Subject: [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
>> >> >
>> >> > 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
>> >> >
>> >> >
>> >> >
>> >> >
>> >>
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > 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
>> >
>> >
>> >
>> >
>>
>
>
>
> ------------------------------------
>
> 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
>
>
>
>
------------------------------------
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