Re: [EnergyPlus_Support] Doubt About VRF System Warning (Severe)

Richard, I noticed this problem too.

Maybe it's a bug in EnergyPlus.

I'm entering all the correct information and it keeps expidf different.

Jean, I did not use autosize. Insert the correct data but does not copy the expidf the same way.

The best solution is to modify the data in expidf.

Thank you all!

Técg. Ivan Mezzacapa

Projetista de Ar Condicionado / Consultor em Eficiência Energética

LinkedIN: http://www.linkedin.com/in/ivanmezzacapa

Celular: (11)9963-9326

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
Date: Fri, 7 Nov 2014 09:29:36 -0500
Subject: Re: [EnergyPlus_Support] Doubt About VRF System Warning (Severe)

The HVACTemplate is not copying the inputs for the VRF coil correctly.
In your input file you have specified 3 m3/s cooling and heating flow rate and 55950.76 W capacity for the coils.

HVACTemplate:Zone:VRF,
    06SUBSOLO:NOBREAK,       !- Zone Name
    3,                       !- Supply Air Flow Rate During Cooling Operation {m3/s}
    3,                       !- Supply Air Flow Rate During Heating Operation {m3/s}
    55950.76,                !- Cooling Coil Gross Rated Total Capacity {W}

Open the Model.expidf file and find this coil, you will see this:

ZoneHVAC:TerminalUnit:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Terminal Unit,                     !- Zone Terminal Unit Name
autosize,                                                !- Supply Air Flow Rate During Cooling Operation {m3/s}
autosize,                                                !- Supply Air Flow Rate During Heating Operation {m3/s}

Fan:OnOff,
06SUBSOLO:NOBREAK VRF Supply Fan,                        !- Name
autosize,                                                !- Maximum Flow Rate {m3/s}

Coil:Cooling:DX:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Cooling Coil,                      !- Name
Sch_HVAC,                                                !- Availability Schedule Name
55950.76,                                                !- Gross Rated Total Cooling Capacity {W}
autosize,                                                !- Gross Rated Sensible Heat Ratio
autosize,                                                !- Rated Air Flow Rate {m3/s}

Coil:Heating:DX:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Heating Coil,                      !- Name
Sch_HVAC,                                                !- Availability Schedule Name
55950.76,                                                !- Gross Rated Heating Capacity {W}
autosize,                                                !- Rated Air Flow Rate {m3/s}

Correct the inputs that show "autosize" to the values you entered in your input file. Then save that file as Model2.idf and run it.

For example, make these changes:

ZoneHVAC:TerminalUnit:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Terminal Unit,                     !- Zone Terminal Unit Name
3,                                                !- Supply Air Flow Rate During Cooling Operation {m3/s}
3,                                                !- Supply Air Flow Rate During Heating Operation {m3/s}

Coil:Cooling:DX:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Cooling Coil,                      !- Name
3,                                                !- Rated Air Flow Rate {m3/s}

Coil:Heating:DX:VariableRefrigerantFlow,
06SUBSOLO:NOBREAK VRF Heating Coil,                      !- Name
3,                                                !- Rated Air Flow Rate {m3/s}

Do the same to correct other issues in the expanded file.

On 11/6/2014 5:30 PM, Ivan Mezzacapa ivan_slip@xxxxxxxxxxx [EnergyPlus_Support] wrote:

Hello everyone!

I am having a problem simulating a VRF system. I created the entire system and the simulation shows me an error that makes no sense for me.

Is reporting that i was inserted data that do not conform to the model input. It's the first time I see this error.

** Warning ** SizeDXCoil: Coil:Cooling:DX:VariableRefrigerantFlow 06SUBSOLO:NOBREAK VRF COOLING COIL

** ~~~ ** ...Rated Total Cooling Capacity will be limited by the maximum rated volume flow per rated total capacity ratio.

** ~~~ ** ...DX coil volume flow rate (m3/s) = 3.000000

** ~~~ ** ...Requested capacity (W) = 36641.887

** ~~~ ** ...Requested flow/capacity ratio (m3/s/W) = 8.187E-005

** ~~~ ** ...Maximum flow/capacity ratio (m3/s/W) = 6.041E-005

** ~~~ ** ...Adjusted capacity (W) = 49660.652



************* SizeDxCoil: Potential issue with equipment sizing for Coil:Cooling:DX:VariableRefrigerantFlow 06SUBSOLO:NOBREAK VRF COOLING COIL

** ~~~ ** User-Specified Total Cooling Capacity of 55950.76 [W]

** ~~~ ** differs from Design Size Total Cooling Capacity of 49660.65 [W]

** ~~~ ** This may, or may not, indicate mismatched component sizes.

** ~~~ ** Verify that the value entered is intended and is consistent with other components.

  ************* SizeVRF: Potential issue with equipment sizing for AirConditioner:VariableRefrigerantFlow 03SUBSOLO:SUPERVISAOPREDIAL VRF TERMINAL UNIT

** ~~~ ** User-Specified Rated Total Heating Capacity of 63000.00 [W]

** ~~~ ** differs from Design Size Rated Total Heating Capacity of 55950.76 [W]

** ~~~ ** This may, or may not, indicate mismatched component sizes.

** ~~~ ** Verify that the value entered is intended and is consistent with other components.



** Warning ** SizeDXCoil: Coil:Cooling:DX:VariableRefrigerantFlow 06SUBSOLO:DADOSEVOZ VRF COOLING COIL

** ~~~ ** ...Rated Total Cooling Capacity will be limited by the minimum rated volume flow per rated total capacity ratio.

** ~~~ ** ...DX coil volume flow rate (m3/s) = 0.000000

** ~~~ ** ...Requested capacity (W) = 0.000

** ~~~ ** ...Requested flow/capacity ratio (m3/s/W) = 0.000

** ~~~ ** ...Minimum flow/capacity ratio (m3/s/W) = 4.027E-005

** ~~~ ** ...Adjusted capacity (W) = 0.000

** Severe ** Sizing: Coil:Cooling:DX:VariableRefrigerantFlow 06SUBSOLO:DADOSEVOZ VRF COOLING COIL has zero rated air flow rate

If anyone can help, I'd be grateful. Follow the idf.

Best regards,

Técg. Ivan Mezzacapa

Projetista de Ar Condicionado / Consultor em Eficiência Energética

LinkedIN: http://www.linkedin.com/in/ivanmezzacapa
Celular: (11)9963-9326

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