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Hi @Anna

Did you verify that the field System Availability Schedule Name, Supply Fan Maximum Flow Rate and Supply Fan Minimum Flow Rate for all objects in the group HVACTemplate:System:VAV are modelled correctly? You would need to hardsize the max and min flowrates in these objects and apply the appropriate schedule in this object.

As per the I/O ref guide, Sizing:System is used for calculating system sizing for every design day in the IDF and the max heating & cooling air flow rates and capacities are saved for use in the component sizing calculations.

Hope that helps,

Raghu

Hi @Anna

Did you verify that the field System Availability Schedule Name, Supply Fan Maximum Flow Rate and Supply Fan Minimum Flow Rate for all objects in the group HVACTemplate:System:VAV are modelled correctly? You would need to hardsize the max and min flowrates in these objects and apply the appropriate schedule in this object.

As per the I/O ref guide, Sizing:System is used for calculating system sizing for every design day in the IDF and the max heating & cooling air flow rates and capacities are saved for use in the component sizing calculations.

Hope that helps,

Raghu

Did Once you run a model with HVACTemplate objects, it is a good idea to verify the inputs in the expidf to make sure that the field System Availability Schedule Name, Supply Fan Maximum Flow Rate and Supply Fan Minimum Flow Rate for inputs in the HVACTemplate objects get translated as desired.

I would suggest that you make a copy of the expidf and verify all objects in the group HVACTemplate:System:VAV inputs related to flowrates of the following objects:

DesignSpecification:OutdoorAir - just to make sure that the OA flowrates are modelled correctly? You accurately;

AirTerminal:SingleDuct:VAV:Reheat - I would need to hardsize used the option FixedFlowRate for the field of Zone Minimum Air Flow Input Method and add the max and min flow rate in the respective fields;

Fan:VariableVolume - Use the option of FixedFlowRate for the field Fan Power Minimum FLow Rate Input Method and add the max and min flowrates;

Controller:OutdoorAir - verify the OA flowrates in these objects and apply the appropriate schedule in this object.

are modelled accurately;

AirLoopHVAC - can be autosized.


As per the I/O ref guide, Sizing:System is used for calculating system sizing for every design day in the IDF and the max heating & cooling air flow rates and capacities are saved for use in the component sizing calculations.