modelFlowControlled_dp

Information

This model describes a fan or pump with prescribed head. The input connector provides the difference between outlet minus inlet pressure. The efficiency of the device is computed based on the efficiency and pressure curves that are defined in record per, which is of type IBPSA.Fluid.Movers.SpeedControlled_Nrpm.

Main equations

See the User's Guide.

Typical use and important parameters

If use_inputFilter=true, then the parameter dp_nominal is used to normalize the filter. This is used to improve the numerics of the transient response. The actual pressure raise of the mover at steady-state is independent of the value of dp_nominal. It is recommended to set dp_nominal to approximately the pressure raise that the mover has during full speed.

Options

Parameter prescribeSystemPressure can be used to control the mover such that the pressure difference set point is obtained across two points in the system, instead of across the fan. This allows an efficient implementation of static pressure reset controllers. A measurement of the pressure difference between the two points in system then needs to be connected to RealInput dpMea. This functionality is demonstrated in IBPSA.Fluid.Movers.Validation.FlowControlled_dpSystem.

Parameters

Connectors

Components

Revisions

• May 5, 2017, by Filip Jorissen:
  Added parameters, documentation and functionality for prescribeSystemPressure.
  This is for #770.
• March 24, 2017, by Michael Wetter:
  Renamed filteredSpeed to use_inputFilter.
  This is for #665.
• December 2, 2016, by Michael Wetter:
  Removed min attribute as otherwise numerical noise can cause the assertion on the limit to fail.
  This is for #606.
• November 14, 2016, by Michael Wetter:
  Changed default values for heads.
  This is for #583.
• March 2, 2016, by Filip Jorissen:
  Refactored model such that it directly extends PartialFlowMachine. This is for #417.
• January 22, 2016, by Michael Wetter:
  Corrected type declaration of pressure difference. This is for #404.
• November 5, 2015, by Michael Wetter:
  Removed the parameters use_powerCharacteristics and power from the performance data record per because IBPSA.Fluid.Movers.FlowControlled_dp and IBPSA.Fluid.Movers.FlowControlled_m_flow fix the flow rate or head, which can give a flow work that is higher than the power consumption specified in this record. Hence, users should use the efficiency data for this model. The record has been moved to IBPSA.Fluid.Movers.Data.SpeedControlled_y as it makes sense to use it for the movers IBPSA.Fluid.Movers.FlowControlled_Nrpm and IBPSA.Fluid.Movers.FlowControlled_y.
  This is for issue 457.
• April 2, 2015, by Filip Jorissen:
  Added code for supporting stage input and constant input.
• January 6, 2015, by Michael Wetter:
  Revised model for OpenModelica.
• February 14, 2012, by Michael Wetter:
  Added filter for start-up and shut-down transient.
• May 25, 2011, by Michael Wetter:
  Revised implementation of energy balance to avoid having to use conditionally removed models.
• July 27, 2010, by Michael Wetter:
  Redesigned model to fix bug in medium balance.
• July 5, 2010, by Michael Wetter:
  Changed assert(dp_in >= 0, ...) to assert(dp_in >= -0.1, ...). The former implementation triggered the assert if dp_in was solved for in a nonlinear equation since the solution can be slightly negative while still being within the solver tolerance.
• March 24, 2010, by Michael Wetter:
  Revised implementation to allow zero flow rate.
• October 1, 2009, by Michael Wetter:
  Added model to the IBPSA library.