functionefficiency
Flow vs. efficiency characteristics for fan or pump
Extends from Modelica.Icons.Function (Icon for functions).
Information
This function computes the fan or pump efficiency for given normalized volume flow rate and performance data. The efficiency is
η = s(V̇/rN, d),
where η is the efficiency, rN is the normalized fan speed, V̇ is the volume flow rate, and d are performance data for fan or pump efficiency.
Implementation
The function s(·, ·) is a cubic hermite spline. If the data d define a monotone decreasing sequence, then s(·, d) is a monotone decreasing function.
Inputs
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Movers.BaseClasses.Characteristics.efficiencyParameters | per | Efficiency performance data | |
| Modelica.Units.SI.VolumeFlowRate | V_flow | Volumetric flow rate | |
| Real[:] | d | Derivatives at support points for spline interpolation | |
| Real | r_N | Relative speed | |
| Real | delta | Small value for switching implementation around zero speed |
Outputs
| Type | Name | Default | Description |
|---|---|---|---|
| Real | eta | Efficiency |
Revisions
-
December 2, 2016, by Michael Wetter:
Removedminattribute as otherwise numerical noise can cause the assertion on the limit to fail.
This is for #606. -
November 22, 2014, by Michael Wetter:
Corrected documentation as curve uses V̇ as an independent variable. -
September 30, 2014, by Filip Jorissen:
Changed polynomial to be evaluated atV_flowinstead ofr_V. -
April 19, 2014, by Filip Jorissen:
Changed polynomial to be evaluated atr_V/r_Ninstead ofr_Vto properly account for the scaling law. See #202 for a discussion and validation. -
September 28, 2011, by Michael Wetter:
First implementation.