BuildingSystems.Fluid.Movers.BaseClasses.Characteristics.power

# .BuildingSystems.Fluid.Movers.BaseClasses.Characteristics.power

Flow vs. electrical power characteristics for fan or pump

## Information

This function computes the fan power consumption for given volume flow rate, speed and performance data. The power consumption is

P = rN3 s(V̇/rN, d),

where P is the power consumption, rN is the normalized fan speed, V̇ is the volume flow rate and d are performance data for fan or pump power consumption at rN=1.

#### 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.

#### Interface

>     function power
>       extends Modelica.Icons.Function;
>       input BuildingSystems.Fluid.Movers.BaseClasses.Characteristics.powerParameters per "Pressure performance data";
>       input Modelica.Units.SI.VolumeFlowRate V_flow "Volumetric flow rate";
>       input Real r_N(unit = "1") "Relative speed";
>       input Real d[:] "Derivatives at support points for spline interpolation";
>       input Real delta "Small value for switching implementation around zero speed";
>       output Modelica.Units.SI.Power P "Power consumption";
>     end power;

## Revisions

- February 26, 2014, by Filip Jorissen:
  Changed polynomial to be evaluated at `V_flow/r_N` instead of `V_flow` to properly account for the scaling law. See #202 for a discussion and validation.
- September 28, 2011, by Michael Wetter:
  First implementation.

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