Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics

Functions for fan characteristics

Information

This package implements the performance curve for the fans, and a record for performance data that can be used with the performance curve.

Package Content

Name Description
Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.normalizedPower normalizedPower Normalized flow vs. normalized power characteristics for fan
Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.fan fan Record for fan power consumption
Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.Validation Validation Collection of models that validate the cooling tower models

Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.normalizedPower Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.normalizedPower

Normalized flow vs. normalized power characteristics for fan

Information

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

rP = s(rV, d),

where rP; is the normalized fan power consumption, rV is the normalized 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.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

TypeNameDefaultDescription
fanper Fan relative power consumption
Realr_V Volumetric flow rate divided by nominal flow rate [1]
Reald[:] Derivatives at support points for spline interpolation

Outputs

TypeNameDescription
Efficiencyr_PNormalized power consumption [1]

Modelica definition

function normalizedPower "Normalized flow vs. normalized power characteristics for fan" extends Modelica.Icons.Function; input Characteristics.fan per "Fan relative power consumption"; input Real r_V(unit="1") "Volumetric flow rate divided by nominal flow rate"; input Real d[:] "Derivatives at support points for spline interpolation"; output Modelica.SIunits.Efficiency r_P(max=1) "Normalized power consumption"; protected Integer n = size(per.r_V, 1) "Number of data points"; Integer i "Integer to select data interval"; algorithm if n == 1 then r_P := per.r_V[1]; else // Compute index for power consumption i := 1; for j in 1:n-1 loop if r_V > per.r_V[j] then i := j; end if; end for; // Extrapolate or interpolate the data r_P:=Buildings.Utilities.Math.Functions.cubicHermiteLinearExtrapolation( x=r_V, x1=per.r_V[i], x2=per.r_V[i + 1], y1=per.r_P[i], y2=per.r_P[i + 1], y1d=d[i], y2d=d[i+1]); end if; end normalizedPower;

Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.fan Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.Characteristics.fan

Record for fan power consumption

Information

Data record for performance data that describe normalized volume flow rate versus normalized fan power consumption. The normalized volume flow rate r_V must be increasing, i.e., r_V[i] < r_V[i+1]. Both vectors, r_V and r_P must have the same size.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

TypeNameDefaultDescription
Realr_V[:] Volumetric flow rate divided by nominal flow rate at user-selected operating points [1]
Realr_P[size(r_V, 1)] Fan relative power consumption at these flow rates such that r_P = 1 for r_V=1

Modelica definition

record fan "Record for fan power consumption" extends Modelica.Icons.Record; parameter Real r_V[:](each min=0, each unit="1") "Volumetric flow rate divided by nominal flow rate at user-selected operating points"; parameter Real r_P[size(r_V,1)](each max=1) "Fan relative power consumption at these flow rates such that r_P = 1 for r_V=1"; end fan;