Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.Functions

This function interpolates data for intermediate compressor speeds using cubic hermite splines with linear extrapolation. To avoid linear extrapolation below minimum standard speed, the origin is added to the modified arrays.

Inputs

Outputs

Modelica definition

Name	Description
speedShift	Interpolates value between two speeds
warnIfPerformanceOutOfBounds	Function that checks the performance and writes a warning if it is outside of 0.9 to 1.1

Type	Name	Description
Real	spe	Speed of compressor
Real	speSet[:]	Array of standard compressor speeds
Real	u[:]	Array to be interpolated

Type	Name	Description
Real	y	Interpolated value

function speedShift "Interpolates value between two speeds" //x in cubic Hermite function input Real spe "Speed of compressor"; //x1, x2 in cubic Hermite function input Real speSet[:] "Array of standard compressor speeds"; //y1, y2 in cubic Hermite function input Real u[:] "Array to be interpolated"; output Real y "Interpolated value"; protected Integer n= size(u,1)+1 "Number of elements in modified array"; Real derv[n] "deriative"; Integer i=1 "Integer to select data interval"; Real modSpeSet[n] "Speed set with origin"; Real modU[n]; algorithm //y1d, y2d in cubic Hermite function modSpeSet:= cat(1, {0.00}, speSet); modU := cat(1, {0.00}, u); //Derivatives at standard speeds derv := Buildings.Utilities.Math.Functions.splineDerivatives( x=modSpeSet, y=modU, ensureMonotonicity=Buildings.Utilities.Math.Functions.isMonotonic(x=modU, strict=false)); //locate the range between which compressor operates for j in 1:size(modSpeSet, 1) - 1 loop if spe > modSpeSet[j] then i :=j; end if; end for; y :=Buildings.Utilities.Math.Functions.cubicHermiteLinearExtrapolation( x=spe, x1=modSpeSet[i], x2=modSpeSet[i + 1], y1=modU[i], y2=modU[i + 1], y1d=derv[i], y2d=derv[i + 1]); end speedShift;

Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.Functions.warnIfPerformanceOutOfBounds

Function that checks the performance and writes a warning if it is outside of 0.9 to 1.1

Information

This function checks if the numeric argument is outside of the interval 0.9 to 1.1. If this is the case, the function writes a warning.

Inputs

Outputs

Modelica definition

Type	Name	Description
Real	x	Argument to be checked
String	msg	String to be added to warning message
String	curveName	Name of the curve that was tested

Type	Name	Description
Integer	retVal	0 if x is inside bounds, -1 if it is below bounds, or +1 if it is above bounds

function warnIfPerformanceOutOfBounds "Function that checks the performance and writes a warning if it is outside of 0.9 to 1.1" input Real x "Argument to be checked"; input String msg "String to be added to warning message"; input String curveName "Name of the curve that was tested"; output Integer retVal "0 if x is inside bounds, -1 if it is below bounds, or +1 if it is above bounds"; algorithm if (x > 1.1) then retVal :=1; elseif ( x < 0.9) then retVal :=-1; else retVal :=0; end if; if (retVal <> 0) then Modelica.Utilities.Streams.print( "*** Warning: DX coil performance curves at nominal conditions are outside of bounds. " + msg + " is outside of bounds 0.9 to 1.1. The value of the curve fit is " + String(x) + " Check the coefficients of the function " + curveName + "."); end if; end warnIfPerformanceOutOfBounds;