#*-------------------------------------------------------------------
* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
*
* This LIBRARY is free software; you can distribute it and/or modify
* it under the therms of the ALSOC FREE LICENSE as available at
* http://www.enq.ufrgs.br/alsoc.
*
* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
* from http://www.rps.eng.br Copyright (C) 2002-2004.
* All rights reserved.
*
* EMSO is distributed under the therms of the ALSOC LICENSE as
* available at http://www.enq.ufrgs.br/alsoc.
*
*--------------------------------------------------------------------
* Author: Gerson Balbueno Bicca 
* $Id: Heatex.mso 574 2008-07-25 14:18:50Z rafael $
*--------------------------------------------------------------------*#

using "heat_exchangers/HEX_Engine";

Model Heatex_Basic 

ATTRIBUTES
	Pallete 	= false;
	Brief 	= "Basic Model for Simplified Heat Exchangers";
	Info 		=
"Model of a simplified heat exchanger.
This model perform only material and heat balance.

== Assumptions ==
* Steady-State operation;
* No heat loss to the surroundings.

== Specify ==
* The Inlet streams: Hot and Cold;
";
	
PARAMETERS
outer PP 	    	as Plugin	(Brief="External Physical Properties", Type="PP");
outer NComp   	as Integer  (Brief="Number of Components");
	
	M(NComp)  as molweight 	(Brief="Component Mol Weight",Hidden=true);
	
VARIABLES

in  InletHot		as stream 			(Brief="Inlet Hot Stream", PosX=0, PosY=0.4915, Symbol="^{inHot}");
out OutletHot	as streamPH  	(Brief="Outlet Hot Stream", PosX=1, PosY=0.4915, Symbol="^{outHot}");
in  InletCold		as stream 			(Brief="Inlet Cold Stream", PosX=0.5237, PosY=1, Symbol="^{inCold}");
out OutletCold	as streamPH  	(Brief="Outlet Cold Stream", PosX=0.5237, PosY=0, Symbol="^{outCold}");

	A 		as area						(Brief="Exchange Surface Area");
	Q	   	as power					(Brief="Duty", Default=7000, Lower=1e-6, Upper=1e10);
	U	 	as heat_trans_coeff 	(Brief="Overall Heat Transfer Coefficient",Default=1,Lower=1e-6,Upper=1e10);
	
	PdropHotSide 	as press_delta	(Brief="Pressure Drop Hot Side",Default=0.01, Lower=0,DisplayUnit='kPa' , Symbol ="\Delta P_{hot}");
	PdropColdSide 	as press_delta	(Brief="Pressure Drop Cold Side",Default=0.01, Lower=0,DisplayUnit='kPa' , Symbol ="\Delta P_{cold}");

SET

#"Component Molecular Weight"
	M   = PP.MolecularWeight();

EQUATIONS

"Energy Balance Hot Stream"
	Q = InletHot.F*(InletHot.h-OutletHot.h);

"Energy Balance Cold Stream"
	Q =-InletCold.F*(InletCold.h-OutletCold.h);

"Molar Balance Hot Stream"
	InletHot.F  = OutletHot.F;
	
"Molar Balance Cold Stream"
	InletCold.F = OutletCold.F;

"Hot Stream Molar Fraction Constraint"
	OutletHot.z	=	InletHot.z;
	
"Cold Stream Molar Fraction Constraint"
	OutletCold.z	=	InletCold.z;
	
"Pressure Drop Hot Stream"
	OutletHot.P  = InletHot.P - PdropHotSide;
	
"Pressure Drop Cold Stream"
	OutletCold.P  = InletCold.P - PdropColdSide;
	
end

Model Heatex_LMTD  as Heatex_Basic

ATTRIBUTES
	Pallete 	= true;
	Icon 		= "icon/HeatExchanger_LMTD";	
	Brief 	= "Simplified model for Heat Exchangers";
	Info 		=
"This model perform material and heat balance using the Log Mean Temperature Difference Approach. 
This shortcut calculation does not require exchanger configuration or geometry data.

== Assumptions ==
* Steady-State operation;
* No heat loss to the surroundings.

== Specify ==
* The Inlet streams: Hot and Cold.

== References ==
[1] E.A.D. Saunders, Heat Exchangers: Selection, Design and
 Construction, Longman, Harlow, 1988. 

[2] Taborek, J., Shell-and-tube heat exchangers, in Heat Exchanger Design Handbook, Vol. 3
 Hemisphere Publishing Corp., New York, 1988. 

[3] Fakheri, A. , Alternative approach for determining log mean temperature difference correction factor 
 and number of shells of shell and tube heat exchangers, Journal of Enhanced Heat Transfer, v. 10, p. 407- 420, 2003. 
";
	
PARAMETERS

	ExchangerType 		as Switcher	(Brief="Type of Heat Exchanger",Valid=["Counter Flow","Cocurrent Flow", "Shell and Tube"],Default="Cocurrent Flow");
	LMTDcorrection 	as Switcher	(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakheri"],Default="Bowmann");

VARIABLES

	Method 	as LMTD_Basic		(Brief="LMTD Method of Calculation", Symbol =" ");
	R 				as positive 			(Brief="Capacity Ratio for LMTD Correction Fator",Lower=1e-6,Hidden=true);
	P 				as positive 			(Brief="Non - Dimensional Variable for LMTD Correction Fator ",Lower=1e-6,Hidden=true);
	Rho 			as positive 			(Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakheri Equation",Lower=1e-6,Hidden=true);
	Phi    		as positive 			(Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakheri Equation",Lower=1e-6, Symbol ="\phi",Hidden=true);

EQUATIONS

"Duty"
	Q = U*A*Method.LMTD*Method.Fc;

switch ExchangerType
	
	case "Cocurrent Flow":

"Temperature Difference at Inlet"
	Method.DT0 = InletHot.T - InletCold.T;

"Temperature Difference at Outlet"
	Method.DTL = OutletHot.T - OutletCold.T;

"R: Capacity Ratio for LMTD Correction Fator"
	R=1;

"P: Non - Dimensional Variable for LMTD Correction Fator"
	P=1;

" Variable useless with this model"
	Phi  = 1;
	
" Variable useless with this model"
	Rho = 1;

"LMTD Correction Factor in Cocurrent Flow"
	Method.Fc = 1;

	case "Counter Flow":
	
"Temperature Difference at Inlet"
	Method.DT0 = InletHot.T - OutletCold.T;

"Temperature Difference at Outlet"
	Method.DTL = OutletHot.T - InletCold.T;

"R: Capacity Ratio for LMTD Correction Fator"
	R=1;

"P: Non - Dimensional Variable for LMTD Correction Fator"
	P=1;

" Variable useless with this model"
	Phi  = 1;
	
" Variable useless with this model"
	Rho = 1;

"LMTD Correction Factor in Counter Flow"
	Method.Fc = 1;

	case "Shell and Tube":

"Temperature Difference at Inlet"
	Method.DT0 = InletHot.T - OutletCold.T;

"Temperature Difference at Outlet"
	Method.DTL = OutletHot.T - InletCold.T;

switch LMTDcorrection

	case "Bowmann":

" Variable not in use with Bowmann equation"
	Phi  = 1;
	
" Variable not in use with Bowmann equation"
	Rho = 1;

"R: Capacity Ratio for LMTD Correction Fator when Shell and Tube"
	R*(OutletCold.T - InletCold.T ) = (InletHot.T-OutletHot.T);

"P: Non - Dimensional Variable for LMTD Correction Fator when Shell and Tube"
	P*(InletHot.T- InletCold.T)= (OutletCold.T-InletCold.T);
	
 if R equal 1
	
    then
	
"LMTD Correction Fator when 1 Pass Shell Side"
	Method.Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214))));

	else
	
"LMTD Correction Fator when 1 Pass Shell Side"
	Method.Fc = sqrt(R*R+1)*ln(abs((1-P*R)/(1-P)))/((1-R)*ln( abs( ( 2-P*(R+1-sqrt(R*R+1)))/ ( 2-P*(R + 1 + sqrt(R*R+1))))));

end

	case "Fakheri":

"R: Capacity Ratio for LMTD Correction Fator when Shell and Tube"
	R*(OutletCold.T - InletCold.T ) = (InletHot.T-OutletHot.T);

"P: Non - Dimensional Variable for LMTD Correction Fator when Shell and Tube"
	P*(InletHot.T- InletCold.T)= (OutletCold.T-InletCold.T);
	
"Non Dimensional Variable for LMTD Correction Fator in Fakheri Equation "
	Phi  = (sqrt(((InletHot.T- OutletHot.T)*(InletHot.T- OutletHot.T))+((OutletCold.T - InletCold.T)*(OutletCold.T - InletCold.T))))/(2*((InletHot.T+ OutletHot.T)-(InletCold.T+ OutletCold.T)));

"Non Dimensional Variable for LMTD Correction Fator in Fakheri Equation"
	Rho*(1-P*R) = (1-P);

if Rho equal 1
	
	then
	
"LMTD Correction Fator when 1 Pass Shell Side"
	Method.Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi))));

	else

"LMTD Correction Fator when 1 Pass Shell Side"
	Method.Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1));
	
end

end

end

end

Model Heatex_NTU  	as Heatex_Basic

ATTRIBUTES
	Pallete 	= true;
	Icon 		= "icon/HeatExchanger_NTU";	
	Brief 	= "Simplified model for Heat Exchangers";
	Info 		=
"This model perform material and heat balance using the NTU-Effectiveness Approach. 
This shortcut calculation does not require exchanger configuration or geometry data.

== Assumptions ==
* Steady-State operation;
* No heat loss to the surroundings.

== Specify ==
* The Inlet streams: Hot and Cold.

== References ==
[1] E.A.D. Saunders, Heat Exchangers: Selection, Design and
 Construction, Longman, Harlow, 1988. 

";
	
PARAMETERS

	ExchangerType 		as Switcher	(Brief="Type of Heat Exchanger",Valid=["Counter Flow","Cocurrent Flow", "Shell and Tube"],Default="Cocurrent Flow");

VARIABLES

Method 	as NTU_Basic	(Brief="NTU Method of Calculation", Symbol =" ");

	xh(NComp) 	as fraction		(Brief = "Liquid Molar Fraction in Hot Side",Hidden=true);
	yh(NComp)	as fraction		(Brief = "Vapour Molar Fraction in Hot Side",Hidden=true);
	vh 				as fraction		(Brief = "Vapour Fraction in Hot Side",Hidden=true);
	
	xc(NComp) 	as fraction		(Brief = "Liquid Molar Fraction in Cold Side",Hidden=true);
	yc(NComp)	as fraction		(Brief = "Vapour Molar Fraction in Cold Side",Hidden=true);
	vc 				as fraction		(Brief = "Vapour Fraction in Cold Side",Hidden=true);

EQUATIONS

"Flash Calculation in Hot Side"
	[vh, xh, yh] = PP.Flash(InletHot.T, InletHot.P, InletHot.z);

"Flash Calculation in Cold Side"
	[vc, xc, yc] = PP.Flash(InletCold.T, InletCold.P, InletCold.z);

"Number of Units Transference"
	Method.NTU*Method.Cmin = U*A;
	
"Minimum Heat Capacity"
	Method.Cmin  = min([Method.Ch,Method.Cc]);

"Maximum Heat Capacity"
	Method.Cmax  = max([Method.Ch,Method.Cc]);

"Thermal Capacity Ratio"
	Method.Cr    = Method.Cmin/Method.Cmax;

"Duty"
	Q	= Method.Eft*Method.Cmin*(InletHot.T-InletCold.T);

"Hot Stream Average Heat Capacity"
	Method.Ch	= InletHot.F*((1-InletHot.v)*PP.LiquidCp(0.5*InletHot.T+0.5*OutletHot.T,0.5*InletHot.P+0.5*OutletHot.P,xh)+
		InletHot.v*PP.VapourCp(0.5*InletHot.T+0.5*OutletHot.T,0.5*InletHot.P+0.5*OutletHot.P,yh));
	
"Cold Stream Average Heat Capacity"
	Method.Cc 	= 	InletCold.F*((1-InletCold.v)*PP.LiquidCp(0.5*InletCold.T+0.5*OutletCold.T,0.5*InletCold.P+0.5*OutletCold.P,xc)+
		InletCold.v*PP.VapourCp(0.5*InletCold.T+0.5*OutletCold.T,0.5*InletCold.P+0.5*OutletCold.P,yc));
	
"Effectiveness Correction"
	Method.Eft1 = 1;

if Method.Cr equal 0 
	
	then
	
"Effectiveness"
	Method.Eft = 1-exp(-Method.NTU);
	
	else

switch  ExchangerType

	case "Cocurrent Flow":
	
"Effectiveness in Cocurrent Flow"
	Method.Eft = (1-exp(-Method.NTU*(1+Method.Cr)))/(1+Method.Cr);

	case "Counter Flow":

if Method.Cr equal 1
	
	then
"Effectiveness in Counter Flow"
	Method.Eft = Method.NTU/(1+Method.NTU);
	
	else
"Effectiveness in Counter Flow"
	Method.Eft = (1-exp(-Method.NTU*(1-Method.Cr)))/(1-Method.Cr*exp(-Method.NTU*(1-Method.Cr)));
	
end

	case "Shell and Tube":
	
"TEMA E Shell Effectiveness"
	Method.Eft 	= 2*(1+Method.Cr+sqrt(1+Method.Cr^2)*((1+exp(-Method.NTU*sqrt(1+Method.Cr^2)))/(1-exp(-Method.NTU*sqrt(1+Method.Cr^2)))) )^(-1);

end


end

end