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Refrigerant Mixture EES Program

 
{Comments are surrounded by quotes or brackets.}
FUNCTION tk(T) "converts from C to K"
tk:=T+273.15 
END 
$INCLUDE /eesw/userlib/REFPROP.TXT

{Calculating what the mdot ratio is from the end point data.} {m_ratio = m_w / m_m} m_ratio=(h_end_mix-h_start_mix)/(h_end_h20-h_start_h20)

{The components and compositions listed below vary for each} {refrigerant mixture.} CALL REFPROP(3,R32,R125,R134a,TQX,TK(29)+Pinch,0,0.3811,0.1796: T_hi,P_hi,v_hi,h_hi,s_hi) CALL REFPROP(3,R32,R125,R134a,PQX,P_hi,0,0.3811,0.1796:T_1m, P_1m,v_1m,h_start_mix,s_1m) CALL REFPROP(3,R32,R125,R134a,PQX,P_hi,1,0.3811,0.1796:T_Nm, P_Nm,v_Nm,h_end_mix,s_Nm) h_start_h20=enthalpy(WATER,T=TK(29),P=P_hi) h_end_h20=enthalpy(WATER,T=TK(34),P=P_hi) T1w=temperature(WATER,h=h_start_h20,P=P_hi) T2w=temperature(WATER,h=h_end_h20,P=P_hi)

{Entered Values} EndPtQ=h_end_mix-h_start_mix "The total heat transferred in the heat exchanger" h_m=Qtot+h_start_mix h_w=(Qtot/m_ratio)+h_start_h20 T_w=temperature(WATER,h=h_w,P=P_hi) CALL REFPROP(3,R32,R125,R134a,PHX,P_hi,h_m,0.3811,0.1796:T_m, Pm,vm,hom,sm) DELTAT_mw=T_m-T_w Delta_T_1=T_1m-T1w "Calculation of the LMTD and U0A0 using" Delta_T_2=T_Nm-T2w "the traditional method" LMTD=(Delta_T_2-Delta_T_1)/(ln(Delta_T_2/Delta_T_1)) U0A0_LMTD=(h_end_mix-h_start_mix)/LMTD

{Integration to find the actual U0A0}

U0A0_act=integral(1/DELTAT_mw,Qtot,0,EndPtQ)

{Calculation of the error using two error scales}

LER=-log10(U0A0_LMTD/U0A0_act) SE=(abs(U0A0_act-U0A0_LMTD)/U0A0_act)*100



Laura Atkinson Schaefer
12/3/1997