//Chapter-12, Example 12.12, Page 524 //============================================================================= clc clear //INPUT DATA mh=250;//Mass flow rate of hot liquid in kg/h ch=3350;//Specific heat of hot liquid in J/kg.K Thi=120;//Inlet temperature of hot liquid in degree C mc=1000;//Mass flow rate of cold liquid in kg/h Tci=10;//Inlet temperature of cold liquid in degree C U=1160;//Overall heat transfer coefficient in W/m^2.K A=0.25;//Surface area of heat exchanger in m^2 cc=4186;//Specific heat of cold liquid in J/kg.K //CALCULATIONS Cc=((mc*cc)/3600);//Heat capacity rate for cold liquid in W/K Ch=((mh*ch)/3600);//Heat capacity rate for hot liquid in W/K Cmin=min(Cc,Ch);//Minimum heat capacity rate in W/K Cmax=max(Cc,Ch);//Maximum heat capacity rate in W/K r=(Cmin/Cmax);//Ratio of min amd max heat capacity rates NTU=((U*A)/Cmin);//Number of transfer units e=((1-exp(-NTU*(1+r)))/(1+r));//Effectiveness for a parallel flow heat exchanger Qmax=(Cmin*(Thi-Tci));//Maximum possible heat transfer rate in W Q=(e*Qmax);//Actual rate of heat transfer in W Tco=((Q/Cc)+Tci);//Outlet temperature of cold liquid in degree C Tho=(Thi-(Q/Ch));//Outlet temperature of hot liquid in degree C //OUTPUT mprintf('Effectiveness for a parallel flow heat exchanger is %3.3f \n Outlet temperature of water is %3.2f degree C \n Outlet temperature of cooled liquid is %3.2f degree C',e,Tco,Tho) //=================================END OF PROGRAM==============================