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diff --git a/1073/CH3/EX3.28/3_28.sce b/1073/CH3/EX3.28/3_28.sce
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+clc;
+clear;
+//Example 3.28
+mair_dot=0.90   //[kg/s]
+T1=283  //[K]
+T2=366  //[K]
+dT=(T1+T2)/2    //[K]
+Di=12   //[mm]
+Di=Di/1000  //[m]
+G=19.9  //[kg/(sq m.s)]
+mu=0.0198   //[mN.s/(sq m)]
+mu=mu*10^-3 //[N.s/sq m] or [kg/(m.s)]
+Nre=Di*G/mu //Reynolds number
+//It is greater than 10^4
+k=0.029 //W/(m.K)
+Cp=1    //[kJ/kg.K]
+Cp1=Cp*10^3  //[J/kg.K]
+Npr=Cp1*mu/k //Parndtl number
+//Dittus-Boelter equation is
+hi=0.023*(Nre^0.8)*(Npr^0.4)*k/Di   //[W/sq m.K]
+ho=232  //W/sq m.K
+U=1/(1/hi+1/ho) //Overall heat transfer coefficient  [W/m^2.K]
+Q=mair_dot*Cp*(T2-T1)   //kJ/s
+Q=Q*10^3    //[J/s] or [W]
+T=700   //[K]
+dT1=T-T2    //[K]
+dT2=T2-T1   //[K]
+dTm=(dT1-dT2)/log(dT1/dT2)  //[K]
+//Q=U*A*dTm
+A=Q/(U*dTm) //Area in sq m
+printf("Heat transfer area of equipment is %f sq m",A);