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+clc;clear;
+//Example 7.22
+//difference in answers is arised due the fact the Energy savings have been rounded to the multiple of 100
+
+//given data
+T1=20+273;
+T2=24+273;
+P1=101;
+P2=801;
+D=3/1000;//in m
+Cdischarge=0.65;
+ncomp=0.8;
+nmotor=0.92;
+UC=0.078;//unit cost
+
+//constants used
+R=0.287;//in kJ/kg K
+k=1.4;
+n=1.4;
+
+//calculations
+Win=n*R*T1/(ncomp*(n-1))*((P2/P1)^((n-1)/n)-1);
+A=%pi*D^2/4;
+mair=Cdischarge*(2/(k+1))^(1/(k-1))*P2*A/(R*T2)*sqrt(k*R*1000*2/(k+1)*T2);//factor of 1000 to m^2/s^2
+PW=mair*Win;//Power wasted
+ES=PW*4200/nmotor;//4200 is operating hours ES stands for Energy savings
+disp(ES,'Energy savings in kWh/yr');
+CS=ES*UC;
+disp(ceil(CS),'cost savings in Dollar/yr')