//Chapter-6, Illustration 6, Page 311 //Title: Refrigeration cycles //============================================================================= clc clear //INPUT DATA Tc=35;//Temperature of condenser in oC Te=-15;//Temperature of evaporator in oC m=10;//Mass of ice per day in tons Tw=30;//Temperature of water in oC Ti=-5;//Temperature of ice in oC nv=0.65;//Volumetric efficiency N=1200;//Speed in rpm x=1.2;//Stroke to bore ratio na=0.85;//Adiabatic efficiency nm=0.95;//Mechanical efficiency S=4.187;//Specific heat of water in kJ/kg L=335;//Latent heat of ice in kJ/kg h1=1667.24;//Enthalpy at Te from Ammonia chart in kJ/kg h2=1925;//Enthalpy at Te from Ammonia chart in kJ/kg h4=586.41;//Enthalpy at Tc from Ammonia chart in kJ/kg v1=0.508;//Specific humidity at Te from Ammonia chart in (m^3)/kg //CALCULATIONS Qr=(((m*1000)/24)*((S*(Tw-0))+L+(1.94*(0-Ti))))/3600;//Refrigerating capacity in kW mr=Qr/(h1-h4);//Refrigerant mass flow rate in kg/s T2=112;//Discharge temperature in oC D=((mr*v1*4*60)/(nv*3.14*x*N))^(1/3);//Cylinder diameter in m L=x*D;//Stroke length in m W=(mr*(h2-h1))/(na*nm);//Compressor motor power in kW COPth=(h1-h4)/(h2-h1);//Theoretical COP COPact=Qr/W;//Actual COP //OUTPUT mprintf('Refrigerating capacity of plant is %3.2f kW \n Refrigerant mass flow rate is %3.4f kg/s \n Discharge temperature is %3.0f oC \n Cylinder diameter is %3.3f m \n Stroke length is %3.3f m \n Compressor motor power is %3.2f kW \n Theoretical COP is %3.2f \n Actual COP is %3.2f',Qr,mr,T2,D,L,W,COPth,COPact) //==============================END OF PROGRAM=================================