// Theory and Problems of Thermodynamics // Chapter 9 // Air_water Vapor Mixtures // Example 11 clear ;clc; //Given data RH1 = 0.8 // relative humidity moist air entering T1 = 308.15 // Temp of air entering cooling device in K P = 101.325 // pressure of entering air in kPa RH4 = 0.4 // relative humidity moist air leaving T4 = 293.15 // temperature at air required to leave in K m = 2 // flowrate dry air in kg/s // data from psychometric chart SH1 = 0.029 // in kg H2O/kg air h1 = 110 // in kJ/kg air SH4 = 0.0055 // in kg H2O/kg air h4 = 34 // in kJ/kg air SH2 = SH4 RH2 = 1 h2 = 19 // in kJ/kg air T2 = 278.15 // in K hw3 = 20.97 // at 5 degree C in kJ/kg // masss balance for H2O: ma1*SH1 = ma2*SH2 + mw3 mw3 = m*(SH1-SH2) // amount of water condensed in kg/s // Energy balance: ma1*h1 = ma2*h2 + mw3*hw3 + Qc Qc = m*(h1-h2) - mw3*hw3 // in kJ/s Qh = m*(h4-h2) // Output Results mprintf('The amount of water condensed in refrigeration unit = %4.3f kg/s' , mw3); mprintf('\n The rate of cooling required in refrigeration unit = %2.0f kW' , Qc); mprintf('\n The rate of heating required in refrigeration unit = %2.0f kW' , Qh);