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diff --git a/Thermal_Engineering_by_A_V_Arasu/6-Refrigeration_Cycles.ipynb b/Thermal_Engineering_by_A_V_Arasu/6-Refrigeration_Cycles.ipynb new file mode 100644 index 0000000..ee55b95 --- /dev/null +++ b/Thermal_Engineering_by_A_V_Arasu/6-Refrigeration_Cycles.ipynb @@ -0,0 +1,892 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 6: Refrigeration Cycles" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.10: Ideal_COP_of_system.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 10, Page 309\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"Tg=470;//Heating temperature in K\n", +"T0=290;//Cooling temperature in K\n", +"TL=270;//Refrigeration temperature in K\n", +"\n", +"//CALCULATIONS\n", +"COP=((Tg-T0)/Tg)*(TL/(T0-TL));//Ideal COP of absorption refrigeration system\n", +"\n", +"//OUTPUT\n", +"mprintf('Ideal COP of absorption refrigeration system is %3.2f',COP)\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.11: Maximum_and_minimum_temperature_in_cycle_and_COP_and_Rate_of_refrigeration.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 11, Page 317\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T1=-18;//Temperature at point 1 in oC\n", +"T3=27;//Temperature at point 3 in oC\n", +"rp=4;//Pressure ratio\n", +"m=0.045;//mass flow rate in kg/s\n", +"y=1.4;//Ratio of specific heats\n", +"Cp=1.005;//Specific heat at constant pressure in kJ/kg-K\n", +"\n", +"//CALCULATIONS\n", +"x=(y-1)/y;//Ratio\n", +"T2=(rp^x)*(273+T1);//Temperature at point 2 in K\n", +"Tmax=T2-273;//Maximum temperature in oC\n", +"T4=((1/rp)^x)*(273+T3);//Temperature at point 4 in K\n", +"Tmin=T4-273;//Minimum temperature in oC\n", +"qL=Cp*(T1-Tmin);//Heat rejected\n", +"Wcin=Cp*(Tmax-T1);//Compressor work\n", +"Wtout=Cp*(T3-Tmin);//Turbine work\n", +"Wnet=Wcin-Wtout;//Net work done\n", +"COP=qL/Wnet;//Co-efficient of performance\n", +"Qref=m*qL;//Rate of refrigeration in kW\n", +"\n", +"//OUTPUT\n", +"mprintf('Maximum temperature in the cycle is %3.0foC \n Minimum temperature in the cycle is %3.0foC \n COP is %3.2f \n Rate of refrigeration is %3.2f kW',Tmax,Tmin,COP,Qref)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.12: Work_developed_and_Refrigerating_effect_and_COP.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 12, Page 318\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"P1=1;//Pressure at point 1 in bar\n", +"T1=268;//Temperature at point 1 in K\n", +"P2=5;//Pressure at point 2 in bar\n", +"T3=288;//Temperature at point 3 in K\n", +"n=1.3;//Adiabatic gas constant\n", +"Cp=1.005;//Specific heat at constant pressure in kJ/kg-K\n", +"\n", +"//CALCULATIONS\n", +"x=(n-1)/n;//Ratio\n", +"T2=((P2/P1)^x)*T1;//Temperature at point 2 in K\n", +"T4=((P1/P2)^x)*T3;//Temperature at point 4 in K\n", +"W=Cp*(T3-T4);//Work developed per kg of air in kJ/kg\n", +"Re=Cp*(T1-T4);//Refrigerating effect per kg of air in kJ/kg\n", +"Wnet=Cp*((T2-T1)-(T3-T4));//Net work output in kJ/kg\n", +"COP=Re/Wnet;//Co-efficient of performance\n", +"\n", +"//OUTPUT\n", +"mprintf('Work developed per kg of air is %3.3f kJ/kg \n Refrigerating effect per kg of air is %3.3f kJ/kg \n COP of the cycle is %3.2f',W,Re,COP)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.13: COP_of_refrigerator_and_Driving_power_required_and_Air_mass_flow_rate.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 13, Page 319\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T1=277;//Temperature at point 1 in K\n", +"T3=328;//Temperature at point 3 in K\n", +"P1=0.1;//Pressure at point 1 in MPa\n", +"P2=0.3;//Pressure at point 2 in MPa\n", +"nc=0.72;//Isentropic efficiency of compressor\n", +"nt=0.78;//Isentropic efficiency of turbine\n", +"y=1.4;//Adiabatic gas constant\n", +"Cp=1.005;//Specific heat at constant pressure in kJ/kg-K\n", +"m=3;//Cooling load in tonnes\n", +"\n", +"//CALCULATIONS\n", +"x=(y-1)/y;//Ratio\n", +"T2s=T1*((P2/P1)^x);//Temperature at point 2s in K\n", +"T2=((T2s-T1)/nc)+T1;//Temerature at point 2 in K\n", +"T4s=T3*((P1/P2)^x);//Temperature at point 4s in K\n", +"T4=T3-((T3-T4s)*nt);//Temperature at point 4 in K\n", +"Re=Cp*(T1-T4);//Refrigerating effect in kJ/kg\n", +"Wnet=Cp*((T2-T1)-(T3-T4));//Net work output in kJ/kg\n", +"COP=Re/Wnet;//Co-efficient of performance\n", +"P=(m*3.52)/COP;//Driving power required in kW\n", +"ma=(m*3.52)/Re;//Mass flow rate of air in kg/s\n", +"\n", +"//OUTPUT\n", +"mprintf('COP of refrigerator is %3.2f \n Driving power required is %3.0f kW \n Mass flow rate of air is %3.3f kg/s',COP,P,ma)\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.14: Theoretical_COP_and_Net_cooling_produced.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 14, Page 321\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"P1=2.5;//Pressure at point 1 in bar\n", +"P3=9;//Pressure at point 3 in bar\n", +"COPr=0.65;//Ratio of actual COP to the theoretical COP\n", +"m=5;//Refrigerant flow in kg/min\n", +"T1=309;//Temperature at point 1 in K\n", +"T2s=300;//Temperature at point 2s in K\n", +"h1=570.3;//Enthalpy at P1 from the given tables in kJ/kg\n", +"h4=456.4;//Enthalpy at P3 from the given tables in kJ/kg\n", +"h2g=585.3;//Enthalpy at P3 from the given tables in kJ/kg\n", +"s2=4.76;//Entropy at P1 from the given tables in kJ/kg-K\n", +"s2g=4.74;//Entropy at P3 from the given tables in kJ/kg-K\n", +"Cp=0.67;//Specific heat at P3 in kJ/kg-K\n", +"\n", +"//CALCULATIONS\n", +"T2=(2.718^((s2-s2g)/Cp))*T2s;//Temperature at point 2 in K\n", +"h2=h2g+(Cp*(T2-T2s));//Enthalpy at point 2 in kJ/kg\n", +"COPR=(h1-h4)/(h2-h1);//Refrigerant COP\n", +"COPact=COPr*COPR;//Actual COP\n", +"qL=COPact*(h2-h1);//Heat rejected in kJ/kg\n", +"QL=((m*qL*60)/3600)/3.516;//Cooling produced per kg of refrigerant in tonnes of refrigeration\n", +"\n", +"//OUTPUT\n", +"mprintf('Theoretical COP is %3.2f \n Net cooling produced per hour is %3.2f TR',COPR,QL)\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.15: Theoretical_COP_of_machine.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 15, Page 322\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T2=298;//Temperature at point 2 in K\n", +"T1=268;//Temperature at point 1 in K\n", +"hf1=-7.54;//Liquid Enthalpy at T1 in kJ/kg\n", +"x1=0.6;//Quality factor 1\n", +"hfg1=245.3;//Latent heat at T1 in kJ/kg\n", +"sf1=0.251;//Liquid Entropy at T1 in kJ/kg-K\n", +"s1=0.507;//Entropy at point 1 in kJ/kg-K\n", +"hfg2=121.4;//Latent heat at T2 in kJ/kg\n", +"hf2=81.3;//Liquid Enthalpy at T2 in kJ/kg\n", +"h4=hf2;//Enthalpy at point 4 in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"h1=hf1+(x1*hfg1);//Enthalpy at point 1 in kJ/kg\n", +"x2=((s1-sf1)*T2)/hfg2;//Quality factor 2\n", +"h2=hf2+(x2*hfg2);//Enthalpy at point 2 in kJ/kg\n", +"COP=(h1-h4)/(h2-h1);//COP of the machine\n", +"\n", +"//OUTPUT\n", +"mprintf('COP of the machine is %3.2f',COP)\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.16: Theoretical_COP_of_refrigerator_and_Capacity_of_refrigerator.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 16, Page 323\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"P1=25;//Pressure at point 1 in bar\n", +"P2=60;//Pressure at point 2 in bar\n", +"h2=208.1;//Vapour enthalpy at P2 in kJ/kg\n", +"h3=61.9;//Liquid enthalpy at P2 in kJ/kg\n", +"h4=h3;//Liquid enthalpy at P2 in kJ/kg\n", +"s2=0.703;//Vapour entropy at P2 in kJ/kg-K\n", +"sf1=-0.075;//Liquid entropy at P1 in kJ/kg-K\n", +"sfg1=0.971;//Entropy in kJ/kg-K\n", +"hf1=-18.4;//Liquid Enthalpy at P1 in kJ/kg\n", +"hfg1=252.9;//Latent heat at P1 in kJ/kg\n", +"m=5;//Refrigerant flow in kg/min\n", +"\n", +"//CALCULATIONS\n", +"x1=(s2-sf1)/sfg1;//Quality factor 1\n", +"h1=hf1+(x1*hfg1);//Enthalpy at point 1 in kJ/kg\n", +"COP=(h1-h4)/(h2-h1);//Co-efficient of performance\n", +"QL=(m*(h1-h4))/60;//Capacity of the refrigerator in kW\n", +"\n", +"//OUTPUT\n", +"mprintf('COP of refrigerator is %3.2f \n Capacity of refrigerator is %3.2f kW',COP,QL)\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.17: COP_and_Theoretical_power_required.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 17, Page 324\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T1=271;//Temperature at point 1 in K\n", +"T=265;//Temperature at point 1' in K\n", +"Ta=303;//Temperature at point 2' in K\n", +"Cpv=0.733;//Specific heat of vapour in kJ/kg\n", +"Cpl=1.235;//Specific heat of liquid in kJ/kg\n", +"h=184.07;//Liquid enthalpy at T in kJ/kg\n", +"s=0.7;//Entropy at point 1' in kJ/kg-K\n", +"sa=0.685;//Vapour entropy at Ta in kJ/kg-K\n", +"ha=199.62;//Enthalpy at point 2' in kJ/kg\n", +"hfb=64.59;//Liquid enthalpy at Ta in kJ/kg\n", +"DT3=5;//Temperature difference in oC\n", +"Q=2532;//Refrigeration capacity in kJ/min\n", +"\n", +"//CALCULATIONS\n", +"s2=s+(Cpv*((log(T1/T))/(log(2.718))));//Entropy at point 1 in kJ/kg-K\n", +"h1=h+(Cpv*(T1-T));//Enthalpy at point 1 in kJ/kg-K\n", +"T2=(2.718^((s2-sa)/Cpv))*Ta;//Temperature at point 2 in K\n", +"h2=ha+(Cpv*(T2-Ta));//Enthalpy at point 2 in kJ/kg\n", +"h4=hfb-(Cpl*DT3);//Enthalpy at point 4 in kJ/kg\n", +"COP=(h1-h4)/(h2-h1);//Co-efficient of performance\n", +"m=Q/(h1-h4);//Mass flow rate of refrigerant in kJ/min\n", +"P=(m*(h2-h1))/(60*12);//Power required in kW/TR\n", +"\n", +"//OUTPUT\n", +"mprintf('COP is %3.2f \n Theoretical power required per tonne of refrigeration is %3.3f kW/TR',COP,P)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.1: Claim_is_correct_or_not.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 1, Page 308\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"COP=8.5;//Co-efficient of performance\n", +"T1=300;//Room temperature in K\n", +"T2=267;//Refrigeration temperature in K\n", +"\n", +"//CALCULATIONS\n", +"COPmax=T2/(T1-T2);//Maximum COP possible\n", +"\n", +"//OUTPUT\n", +"mprintf('Maximum COP possible is %3.2f \n Since the COP claimed by the inventor is more than the maximum possible COP his claim is not correct',COPmax)\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.2: Weight_of_ice_formed_and_Minimum_power_required.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 2, Page 309\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"TL=268;//Low temperature in K\n", +"TH=293;//High temperature in K\n", +"t=24;//time in hrs\n", +"C=2100;//Capacity of refrigerator in kJ/s\n", +"Tw=10;//Water temperature in oC\n", +"L=335;//Latent heat of ice in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"COP=TL/(TH-TL);//Co-efficient of performance\n", +"Pmin=C/COP;//Minimum power required in kW\n", +"Qr=(4.187*(Tw-0))+L;//Heat removed from water in kJ/kg\n", +"m=C/Qr;//mass of ice formed in kg/s\n", +"W=(m*t*3600)/1000;//Weight of ice formed in tons\n", +"\n", +"//OUTPUT\n", +"mprintf('Minimum power required is %3.2f kW \n Weight of ice formed in 24 hours is %3.2f tons',Pmin,W)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.3: Mass_of_ice_formed.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 3, Page 309\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"TL=-10;//Temperature of brine in oC\n", +"TH=20;//Temperature of water in oC\n", +"L=335;//Latent heat of ice in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"Qr=(4.187*(TH-0))+L;//Heat removed from water in kJ/kg\n", +"COP=(TL+273)/(TH-TL);//Co-efficient of performance\n", +"mi=(COP*3600)/Qr;//mass of ice formed per kWh in kg\n", +"\n", +"//OUTPUT\n", +"mprintf('Mass of ice formed per kWh is %3.1f kg',mi)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.4: EX6_4.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 4, Page 310\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"P1=1.2;//Pressure at point 1 in bar\n", +"P2=7;//Pressure at point 2 in bar\n", +"m=0.05;//mass flow rate of refrigerant in kg/s\n", +"h1=340.1;//Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n", +"s1=1.57135;//Entropy at point 1 from refrigerant-12 tables in kJ/kg-K\n", +"s2=1.57135;//Entropy at point 2 from refrigerant-12 tables in kJ/kg-K\n", +"h2=372;//Enthalpy at point 2 from refrigerant-12 tables in kJ/kg\n", +"h3=226.575;//Enthalpy at point 3 from refrigerant-12 tables in kJ/kg\n", +"h4=226.575;//Enthalpy at point 4 from refrigerant-12 tables in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"Q2=m*(h1-h4);//Rate of heat removed from the refrigerated space in kW\n", +"W=m*(h2-h1);//Power input to the compressor in kW\n", +"Q1=m*(h2-h3);//Rate of heat rejection to the environment in kW\n", +"COP=Q2/W;//Co-efficient of performance\n", +"\n", +"//OUTPUT\n", +"mprintf('Rate of heat removed from the refrigerated space is %3.2f kW \n Power input to the compressor is %3.3f kW \n Rate of heat rejection to the environment is %3.2f kW \n Co-efficient of performance is %3.2f',Q2,W,Q1,COP)\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.5: COP_of_system.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 5, Page 311\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T2=40;//Temperature at point 2 in oC\n", +"T1=-10;//Temperature at point 1 in oC\n", +"h2=367.155;//Enthalpy at point 2 from refrigerant-12 tables in kJ/kg\n", +"s2=1.54057;//Entropy at point 2 from refrigerant-12 tables in kJ/kg-K\n", +"s1=1.54057;//Entropy at point 1 from refrigerant-12 tables in kJ/kg-K\n", +"sg=1.56004;//Entropy from refrigerant-12 tables in kJ/kg-K\n", +"sf=0.96601;//Entropy from refrigerant-12 tables in kJ/kg-K\n", +"hf=190.822;//Enthalpy from refrigerant-12 tables in kJ/kg-K\n", +"hfg=156.319;//Enthalpy from refrigerant-12 tables in kJ/kg-K\n", +"h3=238.533;//Enthalpy at point 3 from refrigerant-12 tables in kJ/kg-K\n", +"h4=h3;//Enthalpy at point 4 from refrigerant-12 tables in kJ/kg-K\n", +"\n", +"//CALCULATIONS\n", +"x1=(s1-sf)/(sg-sf);//Quality factor\n", +"h1=hf+(x1*hfg);//Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n", +"COP=(h1-h4)/(h2-h1);//Co-efficient of performance\n", +"\n", +"//OUTPUT\n", +"mprintf('COP of the system is %3.2f',COP)\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.6: EX6_6.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 6, Page 311\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"Tc=35;//Temperature of condenser in oC\n", +"Te=-15;//Temperature of evaporator in oC\n", +"m=10;//Mass of ice per day in tons\n", +"Tw=30;//Temperature of water in oC\n", +"Ti=-5;//Temperature of ice in oC\n", +"nv=0.65;//Volumetric efficiency\n", +"N=1200;//Speed in rpm\n", +"x=1.2;//Stroke to bore ratio\n", +"na=0.85;//Adiabatic efficiency\n", +"nm=0.95;//Mechanical efficiency\n", +"S=4.187;//Specific heat of water in kJ/kg\n", +"L=335;//Latent heat of ice in kJ/kg\n", +"h1=1667.24;//Enthalpy at Te from Ammonia chart in kJ/kg\n", +"h2=1925;//Enthalpy at Te from Ammonia chart in kJ/kg\n", +"h4=586.41;//Enthalpy at Tc from Ammonia chart in kJ/kg\n", +"v1=0.508;//Specific humidity at Te from Ammonia chart in (m^3)/kg\n", +"\n", +"//CALCULATIONS\n", +"Qr=(((m*1000)/24)*((S*(Tw-0))+L+(1.94*(0-Ti))))/3600;//Refrigerating capacity in kW\n", +"mr=Qr/(h1-h4);//Refrigerant mass flow rate in kg/s\n", +"T2=112;//Discharge temperature in oC\n", +"D=((mr*v1*4*60)/(nv*3.14*x*N))^(1/3);//Cylinder diameter in m\n", +"L=x*D;//Stroke length in m\n", +"W=(mr*(h2-h1))/(na*nm);//Compressor motor power in kW\n", +"COPth=(h1-h4)/(h2-h1);//Theoretical COP\n", +"COPact=Qr/W;//Actual COP\n", +"\n", +"//OUTPUT\n", +"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)\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.7: Circulation_rate_of_ammonia_and_Power_required_and_COP.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 7, Page 313\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T1=-5;//Temperature at point 1 in oC\n", +"T2=30;//Temperature at point 2 in oC\n", +"m=13500;//mass of ice per day in kg\n", +"Tw=20;//Temperature of water in oC\n", +"COP=0.6;//Co-efficient of performance\n", +"h2=1709.33;//Enthalpy at point 2 in kJ/kg\n", +"s2=6.16259;//Entropy at point 2 in kJ/kg-K\n", +"s1=6.16259;//Entropy at point 1 in kJ/kg-K\n", +"sf=1.8182;//Entropy in kJ/kg-K\n", +"sg=6.58542;//Entropy in kJ/kg-K\n", +"hf=400.98;//Enthalpy in kJ/kg\n", +"hfg=1278.35;//Enthalpy in kJ/kg\n", +"h4=562.75;//Enthalpy at point 4 in kJ/kg\n", +"S=4.187;//Specific heat of water in kJ/kg\n", +"L=336;//Latent heat of ice in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"x1=(s1-sf)/(sg-sf);//Quality factor\n", +"h1=hf+(x1*hfg);//Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n", +"COPi=(h1-h4)/(h2-h1);//Ideal COP\n", +"COPact=COP*COPi;//Actual COP\n", +"Qr=((m*S*(Tw-0))+(m*L))/(24*3600);//Total amount of heat removed in kJ/s\n", +"mr=Qr/(h1-h4);//Circulation rate of ammonia in kg/s\n", +"W=mr*(h2-h1);//Power required in kW\n", +"\n", +"//OUTPUT\n", +"mprintf('Circulation rate of ammonia is %3.3f kg/s \n Power required is %3.3f kW \n COP is %3.3f',mr,W,COPact)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.8: EX6_8.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 8, Page 314\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"Tc=20;//Temperature of condenser in oC\n", +"Te=-25;//Temperature of evaporator in oC\n", +"m=15;//Mass of ice per day in tons\n", +"Ts=5;//Subcooled temperature in oC\n", +"Tsh=10;//Superheated temperature in oC\n", +"n=6;//No. of cylinders\n", +"N=950;//Speed of compressor in rpm\n", +"x=1;//Stroke to bore ratio\n", +"h1=402;//Enthalpy at point 1 from R-22 tables in kJ/kg\n", +"h2=442;//Enthalpy at point 2 from R-22 tables in kJ/kg\n", +"h3=216;//Enthalpy at point 3 from R-22 tables in kJ/kg\n", +"h4=216;//Enthalpy at point 4 from R-22 tables in kJ/kg\n", +"v1=2.258;//Specific volume at point 1 in (m^3)/min\n", +"\n", +"//CALCULATIONS\n", +"Re=h1-h4;//Refrigerating effect in kJ/kg\n", +"mr=(m*14000)/(Re*60);//Mass flow of refrigerant in kg/min\n", +"Pth=(mr*(h2-h1))/60;//Theoretical power in kW\n", +"COP=(h1-h4)/(h2-h1);//Co-efficient of performance\n", +"Dth=v1/n;//Theoretical displacement per cylinder\n", +"D=(((Dth*4)/(3.147*N))^(1/3))*1000;//Theoretical bore of compressor in mm\n", +"L=D;//Theoretical stroke of compressor in mm\n", +"\n", +"//OUTPUT\n", +"mprintf('Refrigerating effect is %3.0f kJ/kg \n Mass flow of refrigerant per minute is %3.2f kg/min \n Theoretical input power is %3.2f kW \n COP is %3.2f \n Theoretical bore of compressor is %3.2f mm \n Theoretical stroke of compressor is %3.2f mm',Re,mr,Pth,COP,D,L)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.9: COP_when_there_is_no_subcooling_and_when_there_is_subcooling.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//Chapter-6, Illustration 9, Page 316\n", +"//Title: Refrigeration cycles\n", +"//=============================================================================\n", +"clc\n", +"clear\n", +"\n", +"//INPUT DATA\n", +"T2=40;//Temperature at point 2 in oC\n", +"T1=-5;//Temperature at point 1 in oC\n", +"h2=367.155;//Enthalpy at point 2 from F-12 tables in kJ/kg\n", +"sg=1.55717;//Entropy from F-12 tables in kJ/kg-K\n", +"s1=1.54057;//Entropy at point 1 from F-12 tables in kJ/kg-K\n", +"sf=0.98311;//Entropy from F-12 tables in kJ/kg-K\n", +"hf=195.394;//Enthalpy from F-12 tables in kJ/kg\n", +"hfg=153.934;//Enthalpy from F-12 tables in kJ/kg\n", +"h4=238.533;//Enthalpy at point 4 from F-12 tables in kJ/kg\n", +"h4s=218;//Enthalpy at point 4 with subcooling from F-12 tables in kJ/kg\n", +"\n", +"//CALCULATIONS\n", +"x1=(s1-sf)/(sg-sf);//Quality factor\n", +"h1=hf+(x1*hfg);//Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n", +"COPns=(h1-h4)/(h2-h1);//Co-efficient of performance with no subcooling\n", +"COPs=(h1-h4s)/(h2-h1);//Co-efficient of performance with subcooling\n", +"\n", +"//OUTPUT\n", +"mprintf('COP with no subcooling is %3.3f \n COP with subcooling is %3.3f',COPns,COPs)\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"\n", +"//==============================END OF PROGRAM=================================" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} |