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diff --git a/Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter14.ipynb b/Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter14.ipynb new file mode 100644 index 00000000..5a2f6b45 --- /dev/null +++ b/Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter14.ipynb @@ -0,0 +1,729 @@ +{
+ "metadata": {
+ "name": "",
+ "signature": "sha256:b2f54f310fd29f155b5ab8bf6130bc373840081bfb6b07a6cc4e8d0ed69571ef"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "Chapter 14: Refrigeration cycle"
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.1:pg-602"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "T2 = -5.0 # Cold storage temperature in degree Celsius\n",
+ "T1 = 35.0 # Surrounding temperature in degree Celsius\n",
+ "COP = (T2+273)/((T1+273)-(T2+273))\n",
+ "ACOP = COP/3 # Actual COP\n",
+ "Q2 = 29.0 # Heat leakage in kW\n",
+ "W = Q2/ACOP\n",
+ "print \"\\n Example 14.1\\n\"\n",
+ "print \"\\n Power required to drive the plane is \",W ,\" kW\"\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.1\n",
+ "\n",
+ "\n",
+ " Power required to drive the plane is 12.9850746269 kW\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.2:pg-603"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "# At P = 0.14 MPa\n",
+ "h1 = 236.04 # Enthalpy at state 1 in kJ/kg\n",
+ "s1 = 0.9322 # Entropy at state 2 in kJ/kgK\n",
+ "s2 = s1 # Isenthalpic process\n",
+ "# At P = 0.8 MPa\n",
+ "h2 = 272.05 # Enthalpy at state 2 in kJ/kg\n",
+ "h3 = 93.42 # Enthalpy at state 3 in kJ/kg\n",
+ "h4 = h3 # Isenthalpic process\n",
+ "m = 0.06 # mass flow rate in kg/s\n",
+ "Q2 = m*(h1-h4) # Heat absorption\n",
+ "Wc = m*(h2-h1) # Compressor work\n",
+ "Q1 = m*(h2-h4) # Heat rejection in evaporator\n",
+ "COP = Q2/Wc # coefficient of performance\n",
+ "\n",
+ "print \"\\n Example 14.2\\n\"\n",
+ "print \"\\n The rate of heat removal is \",Q2 ,\" kW\"\n",
+ "print \"\\n Power input to the compressor is \",Wc ,\" kW\"\n",
+ "print \"\\n The heat rejection rate in the condenser is \",Q1 ,\" kW\"\n",
+ "print \"\\n COP is \",COP ,\" kW\"\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.2\n",
+ "\n",
+ "\n",
+ " The rate of heat removal is 8.5572 kW\n",
+ "\n",
+ " Power input to the compressor is 2.1606 kW\n",
+ "\n",
+ " The heat rejection rate in the condenser is 10.7178 kW\n",
+ "\n",
+ " COP is 3.9605665093 kW\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.3:pg-604"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "h1 = 183.19 # Enthalpy at state 1 in kJ/kg\n",
+ "h2 = 209.41 # Enthalpy at state 2 in kJ/kg\n",
+ "h3 = 74.59 # Enthalpy at state 3 in kJ/kg\n",
+ "h4 = h3 # Isenthalpic process\n",
+ "T1 = 40.0 # Evaporator temperature in degree Celsius \n",
+ "T2 = -10.0 # Condenser temperature in degree Celsius\n",
+ "W = 5.0 # Plant capacity in tonnes of refrigeration\n",
+ "w = (W*14000/3600)/(h1-h4) # Refrigerant flow rate\n",
+ "v1 = 0.077 # Specific volume of vapor in m**3/kg\n",
+ "VFR = w*v1 # volume flow rate\n",
+ "T = 48.0 # Compressor discharge temperature in degree Celsius\n",
+ "P2 = 9.6066 # Pressure after compression\n",
+ "P1 = 2.1912 # Pressure before compression\n",
+ "rp = P2/P1 # Pressure ratio\n",
+ "Q1 = w*(h2-h3) # Heat rejected in condenser\n",
+ "hf = 26.87 # Enthalpy of fluid in kJ/kg\n",
+ "hfg = 156.31# Latent heat of vaporization in kJ/kg\n",
+ "x4 = (h4-hf)/hfg # quality of refrigerant\n",
+ "COP_v = (h1-h4)/(h2-h1) # Actual coefficient of performance of cycle\n",
+ "PI = w*(h2-h1) # Power input\n",
+ "COP = (T2+273)/((T1+273)-(T2+273)) # Ideal coefficient of performance\n",
+ "r = COP_v/COP\n",
+ "print \"\\n Example 14.3\\n\"\n",
+ "print \"\\n Refrigerant flow rate is \",w ,\" kg/s\"\n",
+ "print \"\\n Volume flow rate is \",VFR ,\" m**3/s\"\n",
+ "print \"\\n Compressor discharge temperature is \",T ,\" degree Celsius \"\n",
+ "print \"\\n Pressure ratio is \",rp\n",
+ "print \"\\n Heat rejected to the condenser is \",Q1 ,\" kW\"\n",
+ "print \"\\n Flash gas percentage is \",x4*100 ,\" percent\"\n",
+ "print \"\\n COP is \",COP_v ,\" kW\"\n",
+ "print \"\\n Power required to drive the compressor is \",PI ,\" kW\"\n",
+ "print \"\\n Ratio of COP of cycle with Carnot refrigerator is \",r\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.3\n",
+ "\n",
+ "\n",
+ " Refrigerant flow rate is 0.179046449765 kg/s\n",
+ "\n",
+ " Volume flow rate is 0.0137865766319 m**3/s\n",
+ "\n",
+ " Compressor discharge temperature is 48.0 degree Celsius \n",
+ "\n",
+ " Pressure ratio is 4.38417305586\n",
+ "\n",
+ " Heat rejected to the condenser is 24.1390423573 kW\n",
+ "\n",
+ " Flash gas percentage is 30.5290768345 percent\n",
+ "\n",
+ " COP is 4.14187643021 kW\n",
+ "\n",
+ " Power required to drive the compressor is 4.69459791283 kW\n",
+ "\n",
+ " Ratio of COP of cycle with Carnot refrigerator is 0.787428979127\n"
+ ]
+ }
+ ],
+ "prompt_number": 4
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.4:pg-605"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "h3 = 882 # Enthalpy at state 3 in kJ/kg\n",
+ "h2 = 1034 # Enthalpy at state 2 in kJ/kg\n",
+ "h6 = 998 # Enthalpy at state 6 in kJ/kg\n",
+ "h1 = 1008 # Enthalpy at state 1 in kJ/kg\n",
+ "v1 = 0.084 # Specific volume at state 1 in m**3/kg\n",
+ "t4 = 25 # Temperature at state 4 in degree Celsius\n",
+ "m = 10 # mass flow rate in kg/s\n",
+ "h4 = h3-h1+h6 \n",
+ "h5 = h4 # isenthalpic process\n",
+ "w = (m*14000)/((h6-h5)*3600) # in kg/s\n",
+ "VFR = w*3600*v1 # Volume flow rate in m**3/h\n",
+ "ve = 0.8 # volumetric efficiency\n",
+ "CD = VFR/(ve*60) # Compressor displacement in m**3/min\n",
+ "N = 900 # Number of strokes per minute\n",
+ "n = 2 # number of cylinder\n",
+ "\n",
+ "D = ((CD*4)/(math.pi*1.1*N*n))**(1/3) # L = 1.1D L = length D = diameter\n",
+ "L = 1.1*D\n",
+ "COP = (h6-h5)/(h2-h1) # coefficient of performance\n",
+ "PI = w*(h2-h1) # Power input\n",
+ "\n",
+ "print \"\\n Example 14.4\\n\"\n",
+ "print \"\\n Refrigeration effect is \",h6-h5 ,\" kJ/kg\"\n",
+ "print \"\\n Refrigerant flow rate is \",w ,\" kg/s\"\n",
+ "print \"\\n Diameter of cylinder is \",D*100 ,\" cm\"\n",
+ "print \"\\n Length of cylinder is \",L*100 ,\" cm\"\n",
+ "print \"\\n COP is \",COP\n",
+ "print \"\\n Power required to drive the compressor is \",PI ,\" kW\"\n",
+ "\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.4\n",
+ "\n",
+ "\n",
+ " Refrigeration effect is 126 kJ/kg\n",
+ "\n",
+ " Refrigerant flow rate is 0 kg/s\n",
+ "\n",
+ " Diameter of cylinder is 100.0 cm\n",
+ "\n",
+ " Length of cylinder is 110.0 cm\n",
+ "\n",
+ " COP is 4\n",
+ "\n",
+ " Power required to drive the compressor is 0 kW\n"
+ ]
+ }
+ ],
+ "prompt_number": 5
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.5:pg-607"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "P2 = 1554.3 # Pressure at state 2 in kPa\n",
+ "P1 = 119.5# Pressure at state 1 in kPa\n",
+ "Pi = sqrt(P1*P2)\n",
+ "h1 = 1404.6 # Enthalpy at state1 in kJ/kg\n",
+ "h2 = 1574.3 # Enthalpy at state2 in kJ/kg\n",
+ "h3 = 1443.5 # Enthalpy at state3 in kJ/kg\n",
+ "h4 = 1628.1# Enthalpy at state4 in kJ/kg\n",
+ "h5 = 371.7 # Enthalpy at state5 in kJ/kg\n",
+ "h6 = h5 # Isenthalpic process\n",
+ "h7 = 181.5# Enthalpy at state7 in kJ/kg\n",
+ "w = 30 # capacity of plant in tonnes of refrigeration\n",
+ "m2_dot = (3.89*w)/(h1-h7) # mass flow rate in upper cycle\n",
+ "m1_dot = m2_dot*((h2-h7)/(h3-h6))# mass flow rate in lower cycle\n",
+ "Wc_dot = m2_dot*(h2-h1)+m1_dot*(h4-h3) # Compressor work\n",
+ "COP = w*3.89/Wc_dot # Coefficient of performance of cycle\n",
+ "# single stage\n",
+ "h1_ = 1404.6 #Enthalpy at state1 in kJ/kg \n",
+ "h2_ = 1805.1 # Enthalpy at state2 in kJ/kg \n",
+ "h3_ = 371.1 # Enthalpy at state3 in kJ/kg \n",
+ "h4_ = h3_ # Isenthalpic process\n",
+ "m_dot = (3.89*30)/(h1_-h4_) # mass flow rate in cycle\n",
+ "Wc = m_dot*(h2_-h1_) # Compressor work\n",
+ "COP_ = w*3.89/Wc # Coefficient of performance of cycle\n",
+ "IW = (Wc-Wc_dot)/Wc_dot # Increase in compressor work\n",
+ "ICOP = (COP-COP_)/COP_ # Increase in COP for 2 stage compression\n",
+ "print \"\\n Example 14.5\\n\"\n",
+ "print \"\\n Increase in work of compression for single stage is \",IW*100 ,\" percent\"\n",
+ "print \"\\n Increase in COP for 2 stage compression is \",ICOP*100 ,\" percent\"\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.5\n",
+ "\n",
+ "\n",
+ " Increase in work of compression for single stage is 15.719846307 percent\n",
+ "\n",
+ " Increase in COP for 2 stage compression is 15.719846307 percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 6
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.6:pg-608"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "# Given that\n",
+ "te = -10 # Evaporator temperature in degree celsius\n",
+ "pc = 7.675 # Condenser pressure in bar\n",
+ "pf = 4.139 # Flash chamber pressure in bar\n",
+ "P = 100 # Power input to compressor in kW\n",
+ "print \"\\n Example 14.6\\n\"\n",
+ "# From the property table of R-134a,\n",
+ "h7 = 140.96 # In kJ/kg\n",
+ "hf = 113.29 # In kJ/kg\n",
+ "hfg = 300.5-113.29 # In kJ/kg\n",
+ "hg = 300.5 # In kJ/kg\n",
+ "h1 = 288.86 # In kJ/kg\n",
+ "s1 = 1.17189 # # In kJ/kgK\n",
+ "s2 =s1\n",
+ "#By interpolation \n",
+ "h2 = 303.468 # In kJ/kg\n",
+ "x8 = (h7-hf)/hfg\n",
+ "m1=x8\n",
+ "h5 = (1-m1)*h2 + m1*hg\n",
+ "# By interpolation\n",
+ "s5 = 1.7174 # In kJ/kgK\n",
+ "s6=s5\n",
+ "h6 = 315.79 # In kJ/kg\n",
+ "m = P/((h6-h5) + (1-m1)*(h2-h1))\n",
+ "m_e = (1-m1)*m\n",
+ "COP = m_e*(h1-hf)/P\n",
+ "print \"\\n The COP of the plant is \",COP ,\", \\n The mass flow rate of refrigerant in the evaporator is \",m_e ,\" kg/s\"\n",
+ "\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.6\n",
+ "\n",
+ "\n",
+ " The COP of the plant is 5.93506047745 , \n",
+ " The mass flow rate of refrigerant in the evaporator is 3.38045251321 kg/s\n"
+ ]
+ }
+ ],
+ "prompt_number": 8
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.7:pg-609"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "tsat = 120.2 # Saturation temperature in degree Celsius\n",
+ "hfg = 2201.9 # Latent heat of fusion in kJ/kg\n",
+ "T1 = 120.2 # Generator temperature in degree Celsius\n",
+ "T2 = 30 # Ambient temperature in degree Celsius\n",
+ "Tr = -10 # Operating temperature of refrigerator in degree Celsius\n",
+ "COP_max = (((T1+273)-(T2+273))*(Tr+273))/(((T2+273)-(Tr+273))*(T1+273)) # Ideal coefficient of performance \n",
+ "ACOP = 0.4*COP_max # Actual COP\n",
+ "L = 20 # Refrigeration load in tonnes\n",
+ "Qe = (L*14000)/3600 # Heat extraction in KW\n",
+ "Qg = Qe/ACOP # Heat transfer from generator \n",
+ "x = 0.9 # Quality of refrigerant\n",
+ "H = x*hfg # Heat extraction\n",
+ "SFR = Qg/H # Steam flow rate\n",
+ "print \"\\n Example 14.7\\n\"\n",
+ "print \"\\n Steam flow rate required is \",SFR ,\" kg/s\"\n",
+ "#The answers vary due to round off error\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.7\n",
+ "\n",
+ "\n",
+ " Steam flow rate required is 0.0644023696678 kg/s\n"
+ ]
+ }
+ ],
+ "prompt_number": 9
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.8:pg-611"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "# Given that\n",
+ "tf = 5 # Temperature of flash chamber in degree celsius\n",
+ "x = 0.98 # Quality of water vapour living the evaporator\n",
+ "t2 = 14 # Returning temperature of chilled water in degree celsius\n",
+ "t0 = 30 # Make up water temperature in degree celsius\n",
+ "m = 12 # Mass flow rate of chilled water in kg/s\n",
+ "nc = 0.8 # Compressor efficiecy \n",
+ "pc = 0.1 # Condenser pressure in bar\n",
+ "print \"\\n Example 14.8\\n\"\n",
+ "#From the steam table\n",
+ "hf = 58.62 # In kJ/kg at 14 degree celsius\n",
+ "hf_ = 20.93 # In kJ/kg at 5 degree celsius\n",
+ "hf__ = 125.73 # In kJ/kg at 30 degree celsius\n",
+ "hv = x*2510.7\n",
+ "Rc = m*(hf-hf_)/3.5\n",
+ "m_v = Rc*3.5/(hv-hf__)\n",
+ "# At 0.10 bar\n",
+ "hg = 2800 # In kJ/kg \n",
+ "Win = m_v*(hg-hv)/nc\n",
+ "COP = Rc*3.5/Win\n",
+ "print \"\\nCOP of the system is \",COP"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.8\n",
+ "\n",
+ "\n",
+ "COP of the system is 5.50140730574\n"
+ ]
+ }
+ ],
+ "prompt_number": 10
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.9:pg-611"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "\n",
+ "T1 = 4.0 # Compressor inlet temperature in degree Celsius\n",
+ "T3 = 55.0 # Cooling limit in heat exchanger in degree Celsius\n",
+ "rp = 3.0 # Pressure ratio\n",
+ "g = 1.4 # Heat capacity ratio\n",
+ "cp = 1.005 # Constant volume heat capacity\n",
+ "L = 3.0 # Cooling load in tonnes of refrigeration\n",
+ "nc = 0.72 # compressor efficiency\n",
+ "T2s = (T1+273)*(rp**((g-1)/g)) # Ideal temperature after compression\n",
+ "T2 = (T1+273)+(T2s-T1-273)/nc # Actual temperature after compression\n",
+ "T4s = (T3+273)/(rp**((g-1)/g)) # Ideal temperature after expansion\n",
+ "T34 = 0.78*(T3+273-T4s) # Change in temperature during expansion process\n",
+ "T4 = T3+273-T34 # Actual temperature after expansion\n",
+ "COP = (T1+273-T4)/((T2-T1-273)-(T3+273-T4)) # Coefficient of performance of cycle\n",
+ "P = (L*14000)/(COP*3600) # Driving power required\n",
+ "m = (L*14000)/(cp*(T1+273-T4)) # Mass flow rate of air\n",
+ "print \"\\n Example 14.9\\n\"\n",
+ "print \"\\n COP of the refrigerator is \",COP\n",
+ "print \"\\n Driving power required is \",P ,\" kW\"\n",
+ "print \"\\n Mass flow rate is \",m/3600 ,\" kg/s\"\n",
+ "#The answers vary due to round off error"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.9\n",
+ "\n",
+ "\n",
+ " COP of the refrigerator is 0.245731992881\n",
+ "\n",
+ " Driving power required is 47.4771987558 kW\n",
+ "\n",
+ " Mass flow rate is 0.64768311581 kg/s\n"
+ ]
+ }
+ ],
+ "prompt_number": 11
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.10:pg-611"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "P1 = 2.4 #Compressor inlet pressure in bar\n",
+ "T1 = 0 # Compressor inlet temperature in degree Celsius\n",
+ "h1 = 188.9 # Enthalpy of refrigerant at state 1 in kJ/kg\n",
+ "s1 = 0.7177 # Entropy of refrigerant at state 1 in kJ/kgK\n",
+ "v1 = 0.0703 # Specific volume at state 1 in m**3/kg\n",
+ "P2 = 9 # Compressor outlet pressure in bar\n",
+ "T2 = 60 # Compressor outlet pressure in degree Celsius\n",
+ "h2 = 219.37 # Actual compressor outlet enthalpy in kJ/kgK\n",
+ "h2s = 213.27 # Ideal compressor outlet enthalpy in kJ/kgK\n",
+ "h3 = 71.93 # Enthalpy of refrigerant at state 3 in kJ/kg\n",
+ "h4 = h3 # Isenthalpic process\n",
+ "\n",
+ "A1V1 = 0.6/60 # volume flow rate in kg/s\n",
+ "m_dot = A1V1/v1 # mass flow rate\n",
+ "Wc_dot = m_dot*(h2-h1) # Compressor work\n",
+ "Q1_dot = m_dot*(h2-h3) # Heat extracted \n",
+ "COP = Q1_dot/Wc_dot # Coefficient of performance\n",
+ "nis = (h2s-h1)/(h2-h1) # Isentropic compressor efficiency\n",
+ "print \"\\n Example 14.10\\n\"\n",
+ "print \"\\n Power input is \",Wc_dot ,\" kW\"\n",
+ "print \"\\n Heating capacity is \",Q1_dot ,\" kW\"\n",
+ "print \"\\n COP is \",COP\n",
+ "print \"\\n The isentropic compressor efficiency is \",nis*100 ,\" percent\"\n",
+ "#The answers vary due to round off error"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.10\n",
+ "\n",
+ "\n",
+ " Power input is 4.33428165007 kW\n",
+ "\n",
+ " Heating capacity is 20.972972973 kW\n",
+ "\n",
+ " COP is 4.83885789301\n",
+ "\n",
+ " The isentropic compressor efficiency is 79.9803085002 percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 12
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "\n",
+ "Ex14.11:pg-611"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "\n",
+ "T1 = 275.0 # Temperature of air at entrance to compressor in K \n",
+ "T3 = 310.0 # Temperature of air at entrance to turbine in K \n",
+ "P1 = 1.0 # Inlet presure in bar\n",
+ "P2 = 4.0 # Outlet pressure in bar\n",
+ "nc = 0.8 # Compressor efficiency\n",
+ "T2s = T1*(P2/P1)**(.286) # Ideal temperature after compression\n",
+ "T2 = T1 + (T2s-T1)/nc # Actual temperature after compression\n",
+ "pr1 = 0.1 # Pressure loss in cooler in bar\n",
+ "pr2 = 0.08 #Pressure loss in condensor in bar \n",
+ "P3 = P2-0.1 # Actual pressure in condesor\n",
+ "P4 = P1+0.08 # Actual pressure in evaporator\n",
+ "PR = P3/P4 # Pressure ratio\n",
+ "T4s = T3*(1/PR)**(0.286) # Ideal temperature after expansion\n",
+ "nt = 0.85 # turbine efficiency\n",
+ "T4 = T3-(T3-T4s)*nt # Actual temperature after expansion\n",
+ "COP = (T1-T4)/((T2-T3)-(T1-T4)) # Coefficient of performance \n",
+ "print \"\\n Example 14.11\\n\"\n",
+ "print \"\\n Pressure ratio for the turbine is \",PR\n",
+ "print \"\\n COP is \",COP\n",
+ "#The answers vary due to round off error\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.11\n",
+ "\n",
+ "\n",
+ " Pressure ratio for the turbine is 3.61111111111\n",
+ "\n",
+ " COP is 0.533011099882\n"
+ ]
+ }
+ ],
+ "prompt_number": 13
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Ex14.12:pg-611"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "# Given that\n",
+ "L = 60.0 # Cooling load in kW\n",
+ "p = 1.0 # Pressure in bar\n",
+ "t = 20.0 # Temperature in degree celsius\n",
+ "v = 900.0 # Speed of aircraft in km/h\n",
+ "p1 = 0.35 # Pressure in bar\n",
+ "T1 = 255 # Temperature in K\n",
+ "nd = .85 # Diffuser efficiency \n",
+ "rp = 6.0 # Pressure ratio of compressor\n",
+ "nc = .85 # Copressor efficiency \n",
+ "E = 0.9 # Effectiveness of air cooler\n",
+ "nt = 0.88 # Turbine efficiency \n",
+ "p_ = 0.08 # Pressure drop in air cooler in bar\n",
+ "p5 = 1.08 # Pressure in bar\n",
+ "cp = 1.005 # Heat capacity of air at constant pressure in kJ/kgK\n",
+ "gama = 1.4 # Ratio of heat capacities of air\n",
+ "print \"\\n Example 14.12\\n\"\n",
+ "V = v*(5/18)\n",
+ "T2_ = T1 + (V**2)/(2*cp*1000)\n",
+ "T2 = T2_\n",
+ "p2_ = p1*((T2_/T1)**((gama/(gama-1))))\n",
+ "p2 = p1 + nd*(p2_-p1)\n",
+ "p3 = rp*p2\n",
+ "T3_ = T2*((p3/p2)**((gama-1)/gama))\n",
+ "T3 = T2 + (T3_-T2)/nc\n",
+ "P = cp*(T3-T2)\n",
+ "p4 = p3 - p_\n",
+ "T4 = T3 - E*(T3-T2)\n",
+ "T5_ = T4/((p4/p5)**(.286))\n",
+ "T5 = T4 - (T4-T5_)/nt\n",
+ "RE = cp*(t+273 - T5)\n",
+ "m = L/51.5\n",
+ "Pr = m*P\n",
+ "COP = L/Pr\n",
+ "print \"\\n Mass flow rate of air flowing through the cooling system is \",m\n",
+ "print \"\\n COP is \",COP\n",
+ "#The answers vary due to round off error"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "\n",
+ " Example 14.12\n",
+ "\n",
+ "\n",
+ " Mass flow rate of air flowing through the cooling system is 1.16504854369\n",
+ "\n",
+ " COP is 0.255512245083\n"
+ ]
+ }
+ ],
+ "prompt_number": 14
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+}
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