{ "metadata": { "name": "", "signature": "sha256:abd9968b31b6fc770d85971aacc78f09c6ba4e5596d9831c5736d23440171297" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 12 : Refrigeration" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.1 Page No : 216" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "m = 500.0;#mass of ice produced per hour in Kg\n", "T1 = 15.0;#Initial temperature of water\n", "T2 = -5.0;#Final temperature of ice\n", "Ci = 0.5;#Specific heat of ice in Kcal/Kg deg celsius\n", "Cw = 1.0;#Specific heat of water in Kcal/Kg deg celsius\n", "L_f = 79.71;#Latent heat of fusion in Kcal/Kg\n", "Tf = 0.0;#Frezzing point of ice in deg celsius\n", "\n", "#To Calculate the theoretical horse power required\n", "Q2 = m*(Cw*(T1-Tf)+L_f+Ci*(Tf-T2));#Heat to be extracted per hour in Kcal\n", "#From equation 12.1 (page no 220)\n", "COP = (T2+273)/((T1+273)-(T2+273));\n", "W = Q2/COP;#Work in Kcal/hr\n", "W1 = W*(427/(60*4500.0));\n", "print \"The therotical horse power required is %f hp\"%(W1);\n", "#end\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The therotical horse power required is 5.736411 hp\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.2 Page No : 217" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "from scipy.integrate import quad\n", "\n", "#Given\n", "Ta = 298.0;#Initial temperature in K\n", "Tb = 203.0;#Final temperature in k\n", "T1 = 298.0;#Water temperature in K\n", "n = 1.0;#Kgmole of CO2\n", "#Cp = 5.89+0.0112T ; Specific heat of CO2 in Kcal/Kgmole K\n", "\n", "#To Calculate the compressor load\n", "#From equation 12.2a and b (page no 221)\n", "def f(T):\n", " y = ((T1-T)/T)*n*(5.89+0.0112*T);\n", " return y\n", "W = quad(f,Ta,Tb)[0];\n", "print \"The compressor load is %f Kcal/Kgmole\"%(W);\n", "#end\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The compressor load is -164.797031 Kcal/Kgmole\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.3 Page No : 221" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Given\n", "#Consider the figure 12.4 (page no 226) \n", "m = 5.0;#tonnes of refrigeration\n", "T1 = 273-10.0;#temperature of the saturated vapour in K\n", "T2 = 273+35.0;#temperature of the super heated vapour in K\n", "T3 = 273+25.0;#temperature of the saturated liquid in K\n", "T4 = 273+25.0;#temperature of the wet vapour in K\n", "H1 = 341.8;#enthalpy of the saturated vapour in Kcal/Kg\n", "H2 = 409.0;#enthalpy of the super heated vapour in Kcal/Kg\n", "H3 = 350.0;#enthalpy of the saturated liquid in Kcal/Kg\n", "H4 = 71.3;#enthalpy of the wet vapour in Kcal/Kg\n", "\n", "#To Calculate the C.O.P, mass of refrigerant required, compressor horse power required and the C.O.P & compressor horse power for a reversed Carnot cycle\n", "#(i)Calculation of the C.O.P of the compression cycle\n", "#From equation 12.6 (page no 226)\n", "COP = (H1-H4)/(H2-H1);\n", "print \"i)C.O.P of the compression cycle is %f\"%(COP);\n", "\n", "#(ii)Calculation of mass of refrigerant required\n", "#From equation 12.7 (page no 226)\n", "M = (m*50.4)/(H1-H4);\n", "print \" ii)The mass of refrigerant required is %f Kg/mt\"%(M);\n", "\n", "#(iii)Calculation of the compressor horse power\n", "#From equation 12.5 (page no 226)\n", "C_hp = (H2-H1)*M*(427/4500.0);\n", "print \" iii)The compressor horse power is %f hp\"%(C_hp);\n", "\n", "#(iv)Calculation for reversed Carnot cycle\n", "#From equation 12.1 (page no 220)\n", "COP = T1/(T3-T1);\n", "print \" iv)C.O.P for the reversed Carnot cycle is %f\"%(COP);\n", "Q2 = m*50.4*(427/4500.0);#in hp\n", "C_hp = Q2/COP\n", "print \" Compressor horse power for the reversed Carnot cycle is %f hp\"%(C_hp);\n", "#end\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "i)C.O.P of the compression cycle is 4.025298\n", " ii)The mass of refrigerant required is 0.931608 Kg/mt\n", " iii)The compressor horse power is 5.940430 hp\n", " iv)C.O.P for the reversed Carnot cycle is 7.514286\n", " Compressor horse power for the reversed Carnot cycle is 3.182205 hp\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.4 Page No : 225" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Water at 20 deg cel is chilled to 10 deg cel by flash evaporation\n", "Pv = 0.012;#Vapour pressure of water at 10 deg celsius in Kgf/sq.cm\n", "H1 = 20.03;#Enthalpy of liquid water at 20 deg cel in Kcal/Kg\n", "H2 = 10.4;#Enthalpy of liquid water at 10 deg cel in Kcal/Kg\n", "Hv = 601.6;#Enthalpy of saturated vapour at 10 deg cel in Kcal/kg\n", "\n", "#To calculate the pressure in the math.tank and the amount of make up water required\n", "P = Pv;#pressure in the math.tank = vapour pressure of water\n", "print \"The pressure in the math.tank is %f Kgf/sq.cm\"%(P);\n", "#From equation 12.8 (page no 234)\n", "x = (H1-H2)/(Hv-H2);\n", "print \" The amount of make up water required is %f Kg\"%(x);\n", "#end\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The pressure in the math.tank is 0.012000 Kgf/sq.cm\n", " The amount of make up water required is 0.016289 Kg\n" ] } ], "prompt_number": 5 } ], "metadata": {} } ] }