{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 8 - Refrigeration and liquifaction processes" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.1 Page: 297" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.1 - Page: 297\n", "\n", "\n", "The coeffecient of performance of the cycle is 7.91\n", "\n", "The power required is 3.79 kW\n", "\n", "The rate of heat rejection in the room is 33.79 kW\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.1 - Page: 297\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Tl = 273 - 4## [K]\n", "Th = 273 + 30## [K]\n", "Ql = 30## [kW]\n", "#*************\n", "\n", "# Solution (a)\n", "COP = Tl/(Th - Tl)#\n", "print \"The coeffecient of performance of the cycle is %.2f\\n\"%(COP)\n", "\n", "# Solution (b)\n", "Wnet = Ql/COP## [kW]\n", "print \"The power required is %.2f kW\\n\"%(Wnet)\n", "\n", "# Solution (c)\n", "Qh = Wnet + Ql## [kW]\n", "print \"The rate of heat rejection in the room is %.2f kW\"%(Qh)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.2 Page: 298" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.2 - Page: 298\n", "\n", "\n", "The power consumption is 0.735 kW\n", "\n", "Cooling Effect produced is 2.862 kW\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.2 - Page: 298\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Tl = -10 + 273## [K]\n", "Th = 45 + 273## [K]\n", "Ql = 1## [ton]\n", "#*************\n", "\n", "# Solution (a)\n", "COP = Tl/(Th - Tl)#\n", "Wnet = Ql*3.516/COP## [kW]\n", "print \"The power consumption is %.3f kW\\n\"%(Wnet)\n", "\n", "# Solution (b)\n", "Tl = -20 + 273## [K]\n", "Th = 45 + 273## [K]\n", "COP = Tl/(Th - Tl)#\n", "Ql = Wnet*COP## [kW]\n", "print \"Cooling Effect produced is %.3f kW\\n\"%(Ql)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.3 Page: 298" ] }, { "cell_type": "code", "execution_count": 3, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.3 - Page: 298\n", "\n", "\n", "Increase in percentage of work output is 22.97 %\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.3 - Page: 298\\n\\n\"\n", "\n", "# Solution\n", "\n", "# From Example 8.2:\n", "\n", "# For refrigerated space:\n", "# Wnet = Ql/4.78 = 0.209*Ql\n", "\n", "# For freezer box.\n", "# Wnet = Ql/3.89 = 0.257*Ql\n", "\n", "percent = ((0.257 - 0.209)/0.209)*100#\n", "print \"Increase in percentage of work output is %.2f %%\"%(percent)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.4 Page: 299" ] }, { "cell_type": "code", "execution_count": 4, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.4 - Page: 299\n", "\n", "\n", "Coeffecient of performance of Carnot Heat Pump is 12.38\n", "\n", "Power input can be estimated as 2.02 kW\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.4 - Page: 299\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Th = 273 + 24## [K]\n", "Tl = 0 + 273## [K]\n", "Qh = 25## [kW]\n", "#*************\n", "\n", "COP = Th/(Th - Tl)#\n", "Wnet = Qh/COP## [kW]\n", "print \"Coeffecient of performance of Carnot Heat Pump is %.2f\\n\"%(COP)#\n", "print \"Power input can be estimated as %.2f kW\\n\"%(Wnet)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.5 Page: 299" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.5 - Page: 299\n", "\n", "\n", "Minimum Power input required is 1.669 kW\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.5 - Page: 299\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Tl = -2 + 273## [K]\n", "Th = 20 + 273## [K]\n", "Qh = 80000## [kJ/h]\n", "#*************\n", "\n", "Ql = Qh*Tl/Th## [kJ/h]\n", "Wnet = Qh - Ql## [kJ/h]\n", "print \"Minimum Power input required is %.3f kW\\n\"%(Wnet/3600)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.6 Page: 303" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.6 - Page: 303\n", "\n", "\n", "Enthalpy of saturated vapour is 6.65\n", "\n", "Refrigerating Effect is 113 kJ/kg\n", "\n", "The COP of an ideal Carnot refrigerator is 6.83\n", "\n", "Work done by the compression is 17.00 kJ/kg\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.6 - Page: 303\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Tl = 273## [K]\n", "Th = 313## [K]\n", "H1 = 187## [Enthalpy of saturated vapour at 273 K, kJ/kg]\n", "H3 = 74## [Enthalpy of saturated liquid at 313 K,kJ/kg]\n", "H4 = H3## [kJ/kg]\n", "H2 = 204## [Enthalpy of Supersaturated Vapour at 273 K, kJ/kg]\n", "#****************\n", "\n", "# Solution (i)\n", "# COP = Ql/Wnet#\n", "COP = ((H1 - H4)/(H2 - H1))#\n", "print \"Enthalpy of saturated vapour is %.2f\\n\"%(COP)\n", "\n", "# Solution (ii)\n", "Ref_Effect = H1 - H4## [kJ/kg]\n", "print \"Refrigerating Effect is %d kJ/kg\\n\"%(Ref_Effect)\n", "\n", "# Solution (iii)\n", "COP = Tl/(Th - Tl)#\n", "print \"The COP of an ideal Carnot refrigerator is %.2f\\n\"%(COP)\n", "\n", "# Solution (iv)\n", "W = H2 - H1## [kJ/kg]\n", "print \"Work done by the compression is %.2f kJ/kg\\n\"%(W)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.7 Page: 304" ] }, { "cell_type": "code", "execution_count": 7, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.7 - Page: 304\n", "\n", "\n", "Amount of heat removed from cold space is 9.18 kW\n", "\n", "THe power input required is 1.92 kW\n", "\n", "COP of refrigeration of cycle is 4.77\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.7 - Page: 304\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "P1 = 0.18## [MPa]\n", "T1 = -10 + 273## [K]\n", "mdot = 0.06## [kg/s]\n", "P2 = 1## [MPa]\n", "T2 = 45 + 273## [K]\n", "T = 273 + 29## [K]\n", "P = 0.75## [MPa]\n", "H1 = 245.16## [Enthalpy of superheated vapour at -10 OC & 0.18 MPa, kJ/kg]\n", "H2 = 277.2## [Enthalpy of superheated vapour at 45 OC & 1 MPa, kJ/kg]\n", "H3 = 92.22## [Enthalpy of saturated liquid at 29 OC & 0.75 MPa, kJ/kg]\n", "H4 = H3## [kJ/kg]\n", "#*************\n", "\n", "# Solution (a)\n", "Ql = mdot*(H1 - H4)## [kW]\n", "print \"Amount of heat removed from cold space is %.2f kW\\n\"%(Ql)\n", "\n", "# Solution (b)\n", "Wnet = mdot*(H2 - H1)## [kW]\n", "print \"THe power input required is %.2f kW\\n\"%(Wnet)\n", "\n", "# Solution (c)\n", "COP = Ql/Wnet#\n", "print \"COP of refrigeration of cycle is %.2f\\n\"%(COP)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.8 Page: 305" ] }, { "cell_type": "code", "execution_count": 8, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.8 - Page: 305\n", "\n", "\n", "Mass flow rate of the refrigerant is 0.1546 kg/s\n", "\n", "Power consumption in the compression is 4.57 kW\n", "\n", "The amount of heat rejected in the condenser is 22.15 kW\n", "\n", "Relative COP is 0.78\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.8 - Page: 305\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Ql = 5## [tons]\n", "Tl = -10 + 273## [K]\n", "Th = 35 + 273## [K]\n", "eta = 0.85#\n", "H1 = 183.2## [Enthalpy of saturated vapour at 263 K, kJ/kg]\n", "H2 = 208.3## [Enthalpy of superheated vapour, kJ/kg]\n", "H3 = 69.5## [Enthalpy of saturated vapour at 308 K, kJ/kg]\n", "H4 = H3## [kJ/kg]\n", "#***************\n", "\n", "# Solution (a)\n", "# Mass flow rate:\n", "Ql = Ql*3.516## [kW]\n", "mdot = Ql/(H1 - H4)## [kW]\n", "print \"Mass flow rate of the refrigerant is %.4f kg/s\\n\"%(mdot)\n", "\n", "# Solution (b)\n", "W = H2 - H1## [kJ/kg]\n", "Wnet = W*mdot/eta## [kW]\n", "print \"Power consumption in the compression is %.2f kW\\n\"%(Wnet)\n", "\n", "# Solution (c)\n", "Qh = Ql + Wnet## [kW]\n", "print \"The amount of heat rejected in the condenser is %.2f kW\\n\"%(Qh)\n", "\n", "# Solution (d)\n", "COP_VapourCompression = (H1 - H4)/(H2 - H1)#\n", "COP_Carnot = Tl/(Th - Tl)#\n", "COP_relative = COP_VapourCompression/COP_Carnot#\n", "print \"Relative COP is %.2f\\n\"%(COP_relative)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.9 Page: 308" ] }, { "cell_type": "code", "execution_count": 9, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.9 - Page: 308\n", "\n", "\n", "Claim is Valid and reasonable\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.9 - Page: 308\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Th = 273 + 125## [K]\n", "Tl = 273 - 5## [K]\n", "Ts = 273 + 28## [K]\n", "COP = 2#\n", "#*************\n", "\n", "COP_absorption = (Tl/(Ts - Tl))*((Th - Ts)/Th)#\n", "if ((COP - 0.1) < COP_absorption) or ((COP + 0.1) > COP_absorption):\n", " print \"Claim is Valid and reasonable\"\n", "else:\n", " print \"Claim is not Valid\"\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example: 8.10 Page: 313" ] }, { "cell_type": "code", "execution_count": 10, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example: 8.10 - Page: 313\n", "\n", "\n", "COP of Air Refrigeration System is 2.06\n", "\n", "Mass flow rate of the refrigerant is 1279.07 kg/h\n", "\n", "The work of Compression is 26.13 kW\n", "\n", "The work of expansion is 17.58 kW\n", "\n", "Net work of the system is 8.55 kW\n", "\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example: 8.10 - Page: 313\\n\\n\"\n", "\n", "# Solution\n", "\n", "#*****Data******#\n", "Q = 5## [tons]\n", "T1 = 253## [Temperature of the working fluid leaving the evaporator, K]\n", "T2 = 303## [Temperature of the working fluid leaving the evaporator, K]\n", "T3 = 303## [K]\n", "Pressure_Ratio = 4#\n", "C = 1.008## [kJ/kg]\n", "gama = 1.4#\n", "#**************\n", "\n", "# Solution (a)\n", "T2 = T1*((Pressure_Ratio)**((gama - 1)/gama))## [K]\n", "T2 = T1*(Pressure_Ratio)**((gama - 1)/gama)## [K]\n", "T4 = T3/((Pressure_Ratio)**((gama - 1)/gama))## [K]\n", "COP = T1/(T2 - T1)#\n", "print \"COP of Air Refrigeration System is %.2f\\n\"%(COP)\n", "\n", "# Solution (b)\n", "mdot = Q*12660/(C*(T1 - T4))## [kg/h]\n", "print \"Mass flow rate of the refrigerant is %.2f kg/h\\n\"%(mdot)\n", "\n", "# Solution (c)\n", "Wcompression = mdot*C*(T2 - T3)## [kJ/h]\n", "print \"The work of Compression is %.2f kW\\n\"%(Wcompression/3600)\n", "\n", "# Solution (d)\n", "Wexpansion = mdot*C*(T1 - T4)## [kJ/h]\n", "print \"The work of expansion is %.2f kW\\n\"%(Wexpansion/3600)\n", "\n", "# Solution (e)\n", "Wnet = Wcompression - Wexpansion## [kJ/h]\n", "print \"Net work of the system is %.2f kW\\n\"%(Wnet/3600)#" ] } ], "metadata": { "kernelspec": { "display_name": "Python 2", "language": "python", "name": "python2" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 2 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython2", "version": "2.7.9" } }, "nbformat": 4, "nbformat_minor": 0 }