{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

# Chapter 10: PSYCHROMETRIC APPLICATIONS

" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.01, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "m = 1 #lb\n", "T1 = 70 #degF\n", "phi = 0.7\n", "T2 = 40 #degR\n", "P = 14.7 #lbf/in2\n", "\n", "#calculations:\n", "#from Table T-2E\n", "Pg1 = 0.3632 #lbf/in2\n", "Pv1 = phi*Pg1\n", "w1 = 0.622*Pv1/(P - Pv1)\n", "#dew point Temp\n", "Td = 60 #degF\n", "#\n", "mv1 = 1/(1 + 1/w1)\n", "ma = 1 - mv1\n", "#\n", "Pg2 = 0.1217 #lbf/in2\n", "w2 = 0.622*Pg2/(P - Pg2)\n", "#mass of the water vapor present at the final state\n", "mv2 = w2*ma\n", "#amount of water vapor that condenses is\n", "mw = mv1 - mv2\n", "\n", "#Results\n", "print \"a)the initial humidity ratio is\", round(w1,3),\"lb(vapor)/lb(dry)\"\n", "print \"b) dew point temp is\", Td,\"degF\"\n", "print \"c)mass of water vapor that condenses is\", round(mw,4),\"lb(condensate)\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)the initial humidity ratio is 0.011 lb(vapor)/lb(dry)\n", "b) dew point temp is 60 degF\n", "c)mass of water vapor that condenses is 0.0057 lb(condensate)\n" ] } ], "prompt_number": 1 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.02, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "AV1 = 150 #m3/min\n", "T1 = 10 #degC\n", "phi1 = 0.8\n", "T2 = 30 #degC\n", "P = 1 #bar\n", "R = 8314/28.97 #J/kg-K\n", "\n", "#calculations:\n", "#from Table T-9\n", "ha1 = 283.1 #kJ/kg\n", "ha2 = 303.2 #kJ/kg\n", "hg1 = 2519.8 #kJ/kg\n", "hg2 = 2556.3 #kJ/kg\n", "#From Table T-2\n", "Pg1 = 0.01228 #bar\n", "Pv1 = phi1*Pg1\n", "Pa1 = 0.9902\n", "#specific volume of the dry air\n", "va1 = R*(T1 + 273)/(Pa1*1E5)\n", "#mass flow rate of the dry air\n", "madot = AV1/va1\n", "#humidity ratio\n", "w = 0.622*(Pv1/(P - Pv1))\n", "Qcvdot = madot*((ha2 - ha1) + w*(hg2 - hg1))\n", "# From Table T-2\n", "Pv2 = Pv1\n", "Pg2 = 0.04246\n", "#relative humidity\n", "phi2 = Pv2/Pg2\n", "\n", "#Results\n", "print \"a)heat flow rate is\", round(Qcvdot,0),\"kJ/min\"\n", "print \"b)relative humidity is\", round(phi2*100,1),\"%\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)heat flow rate is 3717.0 kJ/min\n", "b)relative humidity is 23.1 %\n" ] } ], "prompt_number": 2 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.03, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "AV1 = 280 #m3/min\n", "T1 = 30 #degC\n", "phi1 = 0.5\n", "T2 = 10 #degC\n", "Tsat = 10 #degC\n", "P1 = 1.013 #bar\n", "R = 8314/28.97 #J/kg-K\n", "\n", "#calculations:\n", "#from Table T-2\n", "Pg1 = 0.04246 #bar\n", "Pv1 = phi1*Pg1\n", "Pa1 = P1 - Pv1\n", "#mass flow rate\n", "madot = AV1*(Pa1*1E5)/(R*(T1+ 273))\n", "#\n", "w1 = 0.622*Pv1/(P1 - Pv1)\n", "#from Table T-2\n", "Pg2 = 0.01228 #bar\n", "w2 = 0.0076 #kg(vapor)/kg(dry air)\n", "#ratio\n", "mwmadot = w1 - w2\n", "#from Table T-2 and T-9\n", "ha2 = 283.1 #kJ/kg\n", "ha1 = 303.2 #kJ/kg\n", "hg2 = 2519.8 #kJ/kg\n", "hg1 = 2556.3 #kJ/kg\n", "hf2 = 42.01 #kJ/kg\n", "#heat transfer rate\n", "Qcvdot = madot*(ha2 - ha1 - w1*hg1 + w2*hg2 + (w1 - w2)*hf2)/211\n", "\n", "#Results\n", "print \"a) mass flow rate is\", round(madot,2),\"kg/min\"\n", "print \"b) the rate at which water is condensed is\", round(mwmadot,4),\"kg(vapor)/kg(dry air)\"\n", "print \"required refrigerating capacity is\", round(-1*Qcvdot,1),\"tons\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a) mass flow rate is 319.35 kg/min\n", "b) the rate at which water is condensed is 0.0057 kg(vapor)/kg(dry air)\n", "required refrigerating capacity is 52.6 tons\n" ] } ], "prompt_number": 3 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.04, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "madot = 90 #kg/min\n", "T1 = 22 #degC\n", "Twb = 9 #degC\n", "mstdot = 52 #kg/h\n", "Tsat = 110 #degC\n", "\n", "#calculations:\n", "#From Table T-4\n", "w1 = 0.002 #kg(vapor)/kg(dry air)\n", "#\n", "w2 = w1 + (mstdot/60)/madot\n", "#from table T-2 and T-9\n", "T2 = 23.5 #degC\n", "\n", "#Results\n", "print \"a) humidity ratio is\", round(w2,4),\"kg(vapor)/kg(dry air)\"\n", "print \"b) Temperature T2 is\", T2,\"degC\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a) humidity ratio is 0.0116 kg(vapor)/kg(dry air)\n", "b) Temperature T2 is 23.5 degC\n" ] } ], "prompt_number": 4 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.05, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "T1 = 100 #degF\n", "phi1 = 0.10\n", "AV1 = 5000 #ft3/min\n", "Tw = 70 #degF\n", "T2 = 70 #degF\n", "P = 14.696 #lbf/in2\n", "Cpa = 0.24 #Btu/lb-degR\n", "\n", "#calculations:\n", "#From Table T-2E\n", "Pg1 = 0.95 #lbf/in2\n", "#partial pressure of the moist air\n", "Pv1 = phi1*Pg1\n", "#humidity at 1\n", "w1 = 0.622*Pv1/(P- Pv1)\n", "#specific vol of dry air\n", "va1 = 14.2 #ft3/lb(dry air)\n", "#mass flow rate of dry air\n", "madot = AV1/va1\n", "#from Table T-2E\n", "hf = 38.1 #Btu/lb\n", "hg1 = 1105 #Btu/lb\n", "hg2 = 1092 #Btu/lb\n", "#w2\n", "w2 = (Cpa*(T1 - T2) + w1*(hg1 - hf))/(hg2 - hf)\n", "#\n", "mwdot = madot*60*(w2 - w1)\n", "#\n", "Pv2 = w2*P/(w2 + 0.622)\n", "#saturation Pressure at 70 degF\n", "Psat = 0.3632 #lbf/in2\n", "#relative humidity at exit\n", "phi2 = Pv2/Psat\n", "\n", "#Results\n", "print \"a) mass flow rate is\", round(mwdot,1),\"lb(water)/h\"\n", "print \"b) relative humidity is\",round(phi2*100,1),\"%\"\n", "#answer slightly varies with book\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a) mass flow rate is 145.4 lb(water)/h\n", "b) relative humidity is 69.9 %\n" ] } ], "prompt_number": 5 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.06, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "AV1 = 142 #m3/min\n", "T1 = 5 #degC\n", "w1 = 0.002 #kg(vapor)/(kg(dry air)\n", "AV2 = 425 #m3/min\n", "T2 = 24 #degC\n", "phi2 = 0.5\n", "\n", "#calculations:\n", "#from psychometric chart\n", "va1 = 0.79 #m3/kg(dry air)\n", "va2 = 0.855 #m3/kg(dry air)\n", "w2 = 0.0094\n", "#mass flow rate of dry air at 1 and 2\n", "ma1dot = AV1/va1\n", "ma2dot = AV2/va2\n", "#w3\n", "w3 = (w1*ma1dot + w2*ma2dot)/(ma1dot + ma2dot)\n", "#from fig T-4\n", "#ha1 = (ha + w*hv)1\n", "#ha2 = (ha + whv)2\n", "#ha3 = (ha + w*hv)3\n", "ha1 = 10 #kJ/kg(dry air)\n", "ha2 = 47.8 #kJ/kg(dry air)\n", "ha3 = (ma1dot*ha1 + ma2dot*ha2)/(ma1dot + ma2dot)\n", "#from Fig T-4\n", "T3 = 19 #degC\n", "\n", "#Results\n", "print \"a) humidity ratio is\", round(w3,4),\"kg(vapor)/kg(dry air)\"\n", "print \"b) temperature by inspection is\", T3,\"degC\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a) humidity ratio is 0.0074 kg(vapor)/kg(dry air)\n", "b) temperature by inspection is 19 degC\n" ] } ], "prompt_number": 6 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 10.07, page: 250

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "T1 = 38 #degC\n", "m1dot = 4.5E7 #kg/h\n", "T2 = 30 #degC\n", "m2dot = 4.5E7 #kg/h\n", "T3 = 25 #degC\n", "phi3 = 0.35\n", "T4 = 35 #degC\n", "phi4 = 0.9\n", "T5 = 20 #degC\n", "\n", "#calculations:\n", "#from Table T-2 nd T-9\n", "w3 = 0.00688 #kg(vapor)/kg(dry air)\n", "w4 = 0.0327 #kg(vapor)/kg(dry air)\n", "hf1 = 159.21 #kJ/kg\n", "hf2 = 125.79 #kJ/kg\n", "ha4 = 308.2 #kJ/kg\n", "ha3 = 298.2 #kJ/kg\n", "hg4 = 2565.3 #kJ/kg\n", "hg3 = 2547.2 #kJ/kg\n", "hf5 = 83.96 #kJ/kg\n", "#mass flow rate of dry air\n", "madot = m1dot*(hf1 - hf2)/((ha4 - ha3) + w4*hg4 - w3*hg3 - (w4 - w3)*hf5)\n", "#mass flow rate of water\n", "m5dot = madot*(w4 - w3)\n", "\n", "#Results\n", "print \"mass flow rate of dry air and water are\",round(madot,0),\"kg/h and\", round(m5dot,0),\"kg/h\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "mass flow rate of dry air and water are 20270181.0 kg/h and 523376.0 kg/h\n" ] } ], "prompt_number": 7 } ], "metadata": {} } ] }