{ "metadata": { "name": "", "signature": "sha256:574ebb4d4acd5d9e1ca65b924a04ae0a79a40c26934e573f22784629ff1f575c" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter04:Solar Energy-Basics" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.1:pg-98" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "n=319 # 15th November\n", "gamma=math.radians(30) # angle in radian\n", "beta=math.radians(45) # angle in radian\n", "phi=math.radians(18.9) # latitude in radian\n", "solartime=13.5-4*(81.733-72.816)/60 +14.74/60 # in hours\n", "delta=23.45*(math.sin(math.radians(360.0*(284.0+n)/365.0))) # in radian\n", "B=45#(360.0*(n-81)/364)\n", "E=9.87*math.sin(2*B)-7.53*math.cos(B)-15*math.sin(B)\n", "w=math.radians((solartime-12)*15) # hour angle\n", "thetai=math.acos((math.cos(phi)*math.cos(beta)+math.sin(phi)*math.sin(beta)*math.cos(gamma))*math.cos(delta)*math.cos(w) + math.cos(delta)*math.sin(w)*math.sin(beta)*math.sin(gamma) + math.sin(delta)*(math.sin(phi)*math.cos(beta)-math.cos(phi)*math.sin(beta)*math.cos(gamma)))\n", "print round(math.degrees(thetai),2),\"degree\"\n", "# The answer in the textbook is wrong due to wrong expression of Cos(Thetai)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "5.77 degree\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.2:pg-98" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "n1=1 # 1st january\n", "n2=182 # july 1\n", "\n", "phi=34.083 # latitude in degree\n", "\n", "delta1=23.45*math.sin(math.radians(360.0*(284.0+n1)/365.0)) # in degree\n", "delta2=23.45*math.sin(math.radians(360.0*(284.0+n2)/365.0)) # in degree\n", "\n", "td1=(2.0/15)*math.degrees(math.acos(math.tan(phi)/math.tan(delta1))) # daylight hours for january 1\n", "td2=(2.0/15)*math.degrees(math.acos(math.tan(phi)/math.tan(delta2))) # daylight hours for july 1\n", "\n", "print \"daylight hours for january 1 are\",round(td1,2),\"hours\"\n", "print \"daylight hours for july 1 are\",round(td2,2),\"hours\"\n", "\n", "# the answers are slightly different in textbook due to approximation while here ansers are precise" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "daylight hours for january 1 are 9.55 hours\n", "daylight hours for july 1 are 13.87 hours\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.3:pg-101" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "a=0.25 # constant for delhi from table 4.1 \n", "b=0.57 # constant for delhi from table 4.1 \n", "phi=27.166 # latitute in degrees\n", "n=17 # day\n", "nbar=7 # sunshine hours\n", "\n", "delta=23.45*(math.sin(math.radians(360.0*(284.0+n)/365.0))) # in radian\n", "\n", "wt=math.acos(math.radians(-math.tan(phi)*(math.tan(delta)))) # hour angle at sunrise\n", "Nbar=(2*math.degrees(wt)/15.0)# day length\n", "\n", "Ho=3600*(24.0/math.pi)*1.367*(1+0.033*math.cos((360.0*n/365)))*(math.cos(phi)*cos(delta)*sin(wt)+1.3728*sin(delta)*sin(phi)) # in kj/m^2 per day\n", "\n", "Hg=Ho*(a+b*(nbar/Nbar)) # in kj/m^2 per day\n", "print \"The monthly average is \",round(-Hg,2),\" in kj/m^2 per day\"\n", "\n", "# the answer in the book is wrong due to wrong calculations" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The monthly average is 19160.94 in kj/m^2 per day\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.4:pg-103" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "Hg=19160.94 # in kj/m^2 per day from previous example\n", "Ho=32107.62 # in kj/m^2 per day from previous example\n", "KT=Hg/Ho # unitless\n", "Hd=Hg*(1.354-1.570*KT) # in kj/m^2 per day\n", "Hb= Hg-Hd # in kj/m^2 per day\n", "\n", "print \"Monthly average of daily diffused is \",round(Hd,2),\"in kj/m^2 per day\"\n", "print \"beam radiation is \",round(Hb,2),\"in kj/m^2 per day\"\n", "\n", "# the solution inthe textbook is wrong as the values from previous examples are used which too are incorrect" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Monthly average of daily diffused is 7991.4 in kj/m^2 per day\n", "beam radiation is 11169.54 in kj/m^2 per day\n" ] } ], "prompt_number": 44 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.5:pg-104" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "# most of the data is used is from previous example:\n", "phi=27.166 # in degree\n", "n=17 # day\n", "ws=78.66 # degrees\n", "delta=-20.96 # in degrees\n", "Ho=22863.3 # kj/m^2 per day\n", "Hg=14413.82 # kj/m^2 per day\n", "Hd=5259.6 # kj/m^2 per day\n", "\n", "w=(11.5-12)*15 # in degrees\n", "\n", "Io=3600*1.367*(1+0.033*math.cos(360*17/365.0))*(math.cos(math.radians(phi))*math.cos(math.radians(delta))*math.cos(math.radians(w)))+math.sin(math.radians(delta))*math.sin(math.radians(phi))\n", "\n", "a=0.409+0.5016*math.sin(ws-60)\n", "b=0.6609-0.4767*math.sin(ws-60)\n", "\n", "Ig=Hg*(a+b*math.cos(w))*Io/Ho # in kJ/m^2-h\n", "\n", "print \"The monthly average of hourly global radiation is \",round(Ig,2),\"kJ/m^2-h\"\n", "\n", "adash=0.4922+(0.27/(Hd/Hg))\n", "bdash=2*(1-adash)*(math.sin(math.radians(ws)))-1.7328*math.cos(math.radians(78.66))/(1.7328-0.5*math.sin(math.radians(2*78.66))) \n", "\n", "\n", "Id=5259.6*(1.2321-0.3983*math.cos(math.radians(w)))*Io/Ho # kJ/m^2-h\n", "\n", "\n", "\n", "print \"The hourly diffuse radiations are\",round(Id,2),\"kJ/m^2-h\"\n", "\n", "# the solution inthe textbook is wrong as the values from previous examples are used which too are incorrect\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The monthly average of hourly global radiation is 1444.92 kJ/m^2-h\n", "The hourly diffuse radiations are 768.07 kJ/m^2-h\n" ] } ], "prompt_number": 26 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4.6:pg-108" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "phi=28.58 # in degree\n", "n=135 # may 15\n", "delta=23.45*math.sin(math.radians(360*(284+n)/365.0))\n", "\n", "w=(13.5-12)*15 # in degrees\n", "A=3981.6 # in W/m^2 from table 4.2\n", "B=0.177# from table 4.2\n", "C=0.130 # from table 4.2\n", "\n", "costhetaz=math.cos(phi)*math.cos(delta)*math.cos(w)+math.sin(delta)*math.sin(phi)\n", "\n", "Ibn=A*math.exp(-B/0.922)# kJ/m^2-h\n", "\n", "\n", "Id=C*Ibn # kJ/m^2-h\n", "\n", "print \"The diffused radiation is \",round(Id,2),\"kJ/m^2-h\"\n", "Ib=Ibn*0.922 # in kJ/m^2-h\n", "\n", "print \"The beam radiation is \",round(Ib,2),\"kJ/m^2-h\"\n", "Ig=Ib+Id # in kJ/m^2-h\n", "\n", "print \"The global radiation is \",round(Ig,2),\"kJ/m^2-h\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The diffused radiation is 427.2 kJ/m^2-h\n", "The beam radiation is 3029.81 kJ/m^2-h\n", "The global radiation is 3457.01 kJ/m^2-h\n" ] } ], "prompt_number": 44 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex-4.7:pg-111" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# given data\n", "import math\n", "phi=28.58 # in degree\n", "B=30 # in degree\n", "n=318 # november 14\n", "Hg=16282.8 # in kJ/m^2-day from Table C1 appendix C\n", "Hd=4107.6 # in kJ/m^2-day from Table C2 appendix C\n", "\n", "delta=23.45*(math.sin(math.radians(360.0*(284.0+n)/365.0))) # in radians\n", "\n", "ws=math.acos(math.radians(-math.tan(phi)*(math.tan(delta)))) # hour angle at sunrise\n", "\n", "Rb=(ws*sin(math.radians(delta))*math.sin(phi-B)+math.cos((delta))*math.sin(ws)*math.cos(phi-B))/(ws*sin((delta))*math.sin(math.radians(phi))+math.cos(math.radians(delta))*math.sin(ws)*math.cos(math.radians(phi)))\n", "\n", "Rd=(1+math.cos(math.radians(B)))/2 \n", "\n", "Rr=0.2*(1-math.cos(math.radians(B)))/2 \n", "\n", "Ht=((1-(Hd/Hg))*1.56+(Hd/Hg)*Rd + Rr)*Hg\n", "print \"Monthly average total radiation is\",round(Ht,2),\"kJ/m^2-h\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Monthly average total radiation is 23043.9 kJ/m^2-h\n" ] } ], "prompt_number": 8 } ], "metadata": {} } ] }