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{
"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": {}
}
]
}
|
