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{
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"name": "",
"signature": "sha256:86a6812c4487f2208e77d00bcaa9dbc11e08ffaad2279542fa123a87347dc354"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter13-Thermo Electric Power"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.2.1-pg707"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"##Ex13.2.1.;Peltier heats absorbed and rejected\n",
"##peltier coefficients at these junctions are aplha_p_1-2=alpha_s_1-2*T\n",
"##Let A=alpha_s_1-2 at 373 k=55*10^-6 v/degree_k and B=alpha_s_1-2 at 273 k=50*10^-6 v/degree_k\n",
"A=(55*10**-6);\n",
"B=(50*10**-6);\n",
"T1=373.;##k\n",
"T2=273.;##k\n",
"I=10*10**-3;##current;unit=Ampere\n",
"alpha_p_1_2_at_373k=A*T1;\n",
"alpha_p_1_2_at_273k=B*T2;\n",
"print'%s %.2f %s %.2f %s'%(\" alpha_p_1_2_at_373k=\",alpha_p_1_2_at_373k,\" W/amp\"and \" \\n alpha_p_1_2_at_273k=\",alpha_p_1_2_at_273k,\" W/amp\");\n",
"##Peltier heats absorned and rejected to be\n",
"q2_peltier=alpha_p_1_2_at_373k*I;\n",
"q1_peltier=alpha_p_1_2_at_273k*I;\n",
"print'%s %.2e %s %.2e %s '%(\"\\n q2_peltier=\",q2_peltier,\" w \" and\"\\n q1_peltier=\",q1_peltier,\" W\");\n",
"c=q2_peltier-q1_peltier;\n",
"print(\"\\n If no other heat transfer were involved,the difference between these vaues,\");\n",
"print'%s %.2e %s %.2e %s %.2e %s '%(\"\\n \",q2_peltier,\" \"and \"\",q1_peltier,\" W\"and \"\\n,would be supplied as electric power\",c,\"\");\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" alpha_p_1_2_at_373k= 0.02 \n",
" alpha_p_1_2_at_273k= 0.01 W/amp\n",
"\n",
" q2_peltier= 2.05e-04 \n",
" q1_peltier= 1.36e-04 W \n",
"\n",
" If no other heat transfer were involved,the difference between these vaues,\n",
"\n",
" 2.05e-04 1.36e-04 \n",
",would be supplied as electric power 6.87e-05 \n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.3.2-pg708"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"##Ex.13.3.2.;Find the thomson heat transferred\n",
"import math\n",
"import scipy\n",
"from scipy import integrate\n",
"\n",
"##Let D=dalpha_s1/dT;\n",
"D=5.4*10**-3;##unit=micro V/degree k^2\n",
"T1=273;##unit=k\n",
"T2=373;##unit=k\n",
"I=10*10**-3;##unit=A\n",
"##Thomson coefficient sigma,varies with temp. \n",
"##sigma_1_of_T=-T*D;unit=V/degree k\n",
"##The thomson heat is given by equation\n",
"##qth=I*Integration of sigma_1_of_T w.r.t. T\n",
"def fun(T):\n",
" y=T\n",
" return y\n",
"Integration = scipy.integrate.quad(fun,T1,T2);\n",
"qth=I*D*Integration[0];\n",
"print'%s %.2f %s'%(\"The THOMSON HEAT=\",qth,\" micro W\");\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The THOMSON HEAT= 1.74 micro W\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.4.1-pg715"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"##Ex13.4.1.;Determine the efficiency of the thermoelectric generator.what will be its carnot efficiency\n",
"import math\n",
"TH=600.;##degree k;##temperature of the hot reservior of source\n",
"TC=300.;##degree k;##temperature of the sink\n",
"Z=2*(10**-3);##1/degree k;##Figure of merit for the material\n",
"M_optimum=(1.+((Z/2.)*(TH+TC)))**0.5;\n",
"print'%s %.2f %s'%(\" M_optimum=\",M_optimum,\"\");\n",
"##Efficiency of the thermoelectric generator is n=(((TH-TC)/TH)*((M_optimum-1)/(M_optimum+(TC/TH)))*100;\n",
"a=((TH-TC)/TH);\n",
"b=(M_optimum-1)/(M_optimum+(TC/TH));\n",
"n=a*b*100;\n",
"print'%s %.2f %s'%(\"\\n Efficiency of the thermoelectric generator is n=\",n,\" persent\");\n",
"##where as efficiency of the carnot cycle (reversible) nc=((TH-TC)/TH)*100\n",
"nc=a*100;\n",
"print'%s %.2f %s'%(\"\\n Efficiency of the carnot cycle (reversible) nc=\",nc,\" persent\");\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" M_optimum= 1.38 \n",
"\n",
" Efficiency of the thermoelectric generator is n= 10.07 persent\n",
"\n",
" Efficiency of the carnot cycle (reversible) nc= 50.00 persent\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.4.2-pg716"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"##Ex13.4.12.;Calculare maximum generator efficiency and the efficiency for maximum power,power output\n",
"import math\n",
"##seedbeck coefficient(alpha_s);unit=volts/degree celcius\n",
"alpha_s1=-190.*10**-6;##n-type\n",
"alpha_s2=190.*10**-6;##p-type\n",
"##Specific resistivity(p);unit=Ohm-cm\n",
"p1=1.45*10**-3;##n-type\n",
"p2=1.8*10**-3;##p-type\n",
"##Figure of merit(Z);unit=degree k**-1\n",
"Z1=2.*10**-3;##n-type\n",
"Z2=1.7*10**-3;##p-type\n",
"\n",
"\n",
"##conductivity (n-type), \n",
"k1=(alpha_s1**2.)/(p1*Z1);\n",
"##similarly\n",
"k2=(alpha_s2**2.)/(p2*Z2);\n",
"print'%s %.2f %s %.2f %s'%(\" Conductivity k1=\",k1,\" W/cm degree celcius\" and \" \\n Conductivity k2=\",k2,\" W/cm degree celcius\");\n",
"##Z_opt=((alpha_s1-alpha_s2)**2)/[(p1*k1)**2+(p2*k2)**2];\n",
"##let\n",
"a=(alpha_s1-alpha_s2)\n",
"b=(p1*k1)\n",
"c=(p2*k2)\n",
"A=math.sqrt(b)\n",
"B=math.sqrt(c)\n",
"C=(A+B);\n",
"##/therefore\n",
"Z_opt=(a/C)**2.;\n",
"print'%s %.4f %s'%(\"\\n Z_opt=\",Z_opt,\" degree k\");\n",
"##Thermal conductance\n",
"A1=2.3;##cm**2\n",
"A2=1.303;##cm**2\n",
"l1=1.5;##cm\n",
"l2=0.653;##cm\n",
"K=((k1*A1)/l1)+((k2*A2)/l2)\n",
"print'%s %.2f %s'%(\"\\n Thermal conductance K=\",K,\" W/degree celcius\");\n",
"##R=Resistance of the generator=R1+R2\n",
"R=((p1*l1)/A1)+((p2*l2)/A2);\n",
"print'%s %.2f %s'%(\"\\n Resistance of the generator R=\",R,\" ohm\");\n",
"TH=923.;##unit=k\n",
"TC=323.;##unit=k\n",
"M_opt=(1.+((Z_opt/2.)*(TH+TC)))**0.5;\n",
"print'%s %.2f %s'%(\"\\n M_opt=\",M_opt,\" ohm\");\n",
"RL=M_opt*R;\n",
"print'%s %.4f %s'%(\"\\n RL=\",RL,\" ohms\");\n",
"##Optimum efficiency n_opt=(((TH-TC)/TH)*((M_opt-1)/(M_opt+(TC/TH)))*100;\n",
"aa=((TH-TC)/TH);\n",
"##taking M_opt=1.43\n",
"b=(1.43-1.)/(1.43+(TC/TH));\n",
"n_opt=aa*b*100.;\n",
"print'%s %.2f %s'%(\"\\n Optimum efficiency n_opt=\",n_opt,\" persent\");\n",
"##efficiency for max. power output n= (TH-TC)/TH)*m/[((1+m)**2/TH)*(KR/alpha_s_12**2)+(1+m)-(TH-TC)/2TH)]\n",
"##Efficiency power output\n",
"##RL=R i.e. m=1\n",
"## let ab=(1+m)**2/TH;ac=(KR/alpha_s_12**2);ad=(TH-TC)/2TH\n",
"m=1.;\n",
"ab=4./TH;\n",
"ac=1./Z_opt;\n",
"ad=aa/2.;\n",
"n_max=(aa/(ab*ac+2.-ad))*100.;\n",
"print'%s %.2f %s'%(\"\\n max. power output n_max \",n_max,\" persent\")\n",
"##Power output P_opt=I**2*RL=alpha_s12**2(TH-TC)*RL/(R+RL)**2=alpha_s12**2(TH-TC)/(1+M_opt)**2*RL\n",
"##let at=alpha_s12**2(TH-TC);mi=(1+M_opt)**2*RL\n",
"at=a*a*(TH-TC)*(TH-TC);\n",
"ml=(1.+1.43)*(1.+1.43)*2.63*10**-3\n",
"P_opt=at/ml;\n",
"print'%s %.2f %s'%(\"\\n Power output P_opt=\",P_opt,\" watts\");\n",
"##for max. power P_max (RL=R)\n",
"##P_max=alpha_s12**2(TH-TC)*RL/(r+RL)**2=alpha_s12**2(TH-TC)RL*4RL\n",
"P_max=at/(4.*1.84*10**-3);\n",
"print'%s %.2f %s'%(\"\\n max. power P_max=\",P_max,\" watts\");\n",
"\n",
"\n",
"##Many calcuating mistak are there in a following example,which is corrected in program.\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Conductivity k1= 0.01 \n",
" Conductivity k2= 0.01 W/cm degree celcius\n",
"\n",
" Z_opt= 0.0018 degree k\n",
"\n",
" Thermal conductance K= 0.04 W/degree celcius\n",
"\n",
" Resistance of the generator R= 0.00 ohm\n",
"\n",
" M_opt= 1.47 ohm\n",
"\n",
" RL= 0.0027 ohms\n",
"\n",
" Optimum efficiency n_opt= 15.70 persent\n",
"\n",
" max. power output n_max 16.13 persent\n",
"\n",
" Power output P_opt= 3.35 watts\n",
"\n",
" max. power P_max= 7.06 watts\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.4.3-pg718"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"##Ex.13.4.3;maximum efficiency,no. of thermocouple in series,open ckt voltage,heat i/p and reject at full load.\n",
"import math\n",
"kA=0.02;##unit=watt/cm degree kelvin\n",
"kB=0.03;##unit=watt/cm degree kelvin\n",
"pA=0.01;##unit=ohm cm\n",
"pB=0.012;##unit=ohm cm\n",
"TH=1500.;##unit=degree kelvin\n",
"TC=1000;##unit=degree kelvin\n",
"AA=43.5;##unit=cm**2\n",
"AB=48.6;##unit=cm**2\n",
"LA=0.49;##unit=cm\n",
"LB=0.49;##unit=cm\n",
"I=20.*48.6;##Current density in the element limited to,I=20 amp/cm**2\n",
"output=100.;##unit=kW\n",
"##alpha_SAB at 1250 degree kelvin=0.0012 volt/degree kelvin=alpha_SA-alpha_SB\n",
"alpha_SAB=0.0012;##unit=volt/degree kelvin\n",
"##let\n",
"b=(pA*kA);\n",
"c=(pB*kB);\n",
"A=math.sqrt(b);\n",
"B=math.sqrt(c);\n",
"C=(A+B);\n",
"##figure of merit\n",
"Z=(alpha_SAB/C)**2.;\n",
"print'%s %.4f %s'%(\" Z=\",Z,\" degree k^-1\");\n",
"M=(1+((Z/2.)*(TH+TC)))**0.5;\n",
"print'%s %.2f %s'%(\"\\n M=\",M,\"\");\n",
"##let\n",
"aa=((TH-TC)/TH);\n",
"bb=(M-1)/(M+(TC/TH));\n",
"##1] MAx. efficiency of a thermoelectric converter is given by n_max=((TH-TC)/TH)*[(M-1)/(M+(TC/TH))]*100;\n",
"n_max=aa*bb*100.;\n",
"print'%s %.2f %s'%(\"\\n Maximum efficiency n_max=\",n_max,\" persent\");\n",
"##2] No. of thermocouple in series\n",
"V=alpha_SAB*(TH-TC);\n",
"print'%s %.2f %s'%(\"\\n V=\",V,\" volt\");\n",
"R=((pA*LA)/AA)+((pB*LB)/AB);##since R=RA+RB=((pA*LA)/AA)+((pB*LB)/AB);\n",
"print'%s %.4f %s'%(\"\\n R=\",R,\" ohm\");\n",
"VL=V-(R*I);\n",
"print'%s %.2f %s'%(\"\\n VL=\",VL,\" volt\");\n",
"##NTCS=total voltage required/voltage required by one couple\n",
"NTCS=115./VL;\n",
"print'%s %.2f %s'%(\"\\n No. of thermocouple in series=\",NTCS,\"\");\n",
"##3] Open circuit voltage\n",
"OCV=V*309.;\n",
"print'%s %.2f %s'%(\"\\n Open circuit voltage=\",OCV,\" volt\")\n",
"##4] Heat input and reject at full load.\n",
"##Heat input at full load.=output/efficency=100/0.091\n",
"HIFL=output/n_max;\n",
"print'%s %.2f %s'%(\"\\n Heat input at full load=\",HIFL,\" kW\")\n",
"## Heat reject at full load. =Heat input-Work output\n",
"HRFL=HIFL-output;\n",
"print'%s %.2f %s'%(\"\\n Heat reject at full load=\",HRFL,\"kW\")\n",
"\n",
"\n",
"\n",
"##The value of \"pB\" is misprinted\n",
"##The values are taken in the text book is approximately equal to calculated values\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Z= 0.0013 degree k^-1\n",
"\n",
" M= 1.63 \n",
"\n",
" Maximum efficiency n_max= 9.09 persent\n",
"\n",
" V= 0.60 volt\n",
"\n",
" R= 0.0002 ohm\n",
"\n",
" VL= 0.37 volt\n",
"\n",
" No. of thermocouple in series= 308.39 \n",
"\n",
" Open circuit voltage= 185.40 volt\n",
"\n",
" Heat input at full load= 11.00 kW\n",
"\n",
" Heat reject at full load= -89.00 kW\n"
]
}
],
"prompt_number": 1
}
],
"metadata": {}
}
]
}
|