{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 13: Thermo Electric Power" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 13.2_1: Peltier_heats_absorbed_and_rejected.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//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", "printf(' alpha_p_1_2_at_373k=%f W/amp \n alpha_p_1_2_at_273k=%f W/amp',alpha_p_1_2_at_373k=A*T1,alpha_p_1_2_at_273k=B*T2);\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", "printf('\n q2_peltier=%f w \n q1_peltier=%f W',q2_peltier,q1_peltier);\n", "c=q2_peltier-q1_peltier;\n", "printf('\n If no other heat transfer were involved,the difference between these vaues,');\n", "printf('\n %f-%f=%f W,would be supplied as electric power',q2_peltier,q1_peltier,c);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 13.3_2: Thomson_heat_transferred.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//Ex.13.3.2.;Find the thomson heat transferred\n", "\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", "Integration=integrate('T','T',T1,T2);\n", "qth=I*D*Integration;\n", "printf('The THOMSON HEAT=%f micro W',qth);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 13.4_1: Carnot_Efficiency.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//Ex13.4.1.;Determine the efficiency of the thermoelectric generator.what will be its carnot efficiency\n", "\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", "printf(' M_optimum=%f',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", "printf('\n Efficiency of the thermoelectric generator is n=%f persent',n);\n", "//where as efficiency of the carnot cycle (reversible) nc=((TH-TC)/TH)*100\n", "nc=a*100;\n", "printf('\n Efficiency of the carnot cycle (reversible) nc=%f persent',nc);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 13.4_2: Maximum_generator_efficiency_and_Power_Output.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//Ex13.4.12.;Calculare maximum generator efficiency and the efficiency for maximum power,power output\n", "\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", "printf(' Conductivity k1=%f W/cm degree celcius \n Conductivity k2=%f W/cm degree celcius',k1,k2);\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=sqrt(b)\n", "B=sqrt(c)\n", "C=(A+B);\n", "///therefore\n", "Z_opt=(a/C)^2;\n", "printf('\n Z_opt=%f degree k',Z_opt);\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", "printf('\n Thermal conductance K=%f W/degree celcius',K);\n", "//R=Resistance of the generator=R1+R2\n", "R=((p1*l1)/A1)+((p2*l2)/A2);\n", "printf('\n Resistance of the generator R=%f ohm',R);\n", "TH=923;//unit=k\n", "TC=323;//unit=k\n", "M_opt=(1+((Z_opt/2)*(TH+TC)))^0.5;\n", "printf('\n M_opt=%f ohm',M_opt);\n", "RL=M_opt*R;\n", "printf('\n RL=%f ohms',RL);\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", "printf('\n Optimum efficiency n_opt=%f persent',n_opt);\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", "printf('\n max. power output n_max %f persent',n_max)\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", "printf('\n Power output P_opt=%f watts',P_opt);\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", "printf('\n max. power P_max=%f watts',P_max);\n", "\n", "\n", "//Many calcuating mistak are there in a following example,which is corrected in program." ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 13.4_3: EX13_4_3.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//Ex.13.4.3;maximum efficiency,no. of thermocouple in series,open ckt voltage,heat i/p and reject at full load.\n", "\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=sqrt(b);\n", "B=sqrt(c);\n", "C=(A+B);\n", "//figure of merit\n", "Z=(alpha_SAB/C)^2;\n", "printf(' Z=%f degree k^-1',Z);\n", "M=(1+((Z/2)*(TH+TC)))^0.5;\n", "printf('\n M=%f',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", "printf('\n Maximum efficiency n_max=%f persent',n_max);\n", "//2] No. of thermocouple in series\n", "V=alpha_SAB*(TH-TC);\n", "printf('\n V=%f volt',V);\n", "R=((pA*LA)/AA)+((pB*LB)/AB);//since R=RA+RB=((pA*LA)/AA)+((pB*LB)/AB);\n", "printf('\n R=%f ohm',R);\n", "VL=V-(R*I);\n", "printf('\n VL=%f volt',VL);\n", "//NTCS=total voltage required/voltage required by one couple\n", "NTCS=115/VL;\n", "printf('\n No. of thermocouple in series=%f',NTCS);\n", "//3] Open circuit voltage\n", "OCV=V*309;\n", "printf('\n Open circuit voltage=%f volt',OCV)\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/100);\n", "printf('\n Heat input at full load=%f kW',HIFL)\n", "// Heat reject at full load. =Heat input-Work output\n", "HRFL=HIFL-output;\n", "printf('\n Heat reject at full load=%f kW',HRFL)\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" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }