1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
|
{
"metadata": {
"name": "",
"signature": "sha256:446aceff980b12efb55c191333cfc1afc3a816c084c4cb1a989aad4ec192647e"
},
"nbformat": 3,
"nbformat_minor": 0,
"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 %.2f %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 %.2f %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= 0.00 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= 0.00 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": 7
},
{
"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 %.2f %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 %.2f %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= 0.00 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= 0.00 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": 9
}
],
"metadata": {}
}
]
}
|