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{
"metadata": {
"name": "",
"signature": "sha256:c994036a387ecf3d6e1af15e46c49ba61b58c1363388a5e580f169263936cabd"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 7 : Reversibility and The Thermodynamic Temperature Scale"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.1 Page No : 174"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"print \"Part a\";\n",
"\t\t\t\n",
"# Variables\n",
"Q1 = 500. \t\t\t#kJ \t\t\t#Heat transfer from reservoir at t1\n",
"Q2 = 187.5 \t\t\t#kJ \t\t\t#Heat transfer from reservoir at t2\n",
"\n",
"\t\t\t\n",
"# Calculations and Results\n",
"nr = 1-(Q2/Q1) \t\t\t#Efficiency\n",
"W = nr*Q1 \t\t\t#kJ \t\t\t#Work output of the engine\n",
"print \"Work output of the engine = %.1f kJ\"%(W);\n",
"\n",
"\t\t\t#Part(b)\n",
"print \"Part b\";\n",
"\t\t\t\n",
"# Variables\n",
"Q1 = 500. \t\t\t#kJ \t\t\t#Heat transfer from reservoir at t1\n",
"\t\t\t\n",
"# Calculations and Results\n",
"COP_hp = 1/nr\n",
"W = Q1/COP_hp \t\t\t#kJ \t\t\t#Work input to heat pump\n",
"Q2 = Q1-W \t\t\t#kJ \t\t\t#heat ineraction with reservoir at t2\n",
"print \"Heat ineraction with reservoir at t2 = %.1f kJ\"%(Q2);\n",
"print \"Work input to the heat pump = %.1f kJ\"%(W);\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Part a\n",
"Work output of the engine = 312.5 kJ\n",
"Part b\n",
"Heat ineraction with reservoir at t2 = 187.5 kJ\n",
"Work input to the heat pump = 312.5 kJ\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.2 Page No : 178"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"# Variables\n",
"nr = 0.7 \t\t\t#maximum efficiency\n",
"W = 80. \t\t\t#kJ \t\t\t#Work\n",
"Q1 = 100. \t\t\t#kJ \t\t\t#heat transfered\n",
"\t\t\t\n",
"# Calculations and Results\n",
"nx = W/Q1 \t\t\t#claimed efficiency\n",
"if nx>nr :\n",
" print \"Engine X is not a viable proposition because the claimed efficiency %.2f is greater than maximum efficiency %.2f\"%(nx,nr)\n",
"else:\n",
" print \"Engine X is a viable proposition because the claimed efficiency %.2f is less than maximum efficiency %.2f\"%(nx,nr) \n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Engine X is not a viable proposition because the claimed efficiency 0.80 is greater than maximum efficiency 0.70\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.4 Page No : 191"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"# Variables\n",
"T1 = (527.+273) \t\t\t#K\n",
"T2 = (27.+273) \t\t\t#K\n",
"\n",
"# calculations and results\n",
"#Part (a)\n",
"print \"Part a\";\n",
"nr = 1 - (T2/T1) \t\t\t#reversible efficiency\n",
"print \"Reversible efficiency = %.3f \"%(nr);\n",
"\n",
"#Part(b)\n",
"print \"Part b\";\n",
"print \"As the values of at least any two from among Q1,Q2 and W \\\n",
"are not given the efficiency of the engine cannot be evaluated.However\\\n",
"according to Carnots statement, the efficiency will be less than %.3f\"%(nr)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Part a\n",
"Reversible efficiency = 0.625 \n",
"Part b\n",
"As the values of at least any two from among Q1,Q2 and W are not given the efficiency of the engine cannot be evaluated.Howeveraccording to Carnots statement, the efficiency will be less than 0.625\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.5 Page No : 192"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\t\t\t\n",
"# Variables\n",
"T1 = 273. + 37 \t\t\t#K \n",
"T2 = 273. - 13 \t\t\t#K\n",
"\n",
"\t\t\t#Part(a)\n",
"print \"Part a\";\n",
"COP_ref = T2/(T1-T2) \t\t\t#COP of reversible heat engine as refrigerator.\n",
"print \"COP of reversible heat engine as refrigerator = %.1f\"%(COP_ref)\n",
"\t\t\t#Part(b)\n",
"print \"Part b\";\n",
"COP_hp = T1/(T1-T2) \t\t\t#COP of reversible heat engine as heat pump.\n",
"print \"COP of reversible heat engine as heat pump = %.1f\"%(COP_hp)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Part a\n",
"COP of reversible heat engine as refrigerator = 5.2\n",
"Part b\n",
"COP of reversible heat engine as heat pump = 6.2\n"
]
}
],
"prompt_number": 5
}
],
"metadata": {}
}
]
}
|
