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	   "source": [
       "# Chapter 18: Refrigeration"
	   ]
	},
{
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		   "metadata": {},
		   "source": [
			"## Example 18.1: coefficient_of_performance_mass_flow_and_cooling_water_requirement.sce"
		   ]
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"clear;\n",
"clc;\n",
"disp('Example 18.1');\n",
"\n",
"// aim : To determine\n",
"// (a) the coefficient of performance\n",
"// (b) the mass flow of the refrigerant\n",
"// (c) the cooling water required by the condenser\n",
"\n",
"// given values\n",
"P1 = 462.47;// pressure limit, [kN/m^2]\n",
"P3 = 1785.90;// pressure limit, [kN/m^2]\n",
"T2 = 273+59;// entering saturation temperature, [K]\n",
"T5 = 273+32;// exit temperature of condenser, [K]\n",
"d = 75*10^-3;// bore, [m]\n",
"L = d;// stroke, [m]\n",
"N = 8;// engine speed, [rev/s]\n",
"VE = .8;// olumetric efficiency\n",
"cpL = 1.32;// heat capacity of liquid, [kJ/kg K]\n",
"c = 4.187;// heat capacity of water, [kj/kg K]\n",
"\n",
"// solution\n",
"// from given table\n",
"// at P1\n",
"h1 = 231.4;// specific enthalpy, [kJ/kg]\n",
"s1 = .8614;// specific entropy,[ kJ/kg K\n",
"v1 = .04573;// specific volume, [m^3/kg]\n",
"\n",
"// at P3\n",
"h3 = 246.4;// specific enthalpy, [kJ/kg]\n",
"s3 = .8093;// specific entropy,[ kJ/kg K\n",
"v3 = .04573;// specific volume, [m^3/kg]\n",
"T3= 273+40;// saturation temperature, [K]\n",
"h4 = 99.27;// specific enthalpy, [kJ/kg]\n",
"// (a)\n",
"s2 = s1;// specific entropy, [kJ/kg k]\n",
"// using s2=s3+cpv*log(T2/T3)\n",
"cpv = (s2-s3)/log(T2/T3);// heat capacity, [kj/kg k]\n",
"\n",
"// from Fig.18.8\n",
"T4 = T3;\n",
"h2 = h3+cpv*(T2-T3);// specific enthalpy, [kJ/kg]\n",
"h5 = h4-cpL*(T4-T5);// specific enthalpy, [kJ/kg]\n",
"h6 = h5;\n",
"COP = (h1-h6)/(h2-h1);// coefficient of performance\n",
"mprintf('\n (a) The coefficient of performance of the refrigerator is  =  %f\n',COP);\n",
"\n",
"// (b)\n",
"SV = %pi/4*d^2*L;// swept volume of compressor/rev, [m^3]\n",
"ESV = SV*VE*N*3600;// effective swept volume/h, [m^3]\n",
"m = ESV/v1;// mass flow of refrigerant/h,[kg]\n",
"mprintf('\n (b) The mass flow of refrigerant/h is  =  %f  kg\n',m);\n",
"\n",
"// (c)\n",
"dT = 12;// temperature limit, [C]\n",
"Q = m*(h2-h5);// heat transfer in condenser/h, [kJ]\n",
"// using Q=m_dot*c*dT, so\n",
"m_dot = Q/(c*dT);// mass flow of water required, [kg/h]\n",
"mprintf('\n (c) The mass flow of water required is  =  %f kg/h\n',m_dot);\n",
"\n",
"//  End"
   ]
   }
,
{
		   "cell_type": "markdown",
		   "metadata": {},
		   "source": [
			"## Example 18.2: mass_flow_dryness_fraction_power_and_ratio_of_heat_transfer.sce"
		   ]
		  },
  {
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"clear;\n",
"clc;\n",
"disp('Example 18.2');\n",
"\n",
"// aim : To determine\n",
"// (a) the mass flow of R401\n",
"// (b) the dryness fraction of  R401 at the entry to the evaporator\n",
"// (c) the power of driving motor\n",
"// (d) the ratio of heat transferred from condenser to the power required to the motor\n",
"\n",
"// given values\n",
"P1 = 411.2;// pressure limit, [kN/m^2]\n",
"P3 = 1118.9;// pressure limit, [kN/m^2]\n",
"Q = 100*10^3;// heat transfer from the condenser,[kJ/h]\n",
"T2 = 273+60;// entering saturation temperature, [K]\n",
"\n",
"// given\n",
"// from given table\n",
"// at P1\n",
"h1 = 409.3;// specific enthalpy, [kJ/kg]\n",
"s1 = 1.7431;// specific entropy,[ kJ/kg K\n",
"\n",
"// at P3\n",
"h3 = 426.4;// specific enthalpy, [kJ/kg]\n",
"s3 = 1.7192;// specific entropy,[ kJ/kg K\n",
"T3 = 273+50;// saturation temperature, [K]\n",
"h4 = 265.5;// specific enthalpy, [kJ/kg]\n",
"// (a)\n",
"s2 = s1;// specific entropy, [kJ/kg k]\n",
"// using s2=s3+cpv*log(T2/T3)\n",
"cpv = (s2-s3)/log(T2/T3);// heat capacity, [kj/kg k]\n",
"\n",
"// from Fig.18.8\n",
"h2 = h3+cpv*(T2-T3);// specific enthalpy, [kJ/kg]\n",
"Qc = h2-h4;// heat transfer from condenser, [kJ/kg]\n",
"mR401 = Q/Qc;// mass flow of R401, [kg]\n",
" mprintf('\n (a) The mass flow of R401 is  =  %f kg/h\n',mR401);\n",
"\n",
"// (b)\n",
"hf1 = 219;// specific enthalpy, [kJ/kg]\n",
"h5 = h4;\n",
"// using h5=hf1+s5*(h1-hf1),so\n",
"x5 = (h5-hf1)/(h1-hf1);// dryness fraction\n",
"mprintf('\n (b) The dryness fraction of R401 at the entry to the evaporator is  =  %f\n',x5);\n",
"\n",
"// (c)\n",
"P = mR401*(h2-h1)/3600/.7;// power to driving motor, [kW]\n",
" mprintf('\n (c) The power to driving motor is  =  %f kW\n',P);\n",
"\n",
"// (d)\n",
"r = Q/3600/P;// ratio\n",
"mprintf('\n (d) The ratio of heat transferred from condenser to the power required to the motor is  =  %f : 1\n',r);\n",
"\n",
"//  End"
   ]
   }
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