Cooling tower first model #472
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| within MetroscopeModelingLibrary; | ||
| package Examples | ||
| extends Modelica.Icons.ExamplesPackage; | ||
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| within MetroscopeModelingLibrary.MultiFluid.HeatExchangers; | ||||||
| model CoolingTowerMerkel | ||||||
| MetroscopeModelingLibrary.MoistAir.Connectors.Inlet C_cold_in annotation (Placement(transformation(extent={{-10,80},{10,100}}))); | ||||||
| package Water = MetroscopeModelingLibrary.Utilities.Media.WaterSteamMedium; | ||||||
| package MoistAir = MetroscopeModelingLibrary.Utilities.Media.MoistAirMedium; | ||||||
| import MetroscopeModelingLibrary.Utilities.Units; | ||||||
| import MetroscopeModelingLibrary.Utilities.Units.Inputs; | ||||||
| import MetroscopeModelingLibrary.Utilities.Media.WaterSteamMedium; | ||||||
| import MetroscopeModelingLibrary.Utilities.Media.MoistAirMedium.specificEnthalpy; | ||||||
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| Units.Velocity V_inlet; //Wind velocity entering cooling tower | ||||||
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| Inputs.InputReal hd; //Mass transfer coefficient | ||||||
| Inputs.InputArea Afr; //Tower cross-sectional area | ||||||
| Inputs.InputReal Lfi; //Height of filling | ||||||
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There was a problem hiding this comment. Is if the filling or the packing ? |
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| Inputs.InputFrictionCoefficient Cf; //Friction coefficient of air | ||||||
| Inputs.InputReal afi; //Fill material surface area per unit volume | ||||||
| Inputs.InputReal Ratio; //Ratio used to see if results align with EDF reference paper | ||||||
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There was a problem hiding this comment. This name is not very clear: the ratio of what ? |
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| Inputs.InputReal efan; //Fan effiency | ||||||
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There was a problem hiding this comment. Change the naming og the effiency to be consistent with the library
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| Units.Power W_fan; //Fan power | ||||||
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| parameter String configuration = "natural draft"; | ||||||
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| Units.MassFlowRate Q_cold_in; | ||||||
| Units.MassFlowRate Q_cold_out; | ||||||
| Units.MassFlowRate Q_hot_in; | ||||||
| Units.MassFlowRate Q_hot_out; | ||||||
| Units.MassFlowRate Q_evap; | ||||||
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| Units.Temperature T_cold_in(start=T_cold_in_0); | ||||||
| Units.Temperature T_cold_out(start=T_cold_out_0); | ||||||
| Units.Temperature T_hot_in(start=T_hot_in_0); | ||||||
| Units.Temperature T_hot_out(start=T_hot_out_0); | ||||||
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| Units.Temperature T1(start=T1_0); | ||||||
| Units.Temperature T2(start=T2_0); | ||||||
| Units.Temperature T3(start=T3_0); | ||||||
| Units.Temperature T4(start=T4_0); | ||||||
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| Units.Power W; | ||||||
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| Units.SpecificEnthalpy i_initial(start=i_initial_0); | ||||||
| Units.SpecificEnthalpy i_final(start=i_final_0); | ||||||
| Units.SpecificEnthalpy i1(start=i1_0); | ||||||
| Units.SpecificEnthalpy i2(start=i2_0); | ||||||
| Units.SpecificEnthalpy i3(start=i3_0); | ||||||
| Units.SpecificEnthalpy i4(start=i4_0); | ||||||
| Units.SpecificEnthalpy iTot(start=iTot_0); | ||||||
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| Units.Density rho_air_inlet(start=rho_air_inlet_0); | ||||||
| Units.Density rho_air_outlet(start=rho_air_outlet_0); | ||||||
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| Units.HeatCapacity cp; | ||||||
| Units.Pressure P_in; | ||||||
| Units.Pressure P_out; | ||||||
| Units.Pressure deltaP_fan; //Pressure change across fan | ||||||
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| constant Real g(unit="m/s2") = Modelica.Constants.g_n; | ||||||
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| // Initialization Parameters | ||||||
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| parameter Units.Temperature T_cold_in_0 = 15 + 273.15; | ||||||
| parameter Units.Temperature T_cold_out_0 = 25 + 273.15; | ||||||
| parameter Units.Temperature T_hot_in_0 = 40 + 273.15; | ||||||
| parameter Units.Temperature T_hot_out_0 = 20 + 273.15; | ||||||
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| parameter Units.Temperature T1_0 = 15 + 273.15; | ||||||
| parameter Units.Temperature T2_0 = 18 + 273.15; | ||||||
| parameter Units.Temperature T3_0 = 22 + 273.15; | ||||||
| parameter Units.Temperature T4_0 = 25 + 273.15; | ||||||
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| parameter Units.SpecificEnthalpy i_initial_0 = 0.5e5; | ||||||
| parameter Units.SpecificEnthalpy i_final_0 = 1.05e5; | ||||||
| parameter Units.SpecificEnthalpy i1_0 = 0.65e5; | ||||||
| parameter Units.SpecificEnthalpy i2_0 = 0.8e5; | ||||||
| parameter Units.SpecificEnthalpy i3_0 = 0.9e5; | ||||||
| parameter Units.SpecificEnthalpy i4_0 = 1e5; | ||||||
| parameter Units.SpecificEnthalpy iTot_0 = (1 / (2e5)); | ||||||
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| parameter Units.Density rho_air_inlet_0 = 1.2754; | ||||||
| parameter Units.Density rho_air_outlet_0 = 1.2460; | ||||||
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| MetroscopeModelingLibrary.WaterSteam.Connectors.Inlet C_hot_in annotation (Placement(transformation(extent={{-100,-10},{-80,10}}), iconTransformation(extent={{-100,-10},{-80,10}}))); | ||||||
| MetroscopeModelingLibrary.WaterSteam.Connectors.Outlet C_hot_out annotation (Placement(transformation(extent={{80,-10},{100,10}}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.Connectors.Outlet C_cold_out annotation (Placement(transformation(extent={{-10,-100},{10,-80}}))); | ||||||
| WaterSteam.BaseClasses.IsoPHFlowModel hot_side_cooling annotation (Placement(transformation(extent={{-70,-10},{-50,10}}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.BoundaryConditions.Sink Air_inlet annotation (Placement(transformation( | ||||||
| extent={{-10,-10},{10,10}}, | ||||||
| rotation=270, | ||||||
| origin={0,18}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.BoundaryConditions.Source Air_outlet annotation (Placement(transformation( | ||||||
| extent={{-10,-10},{10,10}}, | ||||||
| rotation=270, | ||||||
| origin={0,-18}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.BaseClasses.IsoPHFlowModel inputflowmodel annotation (Placement(transformation( | ||||||
| extent={{-10,-10},{10,10}}, | ||||||
| rotation=270, | ||||||
| origin={0,38}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.BaseClasses.IsoPHFlowModel outputflowmodel annotation (Placement(transformation( | ||||||
| extent={{-10,-10},{10,10}}, | ||||||
| rotation=270, | ||||||
| origin={0,-60}))); | ||||||
| MetroscopeModelingLibrary.MoistAir.Pipes.Pipe pipe annotation (Placement(transformation( | ||||||
| extent={{-10,-10},{10,10}}, | ||||||
| rotation=270, | ||||||
| origin={0,62}))); | ||||||
| WaterSteam.BoundaryConditions.Sink Water_inlet annotation (Placement(transformation(extent={{-32,-10},{-12,10}}))); | ||||||
| WaterSteam.BoundaryConditions.Source Water_outlet annotation (Placement(transformation(extent={{10,-10},{30,10}}))); | ||||||
| equation | ||||||
| // Definition | ||||||
| Q_cold_in = Air_inlet.Q_in; | ||||||
| Q_cold_out = Air_outlet.Q_out; | ||||||
| Q_hot_in = Water_inlet.Q_in; | ||||||
| Q_hot_out = Water_outlet.Q_out; | ||||||
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| T_hot_in = Water_inlet.T_in; | ||||||
| T_hot_out = Water_outlet.T_out; | ||||||
| P_in = Air_inlet.P_in; | ||||||
| P_out = Air_outlet.P_out; | ||||||
| T_cold_in = Air_inlet.T_in; | ||||||
| T_cold_out = Air_outlet.T_out; | ||||||
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| cp = WaterSteamMedium.specificHeatCapacityCp(hot_side_cooling.state_in); | ||||||
| W = Q_hot_in * cp * (T_hot_in - T_hot_out); | ||||||
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| Q_evap = - (Q_cold_out + Q_cold_in); | ||||||
| Ratio = Q_evap / W; | ||||||
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| // Energy Balance - Supplementary Equation | ||||||
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| Q_hot_in * cp * (T_hot_in - T_hot_out) + Q_cold_in * (i_initial - i_final) = 0; | ||||||
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| // Tchebyshev Integral | ||||||
| T1 = T_hot_out + 0.1 * (T_hot_in - T_hot_out); | ||||||
| T2 = T_hot_out + 0.4 * (T_hot_in - T_hot_out); | ||||||
| T3 = T_hot_out + 0.6 * (T_hot_in - T_hot_out); | ||||||
| T4 = T_hot_out + 0.9 * (T_hot_in - T_hot_out); | ||||||
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| i_initial = Air_inlet.h_in; | ||||||
| i_final = Air_outlet.h_out; | ||||||
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| Air_outlet.relative_humidity = 1; | ||||||
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| Air_outlet.Q_out * (1 - Air_outlet.Xi_out[1]) = - Air_inlet.Q_in *(1 - Air_inlet.Xi_in[1]); | ||||||
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| Water_outlet.P_out = Water_inlet.P_in; | ||||||
| Q_hot_out = -(Q_hot_in - Q_evap); | ||||||
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| i1 = MoistAir.h_pTX(P_in, T1, {MoistAir.massFraction_pTphi(P_in, T1, 1)}) - ((i_initial + 0.1 * (i_final - i_initial))); //First integral section | ||||||
| i2 = MoistAir.h_pTX(P_in, T2, {MoistAir.massFraction_pTphi(P_in, T2, 1)}) - ((i_initial + 0.4 * (i_final - i_initial))); | ||||||
| i3 = MoistAir.h_pTX(P_in, T3, {MoistAir.massFraction_pTphi(P_in, T3, 1)}) - ((i_initial + 0.6 * (i_final - i_initial))); | ||||||
| i4 = MoistAir.h_pTX(P_in, T4, {MoistAir.massFraction_pTphi(P_in, T4, 1)}) - ((i_initial + 0.9 * (i_final - i_initial))); | ||||||
| iTot = 1 / i1 + 1 / i2 + 1 / i3 + 1 / i4; | ||||||
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| // Heat Exchange - Merkel | ||||||
| (Afr * hd * afi * Lfi) / Q_hot_in = cp * iTot * ((T_hot_in - T_hot_out) / 4); | ||||||
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| // Drift Equation | ||||||
| rho_air_inlet = inputflowmodel.rho_in; | ||||||
| rho_air_outlet = outputflowmodel.rho_out; | ||||||
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| pipe.Kfr = 0; | ||||||
| pipe.delta_z = 0; | ||||||
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| (P_in - P_out) = 0; | ||||||
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| deltaP_fan = (W_fan * efan)/(abs(V_inlet) * Afr); | ||||||
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| if configuration == "natural draft" then | ||||||
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| 0.5 * 0.5 *(rho_air_inlet + rho_air_outlet) * Cf * abs(V_inlet) * V_inlet = (rho_air_inlet - rho_air_outlet) * g * Lfi; | ||||||
| Q_cold_in = (V_inlet * Afr * rho_air_inlet * (1 - Air_inlet.Xi_in[1])); | ||||||
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| else | ||||||
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| 0.5 * 0.5 *(rho_air_inlet + rho_air_outlet) * Cf * abs(V_inlet) * V_inlet = (W_fan * efan)/(abs(V_inlet) * Afr); | ||||||
| Q_cold_in = (V_inlet * Afr * rho_air_inlet * (1 - Air_inlet.Xi_in[1])); | ||||||
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| end if; | ||||||
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| connect(C_hot_in, hot_side_cooling.C_in) annotation (Line(points={{-90,0},{-70,0}}, color={28,108,200})); | ||||||
| connect(inputflowmodel.C_out, Air_inlet.C_in) annotation (Line(points={{0,28},{0,23}}, color={85,170,255})); | ||||||
| connect(Air_outlet.C_out, outputflowmodel.C_in) annotation (Line(points={{0,-23},{0,-50}}, color={85,170,255})); | ||||||
| connect(outputflowmodel.C_out, C_cold_out) annotation (Line(points={{0,-70},{0,-90}}, color={85,170,255})); | ||||||
| connect(pipe.C_in, C_cold_in) annotation (Line(points={{1.77636e-15,72},{0,81},{0,90}}, color={85,170,255})); | ||||||
| connect(pipe.C_out, inputflowmodel.C_in) annotation (Line(points={{0,52},{0,48}}, color={85,170,255})); | ||||||
| connect(hot_side_cooling.C_out, Water_inlet.C_in) annotation (Line(points={{-50,0},{-27,0}}, color={28,108,200})); | ||||||
| connect(Water_outlet.C_out, C_hot_out) annotation (Line(points={{25,0},{90,0}}, color={28,108,200})); | ||||||
| connect(C_cold_in, C_cold_in) annotation (Line(points={{0,90},{0,90}}, color={85,170,255})); | ||||||
| connect(C_hot_out, C_hot_out) annotation (Line(points={{90,0},{90,0}}, color={28,108,200})); | ||||||
| annotation (Icon(coordinateSystem(preserveAspectRatio=false, extent={{-120,-120},{120,120}}), graphics={ | ||||||
| Ellipse( | ||||||
| extent={{-20,110},{20,70}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={95,95,95}, | ||||||
| fillPattern=FillPattern.Backward), | ||||||
| Line(points={{-80,-80},{82,-80},{40,60},{-40,60},{-80,-80}}, color={28,108,200}), | ||||||
| Ellipse( | ||||||
| extent={{-48,82},{-40,74}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={95,95,95}, | ||||||
| fillPattern=FillPattern.Backward), | ||||||
| Ellipse( | ||||||
| extent={{32,114},{40,106}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={95,95,95}, | ||||||
| fillPattern=FillPattern.Backward), | ||||||
| Ellipse( | ||||||
| extent={{28,78},{36,70}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={95,95,95}, | ||||||
| fillPattern=FillPattern.Backward), | ||||||
| Ellipse( | ||||||
| extent={{-36,110},{-28,104}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={95,95,95}, | ||||||
| fillPattern=FillPattern.Backward), | ||||||
| Ellipse( | ||||||
| extent={{26,-40},{-28,26}}, | ||||||
| lineColor={28,108,200}, | ||||||
| fillColor={0,0,0}, | ||||||
| fillPattern=FillPattern.Solid)}), Diagram(coordinateSystem(preserveAspectRatio=false, extent={{-120,-120},{120,120}}))); | ||||||
| end CoolingTowerMerkel; | ||||||
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