Serial double regulation - modelica

Question

I am new to Modelica and OpenModelica and I am trying to learn by myself this language.
I am currently working on a model which the objective is to validate the principle of a serial double regulation:
I placed a heat exchanger. In the left of the heat exchanger, the two valves are installed to regulate a heat flow (87 000 W max.). In the right of the heat exchanger, the three-way diverter valve is regulated to obtain the final temperature (T_final) equal to 80 °C. The regulation is the PID regulation. The pump creates a constant mass flow rate (1 kg/s).
I impose different temperatures thanks to the component "temperature_input". The objective is to obtain a final temperature of 80 °C whatever the value of the input temperature (with 87 000 W max.).
With the model below, the valves are not regulated. Also, I would like to assure a maximum heat flow of 87 000 W (maybe with the component "FixedHeatFlow"?). And I don't know if the problem is badly defined, or if the values of the PID controllers are wrong.
Can someone help me please?
Thank you very much for your answers
Here is a schematic diagram to illustrate my problem:
The model:
model SousStation84
replaceable package Medium = Modelica.Media.Water.StandardWaterOnePhase;
replaceable package Medium1 = AixLib.Media.Water "Medium model";
replaceable package Medium2 = AixLib.Media.Water "Medium model";
Modelica.Fluid.Sensors.MassFlowRate m_in_primary(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-150, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_out_primary(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-150, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_in_primary(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-104, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_out_primary(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-70, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Sources.FixedBoundary source(
redeclare package Medium = Medium,nPorts = 1, p = 100000, use_p = true)
annotation(
Placement(visible = true, transformation(extent = {{-340, -70}, {-320, -50}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T2(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-280, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m2(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-242, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Valves.ValveIncompressible Valve_1(
Kv = 16,
dp_nominal = 60000,
m_flow_nominal = 1.8,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-198, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T1(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-228, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Valves.ValveIncompressible Valve_2(
Kv = 16,
dp_nominal = 60000,
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-192, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Blocks.Continuous.LimPID PID_1(
Td = 0,
Ti = 300,
controllerType = Modelica.Blocks.Types.SimpleController.PID,
k = 3,
limitsAtInit = true)
annotation(
Placement(visible = true, transformation(origin = {-224, 98}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Blocks.Sources.Constant constant2(
k = 353)
annotation(
Placement(visible = true, transformation(origin = {-290, 98}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Buildings.Fluid.HeatExchangers.PlateHeatExchangerEffectivenessNTU hex(
redeclare package Medium1 = Medium1,
redeclare package Medium2 = Medium2,
Q_flow_nominal = 87000,
T_a1_nominal = 353.15,
T_a2_nominal = 333.15,
configuration = Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow,
dp1_nominal = 120000,
dp2_nominal = 100000,
m1_flow_nominal = 8,
m2_flow_nominal = 6,
use_Q_flow_nominal = true)
annotation(
Placement(visible = true, transformation(origin = {-25, -17}, extent = {{-25, 25}, {25, -25}}, rotation = -90)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_final(
m_flow_nominal = 1.8,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(extent = {{152, 30}, {172, 50}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_V3V(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {126, -36}, extent = {{-10, 10}, {10, -10}}, rotation = -90)));
Modelica.Fluid.Sources.Boundary_pT temperature_input(
redeclare package Medium = Medium,
T = 333,nPorts = 1,
use_T_in = false)
annotation(
Placement(visible = true, transformation(origin = {270, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_input(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {224, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Blocks.Continuous.LimPID PID_2(
Td = 0,
Ti = 300,
controllerType = Modelica.Blocks.Types.SimpleController.PID,
k = 3,
limitsAtInit = true)
annotation(
Placement(visible = true, transformation(origin = {62, 104}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_input(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {186, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Machines.ControlledPump pump(
N_nominal = 1500,
m_flow_nominal = 1,
p_a_nominal = 110000,
p_b_nominal = 130000,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {146, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Sources.FixedBoundary fixedBoundary(
nPorts = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {272, 40}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_out_secondary(
m_flow_nominal = 1.8,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(extent = {{20, 30}, {40, 50}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_V3V(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {126, -4}, extent = {{10, -10}, {-10, 10}}, rotation = 90)));
AixLib.Fluid.Actuators.Valves.ThreeWayLinear threeWayLinear(
dpValve_nominal = 60000,
m_flow_nominal = 1.8,
use_inputFilter = false,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {128, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_out_secondary(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {88, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_in_secondary(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {82, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Blocks.Sources.Constant constant1(
k = 353)
annotation(
Placement(visible = true, transformation(origin = {-4, 108}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m_final(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {210, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
AixLib.Fluid.Sensors.TemperatureTwoPort T_in_secondary(
m_flow_nominal = 1,
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {30, -76}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.MassFlowRate m1(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-284, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sources.FixedBoundary fixedBoundary1(
redeclare package Medium = Medium,
nPorts = 1,
p = 200000,
use_p = true)
annotation(
Placement(visible = true, transformation(extent = {{-348, 26}, {-328, 46}}, rotation = 0)));
Modelica.Fluid.Sensors.SpecificEnthalpyTwoPort specificEnthalpy(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-64, 36}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
Modelica.Fluid.Sensors.SpecificEnthalpyTwoPort specificEnthalpy1(
redeclare package Medium = Medium)
annotation(
Placement(visible = true, transformation(origin = {-112, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
equation
connect(m_in_primary.port_b, T_in_primary.port_a) annotation(
Line(points = {{-140, 36}, {-114, 36}}, color = {0, 127, 255}));
connect(m2.port_a, Valve_2.port_b) annotation(
Line(points = {{-232, -60}, {-202, -60}}, color = {0, 127, 255}));
connect(source.ports[1], T2.port_b) annotation(
Line(points = {{-320, -60}, {-290, -60}}, color = {0, 127, 255}));
connect(T1.port_b, Valve_1.port_a) annotation(
Line(points = {{-234, 36}, {-208, 36}}, color = {0, 127, 255}));
connect(T2.port_a, m2.port_b) annotation(
Line(points = {{-270, -60}, {-252, -60}}, color = {0, 127, 255}));
connect(Valve_1.port_b, m_in_primary.port_a) annotation(
Line(points = {{-188, 36}, {-160, 36}}, color = {0, 127, 255}));
connect(Valve_2.port_a, m_out_primary.port_b) annotation(
Line(points = {{-182, -60}, {-160, -60}}, color = {0, 127, 255}));
connect(constant2.y, PID_1.u_s) annotation(
Line(points = {{-279, 98}, {-236, 98}}, color = {0, 0, 127}));
connect(PID_1.y, Valve_1.opening) annotation(
Line(points = {{-213, 98}, {-198, 98}, {-198, 44}}, color = {0, 0, 127}));
connect(PID_1.y, Valve_2.opening) annotation(
Line(points = {{-213, 98}, {-192, 98}, {-192, -52}}, color = {0, 0, 127}));
connect(hex.port_b1, T_out_primary.port_a) annotation(
Line(points = {{-40, -42}, {-40, -60}, {-60, -60}}, color = {0, 127, 255}));
connect(T_input.port_a, temperature_input.ports[1]) annotation(
Line(points = {{234, -76}, {260, -76}}, color = {0, 127, 255}));
connect(threeWayLinear.port_2, T_final.port_a) annotation(
Line(points = {{138, 40}, {152, 40}}, color = {0, 127, 255}));
connect(m_input.port_a, T_input.port_b) annotation(
Line(points = {{196, -76}, {214, -76}}, color = {0, 127, 255}));
connect(m_V3V.port_b, T_V3V.port_a) annotation(
Line(points = {{126, -14}, {126, -26}}, color = {0, 127, 255}));
connect(constant1.y, PID_2.u_s) annotation(
Line(points = {{7, 108}, {30, 108}, {30, 104}, {50, 104}}, color = {0, 0, 127}));
connect(m_out_secondary.port_b, threeWayLinear.port_1) annotation(
Line(points = {{98, 40}, {118, 40}}, color = {0, 127, 255}));
connect(T_final.T, PID_2.u_m) annotation(
Line(points = {{162, 51}, {162, 80}, {62, 80}, {62, 92}}, color = {0, 0, 127}));
connect(pump.port_a, m_input.port_b) annotation(
Line(points = {{156, -76}, {176, -76}}, color = {0, 127, 255}));
connect(T_V3V.port_b, pump.port_a) annotation(
Line(points = {{126, -46}, {126, -58}, {156, -58}, {156, -76}}, color = {0, 127, 255}));
connect(T_in_secondary.port_a, m_in_secondary.port_b) annotation(
Line(points = {{40, -76}, {72, -76}}, color = {0, 127, 255}));
connect(m_final.port_b, fixedBoundary.ports[1]) annotation(
Line(points = {{220, 40}, {262, 40}}, color = {0, 127, 255}));
connect(PID_2.y, threeWayLinear.y) annotation(
Line(points = {{73, 104}, {128, 104}, {128, 52}}, color = {0, 0, 127}));
connect(T_out_secondary.port_b, m_out_secondary.port_a) annotation(
Line(points = {{40, 40}, {78, 40}}, color = {0, 127, 255}));
connect(m_in_secondary.port_a, pump.port_b) annotation(
Line(points = {{92, -76}, {136, -76}}, color = {0, 127, 255}));
connect(m_V3V.port_a, threeWayLinear.port_3) annotation(
Line(points = {{126, 6}, {126, 21}, {128, 21}, {128, 30}}, color = {0, 127, 255}));
connect(T_final.port_b, m_final.port_a) annotation(
Line(points = {{172, 40}, {200, 40}}, color = {0, 127, 255}));
connect(hex.port_a2, T_in_secondary.port_b) annotation(
Line(points = {{-10, -42}, {-10, -42}, {-10, -76}, {20, -76}, {20, -76}}, color = {0, 127, 255}));
connect(hex.port_b2, T_out_secondary.port_a) annotation(
Line(points = {{-10, 8}, {-10, 8}, {-10, 40}, {20, 40}, {20, 40}}, color = {0, 127, 255}));
connect(T_final.T, PID_1.u_m) annotation(
Line(points = {{162, 52}, {65.5, 52}, {65.5, 66}, {-224, 66}, {-224, 86}}, color = {0, 0, 127}));
connect(m1.port_b, T1.port_a) annotation(
Line(points = {{-274, 36}, {-238, 36}}, color = {0, 127, 255}));
connect(fixedBoundary1.ports[1], m1.port_a) annotation(
Line(points = {{-328, 36}, {-294, 36}}, color = {0, 127, 255}));
connect(m_out_primary.port_a, specificEnthalpy1.port_b) annotation(
Line(points = {{-140, -60}, {-124, -60}, {-124, -60}, {-122, -60}}, color = {0, 127, 255}));
connect(specificEnthalpy1.port_a, T_out_primary.port_b) annotation(
Line(points = {{-102, -60}, {-80, -60}, {-80, -60}, {-80, -60}}, color = {0, 127, 255}));
connect(T_in_primary.port_b, specificEnthalpy.port_a) annotation(
Line(points = {{-94, 36}, {-74, 36}, {-74, 36}, {-74, 36}}, color = {0, 127, 255}));
connect(specificEnthalpy.port_b, hex.port_a1) annotation(
Line(points = {{-54, 36}, {-40, 36}, {-40, 8}, {-40, 8}}, color = {0, 127, 255}));
end SousStation84;