model Delay extends Modelica.Icons.Example; // We set X_default to a small enough value to avoid saturation at the medium temperature // that is used in this model. package Medium = Buildings.Media.Air(X_default={0.001, 0.999}); Modelica.Blocks.Sources.Constant PAtm(k=101325); Modelica.Blocks.Sources.Ramp P( duration=1, height=20, offset=101315); Buildings.Fluid.FixedResistances.PressureDrop res1( from_dp=true, m_flow_nominal=5, dp_nominal=5, redeclare package Medium = Medium); Buildings.Fluid.Sources.Boundary_pT sou( T=293.15, redeclare package Medium = Medium, use_p_in=true, nPorts=1); Buildings.Fluid.Sources.Boundary_pT sin( T=283.15, redeclare package Medium = Medium, use_p_in=true, nPorts=1); Buildings.Fluid.FixedResistances.PressureDrop res2( from_dp=true, m_flow_nominal=5, dp_nominal=5, redeclare package Medium = Medium); Buildings.Fluid.Delays.DelayFirstOrder del( m_flow_nominal=5, redeclare package Medium = Medium, nPorts=2, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, T_start=283.15) "Fluid volume that is a first order approximation of the transport delay"; equation connect(P.y, sou.p_in); connect(PAtm.y, sin.p_in); connect(sou.ports[1], res1.port_a); connect(sin.ports[1], res2.port_b); connect(res1.port_b, del.ports[1]); connect(res2.port_a, del.ports[2]); end Delay;