Buildings.Fluids.HeatExchangers.CoolingTowers.BaseClasses

Package Content

Name	Description
PartialStaticTwoPortCoolingTower	Cooling tower with variable speed

Buildings.Fluids.HeatExchangers.CoolingTowers.BaseClasses.PartialStaticTwoPortCoolingTower

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dp_nominal		Pressure [Pa]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	1E-4*m_flow_nominal	Small mass flow rate for regularization of zero flow [kg/s]
Diagnostics
Boolean	show_V_flow	true	= true, if volume flow rate at inflowing port is computed
Initialization
AbsolutePressure	p_a_start	system.p_start	Guess value for inlet pressure [Pa]
AbsolutePressure	p_b_start	p_a_start	Guess value for outlet pressure [Pa]
Flow resistance
Boolean	from_dp	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM	0.1	Fraction of nominal flow rate where flow transitions to laminar

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	TAir	Entering air dry or wet bulb temperature

Modelica definition

partial model PartialStaticTwoPortCoolingTower 
  "Cooling tower with variable speed"
  extends Fluids.Interfaces.PartialStaticTwoPortHeatMassTransfer;
  extends Buildings.BaseClasses.BaseIcon;
  Modelica.SIunits.Conversions.NonSIunits.Temperature_degC TWatIn_degC(
                                                  start=35) 
    "Water inlet temperature";
  Modelica.SIunits.Conversions.NonSIunits.Temperature_degC TWatOut_degC(
                                                   start=28) 
    "Water outlet temperature";
  Modelica.SIunits.Conversions.NonSIunits.Temperature_degC TAirIn_degC(
                                                  start=25) 
    "Air dry-bulb inlet temperature";
  Modelica.Blocks.Interfaces.RealInput TAir 
    "Entering air dry or wet bulb temperature";
equation 
  TWatIn_degC  = Modelica.SIunits.Conversions.to_degC(Medium.temperature(sta_a));
  TWatOut_degC = Modelica.SIunits.Conversions.to_degC(Medium.temperature(sta_b));
  TAirIn_degC  = Modelica.SIunits.Conversions.to_degC(TAir);
  mXi_flow     = zeros(Medium.nXi); // no mass added or removed (sensible heat only)
end PartialStaticTwoPortCoolingTower;