Buildings.Fluid.SolarCollectors.Controls

Information

This package contains a controller for solar thermal collectors.

Package Content

Name	Description
SolarPumpController	Controller which activates a circulation pump when solar radiation is above a critical level
Examples	Examples for solar thermal collector controller models
BaseClasses	Package of BaseClass models used to create the models in the Controls package

Buildings.Fluid.SolarCollectors.Controls.SolarPumpController

Information

This component models a pump controller which might be used in a solar thermal system. It controls whether the pump is active or inactive based on the incident solar radiation and the system parameters. The pump is activated when the incident solar radiation is greater than the critical radiation.

The critical radiation is defined per Equation 6.8.2 in Duffie and Beckman (2006). It is

G_TC=(F_RU_L (T_In-T_Env))/(F_R(τα))

where G_TC is the critical solar radiation, F_RU_L is the heat loss coefficient, T_In is the inlet temperature, T_Env is the ambient temperature, and F_R(τα) is the maximum efficiency.

References

J.A. Duffie and W.A. Beckman 2006, Solar Engineering of Thermal Processes (3rd Edition), John Wiley & Sons, Inc.

Parameters

Type	Name	Default	Description
Real	delY	0.01	Width of the smoothHeaviside function [W/m2]
GenericSolarCollector	per		Performance data

Connectors

Type	Name	Description
input RealInput	TIn	Fluid temperature entering the collector [K]
output RealOutput	y	On/off control signal for the pump [1]
Bus	weaBus	Weather data input

Modelica definition

model SolarPumpController 
  "Controller which activates a circulation pump when solar radiation is above a critical level"
  extends Modelica.Blocks.Interfaces.BlockIcon;

  parameter Real delY(final unit = "W/m2") = 0.01 
    "Width of the smoothHeaviside function";
  parameter Buildings.Fluid.SolarCollectors.Data.GenericSolarCollector per 
    "Performance data";

  Modelica.Blocks.Interfaces.RealInput TIn(final unit = "K",
  final displayUnit = "degC", quantity = "ThermodynamicTemperature") 
    "Fluid temperature entering the collector";
  Modelica.Blocks.Interfaces.RealOutput y(min=0, max=1, unit="1") 
    "On/off control signal for the pump";
  Buildings.BoundaryConditions.WeatherData.Bus weaBus "Weather data input";

  Buildings.Fluid.SolarCollectors.Controls.BaseClasses.GCritCalc criSol(final 
      slope=per.slope, final y_intercept=per.y_intercept) 
    "Calculates the critical insolation based on collector design and current weather conditions";
  Modelica.Blocks.Math.Add add(final k2=-1) 
    "Compares the current insolation to the critical insolation";
protected 
  Buildings.Utilities.Math.SmoothHeaviside smoHea(final delta=delY) 
    "Creates a smooth 1/0 output";

equation 
  connect(TIn, criSol.TIn);
  connect(weaBus.TDryBul, criSol.TEnv);
  connect(weaBus.HDirNor, add.u1);
  connect(smoHea.y, y);
  connect(add.y, smoHea.u);
  connect(criSol.G_TC, add.u2);
end SolarPumpController;