Buildings.Fluid.SolarCollectors.Controls.BaseClasses

Information

This package contains base classes that are used in the Buildings.Fluid.SolarCollectors.Controls package.

Package Content

Name	Description
GCritCalc	Model calculating the critical insolation level
Examples	Package containing examples demonstrating the use of Controls.BaseClasses models

Buildings.Fluid.SolarCollectors.Controls.BaseClasses.GCritCalc

Information

This component calculates the solar radiation necessary for the fluid in the collector to gain heat. It is used in the model Buildings.Fluid.SolarCollectors.Controls.SolarPumpController.

The critical solar radiation level is calculated using 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	slope		Slope from ratings data [W/(m2.K)]
Real	y_intercept		y_intercept from ratings data

Connectors

Type	Name	Description
input RealInput	TIn	Temperature of water entering the collector [K]
output RealOutput	G_TC	Critical radiation level [W/m2]
input RealInput	TEnv	Ambient temperature at the collector [K]

Modelica definition

model GCritCalc "Model calculating the critical insolation level"

  extends Modelica.Blocks.Interfaces.BlockIcon;

  parameter Real slope(unit="W/(m2.K)") "Slope from ratings data";
  parameter Real y_intercept "y_intercept from ratings data";

  Modelica.Blocks.Interfaces.RealInput TIn(unit="K",
  displayUnit = "degC", quantity = "ThermodynamicTemperature") 
    "Temperature of water entering the collector";
  Modelica.Blocks.Interfaces.RealOutput G_TC(unit="W/m2",
  quantity = "RadiantEnergyFluenceRate") "Critical radiation level";
  Modelica.Blocks.Interfaces.RealInput TEnv(unit="K",
  displayUnit = "degC", quantity = "ThermodynamicTemperature") 
    "Ambient temperature at the collector";

equation 
  G_TC = -slope * (TIn - TEnv) / y_intercept;
end GCritCalc;