modelCanopy
Information
This model applies an energy balance on the canopy. The energy balance is done by taking into account:
- Sensible heat flows (i.e. all the flows connected to the heat port). These should be the long-wave radiation with the heating pipes, the cover, the floor and the thermal screen. Also, the sensible heat with the main air zone.
- Latent heat flows associated with canopy transpiration. The latent heat flows are determined by multiplying the moisture mass flows at the vapor mass port to the latent heat of vaporization.
- Short-wave radiation absorbed from the sun and/or supplementary lighting (i.e. the forced flow from the short-wave radiation input).
Since the short-wave radiation can origin from two sources (the sun and supplementary illumination), the short-wave radiation input connector (i.e. HeatFluxVectorInput) has the form of a vector. The parameter N_rad defines the dimension of the vector and needs to be set by the user. Therefore, if there is no supplementary lighting, the user must set N_rad to 1 (i.e. radiation only form the sun). However, if there is supplementary lighting, the user must set N_rad to 2 (i.e. radiatio from sun + lighting).
The magnitude of the energy exchanged by the canopy depends on the size of the leaves, which is increased by crop growth and decreased by leaf pruining. To take this into account, the leaf area index (LAI), defined as the leaf area per unit of ground area, is used. The LAI is computed in the crop yield model and input in this model.
The vapor pressure of water at the canopy is defined by the saturated vapor pressure for its temperature.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | N_rad | 2 | Short-wave radiations are 2: if sun and illumination; 1 if just sun |
| Modelica.Units.SI.HeatCapacity | Cap_leaf | 1200 | heat capacity of a square meter of canopy leaves |
| Modelica.Units.SI.Area | A | floor surface | |
| Initialization | |||
| Modelica.Units.SI.Temperature | T_start | 298 | |
| Initialization › Initialization options | |||
| Boolean | steadystate | false | if true, sets the derivative of T to zero during Initialization |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort | Heat port for sensible heat input | |
| Interfaces.Vapour.WaterMassPort_a | massPort | ||
| Interfaces.Heat.HeatFluxVectorInput[N_rad] | R_Can_Glob |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | LAI | 1 | Leaf Area Index |
| Modelica.Units.SI.HeatFlowRate | Q_flow | Heat flow rate from long-wave radiation and convection | |
| Modelica.Units.SI.Temperature | T | ||
| Modelica.Units.SI.Power | P_Can | Total heat flow rate to the canopy from solar short-wave radiation | |
| Modelica.Units.SI.HeatFlowRate | L_can | latent heat to the canopy | |
| Real | FF | ||
| BasicComponents.SurfaceVP | surfaceVP |