Modifying Surface Radiation Properties

Applying the Multiband Thermal Radiation model means that the radiation properties at boundaries and interfaces must be revised.

For each surface material, you now set the emissivity, reflectivity, and transmissivity for each of the spectral bands that you created for the Multiband Thermal Radiation model. For the Thermal 2 spectral band, you use the same radiation property values that as for the Thermal Insulator tutorial. For the Thermal 1 spectral band, you specify different values.

To make sure that almost all of the energy in the Thermal 1 spectral band passes into the box, you assign the top of the collector a reflectivity of 0 and a transmissivity of 0.98. You assign the base of the collector a reflectivity of 0 and a transmissivity of 0 for both spectral bands.

注The non-radiative thermal conditions for the boundaries remain the same as before.
To modify surface radiation properties:
  1. Modify the radiation properties of the boundary materials in the Air continuum:
    1. Expand the Continua > Air > Models > Surface Materials > Surface Materials node.
    2. Set the following properties:
      Node Property Setting
      Collector
      Material Properties
      Emissivity > Constant Value [1.0, 1.0]
      Transmissivity > Constant Value [0.0, 0.0]
      Sides
      Material Properties
      Emissivity > Constant Value [0.95, 0.95]
      Transmissivity > Constant Value [0.0, 0.0]
      Top
      Material Properties
      Emissivity > Constant Value [0.02, 0.8]
      Transmissivity > Constant Value [0.98, 0.15]
  2. Modify the radiation properties of the boundary materials in the Glass continuum:
    1. Expand the Glass > Models > Surface Materials > Surface Materials > side-solid > Material Properties node.
    2. Set the following properties:
      Node Property Setting
      Emissivity > Constant Value [0.0, 0.0]
      Transmissivity > Constant Value [0.0, 0.0]
  3. Modify the radiation properties of the interface materials:
    1. In the solarCollector window, click (Create a custom tree).
    2. Multi-select the following nodes:
      • Air > Models > Surface Materials > Surface Materials
        • bottom-solid1
        • bottom-solid2
        • top-solid1
        • top-solid2
      • Glass > Models > Surface Materials > Surface Materials
        • bottom-solid1
        • bottom-solid2
        • top-solid1
        • top-solid2
    3. Drag and drop the selection of nodes into the Custom Tree window.
    4. Multi-select the following nodes in both continua and set the corresponding properties:
      Node Property Setting
      bottom-solid1
      Material Properties
      Emissivity > Constant Value [0.1, 0.775]
      Transmissivity > Constant Value [0.8, 0.15]
      bottom-solid2
      Material Properties
      Emissivity > Constant Value [0.2, 0.725]
      Transmissivity > Constant Value [0.75, 0.175]
      top-solid1
      Material Properties
      Emissivity > Constant Value [0.15, 0.8]
      Transmissivity > Constant Value [0.8, 0.15]
      top-solid2
      Material Properties
      Emissivity > Constant Value [0.175, 0.75]
      Transmissivity > Constant Value [0.75, 0.175]
    5. Close the Custom Tree window.
  4. Save the simulation.