.Buildings.ThermalZones.Detailed.BaseClasses.RadiationTemperature

Information

This model computes the radiative temperature in the room. For a room with windows but no shade, the radiative temperature is computed as

T_rad = ∑_i   (Aⁱ   εⁱ   Tⁱ) ⁄ ∑_i   (Aⁱ   εⁱ)

where T_rad is the radiative temperature of the room, Aⁱ are the surface areas of the room, εⁱ are the infrared emissivities of the surfaces, and Tⁱ are the surface temperatures.

If a the windows have a shade, then the equation is modified to take the actual shaded and non-shaded surface area into account. In this situation, the shaded part of a window has a infrared radiative power of

E = A   ( u   ε_s   T_s + (1-u)   ε_g τ_s   T_gs)

where A is the surface area of the glass, u is the control signal of the shade, ε_s is the infrared absorptivity of the shade, T_s is the temperature of the shade, ε_g is the infrared absorptivity of the glass, τ_s is the infrared transmittance of the shade, and T_gs is the glass temperature behind the shade.

For the unshaded part of the window, the radiative power is

E = A   (1-u)   ε_g   T_gn

where T_gn is the glass temperature of the non-shaded part of the window.

Revisions

• March 13, 2015, by Michael Wetter:
  Changed model to avoid a translation error in OpenModelica.
• July 16, 2013, by Michael Wetter:
  Added assignment of heat port temperature instead of heat flow rate for the cases where a construction has been conditionally removed. This is required to avoid a singularity.
• March 29 2011, by Michael Wetter:
  Rewrote sum for the radiation temperature.
• Jan. 18 2011, by Michael Wetter:
  First implementation.