.IDEAS.Buildings.Components.BaseClasses.RadiativeHeatTransfer.ExteriorHeatRadiation

Information

Longwave radiation Q̇_lw between the surface and the environment is determined according to the Stefan-Boltzmann law as

Q̇_lw = σ · ε_lw · A · (T_s⁴ - F_sky · T_sky⁴ - (1 - F_sky) · T_db⁴)

where

• σ is the Stefan-Boltzmann constant [Mohr 2008],
• ε_lw is the longwave emissivity of the exterior surface A,
• F_sky is the radiant-interchange configuration factor between the surface and sky [Hamilton 1952], and the surface and the environment, respectively, and
• T_s and T_sky are the exterior surface and sky temperature, respectively.

Shortwave solar irradiation absorbed by the exterior surface Q̇_sw is determined as

Q̇_sw = ε_sw · A · E_sw

where

• ε_sw is the shortwave absorption of the surface A, and
• E_sw the total irradiation on the depicted surface.

References

[Hamilton 1952]: D.C. Hamilton, and W.R. Morgan, "Radiant-interchange configuration factors", Technical Report – National Advisory Committee for Aeronautics, Washington, 1952.
[Mohr 2008]: P.J. Mohr, B.N. Taylor, and D.B. Newell, "CODATA recommended values of the fundamental physical constants: 2006", Review of Modern Physics, vol. 80, pp. 633–730, 2008.

Revisions

• June 17, 2025, by Lucas Verleyen:
  Replaced images with inline equations. See #1440.