convectionCoefficient¶
Natural convection coefficient of Buildings for a surface tilt: wall 1.3, ceiling 0.76/1.51, floor 1.51/0.76
FastSmoothBuildings.Utilities.convectionCoefficient, function (source)
Purpose
The coefficient c of the natural convection law q = c |ΔT|1/3 ΔT of Buildings (see naturalConvection), in W/(m2 K4/3), from the tilt of the surface and the sign of the temperature difference.
Equations
| Surface | Tilt | Surface warmer than the air | Surface colder |
|---|---|---|---|
| Ceiling | sin(til) = 0, cos(til) > 0 | 0.76 | 1.51 |
| Floor | sin(til) = 0, cos(til) < 0 | 1.51 | 0.76 |
| Any other | 1.3 | 1.3 |
A surface counts as horizontal when |sin(til)| < 10−6; an inclined surface takes
the coefficient of a wall. A warm ceiling and a cold floor stratify the air: the lower coefficient.
Use
The function switches on its arguments: call it on parameters only, as the surfaces do (til for the
room side, pi - til for a side that faces the other way: the outside of a window, side b of an
internal wall), so that the coefficients are evaluated before the
simulation. The tilt follows Types.Tilt.
Revisions¶
- October 2026: moved from trano's
FastModel.Utilities.