TiltedSurface¶
Solar irradiance on a tilted surface: direct, Perez diffuse (sky and ground), incidence
FastSmoothBuildings.BoundaryConditions.TiltedSurface, model (source)
Purpose
Solar irradiance on a surface of azimuth azi and tilt til, from the weather bus of
Weather: the cosine of the incidence angle
cosInc, the direct irradiance HDir and the diffuse irradiance HDif from sky
and ground.
Equations
With the declination δ, the hour angle ω, the latitude φ, the tilt s and the azimuth γ,
cos θ = cos s (cos δ cos ω cos φ + sin δ sin φ) + sin s (sin γ cos δ sin ω + cos γ (cos δ cos ω sin φ − sin δ cos φ)),
Hdir = max(cos θ Hdir,nor, 0),
and the Perez model, with the coefficients F1, F2 of the bus and the ground reflectance ρ:
Hdif = Hdif,hor ((1 − F1) (1 + cos s)/2 + F1 max(0, cos θ)/max(cos 85°, cos ζ) + F2 sin s) + Hglo,hor ρ (1 − cos s)/2.
Smoothing
The maximum of Hdir is positivePart (width 0.01), the two others smoothMax over 0.01. The irradiance is continuous when the sun crosses the plane of the surface or the horizon.
Use
The sun on OuterWall, Window and Photovoltaic.
Parameters¶
| Parameter | Type | Unit | Default | Description |
|---|---|---|---|---|
| azi | Real | rad | Surface azimuth: 0 south, pi/2 west | |
| til | Real | rad | Surface tilt: 0 roof, pi/2 wall | |
| rho | Real | 0.2 | Ground reflectance |
Revisions¶
- October 2026: moved from trano's
FastModel.BoundaryConditions.