.Buildings.BoundaryConditions.SolarGeometry.BaseClasses.Declination

Information

This component computes the solar declination, which is the angle between the equatorial plane and the solar beam. The input signal nDay is the one-based number of the day, but in seconds. Hence, during January 1, we should have nDay = 86400 seconds. Since the effect of using a continuous number rather than an integer is small, we approximate this so that nDay = 0 at the start of January 1, and nDay = 86400 at the end of January 1.

Validation

A validation with a more detailed calculation can be found at Buildings.BoundaryConditions.SolarGeometry.BaseClasses.Examples.Declination.

Revisions

• March 27, 2023, by Ettore Zanetti:
  Updated to use partial class for conversion from simulation time to calendar time.
  This is for IBPSA #1716.
• January 6, 2015, by Michael Wetter:
  Updated documentation and added validation. This is for issue 382.
• January 5, 2015, by Michael Wetter:
  Updated comment of output signal as this is used in the weather bus connector. This is for issue 376.
• November 11, 2015, by Michael Wetter:
  Corrected typo in documentation.
• Dec 7, 2010, by Michael Wetter:
  Rewrote equation in explicit form to avoid nonlinear equations in room model.
• May 17, 2010, by Wangda Zuo:
  First implementation.