blockDeclination

Declination angle

Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).

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 IBPSA.BoundaryConditions.SolarGeometry.BaseClasses.Examples.Declination.

Connectors

TypeNameDefaultDescription
Modelica.Blocks.Interfaces.RealInputnDayDay number with units of seconds
Modelica.Blocks.Interfaces.RealOutputdecAngSolar declination angle

Revisions

  • 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.