Tracking Angle

Hi,


I would like to know if there is any posibility to get from SAM as an output the tracking angle (Wcol) used to calculate the loop optical efficiency, as I can´t take it from the "graph & data" and either from the "Data base".


Thanks a lot.

Best regards.

You can calculate the tracking angle as a function of the solar azimuth and elevation angles, both of which SAM reports in the hourly results.

For a N-S oriented field, the tracking angle corresponds to the azimuth angle.

For an E-W oriented field, the tracking angle corresponds to the elevation angle.

For a field not oriented along N-S or E-W axes, SAM uses the following equation:

TrackAngle = Atan ( Cos(SolarAlt) * Sin(SolarAz-ColAz)/(Sin(SolarAlt-ColTilt)+Sin(ColTilt)*Cos(SolarAlt)*(1-Cos(SolarAz-ColAz))) )

That equation is around Line 851 in the Type 250 source code file (in Help, see the Overview topic for the performance model you are using for a list of source code files and their location).

The equation is described in Chapter 4 (Equation 4.18) of the Stine and Harrigan textbook Solar Energy Systems Design (John Wiley and Sons 1986), which is available online at www.powerfromthesun.net/ .

Best regards,
Paul.