SAM 2013.1.15 versus previous versions

Hello Paul,

I am trying the Empirical model of the last version (2013.1.15). There are great differences between the output results of this version and previous versions. Which are the main modifications implemented in this last version that affects the results (clearly lower)?

Thanks and regards

Hello,

The SAM release notes (available from SAM's Help menu) list changes between versions and describe their impact on results. In SAM 2013.1.15, we fixed a bug in the empirical trough model that affected solar field calculations and resulted in the model over-predicting the annual output by about 4%. The current version should be more accurate than older versions.

Best regards,
Paul.

Hello Paul,

Back to question made some months ago, could you please be more accurate about the changes implemented in the 2013 version? The bug fixed in empirical trough model is related to the solar field warm up or solar field losses calculations?

Thanks in advance

Hello,

The empirical trough model issue that we fixed in SAM 2013.1.15 is a little complicated to explain:

The empirical trough model uses an iterative algorithm to calculate the startup energy required at the start of each day. The error involved the value used in the iteration for the system's average temperature in the time step before start-up, which should have been fixed at the system's average temperature in that time step, but instead was allowed to fluctuate and tended to follow the iterated system temperature value in the current time step. This error caused the startup energy value to be significantly lower than it should have been.

Best regards,
Paul.