Transposition of POA irradiance to global horizontal irradiance for tracking system

[jbennett]

Hi Andre,

In a response to a 2013 question from another user, you that said PVsyst was unable to transpose global POA irradiance to global horizontal irradiance for tracking systems. Has any progress been made since that time?

I am working on several single-axis tracking systems that have POA irradiance sensors and sensors for wind speed, ambient temperature and array temperature. There are no global horizontal irradiance sensors. I would like to analyze the measured production against the simulated production, adjusted for weather conditions. However, when I try to format the protocol file and indicate the presence of POA irradiance data, I am not allowed to indicate that the system is a N-S single-axis tracking system with backtracking. There is only a space to indicate the tilt and azimuth of the plane orientation, which would only be relevant for a fixed-tilt system.

Am I missing something, or is this transposition still not possible?

Many thanks!

John

[jbennett]

Thanks for the response.

Follow up question: if we had a dedicated global horizontal irradiance sensor, would that enable PVsyst to compare the measured production against the simulated production for a single-axis tracker? If so, I may be able to convince my superiors to include a horizontal irradiance sensor in future projects.

Thanks again!

[André Mermoud]

Yes of course. The simulation of PVsyst is based on horizontal meteo data, and evaluates the POA using transposition models.

An additional improvement for the accuracy would be to measure also the diffuse component on the horizontal plane.

[jbennett]

Good to know. Thank you for the confirmation!