Dirt on Mirror

Dear Sir,

I would like to know how the "Dirt on Mirror" number calculated in optical properties of the collector for CSP Trough physical model. I saw a default number .95. What that means?

Thanks,

Hello,
The Dirt on Mirror input is intended to account for reduction in absorbed irradiation due to soiling of the collector mirror surface. SAM uses this value to calculate the collector's optical efficiency, as described in Section 2.3 of the physical trough model reference manual (see Table 4 and Equation 2.43), which you can download from the Performance Model Documentation page of the SAM website.
Best regards,

Paul.