Solar Position Table for Linear Fresnel Reflector

Hi,

I am working on Linear Fresnel Reflector to simulate its annual performance by solar position table and Incident Angel Modifier (two of the Optical Characterization Methods) but I have noticed a huge deference on the annual performance of the power plant between these methods, so I have three simple questions:

1- How can I develop, find, or generate a new solar position table for a specific geographic location rather than using the default values? will Solar Trace software be helpful?
2- Is the 4th order polynomial for Incident Angel Modifier (IAM) sufficient and accurate for every geographic location?
3- How were the coefficients for the 4th order polynomial developed? what are the factors on the solar field effect the optimization of the polynomial?

I would be so thankful for any help and response.

Thank you

Hi Ahmed,

Please see the publications listed under "Linear Fresnel" for details about SAM's Linear Fresnel model:

sam.nrel.gov/concentrating-solar-power/csp-publications.html

To answer your questions:

1. Yes, you can use a ray tracing model to generate data characterizing the optical performance of the field. The NREL publications mention NREL's SolTrace model as an example: www.nrel.gov/csp/soltrace.html .

2. The fourth-order polynomial is what is available in SAM and should be suitable for most locations. It is up to you to determine if it is sufficient for your needs.

3. The default solar field data in SAM was developed as part of the collaboration between NREL and Novatec Solar in 2012 described in the SAM Virtual Conference 2012 presentation, which you can find here: sam.nrel.gov/events.html

Best regards,
Paul.