Annual water usage

Dear Professors,

How are you all? I hope you are fine and in good health.

I would like to ask you how to calculate the annual water usage in DSG Linear Fresnel power plants, as I have compared three DSG LFR power plants in different places, and I found that the higher the production of the electrical station, the higher the annual water usage consumption. I would like to know what is the relationship between them? I've even read many of your articles but can't find an answer ( sam.nrel.gov/component/search/?searchword=annual%20water%20usage&searchphrase=all&Itemid=282 ).

So, is there a specific equation or method that I can numerically prove the calculation I came up with?

The same observation I found with the Net capital cost, is there an explanation for that? As the production of the DSG LFR power plant increases, the Net capital cost increases with it (note that the stations are completely similar in their installation).

Please let us know your valuable information on this issue.

Thank you in advance, and we thank you very much for all your valuable efforts.

With best regards.

Hi Mohktar,

For the Direct Steam Linear Fresnel and other CSP models, the water usage depends on 1) the mirror washing inputs on the Solar Field page, and 2) the condenser type for plant cooling on the Power Cycle page.

The source code for plant cooling water loss is here:

github.com/NREL/ssc/blob/ca964fc280268b4e4efe686dc66c3c01ad555430/shared/lib_powerblock.cpp#L1370

Water usage for mirror washing is calculated as following:

Water Usage (L/yr) = Water Usage per Wash (L/m2) * Washes per Year (1/yr) * Actual Aperture (m2)

You can see how the Net Capital Cost is calculated by going to the Cash Flow tab of the Results page and clicking Send to Excel with Equations (Windows only). SAM opens a special Excel file that shows how the financial model calculations work:



Best regards,
Paul.

Dear Prof. Dr. Paul,
How are you? I hope you are fine and in good health.
Thank you very much for your very valuable and useful explanations.
With best regards.
***
M. Ghodbane