Solar Field Land Area Multiplier set up

Dear Paul,

When I am trying to vary the solar multiple of a molten salt power tower to see its influence on the collector and receiver efficiency, I encountered two problems,

1) In the heliostat field setup, I try to vary different "Solar Field Land Area Multiplier" and then optimize the solar field, but the calculated "total land area" doesn't change. Souldn't the area become bigger with larger area multiplier?

2) In the tower and receiver, there is a "solar multiple" under the "design operation". What is the difference between this "solar multiple" and the "Solar Field Land Area Multiplier" in heliostat field? How should I set up those two?

P.S In your opinion, do you think the solar multiple will influence the collector and receiver efficiency much?

Thanks a lot for your help!

Xinyue

Dear Xinyue,

For the Molten Salt Power Tower model, the solar multiple input is on the System Design input page. SAM displays a copy of that value on the Tower and Receiver page, but you cannot edit it on that page.

After you change the solar multiple value, you will need to run the field layout optimization (SolarPILOT) by clicking Optimize solar field geometry on the Heliostat Field page to recalculate the optimal number of heliostats and heliostat positions. The solar multiple determines the solar field size as a multiple of the power cycle nameplate capacity. You can see what effect it has on the system efficiencies by trying different values and looking at those values in the results.

The Land Area inputs are for estimating the land area required by the project so that SAM can calculate a land cost on the System Costs page. The solar field land area multiplier is to account for area required for the project in addition to the solar field. When the multiplier is one, the total land area is equal to the land occupied by the heliostats and tower. You can choose a value greater than one to include additional land are required for project buildings or storage areas.

In general, please see the SAM Help system for definitions of the input variables.

Best regards,
Paul.