Power Tower Receiver Height

In my tower simulation project, I need to put the height of the receiver but this parameter is non modifiable? The same thing is in total land area. Could you help me, please? Thanks in advance.
In the power tower models, you specify the height of the receiver on the Tower and Receiver page. SAM calculates the height of the tower based on the size of the heliostat field when you click Optimize solar field geometry on the Heliostat Field page. You can specify the maximum height as a ratio of the distance between the center of the tower base and the most distant receiver in the field and the tower height.
SAM also calculates the total land area based on the area occupied by the heliostats and additional land requirements that you specify using the Non-Solar Field Land Area and Solar Field Land Area Multiplier inputs. You can adust those values to achieve the land area you want to model. Note that the land area only affects the system costs if you specify costs on the System Costs page in dollars per acre.
Best regards,

Paul.

This mean it is difficult to evaluate the performance of existing tower, because SAM only is used to optimize and make decision???

In general, yes. SAM is designed to help you optimize a new design rather than to model an existing system.

However, if you import the heliostat layout to describe the actual heliostat field instead of having SAM optimize the field, you can use the Solar Field Layout Constrataints inputs to limit the tower height to a value at or close to the tower's actual height.

Best regards,
Paul.