How to input parameters in molten salt CSP model

Hi Francesca,

For the Power Tower models, there are a few options on the Heliostat Field page that determine the value of tower height, receiver height, and receiver diameter.

If you know the values of those parameters and the heliostat positions, you can input the dimensions on the Tower and Receiver input page, and import a heliostat position table on the Heliostat Field page. Do not check either Generate heliostat layout using tower dimensions or Optimize heliostat layout and tower dimensions, and do not click either Calculate button next to those check boxes. When you run a simulation, the results will be based on the inputs you provided.

If you know the tower height, receiver height, and receiver diameter, but do not know the number of heliostats or their positions, you can enter the dimensions on the Tower and Receiver page, and check Generate heliostat layout using tower dimensions, but not the Optimize... button. When you click Simulate, SAM will calculate the number of heliostats and their positions, and populate the heliostat position table before it starts the simulation. You can also click the Calculate button next to the check box to calculate the heliostat positions without running a simulation.

Finally, if you want SAM to automatically calculate the tower height, receiver height, and receiver diameter, and also calculate the number of heliostats and their positions, then you should check Optimize heliostat layout and tower dimensions (or click the Calculate button for that option). SAM will use tower and receiver cost inputs on the System Costs page to calculate tower and receiver dimensions and a field layout that achieves the solar multiple, design turbine gross output given the other assumptions on the System Design page and minimizes the cost of those components. SAM will show you the values it calculates and ask if you want to replace your inputs with the optimized values before it runs the simulation.

To replicate someone else's analysis, you really need to know what all of their assumptions are. In addition to the inputs I mention above, design assumptions like the Design point DNI, Solar multiple, Full load hours of storage, and the location, heliostat dimensions, etc. will all affect the tower and field optimization results.

Best regards,
Paul.

Hi Francesca,

The optimizationalgorithm does not follow a deterministic path because it uses randomization in the step direction as it proceeds. The algorithm also has a relatively flat response surface. Both of these factors can cause the algorithm to return different results given the same set of inputs. A reasonable approach is to run the algorithm several times and choose the best result. This is discussed in SAM's Help topic "Heliostat Field, SolarPILOT Field Layout and Geometry Optimization."

Best regards,
Paul.