Using round heliostats - value to enter for the "Heliostat Height"

Hi together,

i´m working on an optimization for a heliostat field in which i need the comparison between rectangular and round heliostats of the same size( reflective area).

To simulate the case with the round heliostat i set the mark for round heliostats (D = W) by using the scripting language ["(SetInput("csp.pt.sf.use_round_heliostats", 1)"]. Subsequent i have to set the "Heliostat Width" to the desired diameter of the round heliostat and can get the respective "Heliostat Area".

That is also described in a few fora with related subjects. ( for example wrote Paul Gilman in "Thermal Capacity Estimation and 3 more question.." that "the heliostat reflective area is the product of the heliostat length and width for rectangular heliostats. For round heliostats, the heliostat width is the diameter, so the area is (Heliostat Width/2)^2 * pi. The field reflective area is the heliostat area times the number of heliostats.")

My current problem is the "unimportant" value of the "Heliostat Height" for round heliostats ("Heliostat Height" can not have the value zero). If i change the value there is no change in the "Heliostat Area" but for a simulation of the case with an optimization there are a lot of differences. I observed in a lot of calculations that the value of the "Heliostat Height" influences the optimization thereby the simulation and the results. For example the "LCOE real".

Do you know the reasons for this behaviour and the influences of the "Heliostat Height"-value? I thought this value have no meaning for the calculation with round heliostats.....

with kind regards

Jonathan-Leon Finkbeiner

Dear Jonathan-Leon,

I have confirmed this behavior and am waiting to hear back from the CSP model developers for an explanation. I will let you know as soon as I hear from them.

Best regards,
Paul.

Hello,

any news on this one?

Kind regards,
Joe

Hello,

The CSP power tower model's solar field optimization algorithm (DELSOL) uses both the heliostat height and heliostat width values to calculate heliostat spacing, regardless of whether you choose rectangular or round heliostats. Of course, for round heliostats, those two values should be equal, but the algorithm does not automatically set the height value equal to the width value.

When you choose the Use Round Heliostats option, you should manually set the Heliostat Width and Heliostat Height to the same value.

Best regards,
Paul.