Power Tower - wind stow speed to be entered as hourly average value?

Hi,
in SAM's Power Tower module ( /Heliostat Field sheet /Heliostat Properties section) wind stow speed can be entered.
I am using an *.epw weather file. As wind speed data in epw-files are hourly average values, I assume that I also have to enter an hourly average value in the 'Wind Stow Speed' field. Is this correct?

I further assume that for all hours where the wind speed value from the used weather file exceeds the value entered in the 'Wind Stow Speed' field, the heliostat field is assumed to be in stow. Is this correct?

Thank you very much in advance!

Best regards

gary

Hi Gary,

SAM compares the wind stow speed value that you specify on the Heliostat field page with the data in the weather file. So, yes, if the data in the weather file are hourly average values, then the wind stow speed should also be an hourly average value.

And, yes, for hours when the wind speed value in the weather file equals or exceeds the wind stow speed, the heliostat field is assumed to be in stow. SAM calculates the parasitic power required to move the heliostats into and out of stow position.

After running simulations, on the Results page, you can see what happens when the weather file wind speed exceeds the stow speed on the Base Case Time Series graph by plotting the following variables: Hourly Energy and Total Incident Thermal Energy on one graph (you can also show Thermal Energy from Thermal Storage if your system includes storage), and Wind Velocity and Heliostat Drive Electrical Consumption on the other graph.

Best regards,
Paul.