Choppy Field Collector IAM from physical parabolic trough simulation

Hi Matthew,

I cannot replicate those results in SAM. Please attach a .sam file and the weather file that demonstrate these results if you would like me to help troubleshoot.

Also, to include an image in a post on this forum, please attach the image and then insert it. Copying and pasting images into the editor does not work.

Best regards,
Paul.

Hi Matthew, 

The choppiness of the Field Collector Incidence Angle Modifier and Solar Incidence Angle parameters are caused by the system switching between operating modes during the day. The model only calculates the incidence angle when the field is “on”. 

In this case, on June 21-22, the field starts "off" and recirculates HTF while it heats up. The HTF eventually hits a startup temperature and turns “on”, passing the fluid to the rest of the system. However, the trough field does not supply enough heat to keep the htf in the field above the startup temperature, causing the field to turn "off" and recirculate again. This process repeats as the field starts up and shuts down. The output parameters “Field total mass flow delivered” and “Field total mass flow recirculated” demonstrate this behavior. 

Decreasing the minimum single loop flow rate (i.e., 2 kg/s) makes it easier for the HTF temperature to rise and allows it to stay above the startup temperature throughout the day. Therefore, the model calculates the incidence angle and shows expected behavior. 

We recommend changing the system design to ensure that the HTF in the field is supplied enough heat to remain above the startup temperature, especially in design conditions.

Best regards,
Paul.