When using older FEFLOW versions than 8.1, borehole heat exchangers are managed with the OpenLoop plugin. Why is the error message "Reference Distribution OpenLoop not found. Heat transport loop ignored" as seen in Fig 1 displayed?

Fig 1 - Error message "Reference Distribution OpenLoop not found. Heat transport loop ignored"


You may have forgotten to create a nodal distribution under User Data with a name called "OpenLoop". The distribution is to help the plugin identify where the OpenLoop systems are located, and which OpenLoop groups the nodes belong to.  
Be careful, this feature is case sensitive so always use the exact name as: OpenLoop  - see figure 2 in FEFLOW interface. 


Fig 2 - OpenLoop in FEFLOW interface  


Important Note
The Open Loop plugin was discarded from the latest FEFLOW 8.1 release, and you won't be able to include this plugin in your model, because the workflow was implemented directly into the Well Manager Grouping Rules, please find more information about this workflow in the Manuals and Guidelines section.



Manuals and Guidelines
FEFLOW 8.1 Documentation - Well Manager

Related Products: FEFLOW