Discussion Forum

Hi,

I am new to COMSOL, i am attempting to model Thermal energy storage in concrete medium via heat transfer fluid flowing through embedded pipes in the concrete.

I have been able to successfully create a model and obtain results for the charging process (i think). And have used various probes to extract data. I have run this computation several times with no errors. However I returned to the model the next day and attempted same computation with no changes however this time various error messages popped up.

The following error message pop up when clicking compute: Undefined variable. - Variable: comp1.T - Geometry: geom1 - Domain: 1 Failed to evaluate operator Jacobian. - Operator: diskavg - Geometry: geom1 - Edges: 6, 7, 8, 9, 10, 11, 12, 13, 14, 18, ... - Feature: Time-Dependent Solver 1 (sol1/t1)

The study is time dependent with run time of 7500s in 100s intervals.

I am not sure what the issue is, please see attached file which shows the model and the expected results, which i have not made any changes to (which has no errors). The errors pop up when clicking compute. I have had to remove the solutions to be able to attach the file, i have attached the results that i was able to obtain previously. I hope to obtain temperature readings at the probe locations specified in the model.

Any help is greatly appreciated! Please inform me of how to fix the model and if there are any other ways i can model this process, as i also hope to model the discharging process.

Regards Raj