Posted Fri, 22 Sep 2017 11:48:56 GMT by ane epelde
Dear all,

I ´m trying to carry out a manual sensitivity analysis in order to check which are the parameters most affecting my model.

I have a borehole in the model and changing the Heat transport parameters (and keeping them constant throughout the model) I check the BHE outlet temperature.

I noticed a significant change when I modified the overall ground temperature, but when changing the volumetric heat capacity of fluid and solid and the termal conductivity of fluid and solid, I do not see any change in the simulated results. For instance, I have ranged the conductivity of solid from 3 to 200 J/msK but nothing changes...

I guess I´m doing something wrong but I dont see where.. do you have any suggestion?

And, which are the most sensible parameters in your models when simulating BHEs?

Thank you very much in advance,
Posted Mon, 25 Sep 2017 14:56:17 GMT by ane epelde
I would like to add the following:

I remember having checked the outlet and average temperature plots of the BHE and they were identical. But in the latest simulations they are not equal, which doesnt make much sense, right?

Posted Mon, 02 Oct 2017 10:16:25 GMT by Björn Kaiser
Unfortunately, it is not possible to say a priori which parameters are most sensitive with regard to the distribution of the temperature, because there are too many dependencies. As a simple example, in geothermal applications different heat driver may co-exist within the system. If advection is the dominant driver, I would expect a smaller contribution of changes in thermal properties in the computed thermal field. I think a sensitivity study you carry out is quite helpful to identify the major candidates affecting the thermal field.
Posted Mon, 02 Oct 2017 14:41:36 GMT by ane epelde
Thanks Bjorn,
But, it is not strange that no matter the values I use for different parameters the outlet is identical?
I´ve tried changing the thermal conductivity of solid and fluid and also the volumetric capacity of solid and fluid, but nothing changes. So I guess something is not working..

Is there any way to obtain an output file with actually used parameters? It is like the values I´m using are not well read or there is something that disables or camouflages the impact of the changes..

Do you have any suggestion?

Thank you again,

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