How to determine heat rate transfer for a Heat-Transfer BC?

Hi,
I am building a 3D model and plan to have a Heat-Transfer BC that will go on the surface layer and simulate monthly average temperature of the ground and I'm having some trouble. The documentation says in addition to a reference temperature (which I have) and an in/out transfer rate, however I'm not sure how to set this up the transfer rate parameter.

The documentation states that the transfer rate is thermal conductivity divided by the thickness (? = ?/d), but the “thickness” parameter is not defined. My model has four different layers, each with different thermal conductivities and thickness's, so I'm not sure what value to use.
When determining the transfer rate, would I use the thickness of each layer as my thickness value? Or should I use the overall thickness of the model for each layer (i.e. if 1st layer is 10m thick, use 10m. If the 2nd layer is 5m thick, use 15m, etc.)?

Thanks in advance

Hi,

I'm curious about the same question, i.e. which is the value of "d" to attribute in the phi formula of "in-out transfer rate".

In a 3D model, does it refears to the thikness of the clogging layer in horizontal or vertical direction?

Thank you,

Dani

The heat transfer-rates (in / out) are thermal resistance factors. As you correctly indicated, the transfer rate is the thermal conductivity devided by the thickness. In building physics these parameters are related with the heat and geometrical property of the material. In practical groundwater modelling, the parameter is rather related with the current landuse. Unfortunatly, I do not have a reference at hand. You could check the literature or scientific papers (Elsevier, Springer, AGU etc.).