Atributting one face temperature to another face
 

Hello everyone!

I'm having this problem with transfering one face temperature to another (maybe it's due to my newbness).
Anyway, i'll describe the problem:
I've got a room with one heat source and i'm using a blower to move the air through the room. The blower only recirculates the air in the room.

My boundary conditions are:
-velocity inlet for the inlet and for the outlet (the outlet has the inverse module);
-the rest are walls;
-the walls for the heat source have a positive heat flux;
-the walls for the windows have a negative heat flux;

I consider that there exhists mass conservation on the system and that the temperature on the inlet is the same of the outlet.
My problem is: There exhists an evolution in the systems temperature, so, how can i transport the temperature from the outlet to the inlet?

I was thinking on using an UDF, but i don't know wich to use and how.

Thank you for your attention!