PDE: How to refer to temperature of a node in actual time step?

In my transient thermal model of a building envelope, I am trying to assess heat flux from thermal radiation of the ground and apply it to an adjacent wall.

Therefore, I must refer to temperature of selected nodes, that constitute an edge which represents surface of the ground. How to refer to the temperature of selected nodes in any time step?

[Navya Seelam]

Can you provide following details

1.What is the model geomentry?

2. Is the temperature of different nodes on edge different?

3. Is the temperature of each node function of its location?

[Grzegorz]

Answer 1: It is 2D model yet, eventually it will be 3D. It's geometry consists of rectangles representing the ground and building envelope. Mesh is triangular with six nodes per element.

Answer 2: Yes, it is.

Answer 3: Yes , it is.