This chapter also elucidates the issue of particle-particle contact in a multiphase system. The focus is, however, different than in the previous chapters. Those chapters considered the modelling of collision processes where the objective was to explore the collision dynamics (e.g., deformation and velocity). In this chapter, however, we study heat conduction between particles. This indicates that the particles have different temperatures as they collide. First, we examine a mathematical model for heat conduction if the collision is elastic. Later, it is shown how the same strategy can be used if there is a permanent (plastic) deformation during a collision. Finally, consider dissipative forces.