Heat transfer is the way the heat moves from one physical system (or body) to another. Heat transfer requires a difference in temperature. Heat moves from the hotter body (higher temperature) to the colder one (lower temperature). The bodies in question may be in a solid state, a liquid state or a gaseous state. There are three modes of heat transfer: conduction, convection and radiation.
- Tariq Muneer; Jorge Kubie; Thomas Grassie, Heat Transfer: A Problem Solving Approach, Volume 1 (New York: Taylor & Francis, 2003), p. 1
- S.P. Sukhatme, A Textbook on Heat Transfer (Hyderabad, India: Universities Press, 2005), p. 1