ABSTRACT
In this chapter we introduce themechanisms of heat transfer in a system in thermal contact with its surrounding or with other systems. Focuswill be placed on heat conduction and convection. These two mechanisms are relevant to heat flow processes occurring in shallow geothermal systems. We give basic derivations of the involved heat equations, and introduce some important thermal parameters, including thermal material properties and relevant fluid numbers. These parameters will be extensively utilized in subsequent chapters, and hence it is useful to give a short description of their physical and mathematical definitions.
