Heat Conduction                                                 

 In the Heat Conduction process, which is rather observed in solid objects, the heat is transferred from one molecule to the other within the object. The thermal efficiency of heat conduction is a physical characteristics of the substance and has a constant value.

  The heat transfer by conduction is, in fact, the effect of molecular activity; i.e. the increase in the molecular vibration causes increase in the temperature of the material. The molecules with larger vibration amplitudes ( the molecules with higher energy) start to collide with their neighbors with shorter vibration amplitudes (the molecules with lower energy) and some energy transfer from the molecules with higher energy to the molecules with lower energy takes place. The rate of the heat transfer in this manner varies from substance to substance.

  According to the Kelvin's Theory, the absolute temperature point at which molecules of any substance reaches an absolute immobility state (absolute zero) is  - 273.16 ° C. A thermal equilibrium state is reached between two objects having different thermal energy from each other, and the particles of both object undergo heat exchange until
they get equal temperatures when they are in thermal contact with each other.
  The rate of the heat transfer by conduction occurred in the outer layer of the material, depends on the thickness of the layer (d) and the thermal conduction coefficient which is determined by the molecular structure of the material involved. The thermal conduction coefficient is the heat amount (in Joule) transferred through a surface area of 1  m² of a 1 m thick slab of the material, perpendicular to the opposite face of the same, in one hour under the equilibrium conditions of a homogenous material, when a temperature difference of 1 K is measured between the surfaces. (1 W/K  = 1.16 * kcal/mh° C )

  The heat transfer meant for the exterior surfaces of buildings, mostly occurs in the opaque components of the layer and can be minimized by the use of heat insulation material.