Conduction heat transfer occurs when thermal energy is transferred from a hotter region to a cooler region within a solid material or between two solid surfaces in direct contact. It’s governed by the temperature gradient across the material and the material’s thermal conductivity. The formula for conduction heat transfer through a material with uniform cross-sectional area and steady-state conditions is given by:

Where:

• $Q$ is the rate of heat transfer,
• $k$ is the thermal conductivity of the material, 
• $A$ is the cross-sectional area perpendicular to the direction of heat transfer, 
• $\Delta T$ is the temperature difference across the material, 
• $d$ is the thickness of the material through which heat is transferred.