Convection heat transfer occurs when a fluid’s motion, caused by density differences due to temperature variations, results in the transfer of thermal energy between a solid surface and the fluid. It’s commonly observed in natural phenomena such as ocean currents, atmospheric circulation, and the cooling of a hot object in air. The formula for convection heat transfer is given by:

Where:

• $Q$ is the rate of heat transfer,
• $h$ is the convective heat transfer coefficient,
• $A$ is the surface area through which heat is transferred, 
• $\Delta T$ is the temperature difference between the surface and the fluid.