What does convection refer to in the context of heat transfer?

Convection is defined as the transfer of heat through the movement of liquids and gases. In this process, warmer areas of a liquid or gas rise while cooler areas sink, creating a circulation pattern that effectively transfers heat. This is distinct from conduction, which is the transfer of heat through solids where heat travels through direct contact, and from radiation, which involves the transfer of energy through electromagnetic waves, such as heat from the sun reaching the Earth.

In the context of HVAC, understanding convection is essential as it applies to how heated air circulates within spaces to maintain comfortable temperatures, as well as how refrigerants move heat in systems like air conditioning. This principle is critical for designing systems that optimize heat transfer for efficient heating and cooling.