What does the term "latent heat" refer to?

Latent heat refers specifically to the amount of heat energy that is absorbed or released by a substance during a phase change without a change in temperature. This concept is critical in understanding processes such as melting, freezing, vaporization, and condensation. For instance, when ice melts into water, it absorbs heat (latent heat of fusion) without increasing its temperature until it has completely transitioned into the liquid state. Similarly, when water vapor condenses into liquid, it releases heat (latent heat of condensation) while maintaining a constant temperature during that phase transition.

This concept is essential in refrigeration and air conditioning systems, where the efficient transfer of heat during these phase changes is utilized to maintain desired temperature levels in various environments. Understanding latent heat helps engineers design systems that effectively manage thermal energy while ensuring that substances can transition between states as needed.