What does the term "latent heat" refer to?

The term "latent heat" specifically refers to the heat absorbed or released by a substance during a phase change without changing its temperature. This concept is critical in understanding processes such as melting, freezing, condensation, and evaporation. When a substance changes from one state to another—like ice melting into water or water vapor condensing into liquid water—it either absorbs or releases thermal energy, but its temperature remains constant during this transition.

In the context of air conditioning and refrigeration, latent heat plays a significant role since a substantial amount of energy is involved when moisture in the air condenses or evaporates. For instance, when water vapor in the air condenses on cold surfaces, it releases latent heat, which can affect the overall thermal dynamics in an environment.

The other concepts, while related to thermodynamics and heat transfer, do not define latent heat. Temperature changes during cooling focus on sensible heat rather than latent heat, sunlight's thermal load pertains to solar gain, and heat from electrical components relates more to waste heat rather than phase changes. Thus, the core definition of latent heat aligns precisely with the heat absorbed or released during a phase change.