Define "latent heat".

Latent heat refers to the heat absorbed or released during a phase change of a substance while its temperature remains unchanged. This concept is crucial in understanding processes like melting, freezing, vaporization, and condensation. For example, when ice melts into water, it absorbs heat from its surroundings without an increase in temperature until all the ice has changed to water. Similarly, when water vapor condenses into liquid water, it releases heat, but the temperature of the water remains constant during the actual phase change.

This property is essential in HVAC systems, as it helps in effectively transferring heat through processes like refrigeration and air conditioning, where managing temperature and phase changes is critical for system efficiency and performance. Understanding latent heat is fundamental for HVAC professionals as it influences how systems are designed to control indoor climates effectively.