Definition: Heat energy absorbed or released during a phase change (solid to liquid, liquid to gas) without temperature change. For water/ice at 0°C, latent heat of fusion is 334 kJ/kg.
Why It Matters:
- Freezing product requires removing latent heat (not just cooling to 0°C)
- Phase-change materials (PCM, eutectic systems) use latent heat for cooling
- Understanding latent heat is critical for freezing/thawing calculations
Example: To freeze 1,000 kg of water at 0°C to ice at 0°C requires removing 334,000 kJ (93 kWh) of latent heat, even though temperature doesn’t change.
Related Terms: Sensible Heat, Phase Change Material (PCM), Eutectic System, Enthalpy