Latent Heat of Vaporization

Definition

The energy absorbed when water changes phase from liquid to vapor without a temperature change, roughly 970 BTU per pound, often rounded to 1,000 BTU per pound for field calculations.

Most of this energy is spent overcoming intermolecular attraction, especially the Hydrogen-Bond Network, while some pushes back against the pressure above the liquid. It is nearly seven times more energy than the roughly 140 BTU needed to raise one pound of water from 72 degrees F to its boiling point. This stored energy is released when steam condenses, which is why steam heats campuses, sterilizes equipment, and spins turbines.

Related concepts

Phase transition cooling · Phase Change · Heat Transfer

How it connects

• this enables Heat Transfer
• Hydrogen bond drives this
• Latent Heat drives this
• Boiler requires this

---

Part of The Blueprint of Water · 🔥 thermodynamics