1. What is Latent Heat of Vaporization?

Definition: The amount of heat energy required to convert a unit mass of liquid into vapor without changing its temperature.

Purpose: This calculator helps determine the energy needed to vaporize water at its boiling point (212°F or 100°C).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( L_v \) — Latent heat of vaporization (BTU)
• \( m \) — Mass of water (pounds)
• 970 — Latent heat constant for water at 212°F (BTU/lb)

Explanation: The mass of water is multiplied by the standard latent heat value of 970 BTU per pound.

3. Importance of Latent Heat Calculation

Details: Understanding latent heat is crucial for designing heating systems, boilers, and thermodynamic processes involving phase changes.

4. Using the Calculator

Tips: Simply enter the mass of water in pounds that you want to vaporize. The calculator will determine the required heat energy in BTU.

5. Frequently Asked Questions (FAQ)

Q1: Why is the latent heat value 970 BTU/lb?
A: This is the experimentally determined value for water at its boiling point (212°F) under standard atmospheric pressure.

Q2: Does this value change with temperature?
A: Yes, the latent heat decreases as temperature increases above 212°F, but 970 BTU/lb is the standard reference value.

Q3: How does this relate to the metric value?
A: In metric units, the latent heat is approximately 2257 kJ/kg at 100°C.

Q4: What practical applications use this calculation?
A: Boiler design, steam generation, distillation processes, and HVAC systems all rely on latent heat calculations.

Q5: Does this include the energy to raise water to boiling point?
A: No, this only calculates the energy for the phase change. You would need additional calculations for sensible heat.