1. What is Net Calorific Value?

Definition: Net Calorific Value (NCV) is the specific amount of energy released as heat when a fuel undergoes complete combustion with oxygen under standard conditions, minus the energy used to vaporize water in the combustion products.

Purpose: It provides a more accurate measurement of usable energy from fuel combustion since it accounts for energy lost to water vaporization.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( NCV \) — Net Calorific Value (J/m³)
• \( GCV \) — Gross Calorific Value (J/m³)
• \( m \) — Weight of Water Vapour (kg)
• \( \lambda \) — Latent Heat of Vaporization of Water (J/kg)

Explanation: The gross calorific value is reduced by the energy required to vaporize the water produced during combustion.

3. Importance of Net Calorific Value

Details: NCV is crucial for:

• Accurate fuel energy content measurement
• Efficient energy system design
• Fuel comparison and selection
• Combustion efficiency calculations

4. Using the Calculator

Tips:

• Enter the Gross Calorific Value in J/m³
• Enter the Weight of Water Vapour in kg
• Latent Heat of Vaporization defaults to 2257 J/kg (for water at 100°C)
• All values must be ≥ 0

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between GCV and NCV?
A: GCV includes all energy released, while NCV subtracts energy lost to vaporizing water in combustion products.

Q2: Why is latent heat of vaporization important?
A: It represents significant energy that's not available for practical use as it's consumed in vaporizing water.

Q3: When would NCV be significantly lower than GCV?
A: For fuels with high hydrogen content (like methane) that produce more water vapor during combustion.

Q4: What's a typical latent heat value for water?
A: 2257 kJ/kg at 100°C, but it varies slightly with temperature (default value in calculator).

Q5: How do I find the weight of water vapor?
A: Calculate from the fuel's hydrogen content or measure directly from combustion products.