The general formulas for calculating GCV and NCV

 The Gross Calorific Value (GCV) and Net Calorific Value (NCV) of a fuel can be calculated based on its elemental composition, particularly the content of carbon (C), hydrogen (H), sulfur (S), oxygen (O), and other elements. Here are the general formulas for calculating GCV and NCV:

1. Gross Calorific Value (GCV):

$𝐺𝐶𝑉=𝐶\times {𝑞}_{𝐶}+𝐻\times {𝑞}_{𝐻}+𝑆\times {𝑞}_{𝑆}+𝑂\times {𝑞}_{𝑂}+\text{Other elements}$

Where:

• $𝐶$, $𝐻$, $𝑆$, and $𝑂$ represent the mass fractions (expressed as percentages) of carbon, hydrogen, sulfur, and oxygen in the fuel, respectively.
• ${𝑞}_{𝐶}$, ${𝑞}_{𝐻}$, ${𝑞}_{𝑆}$, and ${𝑞}_{𝑂}$ are the calorific values (in units of energy per unit mass) of carbon, hydrogen, sulfur, and oxygen, respectively.
• The calorific value of other elements can also be included if they are present in significant quantities in the fuel.

The calorific values (${𝑞}_{𝐶}$, ${𝑞}_{𝐻}$, ${𝑞}_{𝑆}$, ${𝑞}_{𝑂}$, etc.) are typically known constants based on the energy released per unit mass of each element during combustion.

2. Net Calorific Value (NCV):

$𝑁𝐶𝑉=𝐺𝐶𝑉-\mathrm{\Delta }{𝐻}_{𝑣}\times 𝑊$

Where:

• $\mathrm{\Delta }{𝐻}_{𝑣}$ is the latent heat of vaporization of water (enthalpy of vaporization), which is typically around 2260 kJ/kg (kilojoules per kilogram).
• $𝑊$ is the mass fraction of water vapor in the combustion products, expressed as a percentage.

The Net Calorific Value (NCV) is obtained by subtracting the heat of vaporization of water vapor in the combustion products from the Gross Calorific Value (GCV).

It's important to note that these formulas provide an approximation of the calorific values based on the elemental composition of the fuel. Actual calorific values may vary depending on factors such as the specific chemical compounds present in the fuel, the combustion conditions, and the presence of impurities. Experimental testing is often conducted to determine the precise calorific values of different fuels.