Enter your Fuel Type, Fuel Amount, and Lower Heating Value (LHV) alongside the Heat of Vaporization and Water to Fuel Molar Ratio to calculate the Higher Heating Value (HHV) — plus your Total LHV, Water Vaporization Energy, and Specific HHV accounting for the energy released when water vapor condenses.
Higher Heating Value (HHV)
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Lower Heating Value (Total)
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Water Vaporization Energy
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Specific HHV
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Heat of combustion is the amount of energy released when a fuel undergoes complete combustion with oxygen. It's measured as the higher heating value (HHV) which includes the energy from condensing water vapor produced during combustion.
Heat of combustion is calculated using the formula: HHV = LHV + (Heat of Vaporization × Water to Fuel Molar Ratio × Fuel Amount). This accounts for both the lower heating value and the energy released from condensing water vapor.
Lower Heating Value (LHV) measures energy released without condensing water vapor, while Higher Heating Value (HHV) includes the additional energy from condensing the water vapor produced during combustion. HHV is always higher than LHV.
Heat of vaporization is crucial because combustion produces water vapor. When this vapor condenses, it releases additional energy. Including this energy gives the true total heat released during combustion (HHV).
The heat of vaporization of water at standard conditions is approximately 2.26 MJ/kg or 970 BTU/lb. This is the energy required to convert liquid water to vapor, or released when vapor condenses to liquid.
Yes, the calculator includes predefined values for common fuels like hydrogen, methane, propane, and gasoline. You can also use the custom option to input values for any other fuel by providing its LHV and stoichiometric data.
The calculator supports multiple units including kilograms, pounds, grams, and standard cubic feet. Results are automatically converted and displayed in megajoules (MJ) for energy values.