How to Calculate Net Calorific Value

The amount of heat released during the combustion of a substance--usually either fuel or food--at constant pressure is called heating value or calorific value. Every substance has a unique calorific value. A common source to determine heating value is through the use of a bomb calorimeter.
When the combustion is performed, it generates water in the vapor state. The heat contained in this vapor can be calculated using scientific techniques and is expressed as Higher Heating Value (HHV), Lower Heating Value (LHV), and Gross Heating Value (GHV). A method commonly used in relating HHV to LHV is: HHV = LHV + hv x (nH2O,out/nfuel,in)

Things You'll Need

• Bomb calorimeter
• Combustible substance

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Instructions

Calorific Value of Peanuts

• 1

  There are many types of calorimeters. Determine what type would be best suited by the needed accuracy and material being used. The bomb calorimeter is a very common tool for measuring caloric values.

• 2

  Place the peanuts inside the bomb calorimeter.

• 3

  The bomb calorimeter will combust the peanuts and vaporize the water contained within it. As the peanuts burn, they heat the air inside the calorimeter.

• 4

  The expanded air escapes through a tube from the calorimeter. As the air escapes, it heats up the water outside the tube. This heated water is used for calculating the calorie content.

• 5

  The heat from the water vapor is calculated and compared against standard benchmarks to achieve the calorific value.