Sustainability & Risk / Green Building / Carbon Footprint - Background Data

Adding Heat Content Information

Gaseous, liquid, and solid fuel consumption is usually measured in physical units, such as cubic meters or tonnes. To calculate emissions, fuel consumption data in mass or volume units must first be converted into the energy content of these fuels. To convert this data to common energy units, such as joules, requires calorific or heat content values. Heat content measures a fuel's energy content per unit mass. The heat content value is used in calculating carbon dioxide, methane, and nitrous oxide emissions for stationary fuel combustion.

Use the Add Heat Contents Task to enter:

About Heat Content Measurement

In the United States, the most commonly used value for expressing the energy value or heat content of a fuel is the British thermal unit (Btu). One Btu is the amount of energy needed to raise the temperature of one pound of water 1°F, when water is at about 39°F. One therm is 100,000 Btu. Therm is the unit that utility companies typically use when billing for natural gas use.

Joule is the International System unit for energy measurement. One Btu is equal to 1055.06 Joules.

About Gross and Net Calorific Value

Coal, crude oil, and natural gas all include chemical compounds of carbon and hydrogen. When burned, the carbon and hydrogen in these fuels combine with oxygen in the air to produce carbon dioxide and water. Some of the energy released in burning goes into transforming the water into steam and is usually lost. The amount of heat spent in transforming the water into steam is counted as part of gross heat content, but is not counted as part of net heat content. Gross heat content is also referred to as the higher heating value.

US fossil fuel energy statistics are generally presented using gross calorific values (GCV), also referred to as higher heating values.

International standards report energy statistics in terms of net calorific values (NCV), also referred to as lower heating values. Net Caloric value assumes all water is water vapor at the end of combustion.

You enter the conversion factor to convert NCV to GCV. You find this conversion factor in your heat contents protocol.

Procedure: Adding Heat Contents Information

To add heat contents information:

  1. Select Carbon Footprint - Background Data / Heat Content.

    The Define Heat Contents Version, Fuel Types and Data screen appears.

  2. To add a heat contents protocol version:
    1. Click Add New> Heat Content Version.
    2. Enter the following information for the source of your heat contents data:

      Version: Enter the name of the protocol you are using as a source of heat content information. The Version uniquely identifies this protocol.

      Version Description: Enter information to identify the version and its data. For example, enter the number for the table the heat contents values are shown in.

    3. Click Save.
  3. To add heat contents data:
    1. Select the heat contents protocol for which you are adding data.
    2. Click Add New > Heat Contents Data.
    3. Enter the following data:

      Fuel Base Code: Select the type of fuel you are adding heat contents data for.

      Fuel Name: Select the fuel for which you are adding heat content information.

      Net Calorific Value: Enter the net calorific value for this fuel. This value is defined in the protocol version you are using.

      Net Calorific Value Units: Select the unit used to measure the net calorific value. By default, a fuel's heat content is expressed as MJ/kilogram, but you can define different units if needed. See Defining Units.

      Conversion Factor: Enter the factor used to convert the Net Calorific Value to Gross Caloric Value.

    4. Click Save.

      Conversion to Gross Calorific Value: When you save the Net Calorific Value and the Conversion Factor, the application calculates the gross calorific value by multiplying the heat content value by the Conversion factor.