Heat transfer fluids consumption methodology

The AMEE category at business/processes/production/electronics/heattransferfluids/consumption provides a methodology for calculating emissions of fluorinated compounds (FC) associated with the use of heat transfer fluids during semiconductor manufacturing. Such emissions arise from evaporative losses during use. This methodology represents the Tier 2 approach described by the IPCC Guidelines for National Greenhouse Gas Inventories (NGGIP).

The methodology is based on a mass-balance accounting of heat transfer fluid usage over a specified period. Users have the option of returning absolute quantity of emissions, or, by specifying the particular type of FC fluid used, returning the emissions expressed as CO2e.

How to use this category

Selecting an emissions scenario

To use this category, simply create a profile item - there are no alternative drill choices.

Specifying activity data

Next, users must specify the quantities of heat transfer fluids which represent specific inputs and outputs to the manufacturing process, using the following profile item values:

  • previousFC: the inventory of liquid at the end of the previous period
  • purchasedFC: net purchases of liquid during the period (net of purchases and any returns)
  • newCharge: total charge (or nameplate capacity) of newly installed equipment
  • oldCharge: total charge (or nameplate capacity) of retired or sold equipment
  • remainingFC: inventory of liquid at end of the period
  • recoveredFC: amount recovered and sent offsite from retired equipment during the period

Since fluids are expressed as liquid volumes, users must also specify the density using the density profile item value, in order to express emissions as a mass (e.g. kg).

Users can also convert their emissions into CO2e - i.e. the quantity of CO2 which would produce the same global warming effect as the absolute FC emissions. To convert emissions into CO2e, users must specify which type of fluid is used, as each has a different 'global warming potential'. Users can set the fluid type using the fluid profile item item value. The type of fluid must match one of the options found here - AMEE uses this dataset as a lookup resource for converting absolute emissions into the appropriate quantity of CO2e for the respective fluid.

Results and calculation

The quantity returned represents the absolute quantity of heat transfer fluids emitted due to evaporative losses based on the accounting specified. Three quantities are returned, as follows:

  • rawEmissions: absolute quantity of emissions for the quantity specified
  • CO2e: CO2e emissions (absolute emissions converted using the appropriate global warming potential)
  • default: this value returns either raw emissions or CO2e depending on the presence of a fluid type specification

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