Refrigerant material balance methodology by DEFRA
This methodology estimates refrigerant emissions on the basis of material balance - that is, an accounting of refrigerant inputs, outputs and stores. The discrepancy between inputs and outputs is assumed to represent the quantity of refrigerant which was lost as emissions. This is more accurate than the 'emissions factor' approach (see below) in which assumptions regarding all of the emissions causing processes are incorporated into a single, generalized emissions rate.
Refrigerants differ in their specific physical (particularly thermal) properties and therefore exert a variable effect on atmospheric warming. As such, the absolute quantity of emissions for a given refrigerant type is converted into a standard measure of environmental impact - CO2e: the equivalent quantity of carbon dioxide (CO2) which would produce the same atmospheric warming effect. This conversion is made by multiplying the absolute emissions quantity by the 'global warming potential' (GWP) of the respective refrigerant - a value unique to the gas which represents its warming effect relative to CO2.
DEFRA publishes an alternative methodology for accounting for greenhouse gases associated with refrigerants which uses generic emissions factors relating to the installation, operation and disposal of refrigeration and air conditioning units.
Using this category
Specifying activity type
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Specifying activity data
Since the methodology is based on a material balance accounting of refrigerant quantities, each of the following quantities must be specified in order to make an emissions calculation:
- purchased: Purchases of refrigerant used to charge new equipment
- newCapacity: Total full capacity of the new equipment
- service: Quantity of refrigerant used to service equipment
- retiredCapacity: Total full capacity of retiring equipment
- recovered: Refrigerant recovered from retiring equipment
Results and calculation
CarbonKit calculates the the absolute and CO2e emissions of refrigerant using the material balance methodology. The following quantities are returned:
- absoluteEmissions: Absolute quantity of emissions based on specified input/output quantities
- CO2e: Emissions quantity expressed as CO2e